report on proposals – november 2010 nfpa 79 · 2016. 2. 22. · iec 60204-1 ex8sting iec 60204-1...

Report on Proposals – November 2010 NFPA 79_______________________________________________________________________________________________79-1 Log #206 EEI-AAA

_______________________________________________________________________________________________William E. Anderson, The Procter & Gamble Company

Revise terminology for direct and indirect contact, note the change in sense does not lend therevision to direct replacement

– protection under normal conditions (now designated basic protection) was referred to asprotection against direct contact and– protection under fault conditions (now designated fault protection) was referred to asprotection against indirect contact.

Change in terminology usage in several IEC documents including the next edition of IEC 60204-1.

The submitter did not provide specific references to where the changes should be made. Theproposal does not comply with the requirements of the Regulations Governing Committee Projects, Section 4.3.3(c).

Affirmative: 181 Carpenter, D.

ANDERSON, W.: The specific references as to where each of the changes should be made were presented at thecommittee meeting for action near the end of the ROP meeting, so that any committee proposals affecting the textcontaining direct contact or indirect contact could also be addressed at that time, unfortunately it appears that thespecific proposed revisions in connection with this proposal appear that they could be delt with more effectively duringthe comment stage. In order for these specific revision materias not to be viewed as new materal during the commentstage, the details of the proposed changes, based upon NFPA 79 2007 edition, are presented with this ballot's resultsin word formated table as follows:6.2.2.1 Basic Protection from Outside an Enclosure. Equipment enclosures and enclosure openings shall meet therequirements of UL 508, UL 508A, UL 50, or NEMA 250.6.3 Fault Protection Against Electric Shock (Fault Conditions).6.3.1 General. Fault Protection (see 3.3.18.2) is intended to prevent hazardous conditions to continue in the event of afault condition. (E.g. insulation failure between live and exposed conductive parts)6.3.1.1* Fault Protection Against Contact. Fault Protection against direct contact shall be achieved by:6.4.1 General Requirements. The protective measure PELV (Protective Extra-Low Voltage) as described in Section 6.4,is to protect persons against electric shock from fault condition (e.g., insulation failure between live and exposedconductive parts) and limited area direct contact.9.2.5.4.2.1 Emergency switching off shall be permitted as follows:(1) Where basic protection (e.g., with collector wires, collector bars, slip-ring assemblies, control gear in electricaloperating areas) is achieved only by placing out of reach or by obstacles9.2.5.4.2.2 Emergency switching off shall be accomplished by disconnecting the incoming supply circuit of the machineeffecting a Category 0 stop. Where the machine cannot tolerate the Category 0 stop, it shall be necessary to provideother protection(e.g., basic protection), so that emergency switching off is not necessary.

IndexReplace “direct contact” with “basic protection”Replace “indirect contact” with “fault protection”

***See additional comments in "Anderson affirmative comments on 79-1 ***

1Printed on 10/13/2009

79-1_L206_Anderson_AffCom_F2010

79-1 Log #206 EEI-AAA materials

Date Document Project Nr. 2009-04-22 NFPA 79 2010 TG 1

NFPA code

ref IEC 60204-1

Clause/ Subclause

IEC 60204-1

Paragraph Figure/ Table

IEC 60204-1 ex8sting IEC 60204-1 Proposed change NFPA 79 existing NFPA 79 Proposed change [Ariel Unicode MS 12pt]

New 3.x New 3.x Definition for electrical enclosure is needed and should be used in the text

Add a new definition and use it in the text: electrical enclosure enclosure providing protection against the foreseen dangers created by electricity [195-06-13]

none Enclosure. The case or housing of apparatus, or the fence or walls surrounding an installation to prevent personnel from accidentally contacting energized parts or to protect the equipment from physical damage. [NFPA 70]


NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



3.3.19 3.29 Adapt the text with IEC 60364-4-41 indirect contact contact of persons or livestock with exposed conductive parts which have become live under fault conditions

Replace 3.29 by: fault protection protection against electric shock under single-fault conditions [195-06-02]

3.3.19 Contact. 3.3.19.1 Direct Contact. Contact of persons with live parts. 3.3.19.2 Indirect Contact. Contact of persons with exposed conductive parts that have become live under fault conditions.

3.3.19 Protection. 3.3.19.1 Basic. Protection against contact of persons with live parts. 3.3.19.2 Fault. Protection against electric shock through contact of persons with exposed conductive parts that have become live under single fault conditions.


NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



6.1 6.1 1. para Adapt the text with IEC 60364-4-41 The electrical equipment shall provide protection of persons against electric shock from: – direct contact (see 6.2 and 6.4); – indirect contact (see 6.3 and 6.4).

Replace the text as follow:

The electrical equipment shall provide protection of persons against electric shock by measures for: - basic protection (see 6.2 and 6.4) - fault protection (see 6.2 and 6.4)

6.1 General. Electrical equipment shall provide protection of persons from electric shock from direct and indirect contact.

6.1 General. The electrical equipment shall provide protection of persons against electric shock by measures for: - basic protection (see 6.2 and 6.3) - fault protection (see 6.2 and 6.3)

6.2* 6.2 Headline Adapt the text with IEC 60364-4-41

Protection against direct contact

Replace the headline “protection against direct contact” by “basic protection”

6.2* Protection Against Direct Contact. Live parts operating at 50 volts rms ac or 60 volts dc or more shall be guarded against contact.

6.2* Basic Protection. Live parts operating at 50 volts rms ac or 60 volts dc or more shall be guarded against contact


NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



6.2.1 Exception

Adapt the text with IEC 60364-4-41 Exception: where those measures are not appropriate, other measures for protection against direct contact (for example by using barriers, by placing out of reach, using obstacles, using construction or installation techniques that prevent access) as defined in IEC 60364-4-41 may be applied (see 6.2.5 and 6.2.6).

Replace “for protection against direct contact” into “ as basic protection” Exception: where those measures are not appropriate, other measures for basic protection (for example by using barriers, by placing out of reach, using obstacles, using construction or installation techniques that prevent access) as defined in IEC 60364-4-41 may be applied (see 6.2.5 and 6.2.6).

none none

6.2.2.1 6.2.2.1 Direct Contact from Outside an Enclosure. Equipment enclosures and enclosure openings shall meet the requirements of UL 508, UL 508A, UL 50, or NEMA 250.

6.2.2.1 Basic Protection from Outside an Enclosure. Equipment enclosures and enclosure openings shall meet the requirements of UL 508, UL 508A, UL 50, or NEMA 250.

6.2.1 3. para Adapt the text with IEC 60364-4-41 When the equipment is located in places open to all persons, which can include children, measures of either 6.2.2 with a minimum degree of protection against direct contact corresponding to IP4X or IPXXD (see IEC 60529), or 6.2.3 shall be applied.

Replace “protection against direct contact” by “basic protection” When the equipment is located in places open to all persons, which can include children, measures of either 6.2.2 with a minimum degree of basic protection corresponding to IP4X or IPXXD (see IEC 60529), or 6.2.3 shall be applied.

Existing does not use term direct contact none


NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



6.2.2 1. para Adapt the text with IEC 60364-4-41 Live parts shall be located inside enclosures that conform to the relevant requirements of Clauses 4, 11, and 14 and that provide protection against direct contact of at least IP2X or IPXXB (see IEC 60529).

Replace “protection against direct contact” by “basic protection” Live parts shall be located inside enclosures that conform to the relevant requirements of Clauses 4, 11, and 14 and that provide basic protection of at least IP2X or IPXXB (see IEC 60529).


6.2.2 2. para Adapt the text with IEC 60364-4-41 Where the top surfaces of the enclosure are readily accessible, the minimum degree of protection against direct contact provided by the top surfaces shall be IP4X or IPXXD.

Replace “protection against direct contact” by “basic protection” Where the top surfaces of the enclosure are readily accessible, the minimum degree of basic protection provided by the top surfaces shall be IP4X or IPXXD.


6.2.2 a) 2 para Adapt the text with IEC 60364-4-41 All live parts, that are likely to be touched when resetting or adjusting devices intended for such operations while the equipment is still connected, shall be protected against direct contact to at least IP2X or IPXXB. Other live parts on the inside of doors shall be protected against direct contact to at least IP1X or IPXXA.

Replace “protected against direct contact” by “basic protected” and “protected against direct contact” by “basic protected” All live parts, that are likely to be touched when resetting or adjusting devices intended for such operations while the equipment is still connected, shall have basic protection to at least IP2X or IPXXB. Other live parts on the inside of doors shall have basic protection to at least IP1X or IPXXA.


6.2.2 Exeption 3. dash

Adapt the text with IEC 60364-4-41 all live parts, that are likely to be touched when resetting or adjusting devices intended for such operations while the equipment is still connected, are protected against direct contact to at least IP2X or IPXXB and other live parts on the inside of doors are protected against direct contact to at least IP1X or IPXXA;

Replace “against direct contact” by “by basic protection” an “protection against direct contact” by “have basic protection” all live parts, that are likely to be touched when resetting or adjusting devices intended for such operations while the equipment is still connected, are protected by basic protection to at least IP2X or IPXXB and other live parts on the inside of doors have basic protection of at least IP1X or IPXXA;



NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



6.2.2 b) 3. para

Adapt the text with IEC 60364-4-41 All parts that are still live after switching off the disconnecting device(s) (see 5.3.5) shall be protected against direct contact to at least IP2X or IPXXB (see IEC 60529). Such parts shall be marked with a warning sign in accordance with 16.2.1 (see also 13.2.4 for identification of conductors by colour).

Replace “protected against direct contact” by “basic protected” All parts that are still live after switching off the disconnecting device(s) (see 5.3.5) shall have basic protection to at least IP2X or IPXXB (see IEC 60529). Such parts shall be marked with a warning sign in accordance with 16.2.1 (see also 13.2.4 for identification of conductors by colour).


6.2.2 Note 3 Adapt the text with IEC 60364-4-41 Where protection against direct contact is achieved in accordance with 6.2.2 c), and a hazard can be caused by manual actuation of devices (for example manual closing of contactors or relays), such actuation should be prevented by barriers or obstacles that require a tool for their removal.

Replace “protected against direct contact” by “basic protected” Where basic protection is achieved in accordance with 6.2.2 c), and a hazard can be caused by manual actuation of devices (for example manual closing of contactors or relays), such actuation should be prevented by barriers or obstacles that require a tool for their removal.


2. para Adapt the text with IEC 60364-4-41 In the case of plugs or similar devices, the withdrawal of which results in the exposure of conductors (for example pins), the discharge time shall not exceed 1 s, otherwise such conductors shall be protected against direct contact to at least IP2X or IPXXB.

Replace “protected against direct contact” by “basic protected” In the case of plugs or similar devices, the withdrawal of which results in the exposure of conductors (for example pins), the discharge time shall not exceed 1 s, otherwise such conductors shall have basic protection to at least IP2X or IPXXB.



NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



6.3 6.3 Headline Adapt the text with IEC 60364-4-41 Protection against indirect contact

Replace the headline “protected against direct contact” by “basic protection” Fault protection

6.3 Protection Against Electric Shock from Indirect Contact (Fault Conditions).

6.3 Fault Protection Against Electric Shock (Fault Conditions).

6.3.1 6.3.1 1. para Adapt the text with IEC 60364-4-41 Protection against indirect contact (3.29) is intended to prevent hazardous situations due to an insulation fault between live parts and exposed conductive parts.

Replace “protected against indirect contact” by “fault protection” Fault protection (3.29) is intended to prevent hazardous situations due to an insulation fault between live parts and exposed conductive parts.

6.3.1 General. Protection against indirect contact (see 3.3.18.2) is intended to prevent hazardous conditions to continue in the event of a fault condition. (e.g., insulation failure between live and exposed conductive parts).

6.3.1 General. Fault Protection (see 3.3.18.2) is intended to prevent hazardous conditions to continue in the event of a fault condition. (e.g., insulation failure between live and exposed conductive parts).


NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



6.3.1.1 6.3.1.1* Protection Against Indirect Contact. Protection against indirect contact shall be achieved by:

6.3.1.1* Fault Protection Against Contact. Fault Protection against direct contact shall be achieved by:


NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



6.4.1 6.4.1 1. para Adapt the text with IEC 60364-4-41 The use of PELV (Protective Extra-Low Voltage) is to protect persons against electric shock from indirect contact and limited area direct contact (see 8.2.5).

Replace “use of” by “protective measure” The protective measure PELV (Protective Extra-Low Voltage) is to protect persons against electric shock from indirect contact and limited area direct contact (see 8.2.5).

6.4.1 General Requirements. The use of PELV, as described in Section 6.4, is to protect persons against electric shock from indirect contact and limited area direct contact.

6.4.1 General Requirements. The protective measure PELV (Protective Extra-Low Voltage) as described in Section 6.4 ,is to protect persons against electric shock from fault condition (e.g., insulation failure between live and exposed conductive parts) and limited area direct contact.


NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



9.2.5.4.2.1.(1)

9.2.5.4.3 2. para 1. dash

Adapt the text with IEC 60364-4-41 protection against direct contact (for example with conductor wires, conductor bars, slipring assemblies, controlgear in electrical operating areas) is achieved only by placing out of reach or by obstacles (see 6.2.6); or

Replace “protected against direct contact” by “basic protection” basic protection (for example with conductor wires, conductor bars, slipring assemblies, controlgear in electrical operating areas) is achieved only by placing out of reach or by obstacles (see 6.2.6); or

9.2.5.4.2.1 Emergency switching off shall be permitted as follows: (1) Where protection against direct contact (e.g., with collector wires, collector bars, slip-ring assemblies, control gear in electrical operating areas) is achieved only by placing out of reach or by obstacles

9.2.5.4.2.1 Emergency switching off shall be permitted as follows: (1) Where basic protection (e.g., with collector wires, collector bars, slip-ring assemblies, control gear in electrical operating areas) is achieved only by placing out of reach or by obstacles


NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



9.2.5.4.2.2

9.2.5.4.3 3. para Adapt the text with IEC 60364-4-41 Emergency switching off is accomplished by switching off the relevant incoming supply by electromechanical switching devices, effecting a stop category 0 of machine actuators connected to this incoming supply. When a machine cannot tolerate this stop category 0 stop, it may be necessary to provide other measures, for example protection against direct contact, so that emergency switching off is not necessary.

Replace “protected against direct contact” by “basic protection” Emergency switching off is accomplished by switching off the relevant incoming supply by electromechanical switching devices, effecting a stop category 0 of machine actuators connected to this incoming supply. When a machine cannot tolerate this stop category 0 stop, it may be necessary to provide other measures, for example basic protection, so that emergency switching off is not necessary.

9.2.5.4.2.2 Emergency switching off shall be accomplished by disconnecting the incoming supply circuit of the machine effecting a Category 0 stop. Where the machine cannot tolerate the Category 0 stop, it shall be necessary to provide other protection (e.g., against direct contact), so that emergency switching off is not necessary.

9.2.5.4.2.2 Emergency switching off shall be accomplished by disconnecting the incoming supply circuit of the machine effecting a Category 0 stop. Where the machine cannot tolerate the Category 0 stop, it shall be necessary to provide other protection (e.g., basic protection), so that emergency switching off is not necessary.


NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



10.1.3 2. para Adapt the text with IEC 60364-4-41 In addition, the operator interface control devices shall have a minimum degree of protection against direct contact of IPXXD (see IEC 60529).

Replace “protected against direct contact” by “basic protection” In addition, the operator interface control devices shall have a minimum degree of basic protection of IPXXD (see IEC 60529).


12.7.1 Headline Adapt the text with IEC 60364-4-41 Protection against direct contact

Replace the headline “protected against direct contact” by “basic protection” Basic protection


12.7.1 1. para Adapt the text with IEC 60364-4-41 Conductor wires, conductor bars and slip-ring assemblies shall be installed or enclosed in such a way that, during normal access to the machine, protection against direct contact is achieved by the application of one of the following protective measures:

Replace “protected against direct contact” by “basic protection” Conductor wires, conductor bars and slip-ring assemblies shall be installed or enclosed in such a way that, during normal access to the machine, basic protection is achieved by the application of one of the following protective measures:


18.1 b) Adapt the text with IEC 60364-4-41 in case of protection against indirect contact by automatic disconnection, conditions for protection by automatic disconnection shall be verified according to 18.2;

Replace “protected against in direct contact” by “fault protection …….. of supply” in case of fault protection by automatic disconnection of supply, conditions for protection by automatic disconnection shall be verified according to 18.2;

Existing does not use term indirect contact none

Annex A Headline Adapt the text with IEC 60364-4-41 Protection against indirect contact in TN-systems

Replace the headline “protected against in direct contact” by “fault protection” Fault protection in TN-systems



NFPA coderef

IEC 60204-1Clause/

Subclause

IEC 60204-1



A.1 1. para Adapt the text with IEC 60364-4-41 Protection against indirect contact shall be provided by an overcurrent protective device that automatically disconnects the supply to the circuit or equipment in the event of a fault between a live part and an exposed conductive part or a protective conductor in the circuit or equipment, within a sufficiently short disconnecting time. A disconnecting time not exceeding 5 s is considered sufficiently short for machines.

Replace “protected against in direct contact” by “fault protection” Fault protection shall be provided by an overcurrent protective device that automatically disconnects the supply to the circuit or equipment in the event of a fault between a live part and an exposed conductive part or a protective conductor in the circuit or equipment, within a sufficiently short disconnecting time. A disconnecting time not exceeding 5 s is considered sufficiently short for machines.


A.3 Note 1 Adapt the text with IEC 60364-4-41 Supplementary protective bonding is considered as an addition to protection against indirect contact.

Replace “protected against in direct contact” by “fault protection” Supplementary protective bonding is considered as an addition to fault protection.


A.4.1 1. para Adapt the text with IEC 60364-4-41 The effectiveness of the measures for protection against indirect contact by automatic disconnection of supply in accordance with Clause A.2 is verified as follows:

Replace “protected against in direct contact” by “fault protection” The effectiveness of the measures for fault protection by automatic disconnection of supply in accordance with Clause A.2 is verified as follows:


Index Index Adapt the text with IEC 60364-4-41 direct contact

Replace “direct contact” by “basic protection” Basic protection

direct contact basic protection

Index Index Adapt the text with IEC 60364-4-41 indirect contact

Replace “indirect contact” by “fault protection” Fault protection

indirect contact fault protection

Note revise Contents

Report on Proposals – November 2010 NFPA 79_______________________________________________________________________________________________79-1a Log #CP1 EEI-AAA

_______________________________________________________________________________________________Technical Committee on Electrical Equipment of Industrial Machinery,

Review entire document to: 1) Update any extracted material by preparing separate proposals todo so, and 2) review and update references to other organizations documents, by preparing proposal(s) as required.

To conform to the NFPA Regulations Governing Committee Projects.

See Committee Proposal 79-5a (Log #CP4).


ANDERSON, W.: I agree with the committee's action and to follow the current manual of style as follows:2.3.1.2.1 Chapter 2 shall consist of three sections as follows:(1) 2.1 General. The documents or portions thereof listed in this chapter are referenced within this (standard, code) andshall be considered part of the requirements of this document.(2) 2.2 NFPA Publications.(3) 2.3 Other Publications.2.3.1.2.4 All reference listings in Chapter 2 shall contain complete reference information [i.e., document number (ifapplicable), document title, and date of publication (if applicable)].2.3.1.2.5 References shall be permitted to be referred to throughout the document (other than Chapter 2) by only theirnumerical designation or document title, as used in the field.

HILBERT, M.: The action taken in Proposal 79-5a (Log # CP5) was an effort to recognize that a complete review ofthe document is necessary to comply with the recommendation. However, there was insufficient time to review theentire document as requested before the ROP meeting. The Chair recognizes that a task group will be necessary todevelop a comment with regard to the remaining referenced standards included in 79-5a and that a task group shouldbe appointed to review any other referenced documents and extracted material for the next revision cycle.



_______________________________________________________________________________________________Frank C. DeFelice, Jr., Cytec Industries, Inc.

Delete Section 1.1.2 and replace with a new Fine Print Note beneath Section 1.1.1.1.1.2 This standard shall not include the additional requirements for machines intended for use in hazardous

(classified) locations.FPN: For additional requirements for machines intended to be used in hazardous (classified) areas, see NFPA 70,

National Electrical Code® (NEC®) Article 500.The existing language in unclear; because the requirement in this Section is "shall not include the

additional requirements". This proposal would result in improved clarity for the reader by removing the mandatory ("shallnot") language and refer readers to Article 500 of the NEC.

Revise text to read as follows:1.1.2* This standard shall does not include the additional requirements for machines intended for use in hazardous

(classified) locations.Annex A.1.1.2 to read as follows:A.1.1.2 For additional requirements for machines intended to be used in hazardous (classified) areas, see NFPA 70,

National Electrical Code® (NEC®) Article 500.The committee rejects deleting 1.1.2 in its entirety and replaced the word "shall" with the word

"does" for clarity.The committee agrees that FPN's are not permitted in accordance with the Manual of Style.The committee agrees that adding a reference to the National Electrical Code would benefit users of the document by

providing direction to where the additional requirements can be found. In accordance with 1.9.7 of the NFPA Manual ofStyle, informational text must be placed in an annex and adds an asterisk following 1.1.2. The FPN will be moved to theAnnex as A.1.1.2.


CALLANAN, M.: The Technical Correlating Committee should review the change deleting “shall” and replacing it with“does” in what appears to be the scope of NPFA 79.


Report on Proposals – November 2010 NFPA 79_______________________________________________________________________________________________79-3 Log #2

_______________________________________________________________________________________________

William Anderson, The Procter & Gamble CompanyRecommendation:

Either the full committee, or by a task group, construct an annex containing information concerning existing methodsand/or sources, which could be used in completing the required risk assessment process. This annex would be both aguide and help in establishing future additional tools and methods requirements appropriate for industrial machine’selectrical system design to accomplish safe implementation of industrial machines using existing or state of the artcomponents and methods.

Note: The information proposed in ROP 79-147 (Log #148) (ANSI B11.TR3) is included in the suggested text for thenew annex and should not be duplicated in A.4.1.

A suggested beginning text for the annex is as follows:Annex X (to be determined) Resources for Risk Assessment of Industrial Machines Covered by NFPA 79This annex is not a part of the requirements of this NFPA document but is included for informational purposes only.X.1 Methodologies. Examples of books and articles are as follows:(1) B. W., Main Risk Assessment Basics and Benchmarks. Ann Arbor, MI: Design Safety Engineering, 2004(2) J. R. Thomson, Engineering Safety Assessment: An Introduction, Wiley, NY, 1987(3) R. I. Mehr, R. D. Irwin, Risk Management: Concepts & Applications, Homewood, IL, 1974(4) R. L. Brauer, Safety and Health for Engineers, Van Nostrand Reinhold, NY, 1994.(5) W. W. Lowrance, Of Acceptable Risk, William Kaufmann, Los Altos, CA, 1976(6) W. E. Anderson, Risk Analysis Methodology Applied to Industrial Machine Development, IEEE Transaction son

Industrial Applications, Jan/Feb 2005, vol. 41, no. 1 p. 180–186.X.2 Related Standards and Technical Reports. Examples of published standards and technical reports are as follows:(1) Safety of Machinery – Principles of Risk Assessment, ISO 14121: 1999 (E).(2) Safety of Machinery – Electrotechnical Aspects – Functional Safety of Electrical, Electronic and Programmable

Control Systems, IEC 62061: 2005(3) Technical Report for Machine Tools – Risk Assessment and Risk Reduction – A Guide to Estimate, Evaluate and

Reduce Risks Associated with Machine Tools, ANSI B11 TR3-2000.(4) Safety of Machinery – Safety Related Parts of Control Systems – Part 100: Guide for the Use and Application of

ISO 13849-1, ISO/TR13849-100: 2000.(5) Safety of Machinery – Basic Concepts, General Principles for Design – Part 1: Basic Terminology, Methodology

– Section 4 – Hazards to be taken Into Account When Designing Machinery, ISO 12100-1: 2003.The need for this information seems apparent based upon this and many related proposals on this

subject. The task of doing a risk assessment is called for in Section 4.1 and elsewhere in the standard. An example fromthis and other proposals in the ROP that are dealing with the risk assessment issue [e.g., 79-77 (Log #2), 79-78 (Log#21), through 79-81 (Log #24), 79-82 (Log #44), 79-84 (Log #85), 79-88 (Log #151), 79-92 (Log #153), 79-147 (Log#148), 79-148 (Log #87), 79-152 (Log #155).] An in other parts of the NFPA 79 standard (e.g., 9.2.5.3.2, 9.2.5.4.1.3),the required action by the electrical system of the industrial machine is based upon information from a risk assessmentdone on the machine, (mechanical, operational and electrical).

Comment:I remain in agreement with the committee action on the original proposal but request the committee reconsider the

proposal’s apparent intent that in some form risk assessments have done and they must continue to be performed, anaide to this necessary activity, focusing on electrical equipment of industrial machines, can be accomplished by addingan informative annex concerning sources presenting risk assessment methodologies. This proposed solutionincorporates the Task Group 4 recommendation in ROP 79-147 (Log #148) by it being moved from part of A.4.1 to thenew annex to be included with additional resources on methodologies that could be applied to the electrical equipmentof industrial machines.

The proposal addresses issues above and beyond electrical risk assessment which is beyondthe scope of this document. The submitter has not provided the necessary text for inclusion in the document inaccordance with 4.3.3(c) of the Regulations Governing Committee Projects.


Report on Proposals – November 2010 NFPA 79

Affirmative: 17 Negative: 11 Carpenter, D.

ANDERSON, W.: The committee did error in its reasoning for rejecting the proposal in that the proposal doesaddress issues within the electrical risk assessment process; as example, issues contained within the current edition ofNFPA 79 operating and control function requirements.

The suggested committee action would be to accept in principle and refer to and change to an acceptance of proposal79-212 (Log #161) which contains the necessary text for inclusion in the document in accordance with 4.3.3 (c) of theRegulations governing Committee Projects.

Chapter 4 General Operating Conditions4.1* General Considerations This chapter describes the general requirements and conditions for the operation of the

electrical equipment of the machine. The risks associated with the hazards relevant to the electrical equipment shall beassessed as part of the overall requirements for risk assessment of the machine. The risks associated with the hazardsidentified by the risk assessment shall be reduced such that the safety performance determined by the risk assessmentis met.

Chapter 9 Control Circuits and Control Functions9.2* Control Functions.9.2.5.3 Stop.9.2.5.3.1 Each machine shall be equipped with a Category 0 stop.9.2.5.3.2 Category 0, Category 1, and/or Category 2 stops shall be provided where indicated by an analysis of the riskassessment and the functional requirements of the machine. Category 0 and Category 1 stops shall be operationalregardless of operating modes, and Category 0 shall take priority. Stop function shall operate by de-energizing thatrelevant circuit and shall override related start functions.9.2.5.4* Emergency Operations (Emergency Stop, Emergency Switching Off).9.2.5.4.1.3 The emergency stop shall function as either a Category0 or a Category 1 stop (see 9.2.2). The choice of the category of the emergency stop shall be determined by the riskassessment of the machine.9.4 Control Functions in the Event of Failure.9.4.1* General Requirements. Where failures or disturbances in the electrical equipment cause a hazardous condition ordamage to the machine or the work in progress, measures shall be taken to minimize the probability of the occurrenceof such failures or disturbances. The electrical control circuits shall have an appropriate level of performance that hasbeen determined from the risk assessment of the machine.




Revise 1.3.1.1 as noted:When changes other than repairs are made to machines that do not comply with the provisions of this standard, the

changes shall conform with to the provisions of this standard.Editorial:

"Comply with" or "conform to" generally are the correct English grammars; proposition pairs.Conform, "with" or "to" is using the first definition meaning for conform which is the changes are to be in agreement or

harmony.Conform, using "to" means only using the second definition meaning which is to be obedient or compliant or to act in

accordance with prevailing standards or customs.





Add a new Fine Print Note beneath Section 1.3.2 as follows:1.3.2 This standard shall not apply to the following:(1) Fixed or portable tools judged under the requirements of a testing laboratory acceptable to the authority having

jurisdiction(2) Machines used in dwelling unitsFPN: For examples of machinery covered by this standard, see Annex C.

Familiarizes readers with types of machinery covered by this standard by directing them to theexamples in Annex C.

This material is already in the document in A.1.1.





Revise as follows:2.3 Other Publications.2.3.1 ANSI Publications.American National Standards Institute, Inc., 25 West 43rd Street, 4th Floor, New York, NY 10036.ANSI Z535.4, Product Safety Signs and Labels, 2002.20072.3.2 ASTM Publications.ASTM International, 100 Barr Harbor Drive, P. O. Box C700, West Conshohocken, PA 19428-2959.A ASTM B 174, Standard Specification for Bunch-Stranded Copper Conductors for Electrical Conductors, 2002.ASTM B 286, Standard Specification for Copper Conductors for Use in Hookup Wire for Electronic Equipment, 2002.2.3.3 IEC Publications.International Electrotechnical Commission, 3 rue de Varembe, P.O. Box 131, 1211 Geneva 20, Switzerland.IEC 60072–1, Dimensions and output series for rotating electrical machines — Part 1: Frame numbers 56 to 400 andflange numbers 55 to 1080, 1991-03.IEC 60072–2, Dimensions and output series for rotating electrical machines — Part 2: Frame numbers 355 to 1000 andflange numbers 1180 to 2360, 1990-12.2.3.4 IEEE Publications.Institute of Electrical and Electronics Engineers, Three Park Avenue, 17th Floor, New York, NY 10016-5997.IEEE 315/315A, Graphical Symbols for Electrical and Electronics Diagrams (Including Reference Designation Letters),1993.2.3.5 NEMA Publications.National Electrical Manufacturers Association, 1300 N. 17th Street, Suite 1847, Rosslyn, VA 22209.NEMA ICS 2, Industrial Control and Systems: Controllers, Contactors, and Overload Relays Rated 600 Volts, 2000(R2004).NEMA MG-1, Motors and Generators, 2003.NEMA 250, Enclosures for Electrical Equipment (1000 Volts Maximum), 2003.2.3.6 UL Publications.Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.UL 50, Standard for Enclosures for Electrical Equipment, 2003.UL 508, Standard for Industrial Control Equipment, 2005.UL 508A, Standard for Industrial Control Panels, 2001.UL 870, Standard for Wireways, Auxiliary Gutters and Associated Fittings, 1995.UL 1063, Standard for Machine-Tool Wires and Cables, 1998.2.3.7 U.S. Government Publications.U.S. Government Printing Office, Washington, DC 20402.Title 29, Code of Federal Regulations, Part 1910.331–335, “Safety-Related Work Practices.”2.3.8 Other Publications.Merriam-Webster’s Collegiate Dictionary, 11th edition, Merriam-Webster, Inc., Springfield, MA, 2003.2.4 References for Extracts in Mandatory Sections.NFPA 70, National Electrical Code®, 2005 2008 edition.NFPA 70E, Standard for Electrical Safety in the Workplace, 2004 2009 edition.

The committee reviewed the referenced documents and revised as instructed in Proposal 79-1a.


ANDERSON, W.: I agree with the committee's action and to follow the current manual of style as follows:2.3.1.2.1 Chapter 2 shall consist of three sections as follows:(1) 2.1 General. The documents or portions thereof listed in this chapter are referenced within this (standard, code) and


Report on Proposals – November 2010 NFPA 79shall be considered part of the requirements of this document.(2) 2.2 NFPA Publications.(3) 2.3 Other Publications.2.3.1.2.4 All reference listings in Chapter 2 shall contain complete reference information [i.e., document number (ifapplicable), document title, and date of publication (if applicable)].2.3.1.2.5 References shall be permitted to be referred to throughout the document (other than Chapter 2) by only theirnumerical designation or document title, as used in the field.

HILBERT, M.: See my affirmative comment on 79-1a (Log #CP1).



_______________________________________________________________________________________________Bob Eugene, Underwriters Laboratories Inc.

Revise text to read as follows:2.3.6 UL Publications,Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.ANSI/UL 50, Standard for Enclosures for Electrical Equipment, 2003 2007.ANSI/UL 508, Standard for Industrial Control Equipment, 2005 1999 with revisions through September 2008.UL 508A, Standard for Industrial Control Panels, 2001, with revisions through December 2007.ANSI/UL 870, Standard for Wireways, Auxiliary Gutters and Associated Fittings, 1995 2008.ANSI/UL 1063, Standard for Machine-Tool Wires and Cables, 1998 2006.

Update standards titles to indicate revision dates, ANSI approvals and other title changes.

Accept the insertion of the ANSI references and remove the dates to read as follows:2.3.6 UL Publications,Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.ANSI/UL 50, Standard for Enclosures for Electrical Equipment 2003 .ANSI/UL 508, Standard for Industrial Control Equipment 2005.UL 508A, Standard for Industrial Control Panels.ANSI/UL 870, Standard for Wireways, Auxiliary Gutters and Associated Fittings 1995 .ANSI/UL 1063, Standard for Machine-Tool Wires and Cables 1998 .

The committee removed the dates to allow the latest revised edition to be utilized.


ANDERSON, W.: I agree with the committee's action and to follow the current manual of style as follows:2.3.1.2.1 Chapter 2 shall consist of three sections as follows:(1) 2.1 General. The documents or portions thereof listed in this chapter are referenced within this (standard, code) andshall be considered part of the requirements of this document.(2) 2.2 NFPA Publications.(3) 2.3 Other Publications.

2.3.1.2.4 All reference listings in Chapter 2 shall contain complete reference information [i.e., document number (ifapplicable), document title, and date of publication (if applicable)].2.3.1.2.5 References shall be permitted to be referred to throughout the document (other than Chapter 2) by only theirnumerical designation or document title, as used in the field.

CALLANAN, M.: The Technical Correlating Committee should review the panel statement relative to removing datesallowing for the latest revision date to be used by default.

HILBERT, M.: There were considerable discussions at the meeting relative to the proper way to reference adocument (i.e. meeting the Manual of Style and industry practices) the Committee determined it was best to remove thedates in order to allow use of the most current document. However, it was subsequently realized that the date ofpublication must be included where applicable (see 2.3.1.2.4 of the Manual of Style).

Section 2.3.1.2.4 of the Manual of Style indicates the reference should in include the “date of publication whereapplicable.” Using UL 508 as an example, if the document the Committee intends to reference is the latest one and thatwas published with revisions in 2008 then it appears the published date that should be referenced is 2008. This isconsistent with previous editions of NFPA 79 as well as most other NFPA documents.

With the above considerations in mind, the recommendation should be to accept in principle in part and revise asfollows:

2.3.6 UL Publications,Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.ANSI/UL 50, Standard for Enclosures for Electrical Equipment 2003 2007 .ANSI/UL 508, Standard for Industrial Control Equipment 2005 2008.UL 508A, Standard for Industrial Control Panels 2001 .

10Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 79ANSI/UL 870, Standard for Wireways, Auxiliary Gutters and Associated Fittings 1995 2008.ANSI/UL 1063, Standard for Machine-Tool Wires and Cables 1998 2006.This revision accepts the recommendation to add the “ANSI” reference and accepts in principle the recommendation to

reference the latest revised editions.

11Printed on 10/13/2009


_______________________________________________________________________________________________Lori L. Tennant, Schneider Electric North America

Add a new 3.3.XX to address bonding of machine elements not designed to be part of the faultcurrent path.

For bonding together of normally noncurrent-carrying metallic parts tothe electrical equipment (protective bonding) circuit, in order to minimize electrical touch hazards across machine partsnot designed to be part of the fault current path.

This bonding concept addresses a possible indirect shock exposure by reducing touch voltagedifferentials between adjacent surfaces. This bonding concept is not designed to part of the direct fault current path backto its source.

The committee agrees that bonding is required. However, the language in the other proposedrecommendations by the grounding task group associated with this definition does not recognize other means ofbonding.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


FISHER, D.: This proposed definition should have been rejected but its rejection should not have been the basis ofrejecting all sections in which the term was used.

The NEC definition of “Bonding Jumper” is: A reliable conductor to ensure the required electrical conductivity betweenmetal parts required to be electrically connected.

There is clearly a case for the definition since the sizing and characteristics of the jumpers need specification. But, wecan have one definition rather than two definitions since the proposed text did not specify different attributes or sizingbased upon function which was the basis for the definitional differences.

The NFPA 79 definition of “Bonding Jumper could be: Electrical conductor to ensure continuity of the equipmentgrounding (bonding) circuit where conductive metal parts are not contiguous or where adjacent conductive parts are notsufficiently electrically bonded by their mechanical connections.

HILBERT, M.: Although I completely agree that bonding is required, there was no technical substantiation submittedto require bonding beyond what has been standard machine assembly practices. The bonding jumper that is the subjectof this definition would be a new concept and from an enforcement standpoint it is not entirely clear when it would berequired (see 79-53). I agree with the Committee statement that the companion proposals do not recognize othermethods of bonding. If there is technical substantiation available to require additional bonding then it should besubmitted in the comment stage for review by the Committee.

There were 36 proposals from the Grounding and Bonding Task Group that will significantly change Chapter 8 and theassociated definitions. I truly appreciate all the hard work that went into creating these proposals. However, I do notagree that Chapter 8 was in need of this many changes nor do I agree that this revision of Chapter 8 and its associateddefinitions was all within the scope of the original task. In my opinion, although there is merit is within therecommendations, not all of the recommendations will change the document in a positive manner.

The proposed changes in definitions and grounding and bonding concepts will alter the current relationship with theNFPA 70, the National Electrical Code considerably. Especially Articles 100 and 250. Because the National ElectricalCode is a referenced document in Chapter 2 and it is the “fall back” position for provisions not covered in NFPA 79 (see1.5), the grounding and bonding definitions and requirements should remain consistent between the two documentswherever possible.

If it is the intent of the Committee to change Chapter 8 and the associated definitions as proposed, a task groupshould be appointed that includes the Chair of NEC Panels 1 and 5 and the 79 Committee to review and comment onthe affects of the 36 proposals which consist of 79-7, 79-12, 79-13, 79-14, 79-22, 79-24, 79-26, 79-53, 79-69, 79-70,79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85, 79-86, 79-88, 79-89, 79-90,

12Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 7979-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.

13Printed on 10/13/2009


_______________________________________________________________________________________________Glyn R. Garside, Pilz Automation Safety L.P.

Add new text to read as follows:3. A group of one or more control devices in an accessible location that can be used to

initiate motion or a potentially hazardous condition or process.

“Operator control station” is used about twenty times in NFPA 79, but never defined. There are somemandatory requirements for operator control stations, such as the location of stop or emergency stop buttons. Absent ofa definition, I have seen locations on machines that I think the committee would intend should have an E-stop that thebuilder did not consider an “operator control station”, even though there was a START or JOG button, etc.

(For comparison, ANSI RIA ISO 10218-1 states [5.5.2] “Each control station capable of initiating robot motion or otherhazardous situation shall have a manually initiated emergency stop function that:…”)

The committee concludes that the proposed definition is too prescriptive.


DEFELICE, JR., F.: Although the definition which was originally proposed is perhaps too prescriptive, the proposer'ssuggestion has merit. Consider: 3.3xx Operator Control Station: One or more control devices which require humaninput to initiate, manipulate or stop machine operation

HILBERT, M.: Although I agree with the Committee, the proposed definition would likely create enforcementdifficulties as it is to general. For example: a manually operated remote pump controlled by a standard stop/startconfiguration located adjacent to the pump would be considered operator control station.

14Printed on 10/13/2009



Add definition for term in 10.1.4.2 and A.10.1.4.2:3.3.x Direct Opening Operation: Achievement of contact separation as the direct result of a specified movement of the

switch actuator through non-resilient members (for example not dependent upon springs).Normalization: 10.1.4.2 uses the term "Direct Opening Operation", but references IEC 60947-5-1. The

proposed language is copied from 60947-5-1 Annex K, paragraph K2.2 verbatim. Adoption of the IEC language offers adefinition where none exists, avoids confusion with interpreting NFPA 79, and normalizes NFPA 79 to IEC 60204-1.

Insert into definitions in alphabetical order and renumber remaining definitions.


15Printed on 10/13/2009



Delete definitions for (Electrically ) Instructed Person (Section 3.3.33) and (Electrically) SkilledPerson (Section 3.3.34) from Chapter 3.

Add the definition of Qualified Person (from NFPA 70 National Electrical Code), along with the Fine Print Note fromNFPA 70 as shown below:

Revise references to the deleted terms (in Annex B) to reflect these changes.3.3x Qualified Person. One who has skills and knowledge related to the construction and operation of the electrical

equipment and installations and has received safety training on the hazards involved.FPN: Refer to NFPA 70E-2004, for electrical safety training

requirements.To align with the terms described in the NFPA 70: and the NFPA Glossary of

Terms.

Delete 3.3.33 and 3.3.34.Renumber the remaining definitions.In Figure B.1 delete question 26 and renumber remaining questions.Revise Section 6.24 to read as follows:6.2.4 Enclosure Access. Where a qualified person using appropriate work practices, needs to enter an enclosure that

does not have a disconnect, one of the following conditions shall be met:(1) The use of a key or tool shall be required for opening the enclosure.(2) An enclosure door shall be permitted to be opened without the use of a key or a tool and without disconnection of

live parts only when all live parts inside are separately enclosed or guarded such that there cannot be any direct contactwith live parts.

The committee accepts deleting (Electrically) Instructed Person (Section 3.3.33) and(Electrically) Skilled Person (Section 3.3.34) and question 26 of Annex Figure B.1.

The committee rejects adding the recommended fine print note as Fine Print Notes are not permitted in the standard.The committee recognizes A.3.3.79 in the Annex directs the user of the document to NFPA 70E.

In addition the committee removed the word (skilled) from 6.2.4.


CALLANAN, M.: It is unclear what happened to the recommendation to add the definition of Qualified Person asproposed in the recommendation. In addition, the proposed definition is not that in the 2008 NEC and 2009 Edition ofNFPA 70E.

The TCC should return this proposal to the 79 TC and have them explain why they did not accept the part of therecommendation on the proposed "3.3x Qualified Person. One who has..."

16Printed on 10/13/2009



Add new definition to Chapter 3 and in Annex A:3.3.XX Safety Integrity Level. A measure of safety system performance in terms of probability of failure.A.3.3.XX Safety Integrity Level. The Safety Integrity Level (SIL) is a measure of safety system performance in terms of

probability of failure. The four Safety Integrity Levels (SIL) are SIL 1, SIL 2, SIL 3, and SIL 4. The higher the SIL level,the higher the associated safety level.

This proposal correlates with a related proposal to revise 9.4.3.4.1.

See committee action and statement on Proposal 79-114.


17Printed on 10/13/2009



Add new definition to read as follows:3.3 XX. Supplementary grounding electrode. A grounding electrode installed at an industrial machine for augmentation

of the facility equipment grounding conductor.This will provide a machine locality electrode for electronic frequency referencing.

Technical substantiation has not been provided to support the addition of a new definition.The committee does not agree with submitter’s substantiation that the proposed definition would require an electrode atthe machine.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


HILBERT, M.: See my affirmative comment on Proposal 79-7 (Log #155).

18Printed on 10/13/2009



Add new definition to read as follows:3.3 XX Supplementary Grounding Electrode Conductor. The conductor that provides connection between the

supplementary grounding electrode and a designated terminal in the industrial machine control panel.This will provide users with installation criteria.

Technical substantiation has not been provided to support the addition of a new definition.The committee has not accepted the supplementary grounding electrode therefore this definition is not necessary.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



19Printed on 10/13/2009



Delete present 3.3.9 and its related A.3.3.9 text and replace only the present 3.3.9 with new textasfollows. The permanent joining of metallic parts to form an electrically conductive path thatensures electrical continuity and the capacity to conduct safely any current likely to be imposed. [ 100]

See 3.3.77, Protective Bonding Circuit.For bonding of the electrical equipment that in the event of a fault is

designed to be part of the fault current path.This replaces the present definition with new text and deletes the Annex A reference because it is no

longer necessary, and to reflect the machine tool industry applications. This bonding concept is designed to be part ofthe direct fault current path back its source and enhance protection of an overcurrent protective device.

The committee agrees that bonding is required. However, the language in the other proposedrecommendations by the grounding task group associated with this definition does not recognize other means ofbonding.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



20Printed on 10/13/2009


_______________________________________________________________________________________________Jay Tamblingson, Rockwell Automation / Rep. NFPA 79 Technical Committee AWM Task Group

Revise text to read as follows:3.3.11* Cable. A combination of conductors insulated from one another with a common covering that is not a cord or

Type AWM Appliance Wiring Material.A.3.3.11.3 Special Cable. For addition information on types of special cables, see 12.9 or refer to NFPA 70, National

Electrical Code, Chapters 4, 6, 7, and 8.This proposal was developed by the NFPA 79 Technical Committee Task Group on AWM.

Some AWM would meet the requirements of a special cable under the proposed changes to 12.2.7. As such, thereference in 3.3.11 needs to be removed. In addition, a reference to the revised special cables section was added tothe annex note for 3.3.11.3.

See companion proposal to 12.2.7.


21Printed on 10/13/2009



Delete the definition in 3.3.123.3.12 Cableless Control. Control devices employing cableless (e.g., radio, infrared) techniques for transmitting

commands and signals between a machine control system and operator control stations(s).Insert new definition as 3.3.xx to read as follows:Wireless Operator Control. A system which utilizes wireless technology to communicate control instructions between a

human-machine interface (HMI) or other operator control device and one or more machines.We submit that the use of the term "Cableless" is not appropriate as used in this standard; and that the

more commonly used term "Wireless" is more accurate.This is because the term "Cableless" requires that there be no wired ("cabled") connection, to either communications

or power systems of a machine. If a "Cableless" operator control station is placed into a docking station on a machine,or otherwise connected to machine power (for recharging batteries, etc.) it ceases being "Cableless". Thus, the term"Wireless" is more appropriate, since the term refers only to the communications technology used to communicatebetween the operator interface device or control station and the machine. Since all "Cableless" devices utilize wirelesstechnology to communicate, they are appropriately included under the heading of "Wireless Operator Control".

See Proposal 79-32. The term cableless is commonly accepted terminology in the industry.


ANDERSON, W.: I agree with the committee's action.Cableless control is only defined in NFPA 79; however cableless is not definded elsewhere and thus cablelesstechniques used in the cableless control definition is not defined (a defect of the NFPA 79 definition of cabless control)See 79-32

22Printed on 10/13/2009


_______________________________________________________________________________________________Noel Williams, Noel Williams Consulting

Delete this definition (Color Graphic Interface Device) and the associated Annex note.This term is not used anywhere in NFPA 79 and the annex discussion/explanation seems to make a

distinction between color and monochrome devices that is not made anywhere in the body of the document. Thedefinition makes it seem as if there is some rule about this even though there is not, so it adds to confusion ininterpretation and application and wasted time and effort in trying to find the implied rule.

The definition of Color Graphic Interface Device is appropriately located in Section 3.3.16 inaccordance the Manual of Style for NFPA Technical Committee Documents, as the term is used in the followingsections of mandatory text in NFPA 79:

- The title of Section 10.2- The text of Section 10.2.2- The title of Section 10.3- The text of Section 10.3.1- The text of Section 10.3.2


DEFELICE, JR., F.: The definition of Color Graphic Interface Device is appropriately located in Section 3.3.16 inaccordance the Manual of Style for NFPA Technical Committee Documents, as the term is used in the followingsections of mandatory text in NFPA 79:- The title of Section 10.2 - The text of Section 10.2.2 - The title of Section 10.3 - The text of Section 10.3.1 - The text ofSection 10.3.2

23Printed on 10/13/2009



Delete this definition.The term "concurrent" appears only in Chapter 3 and is not used in any rule in the document.

Furthermore, the definition is in no way special or specific to this document, is really an "ordinarily accepted meaning,"as stated in Section 3.1, and as such does not belong in Chapter 3. Defined terms that are never used only make thedocument more difficult to use.

The committee agreed to retain the definition as the term is used in 9.2.5.2.4(4) and 9.2.5.6(1).


24Printed on 10/13/2009


_______________________________________________________________________________________________Paul R. Warndorf, Association For Manufacturing Technology (AMT)

New text to read as follows:3.3.26 Cord. A type of cable having Ttwo or more flexible insulted conductors enclosed in a flexible covering that

provides mechanical protection used for.

Revise text to read as follows:3.3.26 Cord. A type of cable having Ttwo or more flexible insulated conductors enclosed in a flexible covering that

provides mechanical protection.The committee accepted the phrase "a type of cable having".

The committee corrected the spelling of the word insulated and did not accept the words "used for" in the proposal forclarity.


CALLANAN, M.: There is inadequate substantiation for this change and I do not believe that IEC 60204 defines cord.

25Printed on 10/13/2009


_______________________________________________________________________________________________Michael L. Gililland, Engineering Systems Inc.

Add text to read as follows:3.3.XX Direct Opening Operation: Achievement of contact separation as the direct result of a specified movement of

the switch actuator through non-resilient members (for example not dependent upon springs).Normalization: 10.1.4.2 uses the term, but references IEC 60947-5-1. The proposed language is

copied from 60947-5-1 Annex K, paragraph K2.2 verbatim. Adoption of the IEC language offers a definition where noneexists, avoids confusion with interpreting NFPA 79, and normalizes NFPA 79 to IEC 60204-1.

Insert the definition alphabetically and renumber remaining definitions.See committee action on Proposal 79-9.


26Printed on 10/13/2009



Delete this definition.This term is defined but never used in NFPA 79. It seems to make a distinction that is not made or

used anywhere else in the standard - at least not using this term. The related term "(Electrically) Skilled Person" is alsoconfusing and misleading, but at least it is used - once in the definition of an instructed person, and once as aparenthetical equivalent to the more commonly understood and better defined term "qualified person." For a person tohave exposures to electrical hazards they must be qualified according to OSHA and NFPA 70E.

See the committee action and statement on Proposal 79-10.


CALLANAN, M.: We do not agree with the last sentence of the substantiation. Unqualified persons are exposed toelectrical hazards as injury and fatality data will bear out.

27Printed on 10/13/2009



Revise as follows.A general term including material, fittings, devices, appliances, luminaires (fixtures),

apparatus, and the like used as a part of, or in connection with, an electrical installation. [70:100]This will clarify use of this term as it relates to use in NFPA 79. Reference to NFPA 70:100 is deleted

as it no longer is a duplicate of its use in that document.

Revise text as follows:A general term including material, fittings, devices, appliances, luminaires (fixtures),

apparatus, and the like.The proposed revision reflects that NFPA 79 is not an installation document. In addition, the

new definition in NFPA 70 included the term "machinery" which would add confusion in using the extracted definition inNFPA 79.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


CALLANAN, M.: The Technical Correlating Committee should review the change made to the definition of “electricalequipment” that now differs from that of the NEC.

KOVACIK, J.: This proposal appears to be an attempt to create a definition for equipment that is separate from thedefinition for equipment in the NEC since the NEC definition now includes the term "machinery." I don't see that beingaccomplished by adding the word "Electrical" to quantify the definition. The "equipment" referred to in the two definitionsis essentially the same. If this revised definition is accepted it would beg the question, wouldn't a definition fornon-electrical equipment be needed? As an aside, no explanation is given why the term "machinery" adds confusion inusing the extracted definition.

HILBERT, M.: Although I agree that NFPA 79 is an equipment standard, this proposal should have been accepted inprinciple for a different reason or accepted in part. The part that would be accepted would be the removal of the term“(fixtures). Because the current definition is extracted from the National Electrical Code it will be updated automaticallyand the term “fixtures” has been removed from the definition in the 2008 National Electrical Code. Adding the word“electrical” to the definition title and removing it from the text should have been rejected.

I disagree the proposed changes will add clarity as to the use of the definition in NFPA 79. Whether the word"electrical" is used in the title or text the equipment defined is electrical. Further, the term “equipment” is used manytimes in NFPA 79 and the proposed changes may exclude that equipment from a definition that formally applied. In myopinion, this would create inconsistency within the document which will also add confusion.

I also disagree with the Committee statement that adding the term “machinery” to the 2008 NEC definition addsconfusion to the use of NFPA 79. No substantiation was provided to indicate how the extracted definition with the term“machinery” added would create confusion to users of NFPA 79 nor were there any proposals submitted to remove theword “machinery” from the definition of “equipment in” the 2011 National Electrical Code.

See my affirmative comment on Proposal 79-7 (Log #155).

28Printed on 10/13/2009



Revise text to read as follows:Delete existing Definition in 3.3.44. Revise the definition of the present 3.3.44 as shown below and relocate in

Chapter 3 alphabetically. Delete the related information in Annex A (A.3.3.44).3.3.44 3.3x Logic Fault. The state of an item characterized by inability to perform a required function, excluding the

inability, during preventive maintenance or other planned actions., or due to lack of external resources.To clarify that the fault condition defined is a Logic Fault; rather than an electrical fault, such as a

ground fault; and to remove the "lack of external resources" language to avoid confusion as to the meaning of externalresources.

The term Logic Fault is not used in the document, therefore the definition is not required.


29Printed on 10/13/2009



Revise as follows.The conductor installed used to connect the normally noncurrent-carrying

metal parts of an individual piece of equipment or an assembly of equipment together and, raceways, and otherenclosures to the source system grounded conductor or to, the grounding electrode conductor, or both, at the serviceequipment or at the source of a separately derived system. [70:100]

Revise Equipment Grounding Conductor definition to clarify that the individual conductor is beingaddressed and not the total installed base of equipment grounding conductors on the machine. Change “system” to“source” as machinery is typically supplied by a facility circuit. Reference to NFPA 70:100 is deleted as it no longer is aduplicate of its use in that document.

See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12,79-13, 79-14, 79-22, 79-24, 79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80,79-81, 79-82, 79-83, 79-85, 79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104,79-153.


CALLANAN, M.: The Technical Correlating Committee should review the change made to the definition of“equipment grounding conductor” that now differs from that of the NEC.

KOVACIK, J.: Acceptance of this proposal creates a definition for the equipment grounding conductor which differsfrom the definition of same in the NEC. No substantiation has been given to support different definitions for theequipment grounding conductor in NFPA 70 and 79.

HILBERT, M.: See my affirmative comment on Proposal 79-7 (Log #155) .

30Printed on 10/13/2009



Keep NFPA 79: 2007; 3.3.57 Industrial Manufacturing Systems definition, the term appears inNFPA 79: 2007: 1.4 and 1.4 exception and in 13.5.10(3).

NEC Proposal 12-147 (Log #2171) from the 2008 NEC Report on Proposals was referred to the NFPA79 Committee for information:

"TCC Action: The Technical Correlating Committee directs that this Proposal be referred to the NFPA Committee onElectrical Equipment of Industrial Machinery for Information.

Submitter: Dann Strube, Strube ConsultingSection: 670.2Recommendation: Delete the definition of "Industrial Manufacturing System".

Substantiation: This definition must be a carry over from earlier code, but the term is not used in the NEC today."However, term is used in NFPA 79 besides in the definitions.


31Printed on 10/13/2009



Delete 3.3.77* and its related A.3.3.77. Renumber remaining sections as necessary.The whole of the protective conductors and conductive parts used for protection

against electric shock in the event of an insulation failure.See 3.3.9, Bonding.

This definition is not correct in that it erroneously leaves the impression the bonding element is part ofthe designed fault current path. Changes and modifications to 3.3.9 along with new 3.3.X clarifies that some bonding isdesigned to form part of the fault current path (direct), and some bonding is not designed to be part of the fault currentpath; instead this machine bonding jumper is to reduce touch hazard potentials across machine structural parts from anycurrent, from any source, not part of any particular machine.Deletion of 3.3.77* removes need for A.3.3.77.

The substantiation for the proposal is no longer valid due to the rejection of ROP 79-7 andROP 79-14.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


FISHER, D.: Since we use the concept repeatedly in our document, the IEC term (3.3.77) could have been retainedbut with the definition revised as follows to reflect NFPA terminology: “The whole of the equipment grounding conductorsand conductive parts used for protection against electrical shock in the event of an insulation failure.” Alternatively, theterm could also change to: Equipment Grounding Circuit

The motivation to have a second Bonding Jumper definition was to help clarify the different functions performed by thebonding jumpers; that of direct sharing of fault current and that of minimizing touch voltages between adjacent machineelements (arms lengths apart) during the clearing of fault currents. But since there were no differences in the physicalrequirements, those functional distinctions alone do not seem to warrant the two definitions which were largely forpedagogical reasons.


32Printed on 10/13/2009



Delete this definition.This term is defined but never used in NFPA 79. Section 3.1 says the definitions "apply to terms used

in this standard." Therefore this term has no legitimate place in Chapter 3, and only makes the document more difficultand confusing to use.


33Printed on 10/13/2009



Edit the definition of 3.3.90 and the term presently listed in the index under “Safety Function (SafetyMeasure)” as follows:

A means that eliminates or reduces a hazard. A function which isintended to maintain the safe condition of the machine, or prevent or reduce hazardous situations.

Additionally, globally replace the terms “safety-critical”, “safety critical” and “safety related” (without hyphen) throughoutthe document (including Annex A) with the term “safety-related”. The affected sections follow:

A machine that has safety critical safety-related functions that are equipped with cableless control shall havea means of automatically initiating the stopping of the machine and preventing the initiation of potentially hazardousmotions in the following situations:

(1) When a stop signal is received(2) When a fault is detected in the cableless control(3)* When a valid signal has not been detected within a specified period of time

In a machine where the control of safety critical safety-related functions relieson serial data transfer, correct communications shall be ensured by using an error detection method that is able to copewith up to three error bits in any command sequence. The safety capability of the serial data communication systemshall be listed to have the same degree of safety capability as hardware-based components installed in accordance withthis standard.

Where doors or guards have interlocked switches used in circuits with safety relatedsafety-related functions, the interlocking devices shall be listed, have either positive (direct) opening operation, orprovide similar reliability and prevent the operation of the equipment when the doors or guards are open (difficult todefeat or bypass).

Position sensors used in circuits with safety-related control functions either shall have direct openingoperation or shall provide similar reliability.

This term correlates with terminology used in IEC and ISO documents. The use of differing terms(safety-related / safety critical) has been improperly interpreted to suggest differing levels of safety. Multiple levels ofsafety would be a violation of Section 2.2.3.2 of the NFPA Manual of Style. This revision is recommended by TaskGroup #5.

See the committee action on Proposal 79-30.


34Printed on 10/13/2009



Edit the definition of 3.3.90 and the term presently listed in the Index under "Safety Function(Safety Measure)" as follows:

3.3.90 Safety-Related Function (Safety Measure) A means that eliminates or reduces a hazard. A function which isintended to maintain the safe condition of the machine, or prevent or reduce hazardous situations.

Additionally, globally replace the terms "safety-critical", "safety critical" and "safety related" (without hyphen) throughoutthe document (including Annex A) with the term "safety-related". The affected sections follow:

9.2.7.3.2 A machine that has safety critical safety related functions that are equipped with cableless control shall havea means of automatically initiating the stopping of the machine and preventing the initiation of potentially hazardousmotions in the following situations:

(1) When a stop signal is received(2) When a fault is detected in the cableless control(3)* When a valid signal has not been detected within a specified period of time.9.2.7.4* Serial Date Communication. In a machine where the control of safety critical safety-related functions relies on

serial data transfer, correct communications shall be ensured by using an error detection method that is able to copewith up to three error bits in any command sequence. The safety capability of the serial data communication systemshall be listed to have the same degree of safety capability as hardware-based components installed in accordance withthis standard.

9.3.6 Protection Interlock. Where doors or guards have interlocked switches used in circuits with safety relatedsafety-related functions, the interlocking devices shall be listed, have either positive (direct) opening operation, orprovide similar reliability and prevent the operation of the equipment when the doors or guards are open (difficult todefeat or bypass)

This term correlates with terminology used in IEC and ISO documents. The use of differing terms(safety-related / safety critical) has been improperly interpreted to suggest differing levels of safety. Multiple levels ofsafety would be a violation of Section 2.2.3.2 of the NFPA Manual of Style. This revision is recommended by TG #5.

See the committee action on proposal 79-30.


35Printed on 10/13/2009


_______________________________________________________________________________________________J. B. Titus, Siemens Energy & Automation

Revise text to read as follows:A means that eliminates or reduces a hazard. A function which is

intended to maintain the safe condition of the machine, or prevent or reduce hazardous situations.Additionally, globally replace the terms “safety-critical”, “safety critical” and “safety related” (without hyphen) throughout

the document (including Annex A) with the term “safety-related”. The additional affected sections are:A machine that has safety critical safety-related functions that are equipped with cableless control shall have

a means of automatically initiating the stopping of the machine and preventing the initiation of potentially hazardousmotions in the following situations:

(1) When a stop signal is received (2) When a fault is detected in the cableless control (3)* When a valid signal has not been detected within a specified period of time

In a machine where the control of safety critical safety-related functions relies onserial data transfer, correct communications shall be ensured by using an error detection method that is able to copewith up to three error bits in any command sequence. The safety capability of the serial data communication systemshall be listed to have the same degree of safety capability as hardware-based components installed in accordance withthis standard.

Where doors or guards have interlocked switches used in circuits with safety relatedsafety-related functions, the interlocking devices shall be listed, have either positive (direct) opening operation, orprovide similar reliability and prevent the operation of the equipment when the doors or guards are open (difficult todefeat or bypass).

Position Sensors used in circuits with safety related safety-related control functions either shall have directopening operation or shall provide similar reliability.

TG #5 recommends the above edits to properly align with Section 2.2.3.2 of the NFPA Manual of Styleand the adoption where applicable throughout NFPA 79 of the consistent term “safety-related functions”.

This term correlates with terminology used in IEC and ISO documents. The use of differing terms (safety-related /safety critical) has been improperly interpreted to suggest differing levels of safety and presents potential confusion.Also, this is a companion proposal to Log #22 from Frank DeFelice.

Revise 10.1.4.2 to read as follows:Position Sensors used in circuits for with safety related safety-related control functions either shall have

direct opening operation or shall provide similar reliability.The committee accepts the recommendation and changes "with" to "for" in 10.1.4.2 which

makes it clear it is the position sensor that is part of the safety-related function.

Affirmative: 17 Abstain: 11 Carpenter, D.

MARIUZ, D.: I agree with most of all the the text except for section 9.2.7.4 Serial Data Communication the word threebits need to be removed. It restricts the types of communication technology.

FISHER, D.: There is a lot to be happy for in the deletion of the term “safety critical” which is a product liabilitynightmare, but the term “safety-related function” is not the most helpful. It does not align with IEC and ISO documentsas is a claim for its use. Indeed, it is inherently redundant. The term “safety function” is used in IEC 62061. It is crystalclear. It can be implemented by any suitable technology. Now when we insert the word “related” into the term to makeit “safety-related function”, does its meaning change at all? The answer is no; it is simply a wasted word and it

36Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 79separates us from IEC rather than bringing us into closer alignment.

37Printed on 10/13/2009


_______________________________________________________________________________________________Jay Tamblingson, Rockwell Automation

Insert new definition in 3.3.95 and Annex Note as follows and renumber remaining definitions inalphabetical order:

The prospective symmetrical fault current at a nominal voltage to whichan apparatus or system is able to be connected without sustaining damage exceeding defined acceptance criteria.[ -100]

A.3.3.95 The short-circuit current rating of an apparatus or system can be determined either by testing or evaluationusing an approved method such as Supplement SB of UL 508A Safety Standard for Industrial Control Panels.

This proposal is an output of the NFPA 79 Overcurrent Protection Task Group.NFPA 79 references the term Short Circuit current rating in Chapter 7 and 16, but it is not defined. Add definition of

Short Current Current Rating from the 2008 NEC Article 100. In addition, an annex note was added to referencemethods by which SCCR is often determined.


38Printed on 10/13/2009



New text to read as follows:Control devices employing cableless (e.g., radio, infrared) techniques for transmitting

commands and signals between a machine control system and operator control station(s).

An operator control station which is capable of using wireless (e.g., radio,infrared) techniques to communicate with one or more machines, and which incorporates a self-contained power source,such as a battery.

These stations are not physically connected to the machine by eithercommunications or power conductors. While all cableless devices utilize wireless technology, not all wireless devicesare cableless. Examples of cableless devices include cableless teach pendants, cableless crane pendants andcableless jog pendants. Examples of wireless devices include operator interface panel (HMI) or wireless remote I/O; asthese devices communicate wirelessly with the CPU, but are permanently connected to the machine’s power source.

This new definition and Annex note are proposed to support companion proposed changes to 9.2.7and Annex A, regarding Cableless Operator Control Stations. In addition, significant discussion has been reportedregarding confusion between the terms “cableless” and “wireless” and TG #5 proposes these changes to improve theunderstanding.

Revise text to read as follows:Control devices employing cableless wireless (e.g., radio, infrared) techniques for

transmitting commands and signals between a machine control system and operator control station(s).Add

An operator control station which is capable of using wireless (e.g.,radio, infrared) techniques to communicate with one or more machines, and which incorporates a self-contained powersource, such as a battery.

A.3.3.13 These stations are not physically connected to the machine by eithercommunications or power conductors. While all cableless devices utilize wireless technology, not all wireless devicesare cableless. Examples of cableless devices include cableless teach pendants, cableless crane pendants andcableless jog pendants. Examples of wireless devices include operator interface panel (HMI) or wireless remote I/O; asthese devices communicate wirelessly with the CPU, but are permanently connected to the machine’s power source.

The committee changed the undefined term "cableless" to "wireless" in the definition 3.3.12.The asterisk was added to 3.3.13 to refer users to the new A.3.3.13 annex material.The last sentence in proposed annex text was removed for clarity.


39Printed on 10/13/2009



Delete the last sentence of 4.3.2.2:4.3.2.2 Frequency. The electrical equipment shall be designed to operate correctly where the supply frequency is from

99 percent to 101 percent of the nominal frequency continuously. For short periods of time, the supply frequency shallbe permitted to be from 98 percent to 102 percent of the nominal frequency.

The phrase "short periods of time" is undefined, vague and unenforceable. If it is mutually agreeableto the user and the manufacturer, alternate conditions for Supply Frequency are permitted under Section 4.7.

The submitter did not provide adequate technical substantiation to warrant the change.


HILBERT, M.: Chapter 4 provides the assumed operating conditions for electrical equipment on the machine whenthe actual operating conditions have not been determined between the user and the supplier. Section 4.3.2.2 permits adeviation from the normal operating frequency for short periods of time. The period of time will vary depending on themachine and process tolerances. I agree with the Committee that no technical substantiation was provided thatindicated there is a problem with the current text.

40Printed on 10/13/2009



Revise the text of 4.4.1 as follows:4.4.1 General. The electrical equipment shall be suitable for use in the physical environment and operating conditions

specified in 4.4.3 to 4.4.6 and 4.4.8. When the physical environment or the operating conditions are outside thosespecified, an agreement between the supplier manufacturer and the user shall be considered. .

The term "supplier" could be interpreted to mean a salesperson, dealer, or the actual machinemanufacturer. It is critical that the design for the machine be constant with user's intended use and environmentalconditions. Ultimately, it is the manufacturer, not a sales representative or dealer, who must engineer the machine tooperate safely and satisfactorily outside of any conditions stipulated by Section 4.4.3 through 4.4.6 and 4.4.8; includingAmbient Operating Temperature, Relative Humidity, Altitude, Contaminates and Available Fault Current.

Note that Section 4.7 does stipulate that the manufacturer and the user must be in agreement.

The committee concludes that the existing term is adequate. See the definition of "Supplier"in Chapter 3.


41Printed on 10/13/2009



Delete the second sentence of 4.4.3.4.4.3* Ambient Operating Temperature. Electrical equipment shall be capable of operating correctly in the intended

ambient air temperature. The ambient operating temperatures for correct operation of the electrical equipment shall bebetween air temperatures of 5°C and 40°C (41°F to 104°F).

Many industrial machines are designed to operate above and below the limits specified; and severalfactors (e.g., ventilation, thermal transfer, duty cycle) impact the acceptable ranges for Ambient Air Temperature.Agreement between the user and the manufacturer, along with appropriate engineering which consideration the physicaland electrical limits of all electrical components and sub-assemblies within the machine, are the determining factor.

The committee considers the current wording adequate.


DEFELICE, JR., F.: Many industrial machines are designed and constructed to operate in environments which areoutside the present temperature limitations. Severalfactors (e.g., ventilation, thermal transfer, duty cycle) impact what are considered to be acceptable ranges for AmbientAir Temperature. Agreement between the user and the manufacturer, along with appropriate engineering whichconsideration the physical and electrical limits of the electrical components and sub-assemblies within the machine, arethe determining factor.

HILBERT, M.: Please see my affirmative comment on Proposal 79-33 (Log #24).WOLFGANG, E.: I accept the committee's rejection of the proposal, however I agree with the submitter that many

industrial machines are designed and can operate above and below the temperature limits currently stated in thestandard.

42Printed on 10/13/2009



Revise the text of 4.7 as follows and relocate as new Section 4.1.1:4.7 4.1.1 Installation and Operating Conditions.The electrical equipment shall be installed and operated in accordance with the conditions outlined in the

manufacturer's instructions. Any conditions that are outside the operating conditions specified in Chapter 4 Section 4.3shall be permitted where agreed upon in writing by acceptable to both the manufacturer and user.

Having written agreements protects both the user and the manufacturer, and relocating the revisedlanguage places it with related requirements (General Considerations). As presently written, the language of Section4.7 would permit any or all requirements found in Chapter 4 (including the requirement to operate electrical componentswithin their design ratings, as established by their manufacturer (Section 4.2); or within their listing and labelinginstructions (Section 4.2); or to evaluate the hazards associated with the machine's electrical equipment (Section 4.1) tobe waived via mutual consent between the user and the manufacturer. (Note that Section 4.7 does not apply to Section4.4; which already contains language permitting equipment to be operated in environmental conditions which areoutside of the limits established by specific sub-sections of Section 4.4.)

The committee concludes that the operating conditions beyond Chapter 4 agreed upon byboth the manufacturer and user are not required to be in writing.


43Printed on 10/13/2009



Rewrite Section 5.1.1 for clarity:5.1.1* Where practicable, the electrical equipment of a machine shall be connected to a single power supply circuit and

sub-circuits shall be derived from this main power supply. Where it is necessary to use another supply circuit for certainparts of the equipment (e.g., electronic circuits, electromagnetic clutches), that supply circuit shall, as far as ispracticable, be derived from devices (e.g., transformers, converters) forming part of the electrical equipment of themachine.

Improved clarity for the user.

The committee concludes that the change does not provide clarity for the user.


44Printed on 10/13/2009



Revise text to read as follows:5.3.1 General. The following general requirements apply to 5.3.2 through 5.3.5.5.3.1.1 A supply circuit disconnecting means shall be provided for the following:(1) Each incoming supply circuit to a machine(2) The supply circuit to a feeder system using collector wires, collector bars, slip-ring assemblies, or flexible cable

systems (reeled, festooned) to a machine or a number of machines(3) Each on-board power source (e.g., generators, uninterruptible power supplies)

Uninterruptible Power Supplies are more likely to be present on a modern industrial machine thangenerators. In some instances, we have seen where manufacturers do not realize that Uninterruptible Power Suppliesare also "on-board power sources" and as such, require a disconnecting means for protection of maintenancepersonnel.


45Printed on 10/13/2009


_______________________________________________________________________________________________Melvin K. Sanders, Things Electrical Co., Inc. (TECo., Inc.)

Delete 5.3.1.1.1 from Chapter 5 and add as new 16.4.6. Renumber A.5.3.1.1.1 as A.16.4.6.Delete 5.3.1.1.2 from Chapter 5 and add as new 16.4.7

Labeling requirements are the responsibility of Chapter 16.

The committee concurs that the location of the current language is appropriate.


WATSON, E.: The negative vote to the committee action supports the recommendation made by the submitter of thisproposal. Chapter 16 is named "Marking and Safety Signs" and this proposal requests that the marking requirements fordisconnects in 5.3.1.1.1 and 5.3.1.1.2 be moved to chapter 16. While I believe that this is the correct action, I alsobelieve that 5.3.1.1.1 and 5.3.1.1.2 should be moved to be after 16.2.4 instead of after 16.4.5. Section 16.4 deals withMachine Nameplate Data which is not appropriate for the moved items while 16.2.4 discusses safety signs fordisconnects. Placing the marking requirements for disconnects after 16.2.4 would group marking and safety signs fordisconnects in one place.

46Printed on 10/13/2009


_______________________________________________________________________________________________Paul Dobrowsky, Innovative Technology Services

Revise text to read as follows:Exception: Externally mounted supply circuit disconnecting means, whether interlocked or not interlocked with the

control enclosure, supplying machines totaling 2 hp or less shall be permitted to be mounted up to 6 m (20 ft) away fromthe enclosure providing that the disconnecting means is in sight from and readily accessible to the operator.

There are some inherent benefits to locating the disconnecting means within the control enclosure oradjacent to it but there are also other and maybe better benefits to locating it externally. If the disconnecting means iswithin the control enclosure, even when it is in the off position, live parts are present on the line side. If the disconnectingmeans is external to the control enclosure, when it is in the off position, there are no live parts in the control enclosure,which is inherently safer. Presumably, the existing provision that permits this with a 2 HP limitation considers that amachine of that size does not have sufficient space to locate a disconnecting means adjacent to it. Some machineslarger than 2 HP also do not have space. Some facilities require that an external disconnecting means be provided toinsure that all parts within the control enclosure can be put in an electrically safe condition (see NFPA 70E). Also, adisconnecting means for a building system is not required to be interlocked with the control enclosure. It would behelpful for the committee to explain the reason for interlocking in their panel statement.

The existing language limitation "totaling 2 hp or less" is appropriate.


WATSON, E.: The negative vote to the committee action supports the recommendation made by the submitter of thisproposal. The substantion in the original proposal is appropriate and well thought out. If the externally mounted supplydisconnect means fed a large box oven with only resistive heating elements, the size of the load could be of any sizesince the rating would not be HP, but in amperes or kilowatts. The exception only limits the loads in terms of HP whichwould suggest motor loads.

CALLANAN, M.: We agree that adding an additional remote disconnect could increase worker safety.

47Printed on 10/13/2009



Change "safety sign" to "warning sign" in the last sentence.Each supply circuit disconnecting means mounted within or adjacent to the control enclosure shall be

interlocked with the control enclosure in accordance with 6.2.3. Where the supply circuit disconnecting means is notadjacent to the control enclosure, or where the supply disconnecting means is an attachment plug and receptacle, thecontrol enclosure shall comply with 6.2.4 and a warning safety sign shall be provided in accordance with Section 16.2.

This change will correlate with NFPA 70-2008 Section 110.16.

“Safety sign” is the term used within NFPA 79 and is included in the title of Chapter 16. Theterm is better left as “safety sign” for consistency.


ANDERSON, W.: The committee should reconsider this and the other similar changes proposed to revise theterminology from “warning signs” to “safety sign; and to revise the existing terminology of “safety sign” to “warning signthroughout NFPA 79..Safety: 1 : the condition of being safe from undergoing or causing hurt, injury, or loss2 : a device (as on a weapon or a machine) designed to prevent inadvertent or hazardous operation.Warn: 1 a : to give notice to beforehand especially of danger or evil b : to give admonishing advice to : COUNSEL c : tocall to one's attention :The use of the term “safety sign” implies from Webster that it is designed to prevent inadvertent hazardous operation butalso the condition of being safe from harm, which implies more than can always be realized in its application. While theterm “warning sign” implies giving notice of danger, which is what can actually be realized in the application of a sign.Although used in the title of the standard “ANSI Z535.4, Product Safety Signs and Labels”, the use of “safety sign”terminology is in minority usage in the NEC while “warning sign” is prevalent throughout the document.The use of “warning sign” verses “safety sign” would be more appropriate throughout the standard and should be done.

48Printed on 10/13/2009



Revise text as follows.(3) Have a first make, last break electrical grounding (protective) (earthing) contact.

Adding “electrical” for additional clarity and “protective” is added to clarify its relationship to Chapter 6.


CALLANAN, M.: The Technical Correlating Committee should review the changes made to this section. Thereappears to be too many parenthetical usages here.

49Printed on 10/13/2009



Add a new (4) to read as follows:"(4) The enclosure door unlatch step position shall not provide a gap with opening at any point along the door flange

and the enclosure greater than that permitted by IEC IP3X against ingress of solid foreign objects."This will provide guidance to product engineering to determine the initial step unlatch setting and not

be unduly restrictive as to how to accomplish this because of the many types of enclosure operating mechanisms.



ANDERSON, W.: I agree with the committee's action; however there should be a definition of a closed and latchedenclosure as it is usually required for the enclosure to contain defined fault conditions.

50Printed on 10/13/2009



Add a new (4) to read as follows:"(4) The enclosure door or enclosure cover shall be considered open where the opening between the enclosure door or

enclosure cover exceeds that permitted by IP3X of Annex Table F.5.3 against ingress of solid foreign objects."This will clarify what constitutes an open door when applying Section 5.3.4.2(1).

Section 5.3.4.2(1) requires the operating handle of the disconnecting means to be operablewith the door open regardless of how much the door is open. Requirements relative to enclosure openings are betterlocated in Chapter 6.


ANDERSON, W.: I agree with the committee's action; however there should be a definition of a closed and latchedenclosure as it is usually required for the enclosure to contain defined fault condition.,

51Printed on 10/13/2009



Revise text to read as follows:5.3.5.4 Where the excepted circuits are not disconnected by the supply circuit disconnecting means, all of the following

requirements shall be met:(1) Permanent safety sign(s) shall be placed adjacent to the supply circuit disconnecting operating handle(s) indicating

that it does not de-energize all exposed live parts when it is in the open (off) (isolated) position as in 16.2.4.(2) A statement containing the information from 16.2.4 shall be included in the machine documentation.(3) A permanent safety sign shall be placed on a nonremovable part inside the control enclosure in proximity to each

excepted circuit, or shall be identified by color as defined in 13.2.4.Improved clarity that these circuits are the "excepted circuits" which are described in 5.3.5.1. This

format follows the similar one in Section 5.3.5.2.


52Printed on 10/13/2009



Revise text to read as follows:5.4.1 Means for removal of power shall be provided when prevention of unexpected start-up is required (e.g., during

maintenance where the unexpected start-up of a machine or part of the machine results in a hazardous situation). Suchmeans shall be included all of the following:

(1) Appropriate for the intended use(2) Conveniently located(3) Readily identifiable as to their function and purpose(4) Provided with permanent means for locking in the off position only

Improved clarity for the reader.

Revise text as follows:5.4.1 Means for removal of power shall be provided when prevention of unexpected start-up is required (e.g., during

maintenance where the unexpected start-up of a machine or part of the machine results in a hazardous situation). Suchmeans shall be: included all of the following:

(1) Appropriate for the intended use, and(2) Conveniently located, and(3) Readily identifiable as to their function and purpose, and(4) Provided with permanent means for locking in the off position only.

The committee added the word "and" to clarify that all items apply.


53Printed on 10/13/2009



Revise text to read as follows:5.5.4 The following devices shall be permitted to fulfill the isolating function of 5.5.3:(1) Devices described in 5.3.2(2) A manual motor controller marked "suitable as motor disconnect" and compliance with ANSI/UL 508 where located

on the load side of the last short-circuit protective device (in the branch)(3) System isolation equipment that incorporates control lockout stations and is listed for disconnection purposes

where located on the load side of the main supply circuit disconnecting means and overcurrent protectionUpdate standards titles to indicate ANSI approvals.



54Printed on 10/13/2009


_______________________________________________________________________________________________Lauren Crane, Applied Materials Inc.

Add a 4th bullet as indicated below:5.5.4 The following devices shall be permitted to fulfill the isolating function of 5.5.3:(1) Devices described in 5.3.2.(2) A manual motor controller suitable for motor disconnecting and compliant with UL 508 where located on the load

side of the last short-circuit protective device (in the branch)(3) Redundantly monitored, remotely operated contactor isolating system that incorporates control lockout provisions

and is listed for disconnection purposes.(4) A listed supplementary overcurrent protective device.

Supplementary Overcurrent Protection devices are often present in circuits.Where energy isolation is desired before servicing a machine part, such devices present themselves as an obvious first

choice as the isolation means. However, some interpreters read 5.5.4 as "{Only} the following devices shall bepermitted..." and allow only the use of branch circuit rated overcurrent protection devices for energy isolation (along withthe other non OCPD isolation methods). This can result in significant non-value added redesign of machine hardware orenergy isolation procedures.While a supplementary overcurrent protective device may or may not be appropriate forovercurrent protection of a particular machine part, if appropriate protection is otherwise provided for a circuit containinga supplementary device, a properly selected (as per 7.2.1.2) supplementary device could adequately function to isolateelectrical power to a machine part.

The proposal raises the risk of improper use of supplementary overcurrent protective devicesas isolating devices.

Not all listed supplementary overcurrent protective devices have been evaluated as isolating devices.


55Printed on 10/13/2009



Revise Title of Chapter 6 as follows:Chapter 6 Protection from Electric Shock of Personnel

Electric Shock is just one of the hazards of working with electricity. This change recognizes arc-flashand arc-blast.

The current title is adequate for the content of the Chapter.


CALLANAN, M.: We agree with the concerns expressed by Messrs. DeFelice and Hilbert.DEFELICE, JR., F.: Protection of Personnel against all types of hazards related to working with electricity is of

paramount importance to the safety of maintenance personnel and operators. Electric Shock is but one of the potentialhazard of working with electricity. Changing the title of this section convey that the committee recognizes that there areother hazards, such as the potential for thermal burns from electric heaters, optical damage from laser devices, arc-flashand electrocution.

HILBERT, M.: This proposal should have been accepted based on Proposal 79-165a (Log #CP5). See my negativecomment and recommendation on 79-50 (Log #33).

56Printed on 10/13/2009



Revise Section 6.1 as follows:6.1 General.Electrical equipment shall provide protection of persons from electric shock from direct and indirect contact and from

arc-flash hazards.Electric Shock is just one of the hazards of working with electricity. This change recognizes arc-flash

and arc-blast.

The additional material is not consistent with Chapter 6 but is addressed in other documents.The submitter did not provide sufficient detail for the inclusion of arc flash.


CALLANAN, M.: We agree with the concerns expressed by Messrs. DeFelice and Hilbert.DEFELICE, JR., F.: Guarding personnel against all hazards associated with electrical energy is of paramount

importance. Protection of Electrical Maintenance Personnel from arc-flash, thermal, electrical and other injuries can beaccomplished by several methods; including a simple requirement to apply warning labels on enclosures containingelectrical equipment, heaters, laser devices, etc; which alert service personnel to the potential for these hazards.

HILBERT, M.: This proposal should have been accepted in principle. The accept in principle would be to accept thesubmitters recommend text for 6.1 and add a new 6.6 as follows:

6.6 Protection Against Arc Flash.A safety sign shall be provided in accordance with 16.2.3.Accepting the proposal in principle as described is appropriate now that a new 16.2.3 will require a safety sign warning

of an arc flash hazard to placed on equipment such as control panels (See 79-165a, (Log #CP5). Adding a reference toarc flash in 6.1 as proposed by the submitter with the new 6.6 is consistent with current format of Chapter 6 to identifythe hazard and provide a prescriptive requirement(s) and the Committee’s substantiation in Proposal 79-165a (Log#CP5)

ANDERSON, W.: I agree with the committee's action; however arc flash can be connected to the machine electricaldesign and should be addressed in this standard as far as design can affect the hazard risk encountered.

57Printed on 10/13/2009



Revise text to read as follows:6.2.2.1 Direct Contact from Outside an Enclosure. Equipment enclosures and enclosure openings shall meet the

requirements of ANSI/UL 508, UL 508A, ANSI/UL 5O, or NEMA 250. (See Figure 6.2.2.1.)Update standards titles to indicate ANSI approvals.


ANDERSON, W.: I agree with the committee's action and to follow the current manual of style as follows:2.3.1.2.1 Chapter 2 shall consist of three sections as follows:(1) 2.1 General. The documents or portions thereof listed in this chapter are referenced within this (standard, code) andshall be considered part of the requirements of this document.(2) 2.2 NFPA Publications.(3) 2.3 Other Publications

58Printed on 10/13/2009



Delete section entirely.With the addition of Section 6.2.3.3 in the 2007 Edition, this section (6.2.5) becomes redundant and

remains inaccurate. It refers to a "defeat mechanism as permitted in 6.2.3," but the correct reference (correctly made in6.2.3.3) is 6.2.3.1. In all other respects, Section 6.2.5 simply repeats 6.2.3.3, and as such only confuses the issue.


BEACHY, W.: I recommend that this proposal be rejected.Section 6.2.5 relates to the safety from a door closing on a person who is working inside a cabinet and having the

protection that they will not be shocked accidentally by live parts mounted on the door. Section 6.2.5 relates toprevention of shock of an enclosure with a defeat mechanism, section 6.2.4 relates to one without a defeat mechanismboth need to remain since shock from live parts on a door is not covered in 6.2.3.

59Printed on 10/13/2009



Revise (2) as follows. There is no change to A.6.3.1.3.6.3.1.3* Protection by Automatic Disconnection of Supply. Automatic disconnection of the supply of any circuit affected

by the particular circuit overcurrent protective device in the event of a fault is intended to prevent an exposure to acontinuous hazardous touch voltage. These protective measures comprise both of the following:

(1) Protective bonding of Electrical bonding jumpers shall be installed between exposed conductive parts(2) The use of overcurrent protection devices for the automatic disconnection of the supply in the event of a fault.

This revision of 6.3.1.3(1) will clarify to users the intended application of the second meaning of theproposed 3.3.X definition of bonding jumpers where indirect exposure to an electrical shock might occur.

The submitter has not provided sufficient substantiation to justify the change. The addedlanguage in the proposed recommendation does not permit other methods of bonding.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



60Printed on 10/13/2009



Revise the text of 6.5.1 Exception #2 as follows:

To standardize on the use of the term "safety sign" throughout the document.


61Printed on 10/13/2009



Add new Section 6.6 as follows:6/6 Protection for Maintenance Personnel6.6.1 Receptacles for maintenance shall be provided with Ground Fault Protection for Personnel.6.6.2 Circuits which are permitted to be connected ahead of the main supply circuit disconnecting means in 5.3.5.1(1)

and 5.3.5.1(2) shall be provided with Ground Fault Protection for Personnel.Protected not be required to be disconnected by the main supply circuit disconnecting means:(1) Lighting circuits for lighting needed during maintenance or repair(2) Attachment plugs and receptacles (plug and socket outlets) for the exclusive connection of repair or maintenance

tools and equipment (e.g., hand drills, test equipment)Increased protection against electric shock hazards for maintenance personnel.

The committee concluded that these requirements are adequately covered in Chapters 15 and16.


62Printed on 10/13/2009



Revise text to read as follows:Overcurrent protection shall be provided where the current in a machine circuit can exceed either the rating of any

component in the circuit or the current carrying capacity of the conductors in the circuit, whichever is the lesser value.The ratings or settings to be selected are detailed in 7.2.10.

For clarity and harmonization add reference to 7.2.10 in NFPA 79.

The submitter's recommended text does not contain a requirement. Additionally, the proposaldoes not add clarity.


63Printed on 10/13/2009


_______________________________________________________________________________________________Dan Neeser, Cooper Industries

Revise text to read as follows:7.2.8 Location of Overcurrent Protective Devices. An overcurrent protective device shall be located at the point where

the conductor to be protected is connected to the supply except as follows:(1) Overcurrent protection at the supply shall not be required if all of the following conditions are met:(a) The current carrying capacity of each of the conductors is at least equal to that required for the their respective

load.(b) Each connecting conductor to the overcurrent protective devices is no longer than 3 m (10 ft). and(c) The conductor is suitably protected from physical damage.(d) The conductor does not extend beyond the control panel enclosure.

(ec) The conductor terminates in either a single branch circuit protective device rated circuit breaker, or a branchcircuit rated set of fuses or a listed self protected combination controller or on the line side of multiple branch circuitprotective devices that have a common line side connection either by use of bus-bar wiring accessories identified forsuch use or by the use of additional conductor(s) to interconnect between terminals where the total length of the tap andall interconnecting conductors does not exceed 3 m (10 ft). The current carrying capacity of the line side conductor shallbe equal to the load side connections of the bus-bar wiring accessories or the interconnecting conductor(s) and have anampacity suitable for all connected loads.

(2) Overcurrent protection at the supply shall not be required if all of the following conditions are met:(a) The conductor has an ampacity of at least one-third that of the conductor from which it is supplied.(b) The conductor is suitably protected from physical damage.(c) The conductor is not over 7.5 m (25 ft) long and the conductor terminates in a single branch circuit protective

device circuit breaker or set of fuses.This proposal permits the proper use of bus bar wiring accessories or interconnecting conductors in

tap conductor applications.In addition, circuit breaker or set of fuses was changed to branch curcuit protective device since other devices may be

suitable in some applications as permitted in this standard.

The committee did not accept the last sentence of the proposed Sub part (1)(c) as it wasoverly restrictive.

See the action and statement on Proposal 79-58.


64Printed on 10/13/2009




the conductor to be protected is connected to the supply except as follows:(1) Overcurrent protection at the supply shall not be required if all of the following conditions are met: (a) The current

carrying capacity of each of the conductors is at least equal to that required for the their respective load in accordancewith 12.5. (b) Each connecting conductor to the overcurrent protective devices is no longer than 3 m (10 ft).and (c) Theconductor is suitably protected from physical damage. (d) The conductor does not extend beyond the control panelenclosure. (ec) The conductor terminates in either a single branch circuit protective devicerated circuit breaker, or abranch circuit rated set of fuses or a listed self-protected combination controller or on the line side of multiplebranch-circuit protective devices that have a common line side connection either by use of bus-bar wiring accessoriesidentified for such use or by use of additional conductor(s) to interconnect between terminals where the total length ofthe conductor and all interconnecting conductors to any of the branch-circuit protective devices does not exceed 3m(10ft). The current carrying capacity of the bus-bar wiring accessories or interconnecting conductor(s) shall be at leastequal to that required for their respective load(s) in accordance with 12.5.

(2) Overcurrent protection at the supply shall not be required if all of the following conditions are met: (a) Theconductor has an ampacity of at least one-third that of the conductor from which it is supplied. (b) The conductor issuitably protected from physical damage. (c) The conductor is not over 7.5 m (25 ft) long and the conductor terminatesin a single branch circuit protective device circuit breaker or set of fuses.

This is proposal is an output of the NFPA 79 Technical Committee Overcurrent Protection Task Group.This is version one of two proposals for the same clause. The task group was split on whether to permit downsizing of

daisy chain conductors based on load served. As such, both versions of the proposal are being put forth forconsideration.

The current language states that a conductor must terminate in a branch-protective device, and is not clear in itspermission of termination onto multiple branch circuit devices in parallel. This proposal clarifies the use of readilyavailable bus bar wiring accessories or daisy chaining using conductors when the motor branch-circuit short-circuitprotective device terminals are designed for such use. The language provides a mean to size the interconnections baseon load served. This, for example, would facilitate daisy chaining from the protective device for a large motor controllerto several small ones (such as a machine tool with auxiliary pumps, etc.) which likely would not be able to accommodatethe large size conductors.

The revisions to 7.2.8(2) is consistent with current practice in NEC 430.28 which permits termination on any branchcircuit protective device, which now includes a self protected combination motor controller as defined by the companionproposal to 7.2.10.1.1

The 7.2.8(1)(C) requirement for protection from physical damage is redundant with the existing requirement in (d) thatrequires the conductors to be enclosed, and therefore can be deleted.

See companion proposal to 7.10.1.1 and alternate version proposal to 7.2.8.

Revise the text to read as follows:7.2.8 Location of Overcurrent Protective Devices. An overcurrent protective device shall be located at the point where

the conductor to be protected is connected to the supply except as follows:(1) Overcurrent protection at the supply shall not be required if all of the following conditions are met:(a) The current carrying capacity of each of the conductors is at least equal to that required for the their respective load

in accordance with 12.5.(b) Each connecting conductor to the overcurrent protective devices is no longer than 3 m (10 ft).(c) The conductor is suitably protected from physical damage.(d) The conductor does not extend beyond the control panel enclosure.(e) The conductor terminates in either a single branch circuit protective device rated circuit breaker, or a branch circuit

rated set of fuses or a listed self-protected combination controller or on the line side of multiple branch-circuit protectivedevices that have a common line side connection either by use of bus-bar wiring accessories identified for such use orby use of additional conductor(s) to interconnect between terminals where the total length of the conductor and all

65Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 79interconnecting conductors to any of the branch-circuit protective devices does not exceed 3m (10ft). The currentcarrying capacity of the bus-bar wiring accessories or interconnecting conductor(s) shall be at least equal to thatrequired for their respective load(s) in accordance with 12.5.

(2) Overcurrent protection at the supply shall not be required if all of the following conditions are met: (a) The conductorhas an ampacity of at least one-third that of the conductor from which it is supplied. (b) The conductor is suitablyprotected from physical damage. (c) The conductor is not over 7.5 m (25 ft) long and the conductor terminates in asingle branch circuit protective device circuit breaker or set of fuses.

The committee restored the physical damage requirement of 1(c) due to possible abrasion ofthe insulation within the enclosure. This then required the identification of the original sub sections to be reinstated. Theremainder of the proposal remained unchanged.


CALLANAN, M.: This action allows the tapping of a tap.

*** Insert 72-58 Callanan Illustration here ****

We believe that the only way to properly apply a busbar or “daisy chaining” is to have overcurrent protection for the lineside conductors in accordance with its ampacity. This is additionally important from a short-circuit current ratingperspective for the busbar as it may only be tested with an overcurrent device sized in accordance with the busbarampacity. Allowing what is proposed by this proposal may result in improper protection from short-circuits. For example,a busbar with an ampacity of 100A would typically have a 100A OCPD supplying a 100A feeder conductor supplying thebusbar.

66Printed on 10/13/2009

Supply Circuit

Power Distribution Block

Feeder (protected at

Tap (ampacity less than pstream s ppl

Busbar or Daisy Chaining

Busbar or Daisy Chaining

(protected at ampacity)

than upstream supply circuit OCPD)

Tapping a tap (ampacity less than upstream tap

Tap

Chaining Chaining

than upstream tap conductor)

Proper use Improper useProper use p p




the conductor to be protected is connected to the supply except as follows:(1) Overcurrent protection at the supply shall not be required if all of the following conditions are met: (a) The current

carrying capacity of each of the conductors is at least equal to that required for the their respective load in accordancewith 12.5. (b) Each connecting conductor to the overcurrent protective devices is no longer than 3 m (10 ft).and (c) Theconductor is suitably protected from physical damage. (d) The conductor does not extend beyond the control panelenclosure. (ec) The conductor terminates in either a single branch circuit protective devicerated circuit breaker, or abranch circuit rated set of fuses or a listed self-protected combination controller or on the line side of multiplebranch-circuit protective devices that have a common line side connection either by use of bus-bar wiring accessoriesidentified for such use or by use of additional conductor(s) to interconnect between terminals where the total length ofthe conductor and all interconnecting conductors to any of the branch-circuit protective devices does not exceed 3m(10ft). The current carrying capacity of the bus-bar wiring accessories or any interconnecting conductor(s) shall be atleast equal to that determined in 7.2.8(1)(a).

(2) Overcurrent protection at the supply shall not be required if all of the following conditions are met: (a) Theconductor has an ampacity of at least one-third that of the conductor from which it is supplied. (b) The conductor issuitably protected from physical damage. (c) The conductor is not over 7.5 m (25 ft) long and the conductor terminatesin a single branch circuit protective device circuit breaker or set of fuses.

This proposal is an output of the NFPA 79 Technical Committee Overcurrent Protection Task Group.This is version two of two proposals for the same clause. The task group was split on whether to permit downsizing of

daisy chain conductors based on load served. As such, both versions of the proposal are being put forth forconsideration.

The current language states that a conductor must terminate in a branch-protective device, and is not clear in itspermission of termination onto multiple branch circuit devices in parallel. This proposal clarifies the use of readilyavailable bus bar wiring accessories or daisy chaining using conductors when the motor branch-circuit short-circuitprotective device terminals are designed for such use. These devices must be sized according to the total load served,and as such cannot be downsized from one protective device to the next.

The revisions to 7.2.8(2) is consistent with current practice in NEC 430.28 which permits termination on any branchcircuit protective device, which now includes a self protected combination motor controller as defined by the companionproposal to 7.2.10.1.1

The 7.2.8(1)(C) requirement for protection from physical damage is redundant with the existing requirement in (d) thatrequires the conductors to be enclosed, and therefore can be deleted.

See companion proposal to 7.10.1.1.

The committee did not accept the last sentence of the proposed Sub part (1)(c) as it wassubject to misinterpretation.



67Printed on 10/13/2009



Revise text to read as follows:7.2.9* Short-Circuit Current Rating or Interrupting Rating. The short-circuit current rating or interrupting rating shall be

at least equal to the available fault current at the point of application. Where the short-circuit current to an overcurrentprotective device includes additional currents other than from the supply (e.g., from motors, from power factor correctioncapacitors), these shall be taken into consideration.

This proposal is an output of the NFPA 79 Technical Committee Overcurrent Protection Task Group.Language was changed to reflect that some devices serving as short circuit current protective devices are marked with

short circuit current rating rather than interrupting ratings.


68Printed on 10/13/2009



Add new paragraph 7.2.10.1.17.2.10.1.1 Self-Protected Combination Controller. A listed self-protected combination controller shall be permitted in

lieu of the devices specified in Table 7.2.10.1 for branch circuit and overload protection of a single motor circuit. Wherethe controller has an adjustable instantaneous-trip setting, the setting shall not exceed 1300 percent of full-load motorcurrent for other than Design B energy efficient motors and not more than 1700 percent of full-load motor current forDesign B energy-efficient motors.

This proposal is an output of the NFPA 79 Technical Committee Overcurrent Protection Task Group.The current text in 7.2.10.1 and Table 7.2.10.1 does not address use of self-protected combination controllers for

motor protection. These devices are commonly used and permitted by 430.52(C)(6) in the NEC. The proposal adds anew paragraph 7.2.10.1.1 to address their use. Additional text was added to the NEC text to clarify that the 1300percent instantaneous trip setting only applies to devices with adjustable instantaneous trip settings.



69Printed on 10/13/2009



Revise text to read as follows:7.2.10.4 Two or more motors or one or more motor(s) and other load(s), and their control equipment shall be permitted

to be connected to a single branch circuit where short-circuit and ground-fault protection is provided by a single inversetime circuit breaker or a single set of fuses, provided both of the following conditions under (1) and either (2) or (3) aremet:

(1)*Each motor controller and overload device is either (a) listed for group installation with specified maximumbranch-circuit protection short-circuit current ratings. or (b) selected such that the ampere rating of the motor branchshort-circuit and ground fault protective device does not exceed that permitted by 7.2.10.1 for that individual motorcontroller or overload device and corresponding motor load.

(2) The rating or setting of the branch short-circuit and ground-fault protection overcurrent device does not exceed thevalues in Table 7.2.10.4 for the smallest conductor in the circuit

(3) The rating or setting of the branch short-circuit and ground fault protection does not exceed the value specified insection 7.2.10.1 for the highest rated motor connected to the branch circuit plus an amount equal to the sum of thefull-load current ratings of all other motors and the ratings of other loads connected to the circuit. Where this calculationresults in a rating less than the ampacity of the branch circuit conductors, it shall be permitted to increase the maximumrating of the fuses or circuit breaker to a value not exceeding that permitted by section 12.5 and 12.6. Overcurrentprotection for loads other than motor loads shall be in accordance with 7.2.3, 7.2.4, and 7.2.11.

7.2.10.5 For group installations described in 7.2.10.4(3), the conductors of any tap supplying a single motor shall notbe required to have an individual branch-circuit short-circuit and ground-fault protective device, provided they complywith one of the following:

(1) No conductor to the motor shall have an ampacity less than that of the branch-circuit conductors.(2) No conductor to the motor shall have an ampacity less than one-third that of the branch-circuit conductors, with a

minimum in accordance with 12.5 and 12.6, the conductors to the motor overload device being not more than 7.5 m (25ft) long and being suitably protected from physical damage in accordance with Chapter 13.

(3) Conductors from the branch-circuit short-circuit and ground-fault protective device to a listed manual motorcontroller additionally marked “Suitable for Tap Conductor Protection in Group Installations” or to a branch circuitprotective device shall be permitted to have an ampacity not less than 1/10 the rating or setting of the branch-circuitshort-circuit and ground-fault protective device. The conductors from the controller to the motor shall have an ampacityin accordance with 12.5 and 12.6. The conductors from the branch-circuit short-circuit and ground-fault protective deviceto the controller shall (1) be enclosed either by an enclosed controller or by a raceway and be not more than 3 m (10 ft)long or (2) have an ampacity not less than that of the branch-circuit conductors.

A.7.2.10.4(1) The short-circuit current rating includes the following:(1) The class and rating of the short-circuit protective device(2) The maximum nominal application voltage(3) The maximum available fault current

***Insert Table 7.2.10.4 Here***This proposal is an output of the NFPA 79 Overcurrent Protection Task Group.

The language in 7.2.10.4 (1) requires all motor controllers and overloads devices to be listed for group installation. Insome installations, the group may contain a mix of larger motor controllers or overload devices with several smallermotor circuits. If the branch circuit protective device for the group is sized to within what is permitted by 7.2.10.1 forthese larger devices, they do not need to be listed for group installation as they are protected within the standardrequirements. Only the smaller motor starters and overload devices would need to be listed for group installation.

The reference to short-circuit rating was changed to branch circuit protection rating as group rated devices are markedwith the maximum ampere size of fuse or circuit breakers, not the short-circuit rating of those devices. The annex notereferencing short circuit current rating was deleted.

In addition, the maximum setting in Table 7.2.10.4 can, in some instances, be more restrictive than 430.53 in the NEC.The proposed language under section 7.2.10.4(3) and 7.2.10.5 provides an alternative means to size branch circuitprotection according to similar rules in the NEC. In addition, the scope of group installation was increased to include oneor more motors and other loads as is the case with the NEC.

70Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 79The task group was asked to address expanding Table 7.2.10.4 to include 16 and 18 AWG conductors. After much

debate, specific values to use were not able to be determined. As such, it was revised to indicate that the provisions12.6.1 shall be applied. While it was debated if this table should be retained at all, it is noted that UL2237 Multi-PointPower Cable Assemblies for Industrial Machinery directly references this table and conducts testing based on thesevalues. It is the understanding of the task group that UL2237 is undergoing revisions to address 16 and 18 AWGconductors.

Additional clarifications from the NEC text were added as follows:1. 7.2.10.5(2) Added clarification that Chapter 13 defines methods to protect conductors from physical damage2. 7.2.10.5.(3) Removed requirement from 430.53(D)(3) for protection from physical damage and the requirement

already requires more strict requirements of being enclosed in a raceway or enclosure.3. Revision of title of Table 7.2.10.4 to indicate its alignment with group installations according to 7.2.10.4

See committee action on Proposal 79-62a (Log #CP3).


71Printed on 10/13/2009

79/L200/F2010/ROP

Table 7.2.10.4 Relationship Between Conductor Size and

Maximum Rating or Setting of Short-Circuit Protective

Device for Power Circuits Group Installations

Maximum Rating

Conductor Size (AWG)

Non–Time-Delay Fuse or Inverse Time Circuit Breaker (amperes)

Time-Delay or Dual-Element Fuse (amperes)

18 See Footnote1 See Footnote1


14 60 30

12 80 40

10 100 50

8 150 80

6 200 100

4 250 125

3 300 150

2 350 175

1 400 200

0 500 250

2/0 600 300

3/0 700 350

4/0 800 400 1 Maximum ratings for 16 AWG and 18AWG shall be determined in accordance with 12,6.1



Revise text to read as follows:7.2.10.4 Two or more motors or one or more motor(s) and other load(s), and their control equipment shall be permitted

to be connected to a single branch circuit where short-circuit and ground-fault protection is provided by a single inversetime circuit breaker or a single set of fuses, provided both of the following conditions under (1) and either (2) or (3) aremet:

(1)*Each motor controller and overload device is either (a) listed for group installation with specified maximumbranch-circuit protection short-circuit current ratings. or (b) selected such that the ampere rating of the motor branchshort-circuit and ground fault protective device does not exceed that permitted by 7.2.10.1 for that individual motorcontroller or overload device and corresponding motor load.

(2) The rating or setting of the branch short-circuit and ground-fault protection overcurrent device does not exceed thevalues in Table 7.2.10.4 for the smallest conductor in the circuit

(3) The rating or setting of the branch short-circuit and ground fault protection does not exceed the value specified insection 7.2.10.1 for the highest rated motor connected to the branch circuit plus an amount equal to the sum of thefull-load current ratings of all other motors and the ratings of other loads connected to the circuit. Where this calculationresults in a rating less than the ampacity of the branch circuit conductors, it shall be permitted to increase the maximumrating of the fuses or circuit breaker to a value not exceeding that permitted by section 12.5 and 12.6. Overcurrentprotection for loads other than motor loads shall be in accordance with 7.2.3, 7.2.4, and 7.2.11. Where 16 AWG or 18AWG conductors are used for branch circuit conductors or tap conductors under 7.2.10.5, the rating and type of thebranch short-circuit and ground-fault protection shall be in accordance with 12.6.1.

7.2.10.5 For group installations described in 7.2.10.4(3), the conductors of any tap supplying a single motor shall notbe required to have an individual branch-circuit short-circuit and ground-fault protective device, provided they complywith one of the following:

(1) No conductor to the motor shall have an ampacity less than that of the branch-circuit conductors.(2) No conductor to the motor shall have an ampacity less than one-third that of the branch-circuit conductors, with a

minimum in accordance with 12.5 and 12.6, the conductors to the motor overload device being not more than 7.5 m (25ft) long and being suitably protected from physical damage in accordance with Chapter 13.

(3) Conductors from the branch-circuit short-circuit and ground-fault protective device to a listed manual motorcontroller additionally marked “Suitable for Tap Conductor Protection in Group Installations” or to a branch circuitprotective device shall be permitted to have an ampacity not less than 1/10 the rating or setting of the branch-circuitshort-circuit and ground-fault protective device. The conductors from the controller to the motor shall have an ampacityin accordance with 12.5 and 12.6. The conductors from the branch-circuit short-circuit and ground-fault protective deviceto the controller shall (1) be enclosed either by an enclosed controller or by a raceway and be not more than 3 m (10 ft)long or (2) have an ampacity not less than that of the branch-circuit conductors.

A.7.2.10.4(1) The short-circuit current rating includes the following:(1) The class and rating of the short-circuit protective device(2) The maximum nominal application voltage(3) The maximum available fault current '

Table 7.2.10.4 Relationship Between Conductor Size and Maximum Rating or Setting of Short-Circuit Protective Devicefor Power Circuits Group Installations

**** Include 79_LCP3_Tb 7.2.10.4*****This committee proposal is the combination of proposal 79-62 and 79-63.


72Printed on 10/13/2009

Table 12.5.1AWG 75 deg C NTDF** or TDF** 1/3 Rule 1/10 Rule Max NTDF Max TDF Max CB Max NTDF Max TDF Max CB

ITCB* CB* or F** CB* or F** CC, J, T J CC, J, T J18 7 20 15 20 20 15 15 15 20 10 2016 10 30 20 30 30 25 20 20 30 15 3014 15 60 30 45 15012 20 80 40 60 20010 30 100 50 90 3008 50 150 80 150 5006 65 200 100 195 6504 85 250 125 255 8503 100 300 150 300 10002 115 350 175 345 11501 130 400 200 390 1300

1/0 150 500 250 450 15002/0 175 600 300 525 17503/0 200 700 350 600 20004/0 230 800 400 690 2300

* For ITCB, when used with 16/18AWG, must be marked for use with 16/18AWG conductors.**For NTDF or TDF, when used with 16/18AWG, must be Class CC, J or T.

Indicates highest ampacity possible (per 12.6.1.1 and 12.6.1.2)This column can mistakenly exceed the 1/3 rule column - this column should be deleted.This column should be kept as the "general rule" since the values are less than that permitted by the 1/3 rule

Table 7.2.10.4 New 7.2.10.5 12.6.1.1 & 12.6.1.2 - Exception12.6.1.1 & 12.6.1.2 - AC-4

Report on Proposals – November 2010 NFPA 79CALLANAN, M.: While we agree with the change to allow protection by either a fuse (TD or NTD) or circuit breaker,

we believe the column with the larger sizes should have been deleted. See spreadsheet provided that illustrates how itcould be confusing because the table (general rule) would allow higher sizing than that of the 1/3 rule.

*** Insert 72-62a Callanan Illustration here ****

73Printed on 10/13/2009

;

79/LCP3/Table 7.2.10.4/F2010/ROP

Maximum Rating

Conductor Size (AWG)





14 60 30

12 80 40

10 100 50

8 150 80

6 200 100

4 250 125

3 300 150

2 350 175

1 400 200

0 500 250

2/0 600 300

3/0 700 350

4/0 800 400 1 Maximum ratings and type of branch short-circuit and ground fault protective devices for 16 AWG and 18AWG shall be determined in accordance with 12.6.1


_______________________________________________________________________________________________Daniel R. Neeser, Cooper Bussmann

Revise text as follows:7.2.10.4 Two or more motors or one or more motor(s) and other load(s), and their control equipment shall be permitted

to be connected to a single branch circuit where short-circuit and ground-fault protection is provided by a single inversetime circuit breaker or a single set of fuses, provided both of the following conditions and 7.2.10.5 are met:

(1)*Each motor controller and overload device is listed for group installation with the specified inverse time circuitbreaker or set of fusesshort-circuit current ratings. or protected by a branch circuit overcurrent protective device inaccordance with 7.2.10.1.

(2) The rating or setting of the overcurrent device does not exceed the values in Table 7.2.10.4 for the smallestconductor in the circuit. The rating or setting of the specified inverse time circuit breaker or set of fuses does not exceedthe value specified in 7.2.10.1 for the highest rated motor connected to the branch circuit plus the sum of the full-loadcurrent ratings of all other motors and the ampacity required for other loads connected to the circuit. Where thiscalculation results in a rating less than the ampacity of the branch circuit conductors, it shall be permitted to increase themaximum rating of the fuses or circuit breaker to a value not exceeding that permitted by section 12.5 and 12.6.Overcurrent protection for loads other than motor loads shall be in accordance with 7.2.3, 7.2.4, and 7.2.11.

7.2.10.5 For group installations described in 7.2.10.4, the conductors of any tap supplying a motor or other load shallnot be required to have an individual branch-circuit overcurrent protective device, provided they comply with one of thefollowing:

(1) No conductor from the branch circuit conductors to the motor or other load shall have an ampacity less than that ofthe branch-circuit conductors. Where 16 AWG or 18AWG conductors are used, the branch circuit inverse time circuitbreaker or set of fuses shall not exceed that permitted by 12.6.1.1 or 12.6.1.2.

(2) No conductor from the branch circuit conductors to the motor or other load shall have an ampacity less thanone-third that of the branch-circuit conductors, with a minimum in accordance with 12.5 and 12.6, the conductors to themotor overload device or other load being not more than 7.5 m (25 ft) long and being suitably protected from physicaldamage in accordance with Chapter 13. Where 16 AWG or 18AWG conductors are used, the branch circuit inversetime circuit breaker or set of fuses shall not exceed that permitted by 12.6.1.1 or 12.6.1.2.

(3) Conductors from the branch circuit conductors to a listed manual motor controller additionally marked “Suitable forTap Conductor Protection in Group Installations” or to a branch circuit overcurrent protective device shall be permitted tohave an ampacity not less than 1/10 the rating or setting of the branch circuit inverse time circuit breaker or set of fuses.The conductors from the controller to the motor or from the branch circuit overcurrent protective device to other loadsshall have an ampacity in accordance with 12.5 and 12.6. The conductors from the branch circuit conductors to thecontroller or other loads shall (1) be enclosed either by an enclosed controller or by a raceway and be not more than 3m (10 ft) long or (2) have an ampacity not less than that of the branch-circuit conductors. Where 16 AWG or 18AWGconductors are used, the branch circuit inverse time circuit breaker or set of fuses shall not exceed that permitted by12.6.1.1 or 12.6.1.2.

Delete existing Table A.7.2.10.4.(1)A.7.2.10.4(1) The short-circuit current rating includes the following:(1) The class and rating of the short-circuit protective device(2) The maximum nominal application voltage(3) The maximum available fault current

Delete existing Table 7.2.10.4 79_L179_Tb 7.2.10.4_R here****

This proposal allows for group motor installations (and other loads) similar to NEC 430.53. It alsoallows devices to not be required to be listed for group motor applications if sized in accordance with 7.2.10.1. It alsorewords NEC 430.53 to clearly indicate which conductors are permitted to be reduced in size in group motor

74Printed on 10/13/2009

79_L179_Tb 7.2.10.4_R

Table 7.2.10.4 Relationship Between Conductor Size and Maximum Rating or Setting of Short-Circuit Protective Device for Power Circuits

Maximum Rating Conductor Size (AWG)



14 60 30

12 80 40

10 100 50

8 150 80

6 200 100

4 250 125

3 300 150

2 350 175

1 400 200

0 500 250

2/0 600 300

3/0 700 350

4/0 800 400

Report on Proposals – November 2010 NFPA 79applications.

It also deletes the appendix information as this is not needed with the changes to the proposal.It also deletes the outdated and overly restrictive Table 7.10.2.4 and increases the maximum size of the branch circuit

inverse time circuit breaker or set of fuses for the group motor installation to be similar to that of NEC 430.53. It is bestto delete this table since it would cause confusion to the user since the general rules in this proposal will result in muchhigher setting for the branch circuit inverse time circuit breaker or fuses. At the vary least, the table should not showratings for fuses lower than that of circuit breakers since there is no foundation to require a smaller rated fuse comparedto a circuit breaker for protection of tap conductors.

In addition, it allows the use of 16 AWG and 18 AWG conductors in group motor applications, but limits the size of thebranch circuit inverse time circuit breaker or set of fuses to that of a single motor circuit. Hence, multiple motors can usethe smaller conductor, but not to an excessive amount that could cause excessive short-circuit damage to these smallerconductors. This limitation is needed since protection of these smaller conductors has only been proven in testing viathe UL small wire report which was used to create the requirements in 12.6.1.1 and 12.6.1.2.

See committee action on Proposal 79-62a (Log #CP3).


75Printed on 10/13/2009



Delete existing 7.3.1.2 and related material in Annex A:7.3.1.2* Adjustable Speed (Electronic and Serve Drives and Motors.

Section 7.3.1.2 as it presently exists specifies no requirements and is not a definition; thus this Sectionis not permitted by the NFPA Manual of Style.


76Printed on 10/13/2009



Add new 7.3.2.1 as follows:7.3.2.1 Operability. Pushbuttons and actuators used to reset overload devices shall be operable from the exterior of

the enclosure.This proposal will result in increased safety for operators and maintenance personnel. We have

inspected a number of installations where panel covers must be removed to reset overload devices. In many cases,these covers are not equipped with interlocks, exposing maintenance personnel to potentially hazardous voltages.

The committee reaffirms its position on Proposal 79-70 of the last cycle. See committeestatement on Proposal 79-70 (Log #26), F2005.


DEFELICE, JR., F.: The committee statement reaffirms its position on 79-70 of the last cycle; which essentially statesthat the resetting of external overloads introduces a risk of damage to the machine. We respectfully maintain that therisk to electrical personnel introduced by opening electrical enclosures to reset tripped overload devices introduces a fargreater risk; and that these risks impact human life. We submit that Motor Control Centers and Combination MotorStarters have historically been, and continue to be offered with externally-operated overload reset devices, such asthose incorporating "thru-the-enclosure door" reset pushbuttons; thee are used on machines, and the submitter is notaware of any damage associated with the operation of these external resets. If it is true that damage to a machine couldresult from resetting externally mounted-overload devices, then the same damage would occur from the resetting ofoverload devices located behind enclosure doors or covers. Moreover, overload relays should be arranged such thatmachine motion will not be initiated through the action of resetting the overload; and if the machine were to restartfollowing an overload reset with the electrical enclosure covers removed, there would exist an increased potential ofinjury due to arc-flash, and from thermal burns due to equipment destruction from fault currents.

CALLANAN, M.: We do not believe that reset devices mounted so that they are accessible from outside an enclosureare necessarily a design that should be avoided.

77Printed on 10/13/2009



For clarity and harmonization add requirement in a second sentence as follows:Motor Overspeed Protection: Unless the inherent characteristics of the motor or the controller, or both, are such as to

limit the speed adequately, drive systems motors shall include protection against motor overspeed where overspeedresults in a hazardous condition. Overspeed protection shall initiate appropriate control responses and shall preventautomatic restarting.

The NFPA overspeed protection requirement does not necessarily suggest stopping the motor anddoes not prevent restart should the motor be stopped. This is in contradiction with NFPA 79, 7.5.3 for Undervoltagewhere restart is prohibited.

No substantiation was provided why automatic re-start should not be permitted. Thesubstantiation that this presents a contradiction to Section 7.5.3 is not correct. Section 7.5.3 is concerned withundervoltage causing motor overheating, random circuit outages, inadvertent release of part restraints and the like.


BAS, L.: Overspeed acts as an auto e-stop which does not allow automatic startups. If the overspeed protectioncauses a shutdown means that control could not be obtained and as the purpose of having this protection is to avoidhazardous situations restarting may pose a hazard.

ANDERSON, W.: I agree with the committee's action. However hazardous overspeed protection, being a safetyfunction should initiate appropriate control responses and shall prevent automatic restarting. Rewording should beconsidered in the comment phase.

78Printed on 10/13/2009



Relocate Sections 7.9.2 through 7.9.2.2 to Section 6.5 as new Sections 6.5.3 / 6.5.3.1/ 6.5.3.2.7.9.2 Capacitors shall be provided with a means of discharging stored energy.

[ 460.6]7.9.2.1 The residual voltage of a capacitor shall be reduced to 50 volts, nominal, or less,

within 1 minute after the capacitor is disconnected from the source of supply. [70:460.6]7.9.2.2 The discharge circuit shall be either permanently connected to the terminals of

the capacitor or capacitor bank, or provided with automatic means of connecting it to the terminals of the capacitor bankupon removal of voltage from the line. Manual means of switching or connecting the discharge circuit shall not be used.[70:460.6].

This subject matter address dangers associated with possible residual voltages in capacitors; and assuch, is more appropriately located in Section


79Printed on 10/13/2009



Revise existing NFPA 79-2007 8.1.1 text as follows:“ This chapter shall provides requirements for grounding, bonding, and the grounded conductor

requirements.”Section 8.1.1 is a statement of fact and the use of “shall” is not necessary nor is it needed. Text

additional edited to provide a declarative sentence.

The removal of the word "shall" would create inconsistency in the document in violation of2.3.1.5 of the MOS.


FISHER, D.: During our meeting it was discovered that we could remove a scoping “shall” if we did it uniformly for thewhole document. I believe that we discovered that there may be a half dozen cases where the “shall” existed. Weapproved the removal of the “shall” in an earlier case and we should have removed all of the “shall” from all of theremaining scoping cases.

WATSON, E.: The negative vote to the committee action supports the recommendation made by the submitter of thisproposal. The substantiation in the original proposal is appropriate and the committee action should have been toAccept in Principle. The committee should have accepted the proposal as written and also corrected 10.1.1 so that aviolation of MOS requirements was not present, instead of rejecting the proposal. Item 10.1.1 should be corrected toread:

10.1.1 Applicability. This chapter provides requirements for devices mounted outside or partially outside controlenclosures. (see also proposal 79-129 (Log # 16) in case the chapter title changes and 10.1.1 must be updatedaccordingly)

80Printed on 10/13/2009



Renumber and revise existing NFPA 79-2007 8.1.2 text as follows:“ Grounded conductors shall not be connected to the equipment grounding (protective bonding)

circuit, except for separately derived systems other than at the separately derived source.Transformer mounting hardware shall not be used for either grounding or bonding terminations.”

Add “electrical” for clarity. This will also clarify where the grounded conductor is to be terminated, withthe term “bonding” deleted to correlate with NFPA 70-2008 changes. Provide number for present 2nd sentence becauseit discusses “terminations” as a different topic from the 1st sentence.

The Committee understands that the word “bonding” in the term (“protective bonding”) shouldnot have been underlined and that the word “electrical” was not added to the proposed changes as indicated in thesubmitter’s substantiation.

The committee encourages the submitter to review the recommendations relative to grounding separately derivedsystems and resubmit at the ROC.The committee agrees that renumbering would result in relocating text from previous grounding task group proposalsthat were rejected and is not necessary.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


FISHER, D.: The committee understood and delineated the deficiencies of the text which were essentially editorialand should have given an AIP and done the minor fixes that were identified. I disagree that regrouping the text in acommon location was without merit and did not warrant the effort to renumber.


81Printed on 10/13/2009



Insert new Section 8.1.2 to read as follows. Increment present 8.1.2 to 8.1.3.Machine-mounted separately derived lighting

and power transformers and on-board power sources shall be bonded to the equipment grounding (protective)conductor terminal bar by a bonding jumper.

The bonding jumper shall be an insulated conductor or non-conductive covered or sleeved braided strapidentified in accordance with Section 8.60.1.1.

The minimum size bonding jumper to the supply circuit grounding terminal bar shall comply with Table 8.2.3.5.Dedicated transformers having a voltage rating from 150 V to not more than 1000 V supplying adjustable

speed drives that do not supply neutral loads shall be permitted to be ungrounded.Control transformers shall be permitted to be ungrounded.Where ungrounded separately derived sources are permitted for any purpose, they shall be provided with a

device that either indicates a ground (earth) fault or interrupts the circuit automatically after a ground (earth) fault.”This adds information to provide one location for grounding and bonding requirements for all

machine-mounted separately derived sources, including on-board power systems as covered in 5.3.1.1(3). Include bothseparately derived and on-board power sources in the title and text as indicated. 8.1.2.1 provides information for theelectrical bonding jumper, 8.1.2.2 provides minimum sizing reference, 8.1.2.3 covers small dedicated transformers,8.1.2.4 allows for ungrounded control sources, and 8.1.2.5 requires all ungrounded separately derived sources to haveaccidental ground fault detection. On-board power sources covered by Section 5.3.1.1(3) are intended to always havethat power source grounded, with the term “source” added for clarity.

The committee agrees that bonding is required. However, the language in the submitter'srecommendations by the grounding task group do not recognize other means of bonding.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


FISHER, D.: Only in 8.1.2, the first of 6 subsections was the application of a bonding jumper called for. It requiredthat any derived source that was to be grounded was to be done so by the application of a bonding jumper. How elsedo we allow this to be done? Should we allow a derived source to be grounded by one of its mounting bolts into theback panel? That doesn’t even ground the circuit that is to be grounded. My observation is that the use of a bondingjumper is the common practice for this situation, but the Committee statement indicates that the proposed text does notallow alternative means. This proposal should have been accepted.

SANDERS, M.: The Technical Committee action should have been to “Accept in Principle” because the proposedtext is not dependent upon the acceptance or rejection of any other proposals, and should have been judged upon itsown merits. A revised new 8.1.2 should have been added to read as follows, with existing 8.1.2 incremented to become8.1.3.

“8.1.2 Bonding of Separately Derived and On-Board Power Sources. Machine mounted separately derived lightingand power transformers and on-board power sources shall be bonded to the equipment grounding (protective)conductor terminal bar by a bonding jumper.

8.1.2.1 The minimum size bonding jumper to the supply circuit grounding terminal bar shall comply with Table 8.2.3.3.8.1.2.2 Dedicated transformers having a voltgage rating from 150V to not more than 1000V supplying adjustable

speed drives that do not supply neutral loads shall be permitted to be ungrounded.8.1.2.3 Control transformers shall be permitted to be ungrounded.8.1.2.4 Where ungrounded separately derived sources are permitted for any purpose, they shall be provided with a

device that either indicates a ground (earth) fault or interrupts the circuit automatically after a ground (earth) fault.”The reasons for doing so are as follows.

82Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 79Proposed 8.1.1 states: This covers machine mounted equipment, and the default application is they are to be bonded

to the supply equipment grounding (protective) circuit path.Proposed new 8.1.2 incorporates the first sentence of existing 8.4.1. The present second sentence of existing 8.4.1

would then become the new 8.4.1.Proposed 8.1.2.1 recognizes Table 8.2.2.3 provides the required minimum sizing for these bonding jumpers.Proposed 8.1.2.2 is based upon NFPA 70-2008: 250.21(A)(2) which recognizes dedicated power supplies for

electronic drives.Proposed 8.1.2.3 incorporates existing 8.3 text first sentence. The remaining text of existing 8.3, and both Exceptions,

would remain as a new 8.3.Proposed 8.1.2.4 is based upon NPFA 70-2008: 250.21(B) that requires all ungrounded power supplies within a certain

voltage range to have means to automatically detect a faulted circuit allowing corrective measures to be taken.The revision places requirements in a more general and logical location of Chapter 8.


83Printed on 10/13/2009



Delete Item (2) in this list and renumber Item (3) as 8.2.1(2).The 2007 Edition deleted Section 8.2.2.3.1 that permitted the machine structure to be used as an

equipment grounding conductor. Now that the permission to use the structure has been removed, the other sectionsthat refer to the structure as an equipment grounding conductor should also be removed. As it stands, this is veryconfusing. Two sections refer to the structural members for this purpose, even though the specific permission to use ithas been eliminated. Another proposal will recommend the deletion of similar language in 8.2.3.1.


FISHER, D.: The deletion of item (2) eliminates the structural parts of the electrical equipment and the machine fromthe equipment grounding circuit. This action is in stark contradiction to the Committee statement in response toproposal 79-7 wherein it agreed that such bonding is required. This bonding is a fundamental necessity to protectionagainst electric shock during the clearing of a fault by the most common means, automatic disconnection. Unfortunatelythe submitter appeared to confuse the equipment grounding conductor with the equipment grounding circuit. Of course,the structural parts of the electrical equipment and the machine are not appropriate substitutes for equipment groundingconductors but they are absolutely necessary parts of the equipment grounding circuit. This proposal should have beenrejected.

84Printed on 10/13/2009



Revise 8.2.1 as follows.“ The equipment grounding (protective bonding) circuit shall consist of the following:

(1) Equipment grounding (protective) conductor terminal(s).(2) Conductive enclosures and housings structural parts of the electrical equipment and the machine devices bonded

to the electrical equipment grounding (protective bonding) circuit by electrical equipment bonding jumpers.(3) Equipment grounding (protective) conductors and electrical equipment bonding jumpers.(4) Accessible machine elements bonded to the equipment grounding (protective bonding) circuit by machine bonding

jumpers.Small parts such as screws, rivets, and nameplates that are not likely to become energized shall not be

required to be bonded by a bonding jumper.”Add “enclosures and housings” to (2) to identify those items containing electrical equipment and

devices to be bonded, remove all permission to use machine structural parts from the electrical equipment groundingcircuit, in (3) add the term “electrical”, add a new (4) to have accessible portions of structural machine members to bebonded to the equipment grounding path and move text of present 8.2.1.1 exception to instead follow 8.2.1(4) as anexception.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


FISHER, D.: It is agreed that this is the most overly prescriptive text wherein bonding jumpers are called for whereother means certainly could be used in some cases. We will bring a revised proposal during the comment period.


85Printed on 10/13/2009



Revise 8.2.1.1 as follows:“ All parts of the equipment grounding (protective bonding) circuit shall be capable of

withstanding the highest thermal and mechanical stress that can be caused by fault currents flowing in that part of thecircuit. All exposed conductive parts of the electrical equipment and the machine(s) shall be connected to the equipmentgrounding (protective bonding) circuit.

The second sentence of 8.2.1.1 topic is addressed in the proposed revisions to 8.2.1(2) and (4), and8.2.1.1 Exception is to be added as an exception to 8.2.1(4) in the proposed revisions to 8.2.1(4).

The committee agrees that this change would result in relocating text from previous groundingtask group proposals that were rejected and is not necessary.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



86Printed on 10/13/2009



Revise 8.2.1.2 as follows:“ The machine and all exposed,

noncurrent-carrying conductive parts, material, and equipment likely to be energized shall be effectively grounded.Where electrical devices are mounted on metal mounting panels that are located within nonmetallic enclosures, themetal mounting panels shall be effectively grounded. Where electrical devices are mounted on metal mounting panelsthat are located within nonmetallic enclosures, the metal mounting panels shall be bonded to the equipment grounding(protective bonding) circuit terminal bar by an electrical equipment bonding jumper sized in accordance with the highestrating of the overcurrent protective device protecting the metallic panel mounted devices. Where specified by themanufacturer, components and subassemblies shall be bonded to the equipment grounding (protective bonding) circuitin accordance with the manufacturer’s instructions.”

The deleted 1st sentence text is addressed in the proposed changes to 8.2.1, and the added textprovides guidance for bonding of metal plates within non-metallic enclosures.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



87Printed on 10/13/2009



Delete 8.2.1.3.2 in it’s entirely. Renumber remaining parts of this section accordingly.All of the items in 8.2.1.2 shall be interconnected to the equipment grounding (protective) conductor terminal.

The subject matter is addressed in proposed changes to 8.2.1 and 8.2.1.2.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



88Printed on 10/13/2009



Change “8.2.1.3.3” to “8.2.1.3.2” and change Table 8.2.2.3” to become “Table 8.2.3.5” to reflectchanges in 8.2.3.5.

To reflect deletion of 8.2.1.3.2 and reflect proposed text changes in Section 8.2.3.5.

The committee agrees that this change would result in relocating text from previous groundingtask group proposals that were rejected and is not necessary.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



89Printed on 10/13/2009



Move title to precede figure to correlate with title placement of Table 8.2.2.3.Editorial.

The proposal and substantiation are in violation of 3.7.1.3.4 of the NFPA Manual of Stylewhich requires the caption of the figure to be located below the figure.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



90Printed on 10/13/2009



Revise 8.2.1.3.4 text as follows.“8.2.1.3.3* The equipment grounding (protective) conductor terminal bar(s) shall be identified with the word

“GROUND,” the letters “GND” or “GRD,” the letter “G,” the color GREEN, or the symbol in Figure 8.2.1.3.4. In addition tothe required marking, the letters PE shall also be permitted to identify this terminal.”

Revise A8.2.1.3.4 as follows.“A.8.2.1.3.3 Some other standards require the letters PE for marking the connection to the external protective earthing

system. In addition, the letters PE or the single or multiple bicolor GREEN-AND-YELLOW is used in some countries formarking terminations to other than the terminal bar.”

Adding the term “bar(s)” allows the marking to be on the bar and not restricted to the individualterminal itself, and the term “also” is deleted as being redundant.A.8.2.1.3.4 text is revised to add the term “marking” for clarity in the retained first sentence and to inform users thatalternate usage to these are employed in some countries.

The committee encourages the submitter to review the recommendation referring to terminal"bar" and resubmit at the ROC.

The committee agrees that renumbering would result in relocating text from previous grounding task group proposalsthat were rejected and is not necessary.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


HILBERT, M.: Although I agree with the Committee to reject this proposal, it could have been accepted in part. Thepart that would be accepted would to add of the word “marking” to A.8.2.1.3.4 and remove the word “also” from 8.2.1.3.4as recommended. The addition of the word “marking” to A.8.2.1.3.4 adds clarity to the Standard and removing “also”from 8.2.1.3.4 is editorial.

The remainder of the recommendation should be rejected. As proposed, the recommendation would only requireidentification when the terminal is part a “bar” as opposed to a single terminal. Further, the current language 8.2.1.3.4 isadequate is it would permit the placement of the recognized words, letters or symbols on or adjacent to the terminal forthe equipment grounding conductor even if it is part of a bar.

91Printed on 10/13/2009



Revise and add new text as follows.“ Where a supplementary grounding electrode is specified, the equipment grounding (protective) circuit

terminal bar shall accommodate this the additional supplementary grounding electrode conductor.8.2.1.3.5.1 The supplementary grounding electrode conductor size shall comply with 8.2.3.5 and shall not be less than

6 AWG.8.2.1.3.5.2 The supplementary grounding electrode conductor shall be protected against physical damage.”

This clarifies the application for industrial machinery and provides wire sizing and physical protectionrequirements.

The committee has not accepted the definition "supplementary grounding electrode" proposedby the grounding task group therefore the proposed recommendation is not necessary.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


SANDERS, M.: The Technical Committee action should have been to “Accept in Principle” because the proposedtext is not dependent upon the acceptance or rejection of any other proposals, and should have been judged upon itsown merits. The correct action would have been to change the existing text as follows:

“8.2.1.3.5 Where an auxiliary grounding a supplementary electrode is specified, the terminal shall accommodate thisadditional grounding conductor.”

This will reflect present verbiage in NFPA 70-2008: 250.54 and is not dependent upon the rejected ROP 79-12proposed edition.

HILBERT, M.: See my affirmative comment on Proposal 79-7 (Log #155)

92Printed on 10/13/2009



Insert a new 8.2.2 and increment existing 8.2.2 and its subparts accordingly.“8.2.2 Machine Bonding Jumpers. Machine bonding jumpers shall comply with the following requirements.”

This will ensure the subparts of this new section will be followed where bonding jumpers are providedacross machine elements or between adjacent machining centers.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


FISHER, D.: This proposal required bonding jumpers to conform to certain specifications. It contained norequirements for bonding. The Committee rejected the proposal based upon its claim that the proposal does notrecognize other means of bonding. How is it possible to conclude that other means of bonding are not recognized whenthe proposal only addresses requirements for bonding jumpers? This proposal should have been accepted.


93Printed on 10/13/2009



Renumber 8.2.2 to become 8.2.3, renumber 8.2.2.1 to become 8.2.3.1 and add new exception,renumber 8.2.2.2 to become 8.2.3.3 and renumber 8.2.2.3 to become 8.2.3.5. Move 12.2.1 Ex No 2 to become new8.2.3.1 Exception. Add new 8.2.3.2. Add new exception renumbered 8.2.3.3. Move 8.2.3.7 to become 8.2.3.4. Inaddition, revise text as follows.

“ Equipmentgrounding (protective) conductors and electrical equipment bonding jumpers shall be identified in accordance with 8.60.

Conductors used for equipment grounding (protective bonding) circuits and bonding purposes shall becopper. Stipulations on s Stranding and flexing applications shall comply with as outlined in Chapter 12 shall apply.

Electrical equipment bonding jumper straps shall be permitted to be braided tin plated copper or foil copper.Equipment grounding (protective) conductors and bonding jumpers shall be insulated, or covered, or bare

and shall be protected against physical damage.8.2.3.4 Electrical equipment, such as P portable , pendant, or resilient-mounted equipment, shall be bonded by

separate conductors. Where multiconductor cable is used, the bonding conductor jumper shall be included within as oneconductor of the cable assembly.

Electrical equipment grounding (protective) circuit conductors and related bonding jumpers of the wire typeshall not be smaller than shown in Table 8.2.2.3 5, but shall not be required to be larger than the circuit conductorssupplying the equipment.”

Existing 8.2.2 and subparts are incremented to become 8.2.3 and subparts. 8.2.2 (new 8.2.3 andsubparts) edited to provide information specific to both electrical equipment circuit conductors and related bondingjumpers with references provided to new 8.60 subparts for identification. 8.2.2.1 (new 8.2.3.1) edited for clarity. New8.2.3.2 text added to address braided or foil type straps. 8.2.2.2 (new 8.2.3.3) edited for clarity and bare conductors andbare bonding jumpers are not permitted when applying this section. 8.2.3.7 re-located here to become 8.2.3.4 andedited for clarity. 8.2.2.3 (new 8.2.3.5) edited for clarity.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



94Printed on 10/13/2009



Revise Title of Table 8.2.2.3 as follows.“

Title change reflects other proposed NFPA 79 revisions.

The committee agrees that renumbering would result in relocating text from previousgrounding task group proposals that were rejected and is not necessary.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



95Printed on 10/13/2009



Increment 8.2.3 to become 8.2.4 and revise as follows.“

Attachment plug and receptacle (plug/socket) combinations shall be designed so that both of thefollowing occur:

The equipment grounding (protective bonding) circuit connection shall be made before anycurrent-carrying connections are made.

13.4.5.3.(2) The equipment grounding (protective bonding) circuit connection of an attachment plug shall notbe disconnected before its current-carrying connection(s) is disconnected.

Connections used in PELV circuits or the connectors used only to facilitate assembling and disassembling(multipole connectors) shall not be required to meet the requirements of 8.2.4.1 these requirements.”

Renumber 8.2.3 to become 8.2.4. Re-locate 13.4.5.3, and parts (1) and (2) and exception addressingPELV circuits or assembly/disassembly plug/connectors to become new leading section in 8.2.3 (new 8.2.4). Relocatingdisparate parts of technical grounding concerns will assist in application issues.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


SANDERS, M.: The Technical Committee action should have been to “Accept in Part” and should have been judgedupon its own merits. This action would be to accept only the part moving Exception of 13.4.5.3 to become newException to present 8.2.4* instead of becoming a new subsection of 8.2.3 as originally proposed.

Present text of 8.2.4* contains language concerning separable connections such as attachment plugs and matingconnectors and receptacles and would bring this topic into a more logical location.

In addition, the Technical Committee action should have been to also “Accept” ROP 79-153 Log #159 which thendeletes the entire Section 13.4.5.3, because the subject matter is already addressed in the present 8.2.4*.

Deleting 13.4.5.3 would then require deletion of A.8.3.4 because it points to 13.4.5.3 and an Annex A item wouldtherefore become unnecessary.


96Printed on 10/13/2009



Revise to read as follows:"The continuity of the equipment grounding (protective bonding) circuit shall be ensured by effective connections

through conductors or structural members."The 2007 Edition deleted Section 8.2.2.3.1 that permitted the machine structure to be used as an

equipment grounding conductor. Now that the permission to use the structure has been removed, the other sectionsthat refer to the structure as an equipment grounding conductor should also be removed. As it stands, this is veryconfusing. Two sections refer to the structural members for this purpose, even though the specific permission to use ithas been eliminated. Another proposal will recommend the deletion of similar language in 8.2.1. Section 8.2.3.3 and8.2.3.4 adequately cover the conditions where one structural member is bonded and grounded by connection(s) toanother member, but a conductor would still be required to provide continuity back to the system grounding point.


FISHER, D.: This proposal, like 79-71 (Log #95) suffers from confusion between the needs of the equipmentgrounding conductor and the equipment grounding circuit. Removal of “structural members” from the equipmentgrounding circuit is completely unacceptable. For all the same reasons as cited in my response to 79-71 (Log #95), thisproposal should have been rejected.

97Printed on 10/13/2009



Increment 8.2.3.2 to become 8.2.4.3 and retain existing text as follows.“Removing a device shall not interrupt the continuity of the equipment grounding (protective) circuit.”

Clearly shows the relationship between NFPA 79-2007 and revised edition.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



98Printed on 10/13/2009



Renumber 8.2.3.3 to become 8.2.4.4. Revise as follows:“ Bonding of equipment to the equipment grounding (protective bonding) circuit with bolts or other identified

means shall be permitted where paint and dirt are removed from the mounting joint surfaces or where the bondedmembers are effectively penetrated, and where the bonding is verified in accordance with Chapter 18.”

Coordinates text with other NFPA 79 changes. Chapter 18 provides methods for verification ofbonding.

The committee agrees that bonding is required. However, the language in the proposedrecommendations by the grounding task group do not recognize other means of bonding.

Additionally, the committee agrees that this change would result in relocating text from previous grounding task groupproposals that were rejected and is not necessary.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


FISHER, D.: This proposal addresses bonding, specifically bonding by means other than by bonding jumpers, sohow is it possible to for the Committee to claim that is being rejected because it does not recognize bonding meansother than bonding jumpers? This proposal should have been accepted.


99Printed on 10/13/2009



Delete section 8.2.3.4 in its entirety.“ Moving machine parts, other than accessories or attachments, having metal-to-metal bearing surfaces shall beconsidered as bonded. Sliding parts separated by a nonconductive fluid under pressure shall not be considered asbonded.”

This type bonding path is no longer acceptable for electronic equipment, whether involving eitherelectronic controls or electronic (adjustable speed) drives.

Remove Section 8.2.3.4.Renumber the remaining sections.

The committee accepts the submitters proposal and renumbers the remaining sections.


ANDERSON, W.: I agree with the committee's action. However there seem to be confusion surrounding groundingand bonding termonology which should be addressed during the comment phase.

100Printed on 10/13/2009



Increment existing 8.2.3.5 to become 8.2.4.5 and revise as follows.“8.2.4.5 Metallic R raceways, metallic wireways, and metallic cable trays shall not be used as equipment grounding(protective) conductors.

Re-locate to a more logical location and edit to reflect this section addresses metallic components.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



101Printed on 10/13/2009



Re-number existing 8.2.3.6 to become 8.2.5 and revise as follows.“

Where electrical devices are mounted on conductive doors or covers, an electrical equipment (protective)bonding jumper shall be installed.

Where required, an equipment (protective) bonding jumper shall connect the conductive door or cover tothe equipment enclosure or to an electrical equipment grounding (protective bonding) terminal bar within the enclosure.

Cover or door bonding jumpers shall be insulated or covered with non-conductive sleeving where electroniccontrol or power circuits are present.”

Re-number as new part because it introduces a new topic. Edited to reflect accumulation of otherproposed changes to NFPA 79-2007. Electronic equipment bonding jumpers should not be bare to avoid arcing RFnoise that can affect operation.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


FISHER, D.: The Committee statement to reject gives the oft repeated claim that “renumbering would result inrelocating text from previous grounding task group proposals that were rejected and is not necessary.” This responsecompletely avoids any critique of the merits of the proposed revision to the text except to declare that it “is notnecessary.” The added text is relevant as to the type of jumper that should be used in the particular context. We in oursubgroup have no idea as to how to respond to this Committee comment when it seems imply that the relocation ofcommon ideas does not warrant the energy to renumber it.


102Printed on 10/13/2009



Re-locate 8.2.3.7 to 8.2.3.4, increment the subparts of proposed 8.2.3.4 to 8.2.3.5 and in the text ofproposed 8.2.3.4 increment Table 8.2.3.4 to Table 8.2.3.5, and revise the original text of 8.2.3.7 as follows.

“Electrical equipment, such as P portable, pendant, and resilient-mounted equipment, shall be bonded by separateconductors. Where multiconductor cable is used, the bonding conductor jumper shall be included within as oneconductor of the cable assembly.”

Locates sections concerning bonding into an appropriate section.

The committee agrees that bonding is required. However, the language in the proposedrecommendations by the grounding task group do not recognize other means of bonding.

Additionally, the committee agrees that this change would result in relocating text from previous grounding task groupproposals that were rejected and is not necessary.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



103Printed on 10/13/2009



Delete this section in its entirety.“ Where equipment grounding conductors are subject to physical damage, they shall be protected.

This is redundant to existing NFPA 79 Section 8.2.2.2 and is adequately addressed in proposed8.2.3.3.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


SANDERS, M.: The Technical Committee action should have been to “Accept” the deletion of this section because itis redundant to existing 79 Section 8.2.2.2. Deletion of this section is not dependent upon the acceptance or rejection ofany other proposals, and should have been judged upon its own merits. This action does not cause any text to berelocated, and this action does recognize an existing redundancy.


104Printed on 10/13/2009



Re-number 8.2.4 to become 8.2.7 and revise as follows. Delete existing A.8.2.4.“ The equipment grounding (protective bonding) circuit shall not contain any

switches or overcurrent protective devices. Separable connections such as those provided in drawout equipment orattachment plugs and mating connectors and receptacles shall provide for first-make, last-break of the equipmentgrounding(protective) conductor. First-make, last-break shall not be required where interlocked equipment, plugs,receptacles, and connectors preclude energization without grounding continuity.

For additional information, see 13.4.5.3.A.8.2.4 deleted because it points to 13.4.5.3 which has been incorporated into 8.2.4 (New).

Attachment plugs and mating connectors and receptacles are now covered within Chapter 8 in proposed 8.2.4.1. Editedto incorporate proposed changes to NFPA 79.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


SANDERS, M.: The Technical Committee action should have been to “Accept in Part” the deletion of A.8.2.4.Combined with the action that should have been taken on ROP 79-83 to add an exception concerning PELV, along withacceptance of ROP 79-153 Log #159 which would then delete entire Section 13.4.5.3, the Annex A text would,therefore, become unnecessary. Renumbering the text to place topics in a more logical location provides a greaterclarity and is not an insumountable task.


105Printed on 10/13/2009



Insert new 8.2.4.6 and subparts as follows.“8.2.4. 6 Metallic raceway enclosing electronic control or electronic power circuits shall be bonded to a metallic

enclosure with one or more of the following.8.2.4.6.1 Connections utilizing threaded couplings or threaded bosses on enclosures made up wrenchtight; or8.2.4.6.2 Threadless couplings and connectors where made up tight for metallic raceways and metal-clad cables; or8.2.4.6.3 Other listed devices, such as bonding-type locknuts, bushings, or bushings provided with bonding jumpers.

New text provides guidance for bonding metallic raceway or metal-clad cables enclosing electroniccontrol or electronic power circuits.

The recommendation provided is not sufficient to permit alternate methods of bondingraceways and therefore is too restrictive.


106Printed on 10/13/2009



Re-number 8.2.5 to become 8.2.8 and revise as follows.“

All equipment grounding (protective) conductors shall be terminated in accordance with 13.1.1.The equipment grounding (protective) conductor terminal connecting points shall have no other function.Terminals for more than one conductor shall be so identified .The equipment grounding conductor connecting points, other than the equipment grounding terminal, shall be

identified by the color GREEN, by the bicolor combination of GREEN-AND-YELLOW, or by use of the symbol in Figure8.2.1.3.4.

The letters PE or the bicolor GREEN-AND-YELLOW is used in some countries.Increment to provide additional room and reflect accumulated proposals for NFPA 79. Revise to reflect

other accumulated proposed changes. 8.2.8.3 will require terminations for multiple conductors to be identified. 8.2.5.2*and A8.2.5.2 deleted because it is now covered by proposed 8.2.1.3.4.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



107Printed on 10/13/2009



Insert new section 8.2.6 to read as follows.“8.2.6.1 Flexible cables supplying servo motors containing a single shielding outer layer shall have that layer serve as

the equipment grounding (protective) conductor.8.2.6.2 Flexible cables supplying servo motors containing multiple shielding layers shall have the outer-most layer

serve as the equipment grounding (protective) conductor.”This provides guidance to the servo industry for single shield and multiple layer shield application.

The submitter has not provided adequate technical substantiation to require the shield to serveas an equipment grounding conductor.


ANDERSON, W.: I agree with the committee's action. Looking for more technical information to be presented duringthe comment phase.

108Printed on 10/13/2009



Revise 8.3 as follows:“ Control circuits shall be permitted to be grounded or ungrounded. Where control circuit sources

are grounded, grounding is provided, the unswitched side of the circuit shall be connected to the grounded conductor.that side of the circuit common to the coils shall be grounded at the secondary winding of the control transformer ifalternating current or at the power supply terminal if direct current.

Ungrounded control circuits shall be provided with an insulation monitoring device that either indicates a ground(earth) fault or interrupts the circuit automatically after a ground (earth) fault.

First sentence now covered in 8.1. Second sentence revised to clarify the grounded conductor willconnect to the passive side of operating coils and the like. SELV clarifies the application of Section 6.4. Section 8.3.1deleted because it is now covered in 8.1.2.5 and all circuits should be monitored for insulation failure.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


SANDERS, M.: The Technical Committee action should have been to “Accept”. Combined with the action thatshould have been taken on ROP 79-70 Log #149, ungrounded circuits would be subject to insulation monitoring, andmaintain correlation with NFPA 70-2008: 250.31(B), which requires all ungrounded power supplies within a certainvoltage range to have means to automatically detect a faulted circuit allowing corrective measures to be taken.


109Printed on 10/13/2009



Revise 8.4 as follows, and move present 8.3.3 to become new 8.4.2.

One conductor of all machine lighting and maintenance lighting circuits shall be grounded. The groundedconductor(s) shall be identified in accordance with Section 13.2.

Where the lighting circuit is supplied by a separate isolation transformer, one terminal of the secondary of thetransformer shall be directly connected to the equipment grounding (protective bonding) circuit.

The grounded conductor, where run to a screw-shell lampholder, shall be connected to the screw-shell.”Delete 8.4.2 because it is now covered by 8.1.2. Re-number 8.3.3 to become 8.4.2.


79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



110Printed on 10/13/2009



Insert entire Section 13.2.2 into proposed Section 8.60.1 with sub-parts and revise to reflectaccumulated proposed changes for NFPA 79.. Revise related "A.13.2.2.1" to become "A.8.60.1.1".

Add new 8.60 and subpart as follows.“

The color GREEN with or without one or more YELLOW stripes shall be used to identify the equipmentgrounding (protective) conductor or electrical equipment bonding jumper where insulated or covered. This coloridentification shall be strictly reserved for the equipment grounding (protective) conductor or electrical equipmentbonding jumper.

In multiconductor cable-connected assemblies where electrical equipment grounding or bonding isnot required, the solid color GREEN shall be permanently re-identified where the conductor is available at all accessiblelocations. permitted for other than equipment grounding.

It shall be permitted to use conductors of other colors for equipment grounding (protective bonding)circuit or electrical equipment bonding jumper application provided the insulation or cover is appropriately identified at allpoints of access.

For grounded control circuits, use of a GREEN insulated conductor with or without one or moreYELLOW stripes or a bare conductor from the transformer terminal to a grounding terminal on the control panel shall bepermitted.

The international standards reserve the use of the bicolor combination GREEN-AND-YELLOW for thispurpose. The bicolor combination is such that on any 15 mm (0.6 in.) length, one of the colors covers at least 30 percentand not more than 70 percent of the surface of the conductor, and the other color covers the remainder of the surface.

Where the equipment grounding (protective) conductor or electrical equipment bonding jumper is identified byits shape, position, or construction (e.g., a braided conductor or foil strap) or where the insulated or covered conductor isnot readily accessible, color coding throughout its length shall not be required. The ends or accessible portion shall beclearly identified by the symbol in Figure 8.2.1.3.4, the color GREEN with or without one or more YELLOW stripes, orthe bicolor combination GREEN-AND-YELLOW or the letters PE.”

Revised 13.2.2 to clarify the purpose of this the electrical equipment grounding conductor byemphasizing the term "protective". For Exception No. 1, add "or bonding" as one of the expected purposes of thisreserved color. Add the restriction that where the solid color green is to be used for other than its reserved duty, theaffected conductor must be re-identified so there is no possible confusion. Note this re-identification can be sleeving,tagging or other marking compatible with the insulation and the location environment of the machine. Exception No. 2information was added to note other colors are being used as an electric equipment grounding (protective) circuitconductor (see 3.3.9(1)) or as a non-electrical equipment bonding jumper (see 3.3.9(2)) for clarity.

This follow the stated intent of present Section 8.1.1 to have Chapter 8 provide for all issues affecting grounding andrelated subjects. Proposed 8.60 allows room to re-number sections of Chapter 8 to provide more space between maintopics. This will help avoid the tedious process of continually incrementing and decrementing section numbers.

The submitter did not provide adequate substantiation to move the entire section from Chapter13 to Chapter 8.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



111Printed on 10/13/2009



Insert new 8.80 to read as follows:“8.80 DC Control Circuit Grounding.8.80.1 Where dc control circuits are connected to the equipment grounding (protective bonding) circuit, they shall be

supplied from a separate winding of the ac control circuit transformer or by another control circuit transformer or a listeddc power supply.”

This will provide guidance to address the grounding requirements for DC control circuits.

The proposed text is already contained in 9.1.1.2.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



112Printed on 10/13/2009



Delete the Exception to 9.1.1.4:9.1.1.4 The source of supply for all control circuits shall be taken from the load side of the supply disconnecting means.

The current state of technology makes this exception obsolete. Modern memory elements haveretention times which far exceed 72 hours, making the need to connect power ahead of supply disconnecting meansunnecessary. This proposal will result in increased safety for maintenance personnel

Due to uncertainty of machine outage because of schedule changes or production needs, thecommittee chooses to retain this exception.


DEFELICE, JR., F.: This proposal would result in increased safety for maintenance personnel. The current state oftechnology makes the exception obsolete. Modern memory elements have retention times which far exceed 72 hours,making the need to connect power ahead of supply disconnecting means unnecessary.

113Printed on 10/13/2009



Relocate the last sentence of Section 9.2.5.3.2 and the last sentence of 9.2.5.3.3 as the first andsecond sentences of Section 9.2.2; thus reading as follows:

Stop function shall operate by de-energizing that relevant circuit and shall override related startfunctions. The reset of the stop function shall not initiate any hazardous conditions. The three categories of stopfunctions shall be as follows:

(1) Category 0 is an uncontrolled stop by immediately removing power to the machine actuators.(2) Category 1 is a controlled stop with power to the machine actuators available to achieve the stop then remove

power when the stop is achieved.(3) Category 2 is a controlled stop with power left available to the machine actuators.

Although there is no change in the effectiveness of the requirements, the structure of the text followsthe logic established in 9.2.1 for Start Functions and integrates the functional requirements in one area.


FISHER, D.: The requirement that a reset of a stop function not “initiate any hazardous conditions” needs somemodification. The reset of a stop function, if anything, could initiate motion, operation or a process that could possiblyresult in a hazardous condition. I think that it should be stated that way rather than imply that a control system coulddirectly initiate a hazardous condition.

114Printed on 10/13/2009


_______________________________________________________________________________________________Heinz E. Knackstedt, C&E Sales, Inc.

Revise text to read as follows:9.2.5.4(1) This section specifies the requirements for the emergency stop and the emergency switching off functions of

the emergency operations listed in Annex E, X both of which are, in this section, initiated by a single human action.Annex E has the following title, and is a list of commonly used

technical abbreviations.Add the list of emergency operations which require emergency stop or emergency switching off to a new annex and

correct the reference.Current reference is incorrect.

Date which was intended to be included in the standard has not been provided.Both will be resolved with the above suggested changes.



115Printed on 10/13/2009



Revise text to read as follows:

Emergency operation requirements are as follows:(1) This section specifies the requirements for the emergency stop and the emergency switching off functions of the

emergency operations listed in IEC 60204-1, Annex E, both of which are, in this section, initiated by a single humanaction.

The current Annex E is titled “Device and Component Designations” which has nothing to do withemergency stop or emergency switching off. It is believed that the “Annex E” reference is to IEC 60204-1 which has anAnnex E directed at emergency stop and emergency switching off. TG #5 recommends NFPA 79 add the appropriatereference to IEC 60204-1 for Annex E as a proper clarification.

TG #5 also recommends the small punctuation edits and the removal of “in this section” as they are not needed forproper understanding.


Emergency operation requirements are as follows:(1) This section specifies the requirements for the emergency stop and the emergency switching off functions of the

emergency operations, both of which are initiated by a single human action.(2) Once active operation of an emergency stop (see Section 10.7) or emergency switching off (see Section 10.8)

actuator has ceased following a command, the effect of this command shall be sustained until it is reset. This reset shallbe possible only at that location where the command has been initiated. The reset of the command shall not restart themachinery but only permit restarting.

(3) It shall not be possible to restart the machinery until all emergency stop commands have been reset. It shall not bepossible to reenergize the machinery until all emergency switching off commands have been reset.

Add new last paragraph in Annex A.9.2.5.4 to read as follows: See IEC 60204-1, Annex E.The committee removed the reference (IEC 60204, Annex E) from the mandatory text and

relocated it to Annex A. The existing text was edited for clarity.


116Printed on 10/13/2009



Revise text to read as follows:“(1) This section specifies the requirements for devices initiated by a single human action for the emergency stop and

the emergency switching off functions of the emergency operations listed in Annex E, both of which are, in this section,initiated by a single human action.”

Add the following to Annex A.9.2.5.4 as a new last paragraph. “See Annex E Device and Component Designations foradditional information.”

This clarifies what this 9.2.5.4 addresses, and moves the reference to Annex E to Annex A9.2.5.4 tocomply with NFPA Manual of Style.

The committee understands from the grounding task group that the proposal was submitted inerror.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.



117Printed on 10/13/2009


_______________________________________________________________________________________________Heinz E. Knackstedt, C&E Sales, Inc.

Revise text to read as follows:Where a Category O or Category 1 stop is used for the emergency stop function, it shall have a circuitry

design (including sensors, logic, and actuators) according to the relevant risk as required by Section 4.1 and 9.4.1 FinalCircuit design for the removal of power to the machine actuators shall be determined by the results of the riskassessment insured and shall be by means of electromechanical components.

In several instances the standard refers to the execution and use of the results of a risk assessment todetermine the performance of safety related functions. This is a reasonable requirement and agrees with theconclusions of numerous consensus standards, that a risk assessment is the most efficient and cost effective method ofdeterring such performance requirements. In the subject section there is first the requirement to use the RA to"determine the circuit design and its components", again in agreement with consensus standards. If then, however,goes on to require that final removal of power "shall be assured". This is a totally prescriptive requirement, and in itsstrictest form of interpretation of the meaning of shall, ("to secure against change or risk" Webster New CollegeDictionary 1951) forces a high performance requirement (low probability of failure to perform) on the circuit and function,completely ignoring the previous requirement of using the RA to determine circuit and components and through thatprocess also determining the performance.

The committee is unclear as to the intent of the submitter as he did not correctly quote theparagraph and was inconsistent with the use of legislative text.


ANDERSON, W.: The committee apparently did error in the action for 79-105 Log #11 EEI-AAA, because of obviousprinting reproduction errors in the proposal presented; suggest the action should be to accept in principal the proposaland substantiation while retaining the last sentence.

WATSON, E.: I strongly agree with the Committee Action on this proposal and offer an additional supportivestatement. In parts of industry the emergency stop function is an auxiliary stop function and is NOT included on a riskassessment.

118Printed on 10/13/2009


_______________________________________________________________________________________________Eric Wolfgang, Engel Machinery, Inc.

Revise text as follows:9.2.5.6 Two-Hand Control. All two-hand controls shall have the following features:(1) The provision of two control devices shall require the concurrent actuation by both hands.(2) It shall be necessary to actuate the control devices within a certain time limit of each other, not exceeding 0.5

seconds.(3) Where this time limit is exceeded, both control devices shall be released before operation is initiated.(4) The control devices shall require continuous actuation during the hazardous conditions.(5) Machine operation shall cease upon the release of either control device when hazardous conditions are still

present.(6) Machine operation shall require the release of both control devices, before the machine operation is reinitiated.(See Annex B)

Editorial Correction. There should be no reference in Annex B to this clause. Annex B is an InquiryForm for the Electrical Equipment of Machines. The Index reference on page 79-84 for “control – functions – two-hand”also contains an incorrect reference to Annex B.

See the committee action on Proposal 79-107 which addresses the submitters concern.


SANDERS, M.: The Technical Committee Action should have been to add an asterisk to 9.2.5.6 and add a new itemin Annex A to read as follows:

“A.9.2.5.6 Annex B provides an inquiry form to ensure all parties have reviewed this requirement where certainconditions may be a point of concern.”

For consistency, action should also have been taken to provide an asterisk to 4.4.1 and delete “(See Annex B)” from4.2.1(3) and add a new item to Annex A to read as follows:

“A.4.3.1 Annex B provides an inquiry form to ensure all parties have reviewed any supplier specific requirementsconcerning equipment operation.”

For consistency, action should also have been taken to provide an asterisk to 4.4.1 and delete “(See Annex B)” fromthe main text and add a new item to Annex A to read as follows:

“A.4.4.1 Annex B provides an inquiry form to ensure all parties have reviewed any supplier specific requirementsconcerning any physical environment or operating conditions that are outside those specified in this document.”


“A.4.4.5 Annex B provides an inquiry form to ensure all parties have reviewed requirements for electrical equipmentoperating at altitudes 1000 m (3300 ft) or more above sea level.”


“A.4.4.6 Annex B provides an inquiry form to ensure all parties have reviewed requirements for electrical equipmentoperating where contaminants are of a special concern.”

119Printed on 10/13/2009



Revise text to read as follows:9.2.5.6 Two-Hand Control.(6) Machine operation shall require the release of both control devices, before the machine operation is reinitiated.(See Annex B.)

INDEX:Control functions.................9.2, A.9.2Two-hand...................9.2.5.6, A.9.2.5.6, Annex B

Editorial Correction: There is no reference in Annex B to clause 9.2.5.6. The reference to Annex Bseems to be an artifact from drafts of previous editions.


SANDERS, M.: The Technical Committee Action should have been to “Accept in Principle” and add an asterisk to9.2.5.6 and a new item in Annex A to read as follows:

“A.9.2.5.6 Annex B provides an inquiry form to ensure all parties have reviewed this requirement where certainconditions may be a point of concern.”

For consistency, action should also have been taken to provide an asterisk to 4.4.1 and delete “(See Annex B)” from4.2.1(3) and add a new item to Annex A to read as follows:

“A.4.3.1 Annex B provides an inquiry form to ensure all parties have reviewed any supplier specific requirementsconcerning equipment operation.”

For consistency, action should also have been taken to provide an asterisk to 4.4.1 and delete “(See Annex B)” fromthe main text and add a new item to Annex A to read as follows:“A.4.4.1 Annex B provides an inquiry form to ensure all parties have reviewed any supplier specific requirementsconcerning any physical environment or operating conditions that are outside those specified in this document.”


“A.4.4.5 Annex B provides an inquiry form to ensure all parties have reviewed requirements for electrical equipmentoperating at altitudes 1000 m (3300 ft) or more above sea level.”

For consistency, action should have also been taken to provide an asterisk to 4.4.6 and delete “(See Annex B)” fromthe main text and add a new item to Annex A to read as follows:

“A.4.4.6 Annex B provides an inquiry form to ensure all parties have reviewed requirements for electrical equipmentoperating where contaminants are of a special concern.”

120Printed on 10/13/2009



Replace Sections 9.2.7 through 9.2.7.6 in their entirely with the following:9.2.7 Wireless Operator Control.9.2.7.1 General. Machines employing Wireless Operator Control shall be provided with all of the following:(1) A risk assessment which considers the control functions of the Wireless Operator Control Station(s), the need for

emergency stop or two-hand control, and the location of the docking station.(2) A docking station, integral to the machine, for linking the memory element(s) of the machine to those of the

Wireless Operator Control Station(s) and facilitate recharging of the power supplies (battery) of the Wireless OperatorControl Station(s).

(3) A Mode Selector Switch to activate and deactivate the Wireless Operator Control Mode.(4) A system of supervised communication, which shall cause an emergency stop of the machine when supervision

signals from the active Wireless Operator Control Station have not been received by the machine for a period exceeding550 ms when the Wireless Control Mode of the machine has activated.

(5) A comparator which recognizes differences between the operating instructions residing in memory on the machineand the operating instructions residing in the memory on an active Wireless Operator Control Station when it has beenplaced in the docking station. In the event the comparator determines that differences exist between the operatinginstructions, the comparator shall cause the machine to move to and remain in a pre-determined safe state.

(6) Means (e.g., locked storage, key-operated switch, access code) of preventing unauthorized use of the operatorcontrol station.

(7) Means to indicate the identity of the Operator Control Station (wired or wireless) which is in control of the machine.(8) Means to prohibit multiple Operator Control Stations from controlling the machine simultaneously, except that

activation of any Emergency Stop Initiating Device shall result in an emergency stop of the machine.(9) A hard-wired emergency stop actuator, located immediately adjacent to the docking station for the Wireless

Operator Control Station.9.2.7.2 Wireless Operator Control Station. Wireless Operator Control Station(s) shall comply with all of the following:(1) Wireless Operator Control Station(s) shall carry an unambiguous indication of which machine(s) it is intended to

control.(2) Wireless Operator Control Stations shall provide a visual indication of active and inactive status.(3) Wireless Operator Control Stations shall provide both an audible and a visual warning when the power supply

(battery) voltage is low.(4) Wireless Operator Control Stations shall provide both an audible and a visual warning when the supervision signal

is low (e.g. tdue to approaching the limit of transmission range or a low battery voltage.(5) Wireless Operator Control Stations shall provide a means (e.g. coded transmission) to prevent crosstalk/spurious

operation.(6) Wireless Operator Control Stations shall transmit a supervision signal to the machine at periods not exceeding 550

ms. to maintain integrity of the communications signal.(7) Programming of Wireless Operator Control Stations shall only be possible when located in the docking station at

the machine.(8) Means shall be provided to remove or disconnect the power supply of the Wireless Operator Control Station.9.2.7.3 Wireless Operator Control Stations with Emergency Stop Initiating Devices. In addition to the requirements of

9.2.7.2 Wireless Operator Control Stations equipped with Emergency Stop Initiating Devices shall comply with all of thefollowing:

(1) The emergency stop function of a Wireless Operator Control Station shall provide a level of integrity which isequivalent to that of hardware-based components installed in accordance with this standard for emergency stopfunctions.

(2) The emergency stop function on a Wireless Operator Control Station shall continue to be available when theWireless Operator Control Station is located in the docking station at the machine.

(3) A continuous and distinctive audible and visual alarm shall be annunciated by the Wireless Operator Control Stationin the event that the emergency stop initiating device has been actuated.

(4) Upon activation of the emergency stop function, the Wireless Operator Control Station shall only be permitted to bereset (silenced) when the Wireless Operator Station has been returned to the docking station at the machine.

The new text creates and more clearly identifies the desired functional requirements for each of the

121Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 79major components of a Wireless Operator Control System for use with machinery; including the machine, the WirelessOperator Control Station and the additional requirements if the risk assessment reveals that an emergency stop initiatingdevice is required to be included as part of the Wireless Operator Control Station(s).

We submit that the use of the term "Cableless" is not appropriate as used in this standard; and that the morecommonly used term "Wireless" is more accurate. We have submitted a separate proposal to address Section 3.3.12 inthis regard.

This is because the term "Cableless" requires that there be no wired ("cabled") connection, to either communicationsor power systems of a machine. If a "Cableless" operator control station is placed into a docking station on a machine,or otherwise connected to machine power (for recharging batteries, etc.) it ceases being "Cableless". Thus, the term"Wireless" is more appropriate, since the term refers only to the communications technology used to communicatebetween the operator interface device or control station and the machine. Since all "Cableless" devices utilize wirelesstechnology to communicate, they are appropriately included under the heading of "Wireless Operator Control".

See action and statement on Proposal 79-109. The term cableless is commonly acceptedterminology in the industry.


122Printed on 10/13/2009




Machines employing Cableless Operator cControl Stations (e.g., radio, infrared) techniques fortransmitting commands and signals between a machine control system and operator control station(s) shall meet therequirements of this clause. include all of the following:

Means shall be provided to remove or disconnect the power supply of the operator control station. Thelocation of docking station(s), the control functions of the Cableless Operator Control Station(s), and all actuators andstopping devices shall be determined based on a risk assessment.

A Mmeans (e.g., locked storage, key-operated switch, access code) shall be provided, as necessary, toprevent unauthorized use of the operator control station.

Each operator control station shall carry an unambiguous indication of which machine(s) is intended to becontrolled by that operator control station. Docking station(s) shall be provided integral to the machine to facilitaterecharging of the power supply (battery).

9.2.7.1.4 A means shall be provided for a system of supervised communication, which shall cause an emergency stopof the machine when supervision signals from the active Cableless Operator Control Station have not been received bythe machine for a period, as determined by risk assessment, but not exceeding 550 ms, when the Cableless ControlMode on the machine has been activated.

9.2.7.1.5 An emergency stop of the machine shall be issued when a fault is detected in the cableless control.9.2.7.1.6 A means shall be provided to indicate the identity of the Operator Control Station (Cabled or Cableless) which

is in control of the machine.9.2.7.1.7 A means shall be provided to prohibit multiple Operator Control Stations (Cabled or Cableless) from

controlling the machine simultaneously; except that activation of any Emergency Stop Initiating Device shall result in anEmergency Stop of the machine.

9.2.7.1.8 A hard-wired or approved safety bus emergency stop actuator, located immediately adjacent to the dockingstation for the Cableless Operator Control Station.

Cableless Operator Control Station(s) shall comply with all ofthe following:

Measures shall be taken to ensure that control commands affect only the following: Cableless OperatorControl Station(s) shall carry an unambiguous indication of which machine(s) it is intended to control.

(1) The intended machine(2) The intended functions

Measures shall be taken Cableless Operator Control Stations shall provide a means (for example, codedtransmission) to prevent the machine from responding to signals other than those from the intended operator controlstation(s).

Means shall be provided so that the machine shall only be controlled from operator control stations in one ormore predetermined zones or locations. Cableless Operator Control Stations shall provide a visual indication of activeand inactive status.

9.2.7.2.4 Cableless Operator Control Stations shall provide both an audible and a visual warning when the powersupply (battery) voltage is low.

9.2.7.2.5 Cableless Operator Control Stations shall provide both an audible and a visual warning when the supervisionsignal is low due to approaching the limit of transmission range or low battery voltage).

9.2.7.2.6 Cableless Operator Control Stations shall transmit a supervision signal to the machine at periods notexceeding 550 ms, to maintain integrity of the communications signal.

9.2.7.2.7 Programming of Cableless Operator Control Stations shall only be possible when located in the dockingstation at the machine.

9.2.7.2.8 Means shall be provided to remove or disconnect the power supply of the Cableless OperatorControl Station.

In addition tothe requirements of 9.2.7.2, Cableless Operator Control Stations equipped with Emergency Stop Initiating Devices shallcomply with all of the following:

Operator control stations shall include a separate and clearly identifiable means to initiate the stop function of

123Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 79the machine or of all the motions that causes a hazardous condition. The actuating means to initiate this stop functionshall not be marked or labeled as an emergency stop device, even though the stop function initiated on the machineresults in an emergency stop function.

A machine that has safety critical functions that are equipped with cableless control shall have a means ofautomatically

initiating the stopping of the machine and preventing the initiation of potentially hazardous motions in the followingsituations:

(1) When a stop signal is received(2) When a fault is detected in the cableless control(3)*When a valid signal has not been detected within a specified period of time

In a machine where the control of safety critical functions relies on serialdata transfer, correct communications shall be ensured by using an error detection method that is able to cope with upto three error bits in any command sequence. The safety capability of the serial data communication system shall belisted to have the same degree of safety capability as hardware-based components installed in accordance with thisstandard.

Where a machine has more than one operator control station, measures shall be taken to ensure that only one controlstation shall be enabled at a given time. Indication of which operator control station is in control of the machine shall beprovided at locations where necessary for the safety requirements of the machine.

A variation in the battery voltage shall not cause ahazardous condition.

If one or more potentially hazardous motions are controlled using a battery-powered operator control station, a clearindication shall be given to warn the operator when a variation in battery voltage exceeds specified limits. Under thosecircumstances, the operator control station shall remain functional long enough to put the machine into a nonhazardouscondition.

The emergency stop function on a Cableless Operator Control Station shall continue to be active when theCableless Operator Control Station is located in the docking station at the machine.

The emergency stop function of a Cableless Operator Control Station shall provide a level of integrity whichis equivalent to that of hardware-based components installed in accordance with this standard for the emergency stopfunction.

A continuous and distinctive audible and visual alarm shall be annunciated by the Cableless Operator ControlStation in the event that the emergency stop initiating device has been actuated.

Upon activation of the cableless emergency stop device, the Cableless Operator Control Station shall only bepermitted to be reset (silenced) when the Cableless Operator Control Station has been returned to the docking station atthe machine.

A valid signal also includes the signal that confirms communication is established and maintained.

One way to determine applicable error detection methods is to refer to IEC 60870-5-l.Cableless Operator Control Stations with safety critical functions (like e-stop) are being introduced to

global markets. These panels are tested and certified by NRTL’s (and Notified Bodies) meeting the required standards.Therefore, NFPA 79 needs to be updated for proper application of these cableless operator control stations with safetyfunctions.

Revise text as follows:

Cableless control (e.g., radio, infrared) techniques for transmitting commands and signals between amachine control system and operator control station(s) shall meet the following requirements of this clause.

Means shall be provided to remove or disconnect the power supply of the operator control station. Meansshall be provided to verify the memory elements of the operator control station with the machine.

Means (e.g., key-operated switch, access code) shall be provided, as necessary, to prevent unauthorizeduse of the operator control station.

Each operator control station shall carry an unambiguous indication of which machine(s) is intended to becontrolled by that operator control station.

9.2.7.1.4 Means shall be provided for visual or audible indication of active and inactive status.124Printed on 10/13/2009


Measures shall be taken to ensure that control commands affect only the following:(1) The intended machine(2) The intended functions9.2.7.2.2 1 Measures shall be taken to prevent the machine from responding to signals other than those from the

intended operator control station(s).9.2.7.2.3 2 Where necessary, Mmeans shall be provided so that the machine shall can only be controlled from operator

control station(s) in one or more predetermined zones or locations.

Operator control stations shall include a separate and clearly identifiable means to initiate the stop function ofthe machine or of all the motions that causes a hazardous condition. The actuating means to initiate this stop functionshall not be marked or labeled as an emergency stop device, even though the stop function initiated on the machineresults in an emergency stop function.

9.2.7.3.2 1A machine which that has safety critical functions that are is equipped with cableless control shall have a means of

automatically initiating the stopping of the machine and preventing a potentially hazardous operation, in the followingsituations:

(1) When a stop signal is received;(2) When a fault is detected in the cableless control system;(3)*When a valid signal has not been detected within a specified period of time(4) When the control panel is taken outside the range of the cableless control where no hazardous situation can occur.

9.2.7.3.2 Where an Emergency Stop device is installed to a cableless control panel it shall meet the followingrequirements:

(1) Provide a level of integrity which is equivalent to that of hardware-based components installed in accordance withthis standard for emergency stop functions.

(2) A continuous and distinctive visual or audible alarm shall be annunciated by the Cableless Operator Control Stationin event that the emergency stop initiating device has been actuated

In addition, renumber Annex information as follows:

A valid signal also includes the signal that confirms communication is established and maintained.

The committee made the following revisions:Edited 9.2.7.1 and 9.2.7.1.1 text for user clarity and to be less restrictive and so that the revised text applies to all

cableless control functions, not just cableless operator control stations.Replaced 9.2.7.1.1 to include the requirement for memory verification.Removed “locked storage” text from 9.2.7.1.2 to be less restrictive.Removed 9.2.7.1.3, 9.2.7.1.4, 9.2.7.1.6, 9.2.7.2.5, 9.2.7.2.6, 9.2.7.2.7, 9.2.7.2.8, 9.2.7.3.3 and 9.2.7.3.6 as this

language was too product specific.Removed 9.2.7.1.5, 9.2.7.1.7 and 9.2.7.1.8 since not all cableless controls need an emergency stop button.Moved text 9.2.7.2.1 to 9.2.7.1.3 and 9.2.7.2.3 to 9.2.7.1.4 for better user clarity.Renumbered 9.2.7.2.2 to 9.2.7.2.1Added 9.2.7.2.2 requirement for operator safety.Revised section 9.2.7.3 to clearly separate the requirements for the stop and emergency stop functions. The stop

function requirements now remain the same as the current document with 9.2.7.3.1 (4) added and the emergency stoprequirements were moved from 9.2.7.3.4 and 9.2.7.3.5.

Items 9.2.7.3.1 and 9.2.7.3.2 were removed from the proposal and remain unchanged in the current document as9.2.7.4 and 9.2.7.6.


ANDERSON, W.: I agree with the committee's action.Note: Editorial change needed to the committee action in order to meet the MOS:

125Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 799.2.7.3 Stop function Cabeless Operator Control Stations with Emergency Stop Initiating Devices. In addition to therequirements of 9.2.7.2, Cableless Operator Control Stations equipped with Emergency Stop Initiating Devices shallcomply with 9.2.7.3.1 through 9.2.7.3.6 .all of the following:

126Printed on 10/13/2009



Delete Section 9.2.8 and relocate its text (except the heading) as a new first sentence underSection 9.3.2 and re-number as appropriate:

9.3.2 Exceeding Operating Limits. Movement or action of a machine or part of a machine that can result in ahazardous condition shall be monitored by providing, for example, overtravel limiters, motor overspeed detection,mechanical overload detection, or anti-collision devices. Where an operating limit (e.g., speed, pressure, position) canbe exceeded leading to a hazardous condition, means shall be provided to detect when a predetermined limit(s) isexceeded and initiate an appropriate control action.

This proposal will improve the readability of the document. The material in Sections 9.2.8 and 9.3.2 isrelated, and should be contained in the same section.

Delete A.9.2.8.A.9.3.2 to read as follows: A.9.3.2 On some manually controlled machines, operators provide monitoring.

Add asterisk following 9.3.2.The proposal was accepted as written. However, the associated Annex material also had to

be renumbered as appropriate and an asterisk added following the Section number.


127Printed on 10/13/2009



Add new item (6) to Section 9.4.1.1 as follows:Measures to reduce these risks shall include, but are not limited to, one or more of the following:

(1) Protective devices on the machine (e.g., interlock guards, trip devices)(2) Protective interlocking of the electrical circuit(3) Use of proven circuit techniques and components(4) Provisions of partial or complete redundancy or diversity(5) Provision for functional tests.(6) Arranging machine actuators to fail to a safe postion.

To emphasize that one method of mitigating risks associate with control system failure is to design themachine actuators to fail to the safe position.

The proposed additional item (6) is concerned with a mechanical failure that cannot beaddressed with an electrical control function.


ANDERSON, W.: Add to 9.4.1.1 (6) Arranging machine actuators to fail to a safe position.The committee did not include common solution possibilities which are one or more of the electrical aspect of machinedesign strategies.The proposed additional item (6) is concerned with a mechanical failure that can be addressed with an interfaceelectrical control function solution.

128Printed on 10/13/2009



Add text to read as follows:9.4.3.2.2 Loss of memory shall not result in a hazardous condition. Machine actuators shall be arranged such that they

will fail to a safe state on the loss of instruction.Machine safety in the event of a loss of memory requires both the controller logic and the machine

actuators to fail to a safe state. This proposal makes it clear that both memory and output elements fail to the safe statein the event that machine memory (logic instructions) are lost.

The proposed text is not necessary as the submitter's concerns are addressed by the currentlanguage.


129Printed on 10/13/2009



Delete Section 9.4.3.2.3:9.4.3.2.3 Power supplies for electronic equipment requiring memory retention shall have battery backup of sufficient

capacity to prevent memory loss for a period of at least 72 hours.The current state of technology makes this exception obsolete. Modern memory elements have

retention times which far exceed 72 hours, making the need to connect power ahead of supply disconnecting meansunnecessary. This proposal will result in increased safety for maintenance personnel.

Due to uncertainty of machine outage because of schedule changes or production needs, thecommittee chooses to retain this section.


DEFELICE, JR., F.: This proposal would result in increased safety for maintenance personnel. The current state oftechnology makes the exception obsolete. Modern memory elements have retention times which far exceed 72 hours,making the need to connect power ahead of supply disconnecting means unnecessary.

130Printed on 10/13/2009



Software and firmware based controllers to be used in safety-related functions shall besuitable for the SIL Level required by the risk assessment and listed for such use.

Electronic controllers must be selected which are sufficiently robust and designed to address the levelof risk specific to the particular machine application. For this reason, electronic controllers are rated by their ability toperform safety-related functions, based on the level of complexity and redundancy. This proposal makes it clear that theelectronic controller must be rated to address the level of risk expected to be encountered.

(Note: See related proposal to define SIL in chapter 3 Definitions and Annex A).

The proposal does not adequately address the process of determining the Safety IntegrityLevel (SIL). See action on Proposal 79-11.


131Printed on 10/13/2009



Revise text as follows:Control systems incorporating software and firmware based controllers performing safety-related functions

shall be self-monitoring and conform to all of the following:(1) In the event of any single failure, the failure: shall not lead to the loss of the safety function. Safety function is the

ability to self monitor and stop the application.(a) Shall not lead to the loss of the safety-related function(s)(a) (b) Shall lead to the shutdown of the system in a safe state(b) (c) Shall prevent subsequent operation until the component failure has been corrected(c) (d) Shall prevent unintended startup of equipment upon correction of the failure(2) Provide protection equivalent to that of control systems incorporating hardwired/hardware components.(3) Be designed in conformance with an approved standard that provides requirements for such systems.

Task Group #5 recommends the above edits to improve understanding of the requirements bystandardizing on the term as opposed to , ,

or (no hyphen).Additionally, note that location of a definition within the requirements of 9.4.3.4.2(1) violates Section 1.6.3.2 of the

NFPA Manual of Style.



132Printed on 10/13/2009



Revise Section 9.4.3.4 as follows:9.4.3.4.2 Control systems incorporating software and firmware based controllers performing safety-related functions

shall be self-monitoring and conform to all of the following:(1) In the event of any single failure, the failure: shall not lead to the loss of the safety function. Safety function is the

ability to self monitor and stop the application.(a) Shall not lead to the loss of the safety-related function(s)(a)(b) Shall lead to the shutdown of the system in a safe state(b)(c) Shall prevent subsequent operation until the component failure has been corrected.(c)(d) Shall prevent unintended startup of equipment upon correction of the failure

(2) Provide protection equivalent to that of control systems incorporating hardwired/hardware components.(3) Be designed in conformance with an approved standard that provides requirements for such systems.Additionally, in Annex A.4.1 make the following revisions:A.4.1 A sample inquiry form is provided in Annex B for use in facilitating an agreement between the supplier and the

user.Hazardous situations can result from, but are not limited to, the following causes:(1) Failures or faults in the electrical equipment resulting in the possibility of electrical shock, flash hazard, or electrical

fire(2) Failures or faults in control circuits (or components and devices associated with these circuits) resulting in

malfunctioning of the machine(3) Disturbances or disruptions in power sources as well as failures or faults in the power circuits, resulting in the

malfunctioning of the machine(4) Loss of continuity of circuits that depend upon sliding or rolling contacts, resulting in a failure of a safety function

safety-related function(5) Electrical disturbances (e.g., electromagnetic, electrostatic, or radio interference) either from outside the electrical

equipment or internally generated, resulting in the malfunctioning of the machine(6) Release of electrical or mechanical stored energy, resulting in, for example, electric shock or unexpected

movement that can cause injury(7) Audible noise at levels that cause health problems to persons(8) Surface temperatures that can cause injurySafety measures are a combination of the measures incorporated at the design stage and those measures required to

be implemented by the user. Design and development should be the first consideration in the reduction of risks. Wherethis is not possible, safequarding should be considered. Safeguarding includes the use of safeguards, awarenessmeans, and safe working procedures.

One reference to risk assessment is ANSI B11-TR3.Flash hazard analysis, calculation methods, and ways to address the hazard are found in NFPA 70E.

Task Group No. 5 recommends the above edits to improve understanding of the requirements bystandardizing on the term "safety-related function" as opposed to "safety function", "safety-critical function", "safetycritical function" or "safety related function" (no hyphen).

Additionally, note that location of a definition within the requirement of 9.4.3.4.2(1) violates Section 1.6.3.2 of the NFPAManual of Style.



133Printed on 10/13/2009



Revise text to read as follows:Control systems incorporating software and firmware based controllers performing safety-related functions

shall be self-monitoring and conform to all of the following: (1) In the event of any single failure, the failure shall: shall not lead to the loss of the safety function. Safety function

is the ability to self monitor and stop the application.(a) Not lead to the loss of the safety-related function(s)(a) (b) Lead to the shutdown of the system in a safe state (b) (c) Prevent subsequent operation until the component failure has been corrected (c) (d) Prevent unintended startup of equipment upon correction of the failure(2) Provide protection equivalent to that of control systems incorporating hardwired/hardware components. (3) Be designed in conformance with an approved standard that provides requirements for such systems.

A sample inquiry form is provided in Annex B for use in facilitating an agreement between the supplier and theuser.

Hazardous situations can result from, but are not limited to, the following causes: (1) Failures or faults in the electrical equipment resulting in the possibility of electrical shock, flash hazard, or

electrical fire (2) Failures or faults in control circuits (or components and devices associated with these circuits) resulting in

malfunctioning of the machine (3) Disturbances or disruptions in power sources as well as failures or faults in the power circuits, resulting in the

malfunctioning of the machine (4) Loss of continuity of circuits that depend upon sliding or rolling contacts, resulting in a failure of a safety function

safety-related function (5) Electrical disturbances (e.g., electromagnetic, electrostatic, or radio interference) either from outside the electrical

equipment or internally generated, resulting in the malfunctioning of the machine (6) Release of electrical or mechanical stored energy, resulting in, for example, electric shock or unexpected

movement that can cause injury (7) Audible noise at levels that cause health problems to persons (8) Surface temperatures that can cause injury Safety measures are a combination of the measures incorporated at the design stage and those measures required to

be implemented by the user. Design and development should be the first consideration in the reduction of risks. Where this is not possible,

safeguarding should be considered. Safeguarding includes the use of safeguards, awareness means, and safe workingprocedures.


TG#5 recommends the above edits to improve understanding of the requirements and bystandardizing on the term “safety-related function” as opposed to “safety function”, “safety-critical function”, “safetycritical function” or “safety related function” (no hyphen).

Additionally, note that location of a definition within the requirement of 9.4.3.4.2 (1) violates Section 1.6.3.2 of theNFPA Manual of Style. This is a companion proposal to Log #22 from Frank DeFelice.

Revise text to read as follows:Control systems incorporating software and firmware based controllers performing safety-related functions

shall be self-monitoring and conform to all of the following: (1) In the event of any single failure, the failure shall: shall not lead to the loss of the safety function. Safety function

134Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 79is the ability to self monitor and stop the application.

(a) Not lead to the loss of the safety-related function(s)(a) (b) Lead to the shutdown of the system in a safe state (b) (c) Prevent subsequent operation until the component failure has been corrected (c) (d) Prevent unintended startup of equipment upon correction of the failure(2) Provide protection equivalent to that of control systems incorporating hardwired/hardware components. (3) Be designed in conformance with an approved standard that provides requirements for such systems.

A sample inquiry form is provided in Annex B for use in facilitating an agreement between the supplier and theuser.

Hazardous situations can result from, but are not limited to, the following causes: (1) Failures or faults in the electrical equipment resulting in the possibility of electrical shock, flash hazard, or

electrical fire (2) Failures or faults in control circuits (or components and devices associated with these circuits) resulting in

malfunctioning of the machine (3) Disturbances or disruptions in power sources as well as failures or faults in the power circuits, resulting in the

malfunctioning of the machine (4) Loss of continuity of circuits that depend upon sliding or rolling contacts, resulting in a failure of a safety function

safety-related function (5) Electrical disturbances (e.g., electromagnetic, electrostatic, or radio interference) either from outside the electrical

equipment or internally generated, resulting in the malfunctioning of the machine (6) Release of electrical or mechanical stored energy, resulting in, for example, electric shock or unexpected

movement that can cause injury (7) Audible noise at levels that cause health problems to persons (8) Surface temperatures that can cause injury Safety measures are a combination of the measures incorporated at the design stage and those measures required to

be implemented by the user. Design and development should be the first consideration in the reduction of risks. Where this is not possible,

safeguarding should be considered. Safeguarding includes the use of safeguards, awareness means, and safe workingprocedures.


The committee noted that in two locations there were two unintended underlines and they wereremoved:

In A.4.1 "B" following Annex was not intended to be underlined.In the last paragraph "NFPA 70E" was also not intended to be underlined.


FISHER, D.: The proposed revision of perpetuates an inherent conflict between what we call out as the designdocuments and the requirements stated for the performance of the control system. The documents we reference in theAnnex A are IEC 62061 and ISO 13849-1. Both of these documents are now based upon probabilistic performance. Inother words systems designed in accordance with the referenced standards are designed to execute the plannedprocess/program/control functions in accordance with the designer’s selected level of performance as expressed interms of SIL or Plevel , depending upon whether the system is designed to IEC 62061 or ISO 13849-1.

The problem is that all of the performance requirements listed in the proposed revision are absolute. There are noprobability claims for performance. When 9.4.3.4 was originally written there were still Categories available in theprevious edition of ISO 13849-1 which did not require probabilistic considerations. So, it might then have beenperceived that the absolute performance that we stated was in conformance with at least one of the standards we cited.That is not the case now. This matter needs to be addressed.

Further the use of the term “safety-related function” is unnecessarily bulky as detailed in my response to 79-30 (Log#208)

135Printed on 10/13/2009



Revise text to read as follows:10.1.4.2* Position sensors used in circuits with safety-related control functions either shall have direct opeing

operations or shall provide similar reliability.This term correlates with similar terminology used in IEC and ISO documents and other proposals

submitted to standardize on the term "safety-related".



136Printed on 10/13/2009


_______________________________________________________________________________________________Guy Gargano, Garlyn Associates

Delete exception.The exception removes the requirement for a legend plate from an E-Stop device if it meets the color

requirements. The problem occurs because of color blind or color impaired vision problems. All devices should berequired to have a legend plate regardless of color coding.

Note: Supporting material is available for review at NFPA Headquarters.

The requirement for a legend plate is not practical (such as when pull ropes are utilized) for allE-stop devices.

The color blindness issue the submitter is concerned with also exists in 10.7.3.


ANDERSON, W.: The purpose of the exception was to allow extensions of the E-Stop actuators such as pull ropes tobe used without trying to follow, sometimes impossible requirements, of having a yellow background throughout thelength of the pull rope and to have identification labels along the rope length. With the color blindness issue (at one timecolorblindness was a disqualifier for electrical work and machine operator jobs, this generally is not the case today) ;therope actuator application could have the identification labels at the actuator of which the rope is extended from as wellas all other E-Stop actuators. The proposed elimination of the exception should be as proposed but with an explanatorynote that the identification labels requirement would apply to the actuator and the actuator extension (i.e. the pull rope),where practicable.Some facts about color blindness:Color Blindness is a condition in which certain colors cannot be distinguished.Red/Green color blindness is the most common form, about 99%, and causes problems in distinguishing reds andgreens.Another color deficiency Blue/Yellow also exists, but is rare and there is no commonly available test for it.Total color blindness (seeing in only shades of gray) is extremely rare.WHO IS COLOR BLIND? ; 8% - 12% males of European origin ½ of 1% of females.PROTANOMALY IS; Red weakness; 1 out of 100 males; Difficulty telling the difference in Red, orange, yellow,yellow-green, and green; Violet looks like a shade of blue.DEUTERANOMALY IS; Green Weakness; 5 out of 100 males; Difficulty telling the difference in reds, oranges, yellows,and greens; Colors shift toward red.DICROMASY IS; Red, orange, yellow, and green appear to be the same color; 2 out of 100 males.PROTANOPIA IS; Brightness of red, orange, and yellow is much reduced; 1 out of 100 malesDEUTERANOPIA IS; Red, orange, yellow, and green really mean very little; 1 out of 100 males; All shades of similarcolors mean nothing.

WATSON, E.: While I support the committee's action and committee statement on this proposal, there are still a goodpercentage of color blind people who are interfacing with industrial machinery and potentially not recognizing thelocation of emergency stop actuators. A better action would have been to Agree in Principle and modify the exceptionwording in 10.2.3.1 to read as follows:

Exception: Where is it not practical to provide a legend, emergency stop devices require no legend if they meet therequirements of 10.7.3.

137Printed on 10/13/2009


_______________________________________________________________________________________________Michael L. Gililland, Engineering Systems Inc.

Add text to read as follows:10.3.1.1 Indicator light circuits used for warning or danger lights shall be fitted with facilities to check the operability of

these lights.Normalization: normalizes NFPA 79 to IEC 60204-1. The feature is believed to already be in

widespread use. Addition to NFPA 79 would standardize an already standard practice of "push-to-test" of warninglights.


BAS, L.: Should be APR. Accepting this proposal does not meet MOS clause 1.8.1. Acceptance of 79-122 (Log#165) covers the intent of this proposal.

138Printed on 10/13/2009



Add new text to read as follows:10.3.1.1 Indicator light circuits used for warning or danger lights shall be fitted with facilities to check the operability of

these lights.Normalization: normalizes NFPA 79 to IEC 60204-1. The feature is believed to already be in

widespread use. Addition to NFPA 79 would standardize an already standard practice of "push-to-test" of warning lights.



BAS, L.: Reference should be to 79-122 (Log #205) as 79-120 (Log #117) does not meet MOS 1.8.1.

139Printed on 10/13/2009



Add new (3) as follows:10.3.1 Modes of Use. Indicator lights and icons of color graphic interface devices shall provide the following

information:(1) Indication to attract the operator's attention or to indicate that a certain task should be performed. The colors RED,

Yellow (AMBER), GREEN, and BLUE are normally used in this mode.(2) Confirmation of a command or a condition, or the termination of a change or transition period. The colors BLUE and

WHITE are normally used in this mode. GREEN shall be permitted to be used in some cases.(3) Indicator light circuits used for warning lights shall be fitted with facilities to check the operability of these lights.

Harmonization with IEC 60204-1: Warning lights indicate a potential problem. There should be ameans to check to ensure that these lights are operating properly and not burned out.

See the committee action on Proposal 79-120. The committee concludes that the action takenon Proposal 79-120 meets the intent of the submitter.


BAS, L.: Accept the addition but strike out the word "Information" from main text of 10.3.1

140Printed on 10/13/2009


_______________________________________________________________________________________________Glyn R. Garside, Pilz Automation Safety L.P.

Revise text to read as follows:Stop or eEmergency stop pushbuttons shall be located at each operator control station. and Emergency stop

pushbuttons shall also be located at other locations where emergency stop is required, as determined by the riskassessment of the machine.

The present wording states that anywhere an E-stop is , a Stop can be used instead. So if anE-stop is required… it isn’t. For comparison, IEC 60204-1 2005, 10.7.1, states, “Emergency stop devices shall belocated at each operator control station and at other locations where the initiation of an emergency stop can berequired”.

See also

The revised text will be as follows:Stop or emergency stop pushbuttons shall be located at each operator control station. and Emergency stop

pushbuttons shall also be located at other locations where emergency stop is required.The committee did not agree with the submitter that an Emergency stop button is required at

each operator control station. The reference to risk assessment is is not required as it is already covered in 4.1.The committee does not accept:1. Stop or2. as determined by the risk assessment of the machineThe committee accepted the text: "Emergency stop pushbuttons shall also be located"


141Printed on 10/13/2009



Revise text to read as follows:11.4.2 Where corrosion protection beyond normal requirements is needed, nonmetallic enclosures identified for the

purposes shall be permitted if they meet the requirements of ANSI/UL 508.Update standards titles to indicate ANSI approvals.



142Printed on 10/13/2009



Revise text to read as follows:11.4.7 Door fasteners on enclosures and compartments with door openings shall comply with ANSI/UL 50, ANSI/UL

508, UL 508A, or NEMA 250.Update standards titles to indicate ANSI approvals.



143Printed on 10/13/2009



Delete Exception No. 4 entirely.This reduced working distance implies a reduced hazard that cannot be justified based on the voltage

and other conditions of the exception. Furthermore, this distance is actually likely to be measured in a completedinstallation based on the requirements of the NEC and OSHA, neither of which recognize the reduced distance. While4.1 requires the risks to be reduced this exception actually allows an increased risk with no technical justification basedon risk. The justification for this exception is really based on convenience and possible cost issues, neither of which areabout the stated purpose of the standard in 1.2: "promoting safety to life and property."

The committee finds the current language in the exception acceptable based on the voltagesand the conditions stated.


DEFELICE, JR., F.: With regard to proposals number 79-126, 79-127 and 79-128 submitted for possible inclusioninto the 2011 Edition of NFPA 79 - Electrical Standard for Industrial Machinery, it has been brought to my attention thatan important discrepancy exists between the English-to-Metric Conversion Values shown in Table 11.5.1.1 WorkingSpace Depth shown and Table 110.26(A)(1) Working Spaces shown in NFPA 70 - National Electrical Code.

****Insert tables provided with DeFelice Affirmative Comment***

144Printed on 10/13/2009

79-126_L104_DeFeliece_Aff_Comm_F2010

Comments to the Technical Correlating Committee - Proposals 79-126 / 79-127 / 79-128 NFPA 79-2007

Table 11.5.1.1 Working Space Depth NEC-2008

Respectfully submitted, Frank C. DeFelice

Minimum Clear Distance

Nominal Voltage to Ground Condition 1 Condition 2 Condition 3

0–150 900 mm (3 ft) 900 mm (3 ft) 900 mm (3 ft)

151–600 900 mm (3 ft) 1 m (3 ft) 1.2 m (4 ft)

Note: Where the conditions are as follows: Condition 1 — Exposed live parts on one side and no live or grounded parts on the other side of the working space, or exposed live parts on both sides effectively guarded by insulating materials. Insulated wire or insulated busbars operating at not over 300 volts to ground shall not be considered live parts. Condition 2 — Exposed live parts on one side and a grounded surface on the other side. Concrete, brick, or tile walls shall be considered as grounded. Condition 3 — Exposed live parts on both sides of the working space (not guarded as provided in Condition 1) with the operator between.



Delete Exception No. 5 entirely.This reduced working distance implies a reduced hazard that cannot be justified based on the voltage

and other conditions of the exception. Furthermore, this distance is actually likely to be measured in a completedinstallation based on the requirements of the NEC and OSHA, neither of which recognize the reduced distance. While4.1 requires the risks to be reduced this exception actually allows an increased risk with no technical justification basedon risk. In fact, this exception is based partially on the assumption that "diagnostic troubleshooting and testing on liveparts" somehow justifies a reduced space while the industrial experience (such as OSHA and NIOSH records)demonstrate otherwise. The justification for this exception is really based on convenience and possible cost issues,neither of which are about the stated purpose of the standard in 1.2: "promoting safety to life and property."

Delete Exception No. 5 entirely.Renumber remaining exceptions


DEFELICE, JR., F.: See Affirmative Comment on Proposal 79-126 (Log #104).

145Printed on 10/13/2009



Remove the phrase "or less" in Section 11.5.1.1 Exception No. 2 and Delete Exception No. 6(which is in essence Exception No. 5 with the statement "or less") as follows:

Exception No. 2: By special permission, working space clearance depth of 762 mm (2 1/2 ft) or less shall be permittedwhere all uninsulated parts are at a voltage no greater than 50 volts rms ac or 60 volts dc.

Exception No. 6: By special permission, working space clearance depth of less than 762 mm (2 1/2 ft) shall bepermitted where all of the following conditions are met:

(1) The control cabinet or compartment is operating at not over 150 volts line to line or line to grounds.(2) The conditions of maintenance and supervision ensure that only qualified persons will service the installation.(3) The control cabinet and compartment requires a tool to open.(4) Where only diagnostic troubleshooting and testing on live parts is involved.(5) The door(s) of the control cabinet and compartment open at least 90 degrees or are removable.

Providing adequate Working Clearances around electrical equipment is a principle method ofprotecting the safety of electrical maintenance personnel. Reducing the clearance requirements below those found inNFPA 70 National Electrical Code when the voltages, fault currents and hazards are identical, results in two standardsfor electrical safety.

This proposal requests the removal of the terms "or less" and "less than"; because these terms are vague andunenforceable. In fact, we have encountered several situations where these exceptions were interpreted to provideworking clearances of twelve (12) inches; and this is entirely inadequate to permit electrical personnel to performelectrical testing safely.

Exception No. 6 text as follows:By special permission, the minimum working space clearance depth of less than 762 mm (2 1/2 ft) shall be permitted

where all of the following conditions are met:(1) The control cabinet or compartment is operating at not over 150 volts line to line or line to grounds.(2) The conditions of maintenance and supervision ensure that only qualified persons will service the installation.(3) The control cabinet and compartment requires a tool to open.(4) Where only diagnostic troubleshooting and testing on live parts is involved.(5) The door(s) of the control cabinet and compartment open at least 90 degrees or are removable.

The committee rejects the submitters change to Exception No. 2 as the existing requirement isadequate at the voltage.

The committee rejected deleting Exception No. 6 in its entirety as it contains additional criteria for the reduced workingspace. The committee deleted "less than" in Exception No. 6 in order to maintain adequate working space for thevoltage.The committee accepts the remainder of the submitter's recommendation.


DEFELICE, JR., F.: See Affirmative Comment on Proposal 79-126 (Log #104).

146Printed on 10/13/2009



Relocate Section 11.6 (including 11.6.1, 11.6.2 and 11.6.3) as new Sections 10.1.2.3 / 10.1.2.3.1 /10.1.2.3.2 / 10.1.2.3.3.

This change would consolidate the requirements for these devices in a single, more appropriatelocation. Section 11.6 (including 11.6.1, 11.6.2 and 11.6.3) are more appropriate in Section 10.1.2.3; where

requirements are arranged. Our substantiation follows:Section 11.6 (including 11.6.1, 11.6.2 and 11.6.3) contains requirements for the mounting and protection of machine

mounted control devices and includes examples .Chapter 10 is entitles . Section 10.1.1 states that Chapter 10

contains the requirements for control devices which are " ".Section 10.1.2 along with sub-section 10.1.2.1 address location of andmounting of these devices. Other (neighboring) sections within Chapter 10 also discuss mounting, location andprotection of control devices (see Sections 10.1.3 and 10.1.4).


BAS, L.: Section 11.6 is dealing with sensors and such that are used in the automatic control of the process, whilethe proposed section is for operator interface and control.

WATSON, E.: I agree with the Committee Action on this proposal. This action has moved the requirements formachine-mounted control devices into Chapt.10 Operator Interface and Control Devices. Therefore the acceptance ofthis proposal should have included the renaming of Chapt.10 to Operator Interface and Machine-Mounted ControlDevices, which is also consistent with harmonizing with IEC 60204-1, and a comment should be written to that extent.

147Printed on 10/13/2009



Delete the following text:12.1.4 Conductors and Static Control. Conductors smaller than 18 AWG used to connect electronic programmable

control, input/output, and static control shall be listed.This proposal is an output of the NFPA 79 AWM Task Group.

The requirements for small conductors used for control are defined in other areas (12.2, 12.6,etc) and conflicts with theacceptable use of AWM. In addition, the reference to “static” control is outdated and confusing as it refers to electronicnon-programmable control, but is often misinterpreted as meaning “electrostatic” discharge control.

Delete 12.1.4.Renumber remaining sections.


CALLANAN, M.: We agree with the concerns expressed by Messrs. DeFelice and Hilbert.HILBERT, M.: I disagree with deleting this Section in its entirety as it will remove the requirement for the conductors

to be listed no matter what type they are. The action on this proposal should have been to accept in part revising 12.1.4as follows:

12.1.4 Conductors and Static Control. Conductors smaller than 18 AWG used to connect electronic programmablecontrol, input/output and static control shall be listed or meet the requirements of 12.9.2.2.

Removing the words “static control” from the text was rejected because they still remain in the title of the section. If theterm “static control” is outdated then a comment should be submitted to replace them in the text and title with theappropriate terminology. Revising the existing text by adding a reference to the new 12.9.2.2 will keep the originalrequirement for listing theses small conductors while addressing the submitter’s concern with the acceptable uses ofAppliance Wiring Material (AWM).

148Printed on 10/13/2009



Delete Exception No. 2 entirely.The 2007 Edition deleted Section 8.2.2.3.1 that permitted the machine structure to be used as an

equipment grounding conductor. Now that the permission to use the structure has been removed from Chapter 8, theother sections that refer to the structure as an equipment grounding conductor should also be removed. As it stands,this is very confusing. Two other proposals will recommend the deletion of similar language in Chapter 8.


149Printed on 10/13/2009



Delete 12.2.1 and its exception in its entirely and renumber remaining sections appropriately.“ Conductors shall be copper.

12.2.1 and Exception No.1 is covered in 8.2.3.1. Machine structural members are no longerrecognized as an electrical equipment grounding circuit conductor or related bonding jumpers as defined in 3.3.9(1).

The Committee rejects the recommendation to delete 12.2.1 and Exception No. 1 as theserequirements apply to more than Chapter 8.

The committee action on Proposal 79-131 deleted Exception No. 2.


150Printed on 10/13/2009



Delete 12.2.1 and its exception in its entirely and renumber remaining sections appropriately.“ Conductors shall be copper.

12.2.1 and Exception No.1 is covered in 8.2.3.1. Machine structural members are no longerrecognized as an electrical equipment grounding circuit conductor or related bonding jumpers as defined in 3.3.9(1).

The committee rejects the recommendation to delete 12.2.1 and Exception No. 1 as theserequirements apply to more than Chapter 8.

The committee action on Proposal 79-131 deleted Exception No. 2.


151Printed on 10/13/2009



Replace section 12.2.7 and associated annex note and with new section 12.9 and new annex noteas follows:

12.2.7 Special Cables and Conductors.12.2.7.1 Other listed conductors and listed cables shall be permitted.12.2.7.2 Special conductors such as RG -/U transmission cable shall be permitted where necessary for the proper

functioning of the equipment.12.2.7.3* Appliance Wiring Material. Single conductor or multi-conductor Type AWM shall not be permitted.Exception:

When part of a listed assembly suitable for the intended application, Type AWM shall be permissible.A.12.2.7.3 Insulated conductors are often marked with multiple identifying characteristics. (See 12.3.1, as well as

AWM.)12.9* Special Cables and Conductors.12.9.1 Other listed cables and conductors shall be permitted where identified as suitable for intended use.12.9.2 Appliance Wiring Material (AWM) shall be permitted under 12.9.2.1 through 12.9.2.312.9.2.1 Where part of an assembly that has been identified for intended use12.9.2.2 Where specified for use with approved equipment and used in accordance with the equipment

manufacturer’s instructions.12.9.2.3 Where its construction meets all applicable requirements of sections 12.2 -12.6 with modifications as follows:(1) Stranded conductors with wire sizes smaller than those listed in 12.2.2 shall have a minimum of 7 strands(2) Conductor insulation and cable jacket materials not specified in 12.3.1 shall have flame resistant properties in

compliance with applicable standards for intended use such as FT2 (horizontal wire) flame test or VW-1 (Vertical Wire)flame test in ANSI/UL 1581-2001, Reference Standard for Electrical Wires, Cables and Flexible Cords.

(3) Minimum insulation thicknesses for single conductor AWM shall be as specified in 12.3.2. Minimum insulationthickness for conductors that are part of a multiconductor jacketed AWM cable shall be as specified by the AWM Stylenumber and by the marked voltage rating of the cable.

(4) AWM shall be marked in accordance with 12.4.1, 12.4.3, and 12.4.4. The legend shall include manufacturer’sname or trademark, AWM Style number, voltage rating (unless marking is prohibited by 12.4.2), wire gauge(s),temperature rating, and flame resistance. Additional markings for properties such as oil, water, UV, and chemicalresistance identifiers shall be permitted where in compliance with applicable standards for intended use. Wheremarkings alone are insufficient to identify for the intended application, suitable information shall be included with themachine technical documentation.

A.12.9 Special cables and conductors require additional consideration of their design properties to determinesuitability for intended use (e.g. chemical, flexibility, flammability resistance, shielding, conductor configuration). Thoseevaluated to the UL758 Appliance Wiring Material standard are often marked with multiple identifying characteristics

(See 12.3.1 and 12.8.1) in addition to AWM.This proposal was developed by the NFPA 79 Technical Committee Task Group on AWM.

The 2007 revision adding restrictions to the use of UL759 Appliance Wiring Material. Many machinery manufacturersrequire use of AWM to meet application needs. As such, these manufacturers are no longer able to produce equipmentthat meets the requirement(s) of NFPA 79. The revised wording re-establishes the permitted use of AWM as specialconductors and cables with clarifications on determining suitability for use.

In addition, the section was moved from the cable section (12.2) to its own section (12.9) as it applies to conductors,and cables and is more logically placed at the end.


HILBERT, M.: Accept in Principle in Part and revise as follows:12.9* Special Cables and Conductors.

12.9.1 Other listed cables and conductors shall be permitted where identified as suitable for intended use.12.9.2 Appliance Wiring Material (AWM) shall be permitted under either 12.9.2.1 or 12.9.2.2.12.9.2.1 Where part of a listed assembly that has been identified for intended use.

152Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 7912.9.2.2 Where used with approved equipment and installed in accordance with the manufacturer’s instructions. Theconstruction shall meet all the applicable requirements of sections 12.2 -12.6 with modifications as follows:(1) Stranded conductors with wire sizes smaller than those listed in 12.2.2 shall have a minimum of 7 strands(2) Conductor insulation and cable jacket materials not specified in 12.3.1 shall have flame resistant properties incompliance with applicable standards for intended use such as FT2 (horizontal wire) flame test or VW-1 (Vertical Wire)flame test in ANSI/UL 1581-2001, Reference Standard for Electrical Wires, Cables and Flexible Cords.(3) Minimum insulation thickness for single conductor AWM shall be as specified in 12.3.2. Minimum insulationthicknesses for conductors that are part of a multiconductor jacketed AWM cable shall as specified by the AWM Stylenumber and by the marked voltage rating of the cable.(4) AWM shall be marked in accordance with 12.4.1, 12.4.3, and 12.4.4. The legend shall include manufacturer’s name

or trademark, AWM Style number, voltage rating, (unless marking is prohibited by 12.4.2) wire gauge(s), temperaturerating, and flame resistance. Additional markings for properties such as oil, water, UV, and chemical resistance shall bepermitted when in compliance with applicable standards for the intended use. Where markings alone are insufficient toidentify for the intended application, suitable information shall be included with the machine technical documentationA.12.9 Special cables and conductors require additional consideration of their design properties to determine suitabilityfor intended use (e.g. chemical, flexibility, flammability, resistance, shielding, conductor configuration). Those evaluatedto the UL758 Appliance Wiring Material standard are often marked with multiple identifying characteristics (See 12.3.1and 12.8.1) in addition to AWM.

I do not agree with expanding the use of Appliance Wiring Material to an assembly that was not listed so the term“listed” was added to the proposed 12.9.2.1.

12.9.2.2 and 12.9.2.3 were combined into 12.9.2.2 as the only time AWM should allowed as other than as part of alisted assembly is where it is used with approved equipment in accordance with the manufacturers installationinstructions. In these cases the Appliance Wiring Material construction must meet the proposed list items (1) through (4)in addition to 12.2 – 12.6 so that language was retained. The words “specified for use” were removed from theproposed 12.9.2.2 for clarity as it was unclear as to who would be specifying the Appliance Wiring Material was intendedfor use with the approved equipment and it also limited the application to only those that were specified to be usedtogether.

153Printed on 10/13/2009



Revise text to read as follows:Table 12.3.2 (Note)Source: ANSI/UL 1063, Table 1.1, NEC Construction.

Update standards titles to indicate ANSI approvals.



154Printed on 10/13/2009



Revise 12.4.2 as follows and add annex note:The legend shall include the manufacturer’s name or trademark, the wire type, voltage rating (where permitted

by the National Electrical Code), and gauge or size.*A.12.4.2 Some examples of types that do not permit marking with voltage rating include Class 2 and Class 3 circuit

cable, Power Limited Tray Cable, Instrumentation Tray Cable, and Communications Cable as the voltage rating isincluded in the cable class marking. See 12.9.2 for marking requirements for AWM.

This proposal was developed by the NFPA 79 Technical Committee Task Group on AWM.An exception is required for the current legend voltage marking requirements in 12.4.2 as it conflicts with product listing

(and the NEC) for some cable types.See companion proposal to 12.2.7.


155Printed on 10/13/2009



Add an exception as shown below :12.4.8 A print pocket sized to accommodate electrical diagrams shall be attached to the inside of the door of the

control enclosure or compartment. Single-door and multi-door enclosures shall have at least one print pocket.Exception No. 1: Where this is not practicable, an information label referencing by title and part number the technical

document or set of documents that contain the electrical diagrams, or clear instructions on how to locate the electricaldiagrams in the machine control system may be provided instead.

For large and complex equipment the size and number of electrical diagrams prohibits providing themin a manner that can fit in a print pocket given practical considerations. Also, some equipment must be used in cleanrooms. This prohibits the use of regular paper, and specialty papers are expensive. Many equipment users prefer thatall documentation be provided on CD or DVD format, or already loaded onto the hard disk of the main system controller.Recreating the information on paper would be a non-value-added expense.

Where the equipment is large and complex, the electrical diagrams will also be large and complex. Providing them inelectronic format on a CD or DVD disk, or already loaded into the machine control computer may actually make themmore useable to the machine owner particularly with regard to indexing and durability.

The committee understands that the submitter was referencing 11.4.8 in the currentdocument and notes that not all the current text in the proposal was submitted. The proposal does not comply with theRequirements Governing Committee Projects, Section 4.3.3(c).

There is presently no restriction prohibiting the user from placing an instruction label indicating the location of thedocuments.


156Printed on 10/13/2009


_______________________________________________________________________________________________John Stephens, Stephens Electronics

Delete or clarify 12.5.2.What good is 90 degree C wire if you cannot utilize its capabilities?

What is meant by Ampacity ADJUSTMENT???"...adjustment based on temp correction factor??? -- I certainly hope not because this is covered in 12.5.5

I think I have just figured out what is intended:"Use Adjustment Tables 12.5.5(a) and (b) for 60, 75 and 90 Degree C wire."Why not have a column for 90C Wire as in NEC #310.16? [or skip much of this and refer to the NEC]Suggestions:Delete 12.5.2 and fix table 12.5.5(a) by deleting "75 C".Add the 90 C Wire ColumnThen the adjustments match the NEC.I feel there should be a difference in derating between wires in a conduit or non-ventilated raceway vs. those in [partial]

free air in a plastic-finger-type "Panduit" duct.

The proposal does not meet the requirements of 4.3.3(c) of the Regulations GoverningCommittee Projects as there is no specific recommendation.

Additionally, the UL standards for control and distribution products do not include requirements for testing at 90 degreeC ampacities.


FISHER, D.: The committee correctly noted that the proposal did not meet the proposal format requirements, andthat control equipment is not evaluated at 90C ampacities.However, having a 90C column would provide additional margin for derating adjustments, even though the final adjustedampacity would be required to be limited to the unadjusted maximum of the 75C column to ensure compatibility withcontrol and distribution product terminal ratings.

Similarly, the ampacities for 14, 12, and 10 AWG wire at 75C and 60C need to be corrected to align with NEC Table310.16 at they currently reflect the overcurrent protection limit of 240.4(D) rather than the wire ampacities shown in thetable. As such, NFPA 79 is actually derating the conductors to the overcurrent device limit from 240.4(D), rather thanthe wire ampacity as is done in the NEC.

157Printed on 10/13/2009



Add the following new Exception to Section 12.5.2:"Exception: Ampacities of 90o C insulated conductors or other special purpose conductors with higher temperature

ratings may be determined in accordance with 310.15 of the National Electrical Code."NFPA 79 does not adequately provide for the higher temperature applications that may be

encountered in some equipment. This proposal would allow the use of more complete tables or engineering supervisionin determining ampacities for 90o C and higher ratings. Industrial machinery may be required to operate in conditions ormay produce conditions that require higher temperature ratings, and there is no technical basis for allowing a conductorto be used in accordance with the NEC when run to or between machines (Section 1.4) but then not allowing that sameconductor to be used in the same manner under identical conditions of use. Similar permission is already provided forspecial purpose cords in 12.8.1, Exception.

Presently, the UL standards for control and distribution products do not include requirementsfor testing at 90 degree C ampacities.


158Printed on 10/13/2009


_______________________________________________________________________________________________John Stephens, Stephens Electronics

Revise text to read as follows:10 should be 100 Percent [last line].

If it doesn't mean this, what does it mean?How come this permits operating at 100 percent [if this is indeed correct] when 12.5.4 says 125 percent even for

resistive loads?

The committee does not agree the 10 percent value in the last sentence is incorrect. This 10percent value is consistent with 725.51 of the National Electrical Code.


159Printed on 10/13/2009



Revise text to read as follows:Revise 12.6.1 and add new text in 12.6.1.3, and annex note as follows:

Conductors shall not be smaller than 14 AWG for power circuits unless otherwise permitted in 12.6.1.1, or12.6.1.2, or 12.6.1.3.

16 AWG and 18 AWG shall be permitted for motor and non-motor power circuits where part of a power cableassembly identified as suitable for intended use and provided with overcurrent protection in accordance with its ratings.

A.12.6.1.3 See UL 2237 – Multi-Point Interconnection Power Cable Assemblies for Industrial Machinery.Power cable assemblies for industrial machinery can contain 16 or 18 AWG conductors but may have

marked ratings or protection requirements that differ from the provisions in 12.6.1.1 or 12.6.1.2. The recommended textclarifies that these conductors are permitted but must be applied within their ratings.

The annex note provides a reference to the UL 2237 standard to which these cables are typically evaluated.

Revise text to read as follows:Revise 12.6.1 and add new text in 12.6.1.3, and annex note as follows:

Conductors shall not be smaller than 14 AWG for power circuits unless otherwise permitted in 12.6.1.1, or12.6.1.2, or 12.6.1.3.

16 AWG and 18 AWG shall be permitted for motor and non-motor power circuits where part of a listed powercable assembly identified as suitable for intended use and provided with overcurrent protection in accordance with itsratings.

A.12.6.1.3 See UL 2237 – Multi-Point Interconnection Power Cable Assemblies for Industrial Machinery.The text was revised by adding the word "listed" to assure the cable assembly had proper

evaluation.


160Printed on 10/13/2009



Revise text to read as follows:12.6.4* Conductors for electronic programmable control input/output and static control devices shall not be smaller

than permitted in (1), or (2), or (3):(1) Conductors installed in raceways shall not be smaller than 24 AWG.

(2) Conductors installed within control enclosures shall not be smaller than 26 AWG.

(3) Conductors that are part of a jacketed, multiconductor cable identified as suitable for the application and installed inaccordance with Chapter 13 shall not be smaller than 30 AWG.

This proposal is an output of the NFPA 79 AWM Task Group.The current state of the art for electronic I/O and field devices can necessitate using very small sensors and I/O

devices which require use of small conductors. The revised wording clarifies that small conductors are suitable forconnection of electronic (programmable and non-programmable) input/outputs and field devices. Conductors that arepart of a multiconductor cable, assembly, or cord can be used when identified as suitable and installed in accordancewith Chapter 13. The reference to “static” control is deleted as it is an outdated reference to non-programmableelectronic control and is clarified by the revised wording.


161Printed on 10/13/2009



Add new exception to 12.7.1.1:Exception: Special cables and conductors identified as suitable for flexing applications shall be permitted.

This proposal was developed by the NFPA 79 Technical Committee Task Group on AWM.The new text clarifies that special cables and conductors identified for flexing applications shall be permitted.See companion proposal to 12.2.7.


162Printed on 10/13/2009



Add new paragraph 13.1.1.12 as follows:13.1.1.12 Where AWM cables or conductors permitted under 12.9 will be field installed, installation information shall

be provided in the machine technical documentation.This proposal was developed by the NFPA 79 Technical Committee Task Group on AWM.

Special cables and conductors (such as AWM) may require special knowledge, tools, or techniques for properinstallation. Where these cables and conductors are to be field installed, information on these needs to be included inthe documentation to ensure proper installation.



163Printed on 10/13/2009



New text to read as follows:13.1.2.1 Conductors and cables shall be run from terminal to terminal without splices or joints. Connections using plug

and receptacle (plug/socket) combinations with suitable protection against accidental disconnection are not consideredto be joints for the purpose of this Subclause.

Exception No 1:Splices shall be permitted to leads attached to electrical equipment, such as motors and solenoids. Such splices shall

be insulated with oil-resistant electrical tape or insulation equivalent to that of the conductors and installed in a suitableenclosure.

Exception No 2:Where it is impracticable to provide terminals in a junction box (e.g., on mobile machines, on machines having long

flexible cables), the use of splices or joints shall be permitted.This sentence is added to harmonize with IEC 60204-1 5th Edition and to clarify the use of a plug and

receptacle combination.



164Printed on 10/13/2009



Add new text to read as follows:13.1.2.1* Conductors and cables shall be run from terminal to terminal without splices or joints. Connections using plug

and receptacle (plug/socket) combinations with protection against accidental disconnection shall not be considered to bejoints for this requirement.

Add note:A.13.1.2.1 Protection against accidental disconnection includes plug and receptacle (plug/socket) combinations having

twist lock, latches, or mechanisms for this purpose.Sentence and Annex A note is added to harmonize with IEC 60204-1 5th Edition and to clarify the use

of a plug and receptacle combination.

The committee accepts the addition of the second sentence to 13.1.2.1 and new A.13.1.2.1 asproposed and notes that the exceptions are retained.


165Printed on 10/13/2009


_______________________________________________________________________________________________George Schreck, Komatsu America Industries LLC

Add new 13.1.2.3 to read as follows:Mating molded nylon connectors using crimped terminations, shall not be considered as a splice or a joint when

used/contained in an enclosure, machine compartment or conduit body.Insert new 13.1.2.3 after existing 13.1.2.2. and renumber remaining paragraphs.

Mating molded nylon connectors with crimped wire terminations are a quick and ready means todisconnect and reconnect devices, minimizing wiring errors and labor. Containing them within suitable enclosuresprovides overall environmental and electrical protection. Such connectors are UL recognized with voltages to 600 VACand currents suitable for power circuits.

Add new 13.1.2.2 to read as follows:Mating molded nylon connectors using crimped terminations, shall not be considered as a splice or a joint when

used/contained in an enclosure, machine compartment or conduit body.Insert new 13.1.2.2 after existing 13.1.2.1. and renumber remaining paragraphs.

The committee accepted the recommended text and placed the text to fall after existing13.1.2.1. Existing 13.1.2.2 and the remaining paragraphs will be renumbered accordingly.


WATSON, E.: I voted Negative on the committee action although the action did address some short-comings in theoriginal proposal. However I believe the original proposal and the committee missed an important issue such that thecommittee action should have acted to Accept in Principle and In Part as follows. The words "or conduit body" shouldalso have been deleted. Within conduit is exactly where you do NOT want connectors, and this is not where thebenefits (from the originating substantiation) will be seen. This proposal has now opened other technical correlationissues such as how does one calculate % fill of raceways (13.5.2) most pointedly within conduit? Others can commenton whether the use of potentially multiple connectors within a conduit should effect wire sizing (pull strength, derating,etc.). The proposal may have meant "raceway" or better yet "raceway (except conduit)" and not limited this overallexception to "enclosures, machine compartment or conduit body". Additionally, NFPA79 does not use the term "conduitbody", so a comment will need to correct this as to whether the intent was conduit, or conduit fittings (?)

166Printed on 10/13/2009



New text to read as follows:13.2.1.1 Conductors shall be identified at each termination by number, letter, color (either solid or with one or more

stripes), or a combination thereof and shall correspond with the technical documentation as defined in Chapter 17.Internal wiring on individual devices purchased completely wired shall not require additional identification.

This phrase is added to harmonize with IEC 60204-1 5th edition and to clarify were requirements fordocumentation are located.


167Printed on 10/13/2009



Revise text to read as follows:Conductors shall be identified at each termination by number, letter, color (either solid or with one or more stripes), or a

combination thereof and shall correspond with the technical documentation as defined in Chapter 17. Internal wiring onindividual devices purchased completely wired shall not require additional identification.

A phrase "as defined in Chapter 17" is added to harmonize with IEC 60204-1 5th Edition and to clarifywere requirements for documentation are located.



168Printed on 10/13/2009



Do not revise 13.2.4.1 and A.13.2.4.1 as requested in proposed NFPA 79-2007 TIA Log #90.[13.2.4.1] Yellow is a legacy issue, the existing base using yellow for this purpose may remain in the

installed base or for minor modifications it should remained as an option [13.2.4.3 exception 4]. All new equipmentshould use the color orange for the ungrounded conductor that remains energized when the main supply circuitdisconnection means is in the off position, [13.2.3.2(2)] the associated grounded conductor would still need to be whitewith orange stripe.

Yellow conductors are not as noticeable as orange as a warning method especially with white on the associatedgrounded conductor and thus should not be perpetuated.

If more than one method is used to identify by color that identification method, for worker safety purposes should beposted on each cabinet door where the method is used as well as within the machine's documentation.

Orange has become the more widely accepted color for purposes of identifying ungrounded conductor that remainsenergized when the main supply circuit disconnection means is in the off position (i.e., external interlock circuit).

No action is required as the TIA was not issued.


169Printed on 10/13/2009



Revise wording to Section 13.2.4.3 as follows:13.2.4.3 The use of other colors for the purpose of identification shall be as follows:(1) BLACK for ungrounded (ac) (alternating current (ac) and (dc) (direct current (dc) power conductors(2) RED for ungrounded (ac) (alternating current (ac)) control conductors(3) BLUE for ungrounded (dc) (direct current (dc)) control conductors

To improve the clarity of document for the reader.

The committee does not agree with the submitter's substantiation that the proposed changeswill add clarity.


170Printed on 10/13/2009



Revise text to read as follows:13.2.4.3 The use of other colors for the purpose of identification shall be as follows:Where color-coding is used for identification of conductors, it is recommended that they be color-coded as follows:(1) BLACK for ungrounded ac and dc power conductors(2) RED for ungrounded ac control conductors(3) BLUE for ungrounded dc control conductors

Color acuity is no longer a requirement for electrical workers thus the reduction from requirement torecommended preferred use of particular colors for other than ground and grounded conductors. Harmonization withIEC 60204-1 and NEC.

Revise text as follows:The use of other colors for the purpose of identification shall be as follows: Where color-coding is used for

identification of conductors, it shall be permitted to use the following color codes:(1) BLACK for ungrounded ac and dc power conductors;

(2) RED for ungrounded ac control conductors;(3) BLUE for ungrounded dc control conductors.

13.2.4.4 Where the identification is other than as permitted in 13.2.4.3, the means of identification shall be permanentlyposted on the inside of the main electrical control panel enclosure in a visible location.

In order to follow the MOS the term “recommended” is changed to “shall be permitted”. Theformer exceptions are no longer relevant so they were deleted.

The requirement in the previous Exception 4 is relocated to 13.2.4.4 as mandatory language with an exception.


171Printed on 10/13/2009



Delete Section 13.4.5.3 in its entirety including the exception.This text is being re-located into 8.2.4 (New) as part of the effort to locate all technical grounding

sections into Chapter 8.

The committee agrees that renumbering would result in relocating text from previousgrounding task group proposals that were rejected and is not necessary.

The committee recognizes that there is no A.13.4.5.3.See the following related proposals submitted by the Grounding Task Group: 79-7, 79-12, 79-13, 79-14, 79-22, 79-24,

79-26, 79-53, 79-69, 79-70, 79-72, 79-73, 79-74, 79-75, 79-76, 79-77, 79-78, 79-79, 79-80, 79-81, 79-82, 79-83, 79-85,79-86, 79-88, 79-89, 79-90, 79-91, 79-92, 79-94, 79-96, 79-97, 79-98, 79-99, 79-104, 79-153.


SANDERS, M.: The Technical Committee action should have been to “Accept in Principle” to delete this fromChapter 13 because the subject is already redundant to existing 8.2.4. Correct action on ROP 83 Log #122 wouldcause the Exception to 13.4.5.3 to move into existing 8.2.4. This should have been acted upon on its own merits, andrenumbering is not an insurmountable task.


172Printed on 10/13/2009



New text to read as follows:13.4.3.1.5 Where flexible conduit is adjacent to moving parts, the construction and supporting means shall prevent

damage to the flexible conduit under all conditions of operation. Flexible metallic conduit shall not be used for rapidmovements except when specifically designed for that purpose.

The word "metallic" was deleted to harmonize with IEC 60204-1 5th Edition and to clarify that allmaterial types of conduit shall not be used unless specifically designed for the purpose of rapid movements.


173Printed on 10/13/2009



Revise text to read as follows:Where flexible conduit is adjacent to moving parts, the construction and supporting means shall prevent damage to the

flexible conduit under all conditions of operation. Flexible metallic conduit shall not be used for rapid movements exceptwhen specifically designed for that purpose.

The word "metallic" was deleted to harmonize with IEC 60204-1 5th Edition and to clarify that allmaterial types of conduit shall not be used unless specifically designed for the purpose of rapid movements.



174Printed on 10/13/2009



Revise text to read as follows:13.5.6.6 Metal thickness and construction of wireways shall comply with ANSI/UL 870.




175Printed on 10/13/2009



Revise text to read as follows:13.5.10 Cable Trays. Cable trays to be used for cable or raceway support on industrial machines shall be permitted.

Cable trays shall be permitted to support the following:(1) Single conductors 1/0 or larger that are otherwise permitted on industrial machines(2) Multiconductor flexible cables and cables with flexible properties that are otherwise permitted on industrial

machines(3) Raceways functionally associated with industrial manufacturing systems(4) Special conductors and cables that are otherwise permitted on industrial machines (See 12.9).

This proposal was developed by the NFPA 79 Technical Committee Task Group on AWM.The new text (item 4) permits the use of special conductors and cables, which is only permitted for use on industrial

machines, to be run, for example, between a control cabinet and the machine using a cable tray for support. In addition,use of cables with flexible properties was added as common tray rated cables may meet the requirements of a cablewith flexible properties but not necessarily “flexible cable”.


176Printed on 10/13/2009



Revise text to read as follows:14.2 Reserved Motor Enclosures.14.2.1 It is recommended that motor enclosures be chosen from those included in NEMA MG-1 or IEC 60034-5.14.2.2. The degree of protection shall be at least IP23 (see NEMA MG-1 or IEC 60529) for all motors. More stringent

requirements can be needed depending on the application and the physical environment (see 4.4). Motors incorporatedas an integral part of the machine shall be so mounted that they are adequately protected from mechanical damage.

For harmonization reasons and because NEMA has harmonized motor enclosures in the MG 1 Motorsand Generators standard it is recommend to consider changing 14.2 from Reserved to Motor Enclosures.

The submitter's proposed text does not contain mandatory language in 14.2.1. Section 14.2.2is too restrictive and limits the use of present day technology.


177Printed on 10/13/2009



Add new text to read as follows:14.2 Motor Enclosures14.2.1 Motor enclosures shall be chosen from those included in IEC 60034-514.2.2 The degree of protection shall be at least IP23 (see IEC 60529) for all motors. More stringent requirements can

be needed depending on the application and the physical environment in accordance with Section 4.4. Motorsincorporated as an integral part of the machine shall be so mounted that they are adequately protected from mechanicaldamage.

Continued harmonization with IEC 60204-1. Reference to IEC 60034-5 would need to be added toAnnex I also.

The proposed text is too restrictive and does not harmonize with 60204-1.


ANDERSON, W.: The proposal would solve the too restrictive observation by the committee and still be inharmonization with IEC 60204-1:14.2 Motor enclosuresIt is recommended that motor enclosures be chosen from those included in IEC 60034-5.The degree of protection shall be at least IP23 (see IEC 60529) for all motors. More stringent requirements can beneeded depending on the application and the physical environment (see 4.4). Motors incorporated as an integral part ofthe machine shall be so mounted that they are adequately protected from mechanical damage.Change “IEC 60034-5” to “NEMA MG-1 or IEC 60034-5”.Change “see IEC 60529” to “see NEMA MG-1 or IEC 60529”

178Printed on 10/13/2009



Add an exception to follow 15.1.1(8) to read as follows:"Exception: Covering the receptacle when the plug is removed shall not be required where the receptacle is not

exposed to dirt, dust, oil, or other contaminates in the installed environment."As it stands, there is no consideration of the environment in this rule. It seems to be assumed that

there will be such things as "dust, coolants, and swarf" as mentioned in Section 11.3. However, Section 11.3 simplyrequires a degree of protection that is suitable for the environment. Many machines constructed now require a "cleanroom" environment for operation, and in such cases, the requirement for a cover on a receptacle is not justified.

Revise 15.1.1(8) as follows:(8) Shall be suitable for the environment. Receptacles mounted external to the enclosure and subject to dirt, dust, oil or

other contaminates shall be provided with a means to cover the receptacle when the plug is removed.The committee accepts the recommendation in principle and has added new text to the

existing language, as opposed to an exception, that will address the submitter's concern.


WOLFGANG, E.: The Technical committee should not have added the wording as proposed as the manufacturer ofthe equipment cannot always determine when a receptacle will be exposed to dirt, dust, oil or other contaminates andtherefore, the proposed wording adds uncertainty as to whether a cover is required or not. The previous wording wassufficient.

179Printed on 10/13/2009



Revise 15.1.1(3) to read as follows:"Receptacles shall be of the parallel blade grounding type, 125-volt, single-phase, 15- or 20-ampere configuration and

listed for the applied voltage."Where receptacles are required for accessory equipment, the present rule would prohibit a receptacle

rated at 20 amperes to be mounted in or on the machine. Receptacles rated at 20 amperes will accept the same15-ampere attachment plugs as a 15-ampere receptacle and are often preferred. The standard does not limit accessorycircuits (other than local machine lighting) to 15 amperes, so under the current rule a dedicated 20-ampere circuit with a15-ampere duplex receptacle is permitted, but a 20-ampere receptacle on the same circuit is not, for no apparent reasonthat is within the stated purpose of the standard.


180Printed on 10/13/2009



Revise the text of Section 15.1.1(7) as follows:15.1.1 Receptacles for Accessory Equipment. Where the machine or its associated equipment is provided with

receptacle outlets to be used for accessory equipment (e.g., handheld power tools, test equipment), the followingconditions shall apply:

(1) Receptacles mounted external to the enclosure shall be ground-fault circuit-interrupter (GFCI)-protected.(2) Receptacles shall be supplied from a grounded 120 volt ac source.(3) Receptacles shall be of the parallel blade grounding type, 125-volt, single-phase, 15-ampere configuration and

listed for the applied voltage.(4) Receptacles with their associated attachment plugs (plug/sockets) shall be in accordance with 13.4.5.3.(5) The continuity of the equipment grounding (protective bonding) circuit to the receptacle outlet shall be verified by

Section 18.2.

(6) All ungrounded (unearthed) conductors connected to the receptacle outlet shall be protected against overcurrent inaccordance with the provisions of 7.2.5, and these circuits shall not be connected to other machine circuits.

(7) Where the power supply to the receptacle outlet is not disconnected by the supply disconnecting device for themachine or section of the machine, the warning and marking safety sign requirements of 5.3.5.4 shall apply.

(8) Shall be suitable for the environment. Receptacles mounted external to the enclosure shall be provided with ameans to cover the receptacle when the plug is removed.




181Printed on 10/13/2009


_______________________________________________________________________________________________Drake A. Drobnick, Automotive Components Holdings, LLC

Revise text to read as follows:(4) An listed enclosed isolating transformer disconnect assembly connected to the line side of the supply disconnecting

device which contains when a separate primary disconnecting means and secondary overcurrent protection areprovided and is mounted either externally or within the control enclosure adjacent to the supply disconnecting device.

Comment 79-91 on hold. Proposal 79-136.Restatement of text.

The submitter did not provide adequate substantiation for the listing requirement.The committee accepted in principle the remaining text. See the committee action on Proposal 79-165.


182Printed on 10/13/2009


_______________________________________________________________________________________________

Glen Kampa, Hoffman EnclosuresWithin 16.1.1 Receptacles for Accessory Equipment, replace 120 volt with 250 volt throughout

16.1.1.Remove parallel blade.

This is an effort to globalize and harmonize with IEC, not restrict to a 120 volt receptacle wherenominal 230 volt devices are used. There are currently manufacturers of accessory 250 volt receptacle that routinelyare used without incident.

The proposal has merit however the voltage range is incorrect and would require allreceptacles to be 250 volt.

The committee understands that the submitter's proposal is to 15.1.1 in the 2007 NFPA 79.


183Printed on 10/13/2009


_______________________________________________________________________________________________

Drake A. Drobnick, Automotive Components Holdings LLCAdd additional text to (4) as follows:

(4) An isolating transformer connected to the line side of the supply disconnecting device when a separate primarydisconnecting means and secondary overcurrent protection are provided and mounted either externally or within thecontrol enclosure adjacent to the supply disconnecting device.

Enclosed isolation transformer devices are commonly used to provide lighting circuits that remainenergized when the main disconnect is in the off position. The current language prohibits this type of application.

Section 15.2.2.2(4) to read as follows:(4) An isolating transformer connected to the line side of the supply disconnecting device when a separate primary

disconnecting means and secondary overcurrent protection are provided and mounted either externally immediatelyadjacent to the control enclosure or within the control enclosure adjacent to the supply disconnecting device.

The committee notes that as this proposal originated as Comment 79-91 from the F05 cycle,the applicable section number is now 15.2.2.2(4). The committee added text to clarify the location of the isolatingtransformer


WATSON, E.: I agree with the Committee Action on this proposal. I believe the intent of the committee action toinclude the requirement of "immediately adjacent" should also have been included in item 5.3.5.2(1) - add "immediately"ahead of the first "adjacent". The specifics of proposal 165 apply not only to the excepted circuits which are lighting(15.2.2.2(4)) but also to other excepted circuits (5.3.5.2(1)) where the identical devices are installed.

184Printed on 10/13/2009



New text to read as follows:Electrical equipment for industrial machines, such as industrial control panels, shall be marked to warn

qualified persons of potential electric shock and arc flash hazards.The marking shall be located so as to be clearly visible to qualified persons before examination, adjustment,

servicing, or maintenance of the equipment.It shall be permitted to omit safety signs on a single device with its own enclosure where the size precludes

placement of the label upon the enclosure (e.g., position sensor)Add new line to Annex I.1.2.1 in alphabetical order as follows:ANSI Z535.4 2007Add new A.16.2.3 to read as follows:A.16.2.3 See NFPA 70E-2009, for assistance in determining severity of

potential exposures and ANSI Z535.4 for guidelines for the design of safety signs and labels for application to products.

Inserted recommended text into existing 16.2.3. This action will negate existing 16.2.3(1) and (2). Theexisting 16.2(3) will now become new 16.2.3.1. This places the statement referencing NFPA70E into new A.16.2.3. Thiswill also recommend a specific reference to NFPA70E be added to Annex I.

This proposal is intended to introduce the concept of arc flash hazard in NFPA 79. Electric shock and arc flash areboth recognized hazards by OSHA. NFPA 79, 6.1 already requires that electrical equipment provide protection ofpersons from electric shock. This proposed marking requirement will be consistent with that requirement and serve asan additional means to comply with 6.1. In a February 29, 2008 letter of interpretation, OSHA indicates that the NFPA70E consensus standard is relevant as evidence that arc flash is a recognized hazard. Additionally, NEC 110.16requires that industrial control panels that are likely to require examination, adjustment, servicing, or maintenance whileenergized be marked to warn qualified persons of potential electric arc flash hazards and that the marking shall belocated so as to be clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of theequipment. NEC 110.16 also contains two fine print notes related to arc flash labeling which read as follows:FPN No. 1: NFPA 70E-2004, Standard for Electrical Safety in the Workplace, provides assistance in determiningseverity of potential exposure, planning safe work practices, and selecting personal protective equipment.FPN No. 2: ANSI Z535.4-1998, Product Safety Signs and Labels, provides guidelines for the design of safety signs andlabels for application to products.


185Printed on 10/13/2009



Delete Section 16.2.3(1) and renumber as follows:16.2.3 It shall be permitted to omit safety signs on the following:(1) An enclosure equipped with a supply disconnecting device(2) (1) An operator-machine interface or control station(3) (2) A single device with its own enclosure (e.g., position sensor)

The posting of safety signs on any electrical enclosures containing disconnecting devices is a primarymethod for communicating the potential electrical hazards. Disconnecting devices are known to be major contributors toshock and arc-flash accidents; and these signs serve as a reminder to maintenance personnel. Section 16.2.1 statesthat enclosures which are required to be marked with a safetysign in accordance with the ANSI Z535 Series. Then, Section 16.2.3(1) permits the omission of these signs, whenenclosures are visibly .

The problem is that the excepted disconnecting device mentioned in Section 16.2.3(1) could be any "supplydisconnecting device" besides the Main Supply circuit Disconnecting Means described in Section 16.2.7. Note that thisMain Supply Disconnecting Means does require the posting of a safety sign.


WOLFGANG, E.: Cannot support this action as it appears this is now in conflict with ROP 79-165a, LOG #CP5 andtherefore is no longer necessary.

186Printed on 10/13/2009



Change "safety" sign to "warning" sign in the first sentence.16.2.7 A warning safety sign shall be provided adjacent to the main supply circuit disconnect operating handle to warn

qualified persons of potential electric arc flash hazards. The marking shall be located so as to be clearly visible toqualified persons before examination, adjustment, servicing, or maintenance of the equipment.

This change will correlate with NFPA 70-2008 Section 110.16.




187Printed on 10/13/2009



Add new text as follows:*16.2.8 A safety sign shall be provided when the risk assessment shows the need to warn against the possibility of

hazardous surface temperatures of the electrical equipment enclosure.Continued harmonization with IEC 60204-1.

The proposal does not correlate with the recommendation to harmonize with IEC 60204 asthis proposal pertains to enclosures only.


SANDERS, M.: The Technical Committee action should have been to “Accept in Principle” and combined with ROP79-169 Log #163 as follows.

“16.2.8 A safety sign warning shall be provided when the risk assessment shows the need to warn against of thepossibility of hazardous surface temperatures of the electrical equipment enclosure shall be indicated by the use of thegraphical symbol IEC 60417, 5041 (DB: 2002-10) as shown in Figure 16.2.8.

*** Insert Figure 16.2.8 Thermal Symbol here***

This provides for harmonization with IEC 60204-1 and meets the submitter’s intent of ROP 79-169, Log #163.Placement of the symbol within Chapter 16, eliminates the need to provide Annex A material.

WOLFGANG, E.: The Technical Committee action should have been to “Accept in Principle” and combined withROP 79-169 (Log #163) as follows.

“16.2.8 A safety sign warning shall be provided when the risk assessment shows the need to warn against of thepossibility of hazardous surface temperatures of the electrical equipment enclosure shall be indicated by the use of thegraphical symbol IEC 60417.5041 (DB:2002-10) as shown in Figure 16.2.8.

****Insert Figure 16.2.8 Here****

FIGURE 16.2.8 Thermal Symbol”

This provides for harmonization with IEC 60204-1 and meets the submitter’s intent of ROP 79-169 (Log #163).Placement of the symbol within Chapter 16 eliminates the need to provide Annex A material.

188Printed on 10/13/2009



Add new text and graphic:Where the risk assessment shows the need to warn against the possibility of hazardous surface temperatures of the

electrical equipment, the graphical symbol IEC 60417-5041 (DB:2002-10) shall be used.

***Insert Figure Here***

NOTE: For electrical installations, this measure is dealt with in IEC 60364-4-42, Subclause 423 and Table 42A.

There is no standard warning for hazardous surface temperatures on electrical equipment in NFPA 79but is in IEC 60204-1; for both harmonization and hazardous risk reasons consider adding material from IEC 60204-116.2.2 as new 16.2.8.

The requirement to install warning signs against hazardous thermal temperatures is outsidethe scope of the NFPA 79 committee.


ANDERSON, W.: The committee did error in its conclusion that thermal warning signs are beyond the scope of thisstandard when the root cause of the thermal hazard is in fact the electrical equipment in the area of concern. Warningsigns including thermal hazard warning signs are necessary and are within the scope of this standardExamples:3.3.33 (Electrically) Instructed Person. A person adequately advised or supervised by an electrically skilled person toenable him or her to perceive risks and to avoid hazards that electricity can create.3.3.34 (Electrically) Skilled Person. A person with relevant education and experience to enable him or her to perceiverisks and to avoid hazards that electricity can create.4.1* General Considerations. This chapter describes the general requirements and conditions for the operation of theelectrical equipment of the machine. The risks associated with the hazards relevant to the electrical equipment shall beassessed as part of the overall requirements for risk assessment of the machine. The risks associated with the hazardsidentified by the risk assessment shall be reduced such that the safety performance determined by the risk assessmentis met.

CALLANAN, M.: The Technical Correlating Committee should review the committee action. We do not necessarilyagree that the recommendation is outside the scope of NPFA 79

SANDERS, M.: The Technical Committee action should have been to “Accept in Principle” and combined this actionwith ROP 79-168, Log #114.

WOLFGANG, E.: The Technical Committee action should have been to “Accept in Principle” and combined with ROP79-168 (Log #114).

189Printed on 10/13/2009



Add a word as follows:17.4.2 The full-load current shown on the nameplate shall not be less than the full-load currents for all motors and

other equipment that can be in operation at the same time under normal conditions of anticipated use. Where unusualloads or duty cycles require oversized conductors, the required capacity shall be included in the full-load currentspecified on the nameplate.

The phrase "that can be in operation at the same time" provides the possibility of full-load currentmarkings that are less than the simple sum of full load current ratings for motors and equipment present in the machine,but it does not clearly allow consideration of anticipated use (which seems to be the spirit of clause and relateddiscussions in various code compliance forums).

That is to say, "can" suggests "capability" (and such a reading is not uncommon) and results in nameplate full loadcurrent ratings that reflect all the motors and equipment that are capable of being in operation at the same time ratherthan those that are actually anticipated to be in operation at the same time. This reading results in machine controldevices and conductors, as well as those supplying the machine, being sized of what is needed for theanticipated normal conditions of the machine.

With the addition of "anticipated" there is a more explicit focus on allowing ratings based on how the equipment isanticipated to be used (rather than on how the equipment be used).

This, of course, would allow a variety of name plate ratings for fundamentally equivalent machines if the control systemprogramming, process monitors, instructions, etc., were adjusted to reflect a different mode of anticipated normaloperation.

The committee disagrees with the substantiation for insertion of the word "anticipated". Thecommittee recognizes the submitter was referencing 16.4.2.


WOLFGANG, E.: The submitter makes a valid point about the full-load nameplate rating being artificially high. TheTechnical Committee should really look at trying to clarify and simplify the intent of the clause.

190Printed on 10/13/2009


_______________________________________________________________________________________________George M. Schreck, Komatsu America Industries, LLC

New text to read as follows:19.X.X Unshielded servo motor power conductors and unshielded control/instrumentation conductors not contained in

ferrous conduit shall be installed such that they cross at 90 (ninty) degree angle (perpendicular) to each other.Unshielded servo motor power conductors crossing at 90 (ninty) degrees reduces the potential of

inductive coupling of the EMI from the motor conductors into the control/instrumentation conductors.



191Printed on 10/13/2009



New text to read as follows:19.X.X Use of a grounded servo motor conductor/cable shield to satisfy the equipment grounding conductor

requirements of 8.2.2.2 shall not be permitted.Servo motor conductor shielding may be bonded to ground at both the control enclosure and also at

the servo motor junction box, and when large conductors are used with braided shield (which is similar to a "groundstrap"), may tempt the use instead of a proper equipment ground bonding conductor.



192Printed on 10/13/2009



New text to read as follows:19.X.X Unshielded servo motor power conductors shall be run in separate ferrous conduit from other control and

instrumentation conductors, from the Servo Drive Enclosure to the Servo Motor.Exception: When either the Servo Motor power, control/instrumentation conductors, or both are installed in raceway

system(s) that provides the same level of EMI protection as ferrous conduit.Servo Drives can cause high levels of EMI (electro-magnetic interference) due to the high frequency

power switching of the solid state devices (typ. Insulated Gate Bipolar Transistors (IGBT)). If unshielded motor powerconductors are in close proximity to control and instrumentation conductors, the EMI can be induced into thoseconductors causing data errors, or being confused with proper signaling, causing unintentional device operation (on/off)creating a potential hazard.



193Printed on 10/13/2009



New text to read as follows:19.X.X Where prefabricated, engineered servo motor conductors/cable are specified and supplied by the servo

drive/motor manufacturer, the cable shall be used when listed as type "AWM."Installations of machine have been forced to substitute motor power conductors that meet the

requirements of NFPA79-2007, cause the servo drive/motor system to perform less than designed or caused EMI to betransmitted into the control system causing errors of operation.

See the committee action on Proposal 79-134 which addresses the submitter's concerns. Thecommittee refers the submitter to new 12.9.2.2 in Proposal 79-134.


194Printed on 10/13/2009



New text to read as follows:19.X.X When a contactor is installed in the incoming supply conductors to the servo drive, the contactor current

capacity rating shall not be less than 115 percent of either the maximum servo drive nameplate rating or themanufacturer's specifications.

Inrush of the servo drive upon start-up and operation is not the same as experienced with that ofinduction motors. Allows the reduction of the size of the supply conductors and raceway.



195Printed on 10/13/2009



New text to read as follows:19.X.X Overcurrent protection on the line side of the servo drive shall not exceed either the manufacturer's instructions

or the ampacity of the supply conductors.Inrush of the servo drive upon start-up and operation is not the same as experienced with that of

induction motors. Allows the reduction of the size of the supply conductors and raceway.

The submitter did not provide adequate substantiation to support the proposedrecommendations.


196Printed on 10/13/2009



New text to read as follows:19.X.X Individual overcurrent protection shall be provided for each set of conductors from a single servo drive system

where the servo drive system supplies multiple motors based upon the lesser of the manufacturer's instructions or theampacity of the individual motor supply conductors.

To provide overcurrent protection on a multiple motor usage powered from a single servo drive systemsimilar to that shown in current figure A. 7.2.1 (a) but substituting the overcurrent protection for the overload protectionas shown. System overcurrent protection would be by the servo drive.

The submitter did not provide adequate substantiation to support the proposedrecommendations.


197Printed on 10/13/2009



New text to read as follows:19.X.X Where unshielded Servo Motor power conductors and unshielded control/instrumentation conductors not

isolated by ferrous conduit separation by distance shall be used per table 19.X.X

Table: 19.X.X.0A ≤ 20A: 4” Separation20A ≤ 40A: 6” Separation40A ≤ 80A: 8” Separation

Each Doubling of current adds 2” more to the Separation distanceUn-shielded Servo Motor power conductors may be run in other types of conductor support systems

such as cable ladders and cable trays.



198Printed on 10/13/2009


_______________________________________________________________________________________________George M. Schreck, Komatsu America Industries, LLC / Rep. Task Group #5 Servo Drives/Motors

New text to read as follows:19.3 Servo Drive System Supply Conductors Servo Drive System Conductors. Renumber existing paragraph to 19.3.1.

Make a new Paragraph heading to allow additional related paragraphs to be grouped together.


WATSON, E.: I agree with the committee action as the numbering correlates to many other proposals, however I willcontinue to comment that servos do not require, and/or no longer warrant, their own chapter. Servos may be new insome parts of industry, but in other parts of industry they have been (properly) implemented for over thirty years.Design and approval issues such as wire sizing (including duty-cycle and appropriate derating per 12.5.4),overcurrent-protection, and overload requirements are best found in their respective issue/chapter, not in two(application and also device). Refer also to my statement on proposal 185 as contactor sizing has now been added tothis new technology.

199Printed on 10/13/2009



Revise text as follows:19.3.1 Servo Drive System Supply Conductors. Circuit conductors supplying servo drive systems shall be sized to

have an ampacity of not less than 125 115 percent of the rated input of the equipment.To maintain agreement with the new supply conductor paragraph at 19.3.1. Past practice with

induction motors, 125 percent of overcapacity has traditionally been required. As the current usage of servo drives aresubstantially different, and from actual testing experience, such overcurrent capacity has not been experienced.


200Printed on 10/13/2009



New text to read as follows:19.3.3 Unshielded servo motor power conductors shall be run in separate ferrous conduit from other control and

instrumentation conductors, from the Servo Drive Enclosure to the Servo Motor.Exception: When either the Servo Motor power, control/instrumentation conductors, or both are installed in raceway

system(s) that provides the same level of EMI protection as ferrous conduit.Servo Drives can cause high levels of EMI (electro-magnetic interference) due to the high frequency

power switching of the solid state devices (typ. Insulated Gate Bipolar Transistors (IGBT)). If unshielded motor powerconductors are in close proximity to control and instrumentation conductors, the EMI can be induced into thoseconductors causing data errors, or being confused with proper signaling, causing unintentional device operation (on/off)creating a potential hazard.

New text to read as follows:19.3.3 Unshielded servo motor power conductors shall be run in separate ferrous raceway from other control and

instrumentation conductors, from the Servo Drive Enclosure to the Servo Motor.Exception: When either the servo motor power or control/instrumentation conductors, or both are installed in raceway

system(s) or by separation that shall provide the equivalent level of EMI protection as ferrous raceway utilizing Table19.3.3.

****Insert Table 19.33 CA Here****

Table 19.3.3 Minimum Conductor Separation (Center to Center)The committee replaced "conduit" with "raceway" in both the main text and the exception in

order to include all ferrous raceways. The term "or by separation" was added to provide a design alternative. Theaddition of "equivalent" ensures a level of performance.The committee edited Table 19.3.3 to provide clarity to the user.The committee added "shall" in the exception to comply with MOS


BEACHY, W.: I recommend that this proposal, proposal 79-182, and proposal 79-183 be rejected. These proposalsare overly restrictive in that they do not allow consideration for the multitude of application requirements of all modernpieces of equipment. The following points outline my objections:

1. Machine tools often contain large moving assemblies, comprised of motors and other components, which havepower supplied by non-ferrous power/cable tracks. The machine movement requires the connection points to be highlyflexible and precludes the use of rigid conduit/raceways.

2. Large ampacity motors requiring individual power conductors terminating in a single connector may not always beshielded. The power is supplied via a non metallic power/cable track as the entire assembly must be able to move, inaddition the distance requirements specified in 19.3.3 would require very wide power tracks which are often not possibleas dictated by machine geometry.

3. Table 19.3.3 does not provide adequate technical justification to warrant the separation distances it requires. In factmany of the external connectors supplied on motors violate the separation distances dictated in Table 19.3.5.

4. It is noted and understood that EMI is a design consideration that should be taken into account and it is my opinionthat section 4.4.2 and A 4.4.2 already adequately address these concerns. Since EMI is a subject matter outside thescope of NFPA 79 proper references to design for EMI should be provided in Annex A.

WOLFGANG, E.: The reworded exception does not make sense. I believe the following is a better wording of theintent of the submitter/Technical Committee. "Exception: When servo motor conductors or control/instrumentationconductors are installed in non ferrous raceway system(s), the raceway system(s) shall provide the equivalent level ofEMI protection as ferrous raceway. When servo motor conductors and control/instrumentation conductors are installed

201Printed on 10/13/2009

NFPA 79 Log #70 CA Tbl 19.3.3 F10 ROP

Table 19.3.3 Minimum Conductor Separation (Center to Center)Ampacity Separation mm (inch)

20A or less 100 (4) Over 20A and not greater than 40A 150 (6) Over 40A and not greater than 80A 200 (8)

Over 80A * * Each doubling of current adds 50 mm (2") more to the separation distance.

Report on Proposals – November 2010 NFPA 79together in a non ferrous raceway system(s) they shall be separated by distance as specified in Table 19.3.3."

HILBERT, M.: I agree with the Committee to accept in principle but the accept in principle should be as follows:19.3.3 Unshielded Servo Motor Power Conductors. Unshielded servo motor power conductors shall be run in separate

ferrous raceways from control and instrumentation conductors from the servo drive enclosure to the servo motor.Exception: When either the servo motor power or control/instrumentation conductors or both are installed in a raceway

system(s) or separated in accordance with Table 19.3.3.The submitter’s proposed language has been revised for clarity and to meet the requirements of the manual of style

with regards to the subsection titles. Section 1.8.3.2 of the Manual of Style requires consistent use of subtitles within asection so a title, chosen from the opening words of the paragraph, has been given to the new subsection as all theexisting 19.3 has titles.

Some minor editorial changes were made for clarity and the language “that provides the same level of EMI protectionas ferrous conduit” was removed as it was not necessary with the reference to Table 19.3.3. The submitter shouldreview the proposed title and make the appropriate comment.

202Printed on 10/13/2009



New text to read as follows:19.3.4 Unshielded servo motor power conductors and unshielded control/instrumentation conductors not contained in

ferrous conduit shall be installed such that they cross at 90 (ninety) degree angle (perpendicular) to each other.Unshielded servo motor power conductors crossing at 90 (ninety) degrees reduces the potential of

inductive coupling of the EMI from the motor conductors into the control/instrumentation conductors.

New text to read as follows:19.3.4 Where unshielded servo motor power conductors and unshielded control/instrumentation conductors are not

contained in ferrous raceways and cross each other they shall be installed perpendicular to each other.The committee replaced "conduit" with "raceway" in order to include all ferrous raceways and

edited for clarity and useability.


BEACHY, W.: See comments provided in proposal 79-181 (Log #70).

HILBERT, M.: I agree with the Committee to accept in principle but the accept in principle should be as follows:19.3.3 Unshielded Servo Motor Power Conductors Not Contained in Ferrous Raceways.Where unshielded servo motor power conductors and unshielded control/instrumentation conductors are not contained

in ferrous raceways and cross each other they shall be installed perpendicular to each other.The submitter’s proposed language has been revised to meet the requirements of the manual of style with regards to

subsection titles. Section 1.8.3.2 of the Manual of Style requires consistent use of subtitles within a section so a title,chosen from the opening words of the paragraph, has been given to the new subsection as all the existing 19.3 hastitles.

The submitter is encouraged review the proposed title and make the appropriate comment. It is recognized that theProposal noted in the last sentence of the Committee statement is 79-181 (Log #70).

203Printed on 10/13/2009



New text to read as follows:19.3.5 Where unshielded Servo Motor power conductors and unshielded control/instrumentation conductors not

isolated by ferrous conduit, separation by distance shall be used per Table 19.3.5.

***Insert Table: 19.3.5. Conductor Separation here***Un-shielded Servo Motor power conductors may be run in other types of conductor support systems

such as cable ladders and cable trays. Separation by distance is an accepted practice to reduce the potential forinduced electrical interference.

New text to read as follows:19.3.5 Where unshielded Servo Motor power conductors and unshielded control/instrumentation conductors not

isolated by ferrous raceway, separation by distance shall be used per Table 19.3.3 unless otherwise specified by themanufacturer.

The committee replaced "conduit" with "raceway". The committee also added "otherwisespecified by the manufacturer" to enable consideration of any special condition.

Proposed table 19.3.5 was accepted in principle by action taken on Proposal 79-18.


BEACHY, W.: See comments provided in proposal 79-181 (Log #70).

HILBERT, M.: I agree with the Committee to accept in principle but the accept in principle should be as follows:19.3.5 Unshielded Servo Motor Power Conductors Not Isolated by Ferrous Raceways. Where unshielded Servo

Motor power conductors and unshielded control/instrumentation conductors are not isolated by a ferrous raceway(s)they shall be separated in accordance with Table 19.3.3 unless otherwise specified by the manufacturer.

The submitter’s proposed language has been revised for clarity and to meet the requirements of the manual of stylewith regards to the subsection titles. Section 1.8.3.2 of the Manual of Style requires consistent use of subtitles within asection so a title, chosen from the opening words of the paragraph, has been given to the new subsection as all theexisting 19.3 has titles.

Some minor editorial changes were made for clarity. The submitter is encouraged to review the proposed title andmake the appropriate comment.

204Printed on 10/13/2009

70_L72_Rec_F2010

Table 19.3.5 Conductor Separation Ampacity Separation mm (inch) OA < 20A 100 (4") 20A < 40A 150 (6") 40A < 80A 200 (8")

80A<*** *** *** Each doubling of current adds 50 mm (2") more to the separation distance.



Revise text as follows:19.4 19.3.2 Motor Circuit Conductors. Motor circuit conductors shall have an ampacity of at least 125 115 percent of

the motor full load current when operated in a continuous mode of operation, or as specified by the servo drive systemmanufacturer. Motor circuit conductors for motors operating in other than continuous mode shall be permitted to havereduced ampacity based upon the design load and duty cycle.

Past practice with induction motors, 125 percent of overcapacity has traditionally been required. As thecurrent usage of servo drives are substantially different, and from actual testing experience, such overcurrent capacityhas not been experienced. To be consistent with the requirement in 19.3.1.

Revise text to read as follows:19.4 19.3.2 Motor Circuit Conductors. Motor circuit conductors shall have an ampacity of at least 125 115 percent of

the motor full load current when operated in a continuous mode of operation, or as specified by the servo drive systemmanufacturer. Motor circuit conductors for motors operating in other than continuous mode shall be permitted to havereduced ampacity based upon the design load and duty cycle.

The committee notes that the submitter intended to strike out 125 and underline 115.


205Printed on 10/13/2009



New text to read as follows:19.4 Isolation Contactor. When a contactor is installed in the incoming supply conductors to the servo drive, the

contactor current capacity rating shall not be less than 115 percent of either the maximum servo drive nameplate ratingor the manufacturer's specifications.

Inrush of the servo drive upon start-up and operation is not the same as experienced with that ofinduction motors. Maintains consistency with similar proposed requirements for conductors in this section.

New text to read as follows:19.4 Contactor. When a contactor is installed ahead of the incoming supply conductors to the servo drive, the

contactor current rating shall not be less than 115 percent of the maximum servo drive nameplate rating or sized inaccordance with the manufacturer's specifications.

The term isolation was removed from the title and the text was edited for clarity.


WATSON, E.: I voted Negative on the committee action although it did address two short-comings in the originalproposal. However I believe enough issues have been missed such that the committee should have acted to Reject, asfollows. The right-sizing of a contactor is not a servo particular, contactors are sized for many types of loads, whetherusers are familiar with utilization categories and/or life-load curves or other application issues. NFPA79 has notaddressed right-sizing other applications; the "why" for servos has only been substantiated as being different frominductive motors; so are many non-motor loads, and inductive motors and non-motor loads are all NOT addressed byNFPA79. Second; for some servo systems a contactor(s) is more appropriately applied between the drive and themotor; should this type of application be addressed? Next, to out-right require 115% of maximum nameplate rating canlead to a user falsely believing they've appropriately sized a contactor. Contactors might now be needlessly over-sized;or they might be undersized (not that this might cause a fire, but "life-sizing" of components is out-of-scope of NFPA79).This is all independent of drive manufacturer's recommendations. For clarification, within this proposal servo drivenameplate rating might be in amperage or kW, and manufacturer's specifications can be read to mean either drivemanufacturer or contactor manufacturer, or both. What is actually required here will need to be cleaned-up by acomment depending on the committee's real intent. For these collective issues I believe the original proposal shouldhave been Rejected.

BEACHY, W.: Where isolation contactors are provided they should be sized to the upstream protection and not theload. It is assumed that the protection is sized adequately for the load required. Servo system Power Supply Modules(PSM) units are designed in graduated ampacities. (e.g. 16kw/36kw/55kw) As an example the total electrical loadrequired may be 17kw, which would require a 36kw PSM, a designer may choose to decrease the protection to suit theload, provided it does not violate the manufacturer's recommendations. The protection for the PSM is sized based onthe required electrical load, not necessarily the PSM nameplate rating, and the contactor is sized to the protection.

HILBERT, M.: I agree with the Committee to accept in principle but the accept in principle should be as follows:19.5 Grounded Servo Motor Cable Shields. Use of a grounded servo motor conductor/cable shield shall not be

permitted to satisfy the equipment grounding conductor requirements.The submitter’s proposed language has been revised to meet the requirements of the Manual of Style with regards to

the subsection titles. Section 1.8.3.2 of the Manual of Style requires consistent use of subtitles within a section so atitle, chosen from the opening words of the paragraph, has been given to the new subsection as all the existing 19.3 hastitles. The submitter is encouraged to review the proposed title and make the appropriate comment.

206Printed on 10/13/2009



New text to read as follows:19.5. Use of a grounded servo motor conductor/cable shield to satisfy the equipment grounding conductor

requirements of 8.2.2.2 shall not be permitted.Servo motor conductor shielding may be bonded to ground at both the control enclosure and also at

the servo motor junction box and when large conductors are used with braided shield (which is similar to a "groundstrap"), may tempt the use instead of a proper equipment ground bonding conductor.

New text to read as follows:19.5. Use of a grounded servo motor conductor/cable shield shall not be permitted to satisfy the equipment grounding

conductor requirements.The committee removed the reference to 8.2.2.2 and edited for clarity.


207Printed on 10/13/2009



New text to read as follows:In this standard, the term includes both electrical and electronic equipment. Requirements that apply

only to electronic equipment are so identified.The general terms and as used throughout this standard mean industrial machinery. See Annex C

for examples of industrial machines covered by this standard.The referenced throughout Annex A are listed in Annex I with their appropriate dates of issue.

It has been reported that the publication references in Annex A without editions and/or dates createssome confusion by our readers even though this information is available in Annex I (note Errata No. 79-07-1). TG #5recommends the additional statement indicated above in A.1.1 for clarification.


208Printed on 10/13/2009



Revise text to read as follows:A.3.3.100 Supplementary Overcurrent Protective Device. Supplementary overcurrent protective devices are not

general use devices, as are branch circuit devices, and must be evaluated for appropriate application in every instancewhere they are used. Supplementary overcurrent protective devices are extremely application-oriented, and prior toapplying the devices, the differences and limitations for these devices must be investigated. Such a device is allowed tobe incomplete in construction or restricted in performance, Such a device is notsuitable for branch circuit protection, andis not used where branch circuit protection is required.

One example of the difference and limitations is that a supplementary overcurrent protective device may have spacing,creepage, and clearance that are considerably less than that of a branch circuit overcurrent protective device.

Example: A supplemental protector, ANSI/UL 1077, has spacing that are 9.5 mm (0.375 in.) through air and 12.7 mm(0.5 in.) over surface. A branch circuit rated ANSI/UL 489 molded case circuit breaker has spacing that are 19.1 mm(0.75 in.) through air and 31.8 mm (1.25 in.) over surface.

Another example of differences and limitations is that branch circuit overcurrent protective devices have standardoverload characteristics to protect branch circuits and feeder conductors. Supplementary overcurrent protective devicesdo not have standard overload characteristics and may differ from the standard branch circuit overload characteristics.Also, supplementary overcurrent protective devices have interrupting ratings that can range from 32 amperes to 100,000amperes. When supplementary overcurrent protective devices are considered for proper use, it is important to be surethat the device's interrupting rating equals or exceeds the available short-circuit current and that the device has theproper voltage rating for the installation (including compliance with slash voltage rating requirements, if applicable).

Examples of supplemental overcurrent protective devices include, but are not limited to the following:(1) ANSI/UL 248.14(2) ANSI/UL 1077




209Printed on 10/13/2009



Revise text as follows:A sample inquiry form is provided in Annex B for use in facilitating an agreement between the supplier and the

user.Hazardous situations can result from, but are not limited to, the following causes:(1) Failures or faults in the electrical equipment resulting in the possibility of electrical shock, flash hazard, or electrical

fire(2) Failures or faults in control circuits (or components and devices associated with these circuits) resulting in

malfunctioning of the machine(3) Disturbances or disruptions in power sources as well as failures or faults in the power circuits, resulting in the

malfunctioning of the machine(4) Loss of continuity of circuits that depend upon sliding or rolling contacts, resulting in a failure of a safety function

safety-related function(5) Electrical disturbances (e.g., electromagnetic, electrostatic, or radio interference) either from outside the electrical

equipment or internally generated, resulting in the malfunctioning of the machine(6) Release of electrical or mechanical stored energy, resulting in, for example, electric shock or unexpected

movement that can cause injury(7) Audible noise at levels that cause health problems to persons(8) Surface temperatures that can cause injurySafety measures are a combination of the measures incorporated at the design stage and those measures required to

be implemented by the user.Design and development should be the first consideration in the reduction of risks. Where this is not possible,

safeguarding should be considered.Safeguarding includes the use of safeguards, awareness means, and safe working procedures.One reference to risk assessment is ANSI B11-TR3.Flash hazard analysis, calculation methods, and ways to address the hazard are found in NFPA 70E.

Task Group #5 recommends the above edits to improve understanding of the requirements bystandardizing on the term as opposed to , ,

or (no hyphen).



210Printed on 10/13/2009



Revise text to read as follows:A.4.2 Semiconductor manufacturing equipment for use in semiconductor fabrication facilities may be accepted by one

of the following judged under the requirements of a testing laboratory to an international (e.g., IEC 60204-1 or IEC61010-1), regional (e.g., EN 60204 or EN 61010-1), national (e.g., ANSI/UL 508, UL 508A, UL 61010A-1, NFPA 79), orindustry standard (e.g., SEMI S2 or SEMI S22 ) electrical standard(s) deemed appropriate by the testing laboratory, orfield evaluation to NFPA 79, or another approach, such as "acceptable to the local authority having jurisdiction."




211Printed on 10/13/2009



Revise text to read as follows:A.5.3.3.2 A suitably rated attachment plug and receptacle listed to ANSI/UL498 or ANSI/UL 1682 is a method of

meeting the requirements of 5.3.3.2(2) and 5.3.3.2(3).Update standards titles to indicate ANSI approvals.



212Printed on 10/13/2009



New text to read as follows:A.9.2.5.4.2 Emergency Switching-Off: The action of removing the electrical power source from a machine, system or

process, creating an uncontrolled means of stopping to mitigate a hazard or a hazardous situation. The removal ofpower is by an uncomplicated means of switching (breaking) the electrical energy supply. The Emergency Switching-Offdevice acts prompty and rapidly, and schould be readily accessible. Emergency Switching-Off devices require adeliberate act to reset, allowing re-energizing of the machine, system, or process. It is acknowledged that due to theindiscriminently stopping of all control system(s), additional hazards may be created, and collateral damage to themachine, system, or process may be incurred.

To provide clarity to the term used in the standard.



HILBERT, M.: See my affirmative comment on 79-193 (Log #66).

213Printed on 10/13/2009



New text to read as follows:A.9.2.5.4.2 Emergency Switching-Off: The action of removing the electrical power source from a machine, system or

process, creating an uncontrolled means of stopping to mitigate a hazard or a hazardous situation. The removal ofpower is by an uncomplicated means of switching (breaking) the electrical energy supply. The Emergency Switching-Offdevice acts promptly and rapidly, and should be readily accessible. Emergency Switching-Off devices require adeliberate act to reset, allowing re-energizing of the machine, system, or process. It is acknowledged that due to theindiscriminately stopping of all control system(s), additional hazards may be created, and collateral damage to themachine, system, or process may be incurred.

New term was introduced and used in standard that is not defined or commonly understood.Frequently confused with "Emergency Stop" due to both using the word "Emergency."



HILBERT, M.: The action on this proposal should continue to be accept in principle but the action should be to acceptthe submitter’s recommended text and combine it with the recommendation from 79-194 (Log #109) to read as follows:

A.9.2.5.4.2 Emergency Switching-Off: The action of removing the electrical power source from a machine, system orprocess, creating an uncontrolled means of stopping to mitigate a hazard or a hazardous situation. The removal ofpower is by an uncomplicated means of switching (breaking) the electrical energy supply. The Emergency Switching-Offdevice acts promptly and rapidly, and should be readily accessible. Emergency Switching-Off devices require adeliberate act to reset, allowing re-energizing of the machine, system, or process. It is acknowledged that due to theindiscriminately stopping of all control system(s), additional hazards may be created, and collateral damage to themachine, system, or process may be incurred. The functional aspects of emergency switching off are given in 536.4 ofIEC 60364-5- 53.

Adding this language to Annex A would be a benefit to the users of NFPA 79 as there is much confusion in the industryas to the difference to between “emergency stop” and “emergency switching off.” Although more language should beadded with regard to the emergency stop function to more completely describe the difference between the two, theproposed text is good start in explaining the difference. The submitter, along with others, are encouraged to submitadditional text that will more completely describe the difference between “emergency stop” and “emergency switchingoff” in comments.

214Printed on 10/13/2009



Add the following new Annex material:A 9.2.5.4.2 The functional aspects of emergency switching off are given in 536.4 of IEC 60364-5- 53.

Harmonization with IEC 60204-1 and to better explain the “emergency switching off” concept.

Add an asterisk following 9.2.5.4.2.The committee accepts the submitters recommendation and added an asterisk following

9.2.5.4.2.



215Printed on 10/13/2009



Add the following new annex material:A 9.2.5.5.1 - Hold-to-run control can be accomplished by two-hand control devices.

Harmonization with IEC 60204-1 for clarity

Add an asterisk following 9.2.5.5.1New text as follows:A 9.2.5.5.1 Hold-to-run controls can be accomplished by two-hand control devices.

The committee accepted the submitter's recommendations and added an asterisk following9.2.5.5.1 and added a "s" to "control" to be consistent with the normative text.


216Printed on 10/13/2009



Add the following Annex note:*A.9.2.5.5.1 Hold-to-run control can be accomplished by two-hand control devices.

Harmonization with IEC 60204-1.



217Printed on 10/13/2009



Revise text to read as follows:A.10.1.3 For further information on degrees of protection, see Annex F. Also, see additional publications such as

NEMA 250, ANSI/UL 50, ANSI/UL 508, and IEC 60529.Update standards titles to indicate ANSI approvals.




218Printed on 10/13/2009



Revise text to read as follows:A.13.1.6.1 For additional information on flexible cords, refer to ANSI/UL 62.




219Printed on 10/13/2009



Revise the main text in 13.2.4.3 as follows:A.13.2.4.3 The use of other colors for the purpose of identification shall be as follows:(1) BLACK for ungrounded (ac) (alternating current (ac)) and (dc) (direct current (dc)) power conductors(2) RED for ungrounded (ac) (alternating current (ac)) control conductors(3) BLUE for ungrounded (dc) (direct current (dc)) control conductors.

Add clarity to document.

The committee does not agree with the submitters substantiation that the proposed changeswill add clarity.


220Printed on 10/13/2009



Revise text to read as follows:A.13.5.3.3.1 For additional information about rigid nonmetallic conduit, refer to ANSI/UL 651.




221Printed on 10/13/2009



Revise text to read as follows:A.13.5.7 See Section 16.2 for information on warning marking and safety signs.



ANDERSON, W.: The committee should reconsider this and the other similar changes proposed to revise theterminology from “warning signs” to “safety sign; and to revise the existing terminology of “safety sign” to “warning signthroughout NFPA 79..Safety: 1 : the condition of being safe from undergoing or causing hurt, injury, or loss2 : a device (as on a weapon or a machine) designed to prevent inadvertent or hazardous operation.Warn: 1 a : to give notice to beforehand especially of danger or evil b : to give admonishing advice to : COUNSEL c : tocall to one's attention :The use of the term “safety sign” implies from Webster that it is designed to prevent inadvertent hazardous operation butalso the condition of being safe from harm, which implies more than can always be realized in its application. While theterm “warning sign” implies giving notice of danger, which is what can actually be realized in the application of a sign.Although used in the title of the standard “ANSI Z535.4, Product Safety Signs and Labels”, the use of “safety sign”terminology is in minority usage in the NEC while “warning sign” is prevalent throughout the document.

222Printed on 10/13/2009



Add new text as follows:A.16.2.1 One such safety sign for consideration is the IEC symbol for Electric Shock. See Figure A.16.2.1Figure A.16.2.1 Symbol that Represents Risk of Electrical Shock – IEC Symbol Number 5036

****Insert artwork Here ****(79_L113_R Figure A.16.2.1)

Continued harmonization with IEC 60204-1 and consideration of International signs


223Printed on 10/13/2009



Add new text as follows:A.16.2.8 One such safety sign for consideration is the IEC symbol for Hazardous Surface Temperature. For electrical

installations, reference IEC 60364-4-42, Clause 423 and Table 42A. See Figure A.16.2.8Figure A.16.2.8 Symbol that Represents Hazardous Surface Temperature of Electrical Equipment – IEC Symbol

Number 5041.

****Insert Artwork Here****(79_L115_R Figure A.16.2.8)

Continued harmonization with IEC 60204-1 and consideration of International signs. Reference to IEC60364-4-42 would need to be added to Annex I also.

There submitter recommended annex material for section 16.2.8 which does not exist in thestandard.


ANDERSON, W.: The committee did error in its conclusion that thermal warning signs are beyond the scope of thisstandard when the root cause of the thermal hazard is in fact the electrical equipment in the area of concern. Warningsigns including thermal hazard warning signs are necessary and are within the scope of this standardExamples:3.3.33 (Electrically) Instructed Person. A person adequately advised or supervised by an electrically skilled person toenable him or her to perceive risks and to avoid hazards that electricity can create.3.3.34 (Electrically) Skilled Person. A person with relevant education and experience to enable him or her to perceiverisks and to avoid hazards that electricity can create.4.1* General Considerations. This chapter describes the general requirements and conditions for the operation of theelectrical equipment of the machine. The risks associated with the hazards relevant to the electrical equipment shall beassessed as part of the overall requirements for risk assessment of the machine. The risks associated with the hazardsidentified by the risk assessment shall be reduced such that the safety performance determined by the risk assessmentis met.

WOLFGANG, E.: This proposal was actually Annex material proposed to be used in conjunction with ROP 79-168,(Log #114) and as such is now being incorporated with my comments regarding ROP 79-168 (Log #114) & 79-169, (Log#163).

224Printed on 10/13/2009



Revise text to read as follows:A.18.2 The concepts of SELV are further explained in UL 1950 ANSI/UL 60950-1, UL 61010A-1, and IEC 60364-4-41.

It should be noted that there is a difference in the definitions of SELV in these standards.Update standards titles to indicate revision dates, ANSI approvals and other title changes. ANSI/UL

60950-1 is the successor standard to UL 1950



225Printed on 10/13/2009



Add new Question No 28 and increment remainder of questions accordingly to read as follows:"Are installed maintenance or personnel locks permitted to interfere with enclosure door opening or closing? (see

5.3.3.1(3)."This will allow users to incorporate in-house work practices and procedures.

226Printed on 10/13/2009



Add new text to Annex C as follows:Examples of packaging machines are as follows:

(1) Carton-strapping machine(2) Drum-filling machines(3) Palletizing machines

To provide examples of the packaging machines referred to in Section 3.3.56 of NFPA 79 and Section670.2 of NFPA 70.


227Printed on 10/13/2009



Revise text to read as follows:F.1 Disclaimer.Only IEC 60529 should be considered the source document for accurate information regarding IP-rating and ANSI/UL

50, ANSI/UL 508, and/or NEMA 250 should be considered the source documents regarding type-rating. The informationpresented in Annex F is limited and intended as introductory information. This annex is meant to give the user a senseof the IP-rating system and how it differs from the NEMA 250 type-rating system.


Revise text to read as follows:F.1 Disclaimer.Only IEC 60529 should be considered the source document for accurate information regarding IP-rating and ANSI/UL

50, ANSI/UL 508, and/or NEMA 250 should be considered the source documents regarding type-rating. The informationpresented in Annex F is limited and intended as introductory information. This annex is meant to give the user a senseof the IP-rating system and how it differs from the NEMA 250 type-rating system.

The committee accepts the submitter's intent to include ANSI references before UL 50 and508 but added legislative text to clarify additions.



228Printed on 10/13/2009



Revise text to read as follows:F.2 Rating for Electrical Enclosures.Electrical enclosures are type-rated according to NEMA 250, ANSI/UL 50, and ANSI/UL 508 or IP-rated according to

IEC 60529 based upon the degree of protection provided.Update standards titles to indicate ANSI approvals.




229Printed on 10/13/2009



Revise text to read as follows:Table F.5.5 (Notes)Notes:(1) Type-rated enclosures for hazardous locations and potentially explosive areas have been excluded from the table.

The additional and supplementary letters for IP-ratings have also been excluded from the table. (See NEMA 250,ANSI/UL 508, and IEC 60529.)




230Printed on 10/13/2009



Revise text to read as follows:I.1.2.8 UL Publications. Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.ANSI/UL 50, Standard for Enclosures for Electrical Equipment, 2003 2007.ANSI/UL 62, Standard for Flexible Cord and Fixture Wire, 2006.ANSI/UL 248-14, Standard for Low-Voltage Fuses - Part 14: Supplemental Fuses, 2000 with revisions through August

2005.ANSI/UL 489, Standard for Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit-Breaker Enclosures,

2006 2002 with revisions through March 2009.ANSI/UL 498, Standard for Attachment Plugs and Receptacles, 2001, with revisions through October 2008.ANSI/UL 508, Standard for Industrial Control Equipment, 2005 1999 with revisions through September 2008.UL 508A, Standard for Industrial Control Panels, 2001, with revisions through December 2007.ANSI/UL 651, Standard for Schedule 40 and 80 Rigid PVC Conduit, 2005 2007 with revisions through March 2009.UL 1004, Standard for Electric Motors, 1994, with revisions through March 2006.ANSI/UL 1077, Standard for Supplementary Protectors for Use in Electrical Equipment, 2005, with revisions through

February 2009.ANSI/UL 1682, Plugs, Receptacles, and Cable Connectors of the Pin and Sleeve Type, 2002 2007.UL 1950, Standard for Information Technology Equipment, 1995.ANSI/UL 60950-1 Information Technology Equipment - Part I: General RequirementsUL 61010A-1, Electrical Equipment for Laboratory Use - Part 1: General Requirements, 2002.

Update standards titles to indicate revision dates, ANSI approvals and other title changes. ANSI/UL60950-1 is the successor standard to UL 1950

Revise text to read as follows:I.1.2.8 UL Publications. Underwriters Laboratories Inc., 333 Pfingsten Road, Northbrook, IL 60062-2096.ANSI/UL 50, Standard for Enclosures for Electrical Equipment. 2003 2007.ANSI/UL 62, Standard for Flexible Cord and Fixture Wire. 2006.ANSI/UL 248-14, Standard for Low-Voltage Fuses - Part 14: Supplemental Fuses. 2000 with revisions through August

2005.ANSI/UL 489, Standard for Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit-Breaker Enclosures.

2006 2002 with revisions through March 2009.ANSI/UL 498, Standard for Attachment Plugs and Receptacles. 2001, with revisions through October 2008.ANSI/UL 508, Standard for Industrial Control Equipment. 2005 1999 with revisions through September 2008.UL 508A, Standard for Industrial Control Panels. 2001, with revisions through December 2007.ANSI/UL 651, Standard for Schedule 40 and 80 Rigid PVC Conduit. 2005 2007 with revisions through March 2009.UL 1004, Standard for Electric Motors. 1994, with revisions through March 2006.ANSI/UL 1077, Standard for Supplementary Protectors for Use in Electrical Equipment, 2005, with revisions through

February 2009.ANSI/UL 1682, Plugs, Receptacles, and Cable Connectors of the Pin and Sleeve Type. 2002 2007.UL 1950, Standard for Information Technology Equipment. 1995.ANSI/UL 60950-1 Information Technology Equipment - Part I: General RequirementsUL 61010A-1, Electrical Equipment for Laboratory Use - Part 1: General Requirements. 2002.

The committee accepted addition of the ANSI references but removed the dates to allow thelatest revised edition to be utilized.


ANDERSON, W.: I agree with the committee's action and to follow the current manual of style as follows:2.3.1.2.1 Chapter 2 shall consist of three sections as follows:(1) 2.1 General. The documents or portions thereof listed in this chapter are referenced within this (standard, code) andshall be considered part of the requirements of this document.

231Printed on 10/13/2009

Report on Proposals – November 2010 NFPA 79(2) 2.2 NFPA Publications.(3) 2.3 Other Publications.2.3.1.2.4 All reference listings in Chapter 2 shall contain complete reference information [i.e., document number (ifapplicable), document title, and date of publication (if applicable)].2.3.1.2.5 References shall be permitted to be referred to throughout the document (other than Chapter 2) by only theirnumerical designation or document title, as used in the field.

CALLANAN, M.: The Technical Correlating Committee should review the panel statement for this action relative todates being removed allows for latest revision date by default.

232Printed on 10/13/2009



Add new Annex X as follows:Table X.1 provides a comparison of the conductor cross-sectional areas of the American Wire Gauge (AWG) with

square millimeters, square inches, and circular mils.

***Insert Table X.1- Comparison of conductor sizes here***(79_L162_TbX.1._R)

The resistance for temperatures other than 20°C can be found using the formula:

[1+0.00393 ( =20)]

Where:is the resistance at 20°C

is the resistance at a temperature °C

In IEC 60204-1 there is an annex comparing generically IEC and AWG wire size electrical propertieswhich are necessary to make design and operational conversions between the two systems.

Add asterisk following 12.2.2.Add new A.12.2.2 to read as follows:See Annex I.Add new Annex I as follows:Table I.1 provides a comparison of the conductor cross-sectional areas of the American Wire Gauge (AWG) with

square millimeters, square inches, and circular mils.

Table I.1 Comparison of Conductor Sizes

***Insert Table I.1 Comparison of conductor sizes here***(79_L162_TbI_I.1 CA )

The resistance for temperatures other than 20°C can be found using the formula:

[1+0.00393 ( - 20)]

Where:is the resistance at 20°C

is the resistance at a temperature °C

Re-letter existing Annex I accordingly (K)The committee corrected the printing errors in the formulas and added Fahrenheit notations to

the table.The committee added an asterisk after 12.2.2 and created a new Annex A.12.2.2 to reference the location of the table

in a new Annex I.


233Printed on 10/13/2009

79/L162/R/F2010/ROP

Table X.1 – Comparison of Conductor Sizes

Wire size Gauge No Cross‐sectional area DC resistance of copper at

20 C

Circular mils

mm2 (AWG) mm2 inches2 Ohms per km

0,2 0.196 0,000304 91.62 387

24 0,205 0,000317 87.60 404

0,3 0,283 0,000438 63.46 558

22 0,324 0,000504 55.44 640

0,5 0,500 0,000775 36.70 987

20 0,519 0,000802 34.45 1020

0.75 0,750 0,001162 24.80 1480

18 0,823 0,001272 20.95 1620

1,0 1,000 0,001550 18.20 1973

16 1,31 0,002026 13.19 2580

1,5 1,500 0,002325 12.20 2960

14 2,08 0,003228 8.442 4110

2,5 2,500 0,003875 7.56 4934

12 3,31 0,005129 5.315 6530

4 4,000 0,006200 4.700 7894

10 5.26 0,008152 3.335 10380

6 6,000 0,009200 3.110 11841

8 8,37 0,012967 2.093 16510

10 10,000 0,001550 1.840 19735

6 13,3 0,020610 1.320 26240

16 16,000 0,024800 1.160 31576

4 21,1 0,032780 0.8295 41740

25 25,000 0,0388000 0.7340 49338

2 33,6 0,052100 0.5290 69073

1 42,4 0,065700 0.4139 83690

50 47,000 0,072800 0.3910 92756


234Printed on 10/13/2009



Add text to show as follows:

***INSERT ART HERE***(79_L161_#1_REC)

Looking forward into the future is based on the judgement (analysis), which normally guides ones movement throughthe present into the future. It is that, projection part of the decision making process, which is essentially doing a riskassessment before moving on, in rational daily activity and in the concept of designing out hazards.

establish what level of risk is acceptable.This acceptable risk has several names one is the de-minimus line. The de-minimus line is a more subjective level but

it needs to be consistent. The process of establishing the de-minimus line answers the question, are the negativeconsequences worth the positive goal when the risk is taken?

identifies the hazards whose risks are to be assessed.The hazard identification is mostly brainstorming sessions involving people with different experiential backgrounds, e.g.

operational, construction, design, humal factors, engineering, etc. Guidance is often offered using reminder lists ofthings considered to be source of hazards.

evaluate the severity of the consequences leading from each hazard.determine the chance that hazardous situation will even happen. This step is where a consistent but simple

method is important.establish changes to account for or eliminate the identified hazard risks

that are unacceptable.This iteration process continues until all hazards are addressed and/or eliminated (risk remediation through design).After the last change has been included, start the process one more time from the "start the evaluation" step.

STOP, if not return to "start theevaluation" step developing additional risk remediation solutions. Continue the iterations until the level of acceptablerisk has been reached, the answer tot he question is yes then STOP.

the addressing of the hazarded may be accomplished by changing the design,adding safety devices or guards, instructions and training, etc., items which are added to the machine or situation beingassessed. The iteration after remediation is done to assure that the new change does not introduce new hazards, ifthere are new hazards they too must be addressed.

Life cycle can be broken into phases such as design work during which a risk analysiswould identify hazards and risks and proceed to reduce or eliminate the hazard where possible, within the design. Thefew (if any) remaining hazard residuals from one life cycle phase would be passed to the next and finally throughinstructions for operation to the user.

***INSERT ART HERE***(79_L161_#2_REC)

***INSERT TABLE HERE***(79_l161_Tb1_R)

The risks associated with the hazards relevant

235Printed on 10/13/2009

79/L161‐Tb1/R/F2010/ROP

Table 1 Example of Hazards to be considered

Hazard number Description 1 Mechanical hazard (caused by, for example: shape, relative

location, mass and stability (potential energy of elements) mall and velocity (kinetic energy of elements) Inadequacy of the mechanical strength, accumulation of potential energy by; elastic elements (springs), or liquids or gases under pressure, or vacuum of the machine parts or work-pieces

1.1 Crushing, shearing, cutting, severing, impact, stabbing, or puncture hazard:

1.2 Entanglement, drawing-in or trapping hazard; 1.3 Friction or abrasion hazard; 1.4 High pressure liquids or gases injection hazard; 1.5 Ejection of parts (of machinery or processed materials/work-

pieces); 1.6 Loss of stability (of machinery or machine parts); 1.7 Slip, trip and fall hazards related to machinery. 2 Electrical hazards (electric shock or burn), caused by: 2.1 Contact with live parts normally carrying a voltage (direct

contact)or contact with parts that have become live under fault conditions (e.g. insulation failure) (indirect contact);

2.2 Electrostatic phenomena; 2.3 Thermal radiation or other phenomena such as ejection of

molten particles, and chemical effects from short-circuits, overloads, etc.

3 Thermal hazards resulting in: 3.1 Burns and scalds, from contact with objects or materials with

an extreme temperature, flames or explosions and radiation from heat sources;

3.2 Health-damaging effects generated by hot or cold work environment.

4 Hazards generated by noise resulting in: 4.1 Hearing losses (deafness), other physiological disorders (e.g.

loss of balance, loss of aware-ness); 4.2 Interferences with speech, communication, or acoustic

signals. 5 Hazards generated by vibration (resulting in a variety of

neurological and vascular disorders). 6 Hazards generated by radiation, especially by: 6.1 Electrical arcs; 6.2 Lasers; 6.3 Ionizing radiation sources; 6.4 Machines making use of high frequency, electromagnetic

fields. 7 Hazards generated by materials and substances processed,

used or exhausted by machinery, for example: 7.1 Hazards resulting from contact with or inhalation of harmful

fluids, gases, mists, fumes, and dusts; 7.2 Fire and explosion hazards;

79/L161‐Tb1/R/F2010/ROP

7.3 Biological (e.g. mould) and microbiological (viral or bacterial) hazards.

8 Hazards generated by neglecting ergonomics principles in machine design (mismatch of machinery with human characteristics and abilities) caused for example by: unhealthy postures or excessive efforts, inadequate consideration of human hand-arm or foot-let anatomy, neglected use of personal protection equipment, inadequate area lighting, mental overload or under-load, stress, human error (e.g. because of different location for push-button of similar type of machine).

9 Hazard combination (an individual minor hazard may, when combined with another, become a major hazard).

10 Hazards caused by failure of energy supply, breaking down of machinery parts and other functional disorders, for example:

10.1 Failure of energy supply (pf energy and/or to control circuits);

10.2 Unexpected ejection of machine parts or fluids; 10.3 Failure, malfunction of control system (unexpected start up,

unexpected overrun); 10.4 Fitting errors; 10.5 Overturn, unexpected loss of machine stability. 11 Hazards caused by (temporary) missing and/or incorrectly

positioned safety related measures/means, for example: 11.1 All kinds of guards (fixed and movable); 11.2 All kinds of safety related (protection) devices (interlocking,

bold-to-run control, two-hand control, etc.); 11.3 Starting and stopping devices; 11.4 Safety signs, safety signals and other warning devices; 11.5 Energy supply disconnecting devices (electrical, pneumatic,

hydraulic, steam); 11.6 Emergency devices; 11.7 Feeding/removal means of work-pieces (manual or

automatic); 11.8 Essential equipment on accessories for safe adjusting and/or

maintenance; 11.9 Equipment evacuating gases,etc.

Report on Proposals – November 2010 NFPA 79to the electrical equipment shall be assessed as part of the overall requirements for risk assessment of the machine.The risks associated with the hazards identified by the risk assessment shall be reduced such that the safetyperformance determined by the risk assessment is met.

This proposed new annex presents a way to fulfill the requirements in 4.1 using reasonably acceptable methods,reference NFPA 70E: 2009, Annex F, Safety of machinery —Functional safety of safety-related electrical, electronic and programmable electronic control systems, Annex A SILAssignment [a qualitative approach to risk estimation and SIL assignment}; ISO 14121-2:2007 Safety of machinery —

— Part 2:[This risk

assessment method quantifies the qualitative parameter. It is a hybrid method of numerical scoring and a matrix. Itranges from hazard identification to risk estimation and risk evaluation, to protective measures to be implemented andthe decision to consider the machine adequately safe. Risk assessment using this method and tool can be done by anindividual in the day-to-day work as a first step but should, as with all risk assessments, be reviewed or repeated by ateam].

The committee agrees that the appropriate standards and technical reports addressing thesubject of risk assessment are adequately referenced in this standard.


ANDERSON, W.: While the committee is correct that appropriate standards and technical reports addressing thesubject of risk assessment are referenced in this standard; most if not all address certain aspects of the process but donot present an easily understood application of the risk assessment and risk reduction process. The proposed annex isunique in that it presents the process and suggested documentation of the complete process as applied to industrialmachines and industrial machines electrical risks. The new annex is needed to complete the addressing of the riskassessment and risk reduction methodology required within the NFPA 79 standard.The use of electrical systems through control functions and operational control are often used to address reduction ofrisk for hazards which are not inherently electrical but are still a part of the NFPA 79 standard requirements

236Printed on 10/13/2009