Presented byEWB Engineering, LLC.

To UnderstandWhat is An Arc FlashWhy OSHA Is Addressing This IssueRequirements In NEC & NFPA 70EImpact to IndustryBenefits to completing an Arc-Flashp gAssessment

Arc Flash Event

Every Day 5 75-7 Electricians are Severelyare Severely Injured by an Arc Flash Event

An Arc Flash is a Sudden Release of Heat and Energy Caused By An Electric Arc an

Arc Resistant Switchgear

Electric Arc, an Additional Hazard beyond g

Undergoing Test For an Arcing Fault

Hazard beyond Shock

Arcing faults in power distribution can produce intense heat

- Texas in August: 105 F- Surface of the sun: 8,540 F- Arc (at mid-point): 22,940 F- Arc (at terminals): 35,540 F

I j i f fl h f l l i l Injuries from arc flash refer almost exclusively to the effects of burns received

Arc Blast- 6,000 lbs force won worker’s chest

from moderate fault at MCC- Pressure can cause collapsed lungs,

concussion, etc. Molten copper – Vaporized copper expands 40 000 i i40,000x upon vaporizationShrapnel – Arc Blast can create projectiles that cause injurythat cause injury

Accidental Contact- Misplaced toolsMisplaced tools- Voltage testersEquipment FailuresEquipment FailuresRodentsUnsuccessful short circuit interruptionsUnsuccessful short-circuit interruptions(Maintenance)

OSHA 29 CFR 1910.132 (d) requires employers to assess the workplace to determine if hazards are or could be present, providethe appropriate PPE for each affected employee, and requires itsuse It also requires employers to inform the affected employeesuse. It also requires employers to inform the affected employeesregarding hazards and PPE and to verify that the requiredassessment was performed through a written certification identifying the workplace evaluated identifying the workplace evaluated.

Final Rule 72:7135-7221 Revises CFR 1910 Subpart S – based on pNFPA 70 (NEC) – 2002 . Includes revised Reference to NFPA 70E-2000 (“see also NFPA 70E-2004”).

Effective August 13, 2007SUMMARY: The Occupational Safety and Health Administration (OSHA) is revising the general industry electrical installation standard found in Subpart S of 29 CFR the general industry electrical installation standard found in Subpart S of 29 CFR Part 1910. The Agency has determined that electrical hazards in the workplace pose a significant risk of injury or death to employees, and that the requirements in the revised standard which draw heavily from the 2000 edition of the National Fire revised standard, which draw heavily from the 2000 edition of the National Fire Protection Association's (NFPA) Electrical Safety Requirements for Employee Workplaces (NFPA 70E), and the 2002 edition of the National Electrical Code (NEC), are reasonably necessary to provide protection from these hazards. This final rule y y p pfocuses on safety in the design and installation of electric equipment in the workplace. This revision will provide the first update of the installation requirements in the general industry electrical installation standard since 1981. OSHA is also replacing the reference to the 1971 NEC in the mandatory appendix to the general industry powered platform standard found in Subpart F of 29 CFR Part 1910 with a reference to OSHA's electrical installation standard.

NFPA 70E and NEC were written at OHSA’s request to helpNFPA 70E and NEC were written at OHSAs request to helpemployers meet the content of OSHA 1910 subpart S

NFPA 70E 2000 t II Ch t 2 h 2 1 3 3NFPA 70E-2000, part II Chapter 2 paragraph 2-1.3.3Requires an arc-flash hazard analysis to be performed to determine the level of hazard and the appropriate PPE for the given task

NEC 110 16 States that the equipment must be marked to NEC 110.16 States that the equipment must be marked to warn qualified persons of potential arc flash hazards.

IEEE 1584 M th d l t l t th fl h l l tiIEEE 1584 - Methodology to complete the arc flash calculations

NEC 110.16NEC 110.16

States Equipment must be marked to warn States Equipment must be marked to warn qualified persons of potential electrical arc flash hazards.

Racking a breaker on an energized busg gRemoving covers Voltage checks or troubleshootingVo tage c ecks o t oub es oot gApplication of safety grounds after voltage testInsertion or Removal of MCC BucketsInsertion or Removal of MCC Buckets

Flash Protection BoundaryIncident Arc EnergygyHazard Level for PPE

IEEE 1584IEEE 1584IEEE Method Preferred (Detailed Calculations Requiredq

NFPA 70E TablesCan Be Used if Detailed Calculations Not AvailableLimited Range of Fault Currents and Protective Device CharacteristicsDevice Characteristics

You cannot mix the two methodsYou cannot mix the two methods

R di d E F Fl hRadiated Energy From Flash

Radiated Energy Function of

Arc Power

Distance From Arc

AC Volts Time to Extinguish Arc

Arc Power Function ofArc Power Function of

Arc Voltage & Arc Current

Arc Voltage Function ofArc Voltage Function of

Arc Gap

A distance from exposed liveexposed live parts within which a person pcould receive a second degree burn.

Situation: We have a Main SWBD that has five fused disconnectSwitches that is fed from a 2500KVA utility owned pad mounted transformer 100’ of 6ea 500 MCM cable per phase

We received the primary fuse information and the available faultcurrent from the utility

Need to determine working distance 36”

IEEE 1584 equations determine arcing fault current is approximately36KA. It will take the utility fuse 2.5 secs to clear.This yields an arc-flash incident energy level of 50 cal/cm2 and anThis yields an arc flash incident energy level of 50 cal/cm and anAFPB of 10’.

Example of using the Table Method:

What is the required Arc-Flash PPE for operating a FusedDisconnect Switch located on the Plant’s Mains SWBD operating at 480 volts?at 480 volts?

Table 130.7(C)(9) “CB or Fused Switch operation with the covers on 480 volt SWBD is Hazard Risk Level 0 (See Note 1)on 480 volt SWBD is Hazard Risk Level 0 (See Note 1)

Note1: Maximum of 25KA short circuit current available: Maximum of .03 sec fault clearing time.

Since we don’t meet the requirement of Table 130.7(C)(7)We cannot use the Table Method for the Main SWBD.

This doesn’t mean we cannot use the table at other locations.H i th f lt t i l d th f lt l i However since the fault current is large and the fault clearing times are usually longer, the table is not valid here. We might be able to use the Table at several of the MCC’s located in the be able to use the Table at several of the MCC s located in the plant.

Points to using the Tableg

1. You still have to understand your electrical ydistribution system

2. Need to determine fault currents and clearing timesg

3. Need to understand the task

IEEE 1584IEEE 1584

1 Is not task oriented 1. Is not task oriented 2. Working distance is important3 Do not take credit for doors or other barriers3. Do not take credit for doors or other barriers4. Type of equipment is an important factor in

the calculationsthe calculations5. Identifies device deficiencies6 Opportunities to reduce the required PPE6. Opportunities to reduce the required PPE

Category Cal /cm2 FR Clothing(Minimum Rating)

0 N/A U t t d C tt (L Sl )0 N/A Untreated Cotton, (Long Sleeve)Hearing Protection, Eye Protection

1 4 FR Shirt & FR Pants or FR 1 4 FR Shirt & FR Pants or FR Coveralls, Face Shield, Hearing Protection

2 8 FR Shirt & FR Pants or FR Coveralls, Face Shield, Hearing

Protection

3 25 FR System, FR Hood, Hearing Protection

4 40 S b t hi h 4 40 Same as above except higher rating

An important point to remember …….

Personal Protective Equipment is the last line of defense – making smart safety decisions tog f yprevent an arc flash from occurring must be a top priority

How do we prevent an arc-flash from happening?

There is no fool proof way, however we can minimize the opportunities and its effect.

- Training: NFPA 70E states that only qualified people should operate and perform maintenance on electrical equipmentequipment.Qualified person must understand and be able to mitigate the hazards, know and understand the shock and arc-flash boundaries and how and when to use the proper PPEboundaries, and how and when to use the proper PPE

- Equipment Maintenance: Protection devices must be l d d f d d lproperly rated and must function as designed to clear an

arcing fault. PPM can be used to identify problems before they happen (ie. IR scans).

• The arc-flash analysis is the first step that will bring the facility into The arc flash analysis is the first step that will bring the facility into compliance with the OSHA requirements.

Th l i id d ti t li i t d th• The analysis provides recommendations to eliminate or reduce thearc-flash hazard.

• The analysis provides recommendations to improve reliability thrubetter coordination between protective devices.

• The analysis provides recommendations to eliminate fire hazardsdue to misapplication of protection devices

Th l i id ifi i l i i h i d i • The analysis identifies potential issues with inadequate protective device ratings. This can lead to major equipment damage during an electrical fault and expose persons to increased risk of an p parc-flash.

• The analysis provides the proper electrical data to improve the • The analysis provides the proper electrical data to improve the design process for future changes or expansion saving money.

Th l i id tifi t iti t d th i d • The analysis identifies opportunities to reduce the required arc-flash PPE

• Anticipated Benefits:• Employee Safety – Primarily improving employee and

contractor safety while interacting with electrical systems this contractor safety while interacting with electrical systems, this includes:• Reducing the exposure from arc flash

Matching the PPE req irements to the need th s • Matching the PPE requirements to the need, thus reducing PPE cost

• Establish a means to properly label and rate overcurrent protection.

• Establish Legacy Process:• Establish baseline for overall system design, control

and performance and performance. • Improve change management capability, and• System reliabilitySystem reliability

• Provides critical information for design practices and reviews

1. Train your employees

2. Have a Documented Lock out Procedure

3. Electrical Workers must meet the OHSA’s definition of qualified.Skills and knowledge, safety training, the use of PPE

4. Conduct job briefings (toolbox meetings) JSA or JHA

5. Complete a Hazard Assessment, Document and Label

6. Never ever tell someone to do something you know is unsafe6. Never ever tell someone to do something you know is unsafe

OSHA & NFPA 70E Require An Arc Flash Hazard Analysis For Proper PPEy p

Requirement in NEC States That Arc Flash qWarning Labels Be Placed on Electrical Panels and Switchboards.

IEEE 1584 is Preferred Method for Determining Arc Flash Incident Energy & Arc Flash Arc Flash Incident Energy & Arc Flash Boundaries.

Fault StudyCoordination StudyDetermine Incident Arc Energy and Boundary

ll d hi ll iDo I really need to this? Is OSHA really going to enforce this?OSHA does not say specifically that you must complete an y p y y pArc-Flash Analysis. OSHA does say that you must evaluate the hazards that exist in your facility. This includes electrical hazards and have a policy that address the required PPE needed when exposed to the hazards. OSHA will refer to the pNEC and NFPA as recognized industry standards to operate by. NFPA chapter 2 does say an Arc-Flash Analysis must be completed when working on or near energized equipment. NEC 110.16 states the equipment must be marked to warn q pqualified persons of potential electrical arc-flash.

In August of 2007 OSHA revised CFR 1910 Subpart S based on NFPA 70 (NEC) The revision makes reference to on NFPA 70 (NEC). The revision makes reference to NFPA70E 2000 and 2004

We do not work on energized equipment.g q p

Do you do voltage checks, rack breakers in or out on an energized bus?out on an energized bus?Do you apply safety grounds or remove covers for infarred thermography?g p y

If the answer is “yes” then an arc-flash anal sis must be completed before these task analysis must be completed before these task can be completed.

h h b fi f d i hi fWhat are the benefits of doing this type of analysis?

Provides the knowledge of best possible PPE for electrical workers

ll lPotentially lowers insurance premiumsIncreases knowledge of their electrical distribution systemdistribution systemEnhances system reliabilityEnables easy changes and upgradesy g pgDrastically lessens their chances of having to make a very unpleasant visit to survivors

What kind of data is needed?

Typically the needed data is cable sizes and Typically the needed data is cable sizes and lengths, relay or breaker settings and sizes, transformer nameplate info, and any large motor info that is not controlled by VFD’s If motor info. that is not controlled by VFD s. If the facility has onsite generation, it will be evaluated if depending on the size and percentage of demandpercentage of demand

We have recently purchased some PPE. I We have recently purchased some PPE. I think we are in compliance.

What level did you purchase? How do you know it is adequate for all voltage levels and q gtask? You can’t know these without completing an analysis

Chicken Switch- Remote breaker operationChicken Switch- Remote breaker operationwww.chickenswitch.comRemote racking mechanism Major OEM’sRemote racking mechanism- Major OEM sLight Heat Sensors – ABBM ti D t t SiMotion Detectors – SiememsMaintenance Relay Switches – Major OEM’sZ i l ki l i M j OEM’Zone interlocking relaying – Major OEM’sHigh Resistant GroundingArc-Resistant Switchgear – Major OEM’sIR Viewing Windows