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ELECTRICAL SAFETY ELECTRICAL SAFETY RELATED WORK PRACTICESRELATED WORK PRACTICESFOR GENERAL INDUSTRYFOR GENERAL INDUSTRY

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ELECTRICAL HAZARDSELECTRICAL HAZARDS

What is an electrical hazard?What is an electrical hazard? Electricity and the Human BodyElectricity and the Human Body ElectrocutionElectrocution Arc Blasts & Pressure WavesArc Blasts & Pressure Waves Secondary EffectsSecondary Effects

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Types of Electrical HazardsTypes of Electrical Hazards

ElectrocutionElectrocution Arcs & BlastsArcs & Blasts Secondary Hazards (fire, falls)Secondary Hazards (fire, falls)

An electrical hazard is any potential threat to health and or propertycaused by inadvertent contact with, or release of, electricial energy.

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Electrical ShocksElectrical Shocks

Resistance of human body varies Resistance of human body varies widely; 10,000 ohms is “typical”.widely; 10,000 ohms is “typical”.

5mA of sustained current is usually 5mA of sustained current is usually considered the threshold value of considered the threshold value of physiological damage .physiological damage .

Threshold voltage=10,000 ohms x .005 Threshold voltage=10,000 ohms x .005 amps or 50 volts. amps or 50 volts.

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Electricity and the Human BodyElectricity and the Human Body

At 5 mA pain begins.At 5 mA pain begins. At 10 mA paralysis of limbs (arms) occurs.At 10 mA paralysis of limbs (arms) occurs. At 30 mA breathing stops.At 30 mA breathing stops. At 75 mA fibrillation occurs.At 75 mA fibrillation occurs. Above 250 mA fibrillation ceases.Above 250 mA fibrillation ceases. At 4 amps breathing ceases. At 4 amps breathing ceases. At 5 amps tissue burns. At 5 amps tissue burns.

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Arc Blasts & Pressure WavesArc Blasts & Pressure Waves

Injuries & deaths due to arc burns are Injuries & deaths due to arc burns are roughly one fourth of electrical hazard roughly one fourth of electrical hazard related casualties.related casualties.

Radiation burns can Radiation burns can killkill up to 5 ft up to 5 ft Arc temperatures up to Arc temperatures up to 30,000 degrees 30,000 degrees

Pressure waves created by arc blasts Pressure waves created by arc blasts have been known to knock walls down have been known to knock walls down at at 30 ft30 ft! !

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Electricity is the “perfect” hazard: it can’t beElectricity is the “perfect” hazard: it can’t beseen, smelled or heard!seen, smelled or heard!

The grim statistics from the Natonal Safety Council:The grim statistics from the Natonal Safety Council:

Between 500-600 people in the U.S. die by Between 500-600 people in the U.S. die by electrocution or arc blast yearly. electrocution or arc blast yearly.

350-400 workers die by electrical current yearly.350-400 workers die by electrical current yearly.

Electrical accidents are the 8th leading cause ofElectrical accidents are the 8th leading cause ofdeath in the workplace.death in the workplace.

All electrocutions are preventable!All electrocutions are preventable!

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THE 4 LINES OF DEFENSETHE 4 LINES OF DEFENSE

TRAINING FOR ALL AFFECTED PERSONNELTRAINING FOR ALL AFFECTED PERSONNEL

PROPER EQUIPMENTPROPER EQUIPMENT

SELECTION OF PROPER WORK PRACTICESSELECTION OF PROPER WORK PRACTICES

PLANNING AND PROCEDURESPLANNING AND PROCEDURES

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APPLICATION OF OSHA APPLICATION OF OSHA SRWP IN THE WORKPLACE SRWP IN THE WORKPLACE

Who Needs Training?Who Needs Training? What Kind of Training?What Kind of Training? Work PracticesWork Practices Proper Selection & Use of EquipmentProper Selection & Use of Equipment Are Written Procedures Necessary?Are Written Procedures Necessary?

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WHO NEEDS TRAINING?WHO NEEDS TRAINING?

Anyone who works on or near enough to Anyone who works on or near enough to exposed live parts or parts which might exposed live parts or parts which might become energized (potential hazard) must become energized (potential hazard) must receive training.receive training.

Examples : Electricians, construction Examples : Electricians, construction crews on industrial sites, heavy equipment crews on industrial sites, heavy equipment operators, machine operators, janitors-in operators, machine operators, janitors-in short, potentialy anyone at your facility! short, potentialy anyone at your facility!

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WHAT KIND OF TRAINING?WHAT KIND OF TRAINING?

Training requirements depend on the Training requirements depend on the extent of potential exposure.extent of potential exposure.

Training may be OJT or classroom or Training may be OJT or classroom or both. both.

Extent of training depends on whether Extent of training depends on whether person is qualified or unqualified.person is qualified or unqualified.

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Qualified vs UnqualifiedQualified vs Unqualified

DEFINITION : A qualified person DEFINITION : A qualified person (OSHA definition) is “one who is familiar (OSHA definition) is “one who is familiar with the construction and operation of with the construction and operation of the equipment and the hazards the equipment and the hazards involved.”involved.”

This definition applies to specific This definition applies to specific equipment.equipment.

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TRAININGTRAINING

Training required for both qualified and non Training required for both qualified and non qualified personnel working on or near parts qualified personnel working on or near parts which are energized or might be energized.which are energized or might be energized.

Qualified personnel Qualified personnel must be trained in must be trained in work practices, determine nominal working work practices, determine nominal working voltage, know line clearances. voltage, know line clearances.

Unqualified personnel Unqualified personnel working in vicinity working in vicinity must be trained to extent necessary.must be trained to extent necessary.

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Training for Qualified Training for Qualified PersonnelPersonnel

Must be able to identify energized parts. Must be able to identify energized parts. Ability to determine nominal workimg Ability to determine nominal workimg

voltages.voltages. Must know applicable clearances vs Must know applicable clearances vs

voltages IAW 1910.333(c).voltages IAW 1910.333(c). Trained in SRWP as applied to job.Trained in SRWP as applied to job.

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Training for Unqualified Training for Unqualified PersonnelPersonnel

Unqualified trained to the extent Unqualified trained to the extent necessary.necessary.

EXAMPLE: Housekeeping crews should EXAMPLE: Housekeeping crews should be shown safe cleaning distances from be shown safe cleaning distances from equipment with live circuits and equipment with live circuits and instructed in the use of nonconductive instructed in the use of nonconductive cleaning techniques in potentally cleaning techniques in potentally conductive locations.conductive locations.

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Training for Unqualified Training for Unqualified Personnel (Con’t)Personnel (Con’t)

EXAMPLE: Machine operators trained EXAMPLE: Machine operators trained in their role in LOTO.in their role in LOTO.

EXAMPLE: Fork lift operators instructed EXAMPLE: Fork lift operators instructed by memo and verbally to avoid certain by memo and verbally to avoid certain overhead line locations in your plant.overhead line locations in your plant.

EXAMPLE: Manufacturing personnel EXAMPLE: Manufacturing personnel instructed by supervisor to avoid instructed by supervisor to avoid barricaded areas.barricaded areas.

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Occupations Requiring TrainingOccupations Requiring Training

Blue collar supervisorsBlue collar supervisors Elec/electronic engineers, techs, Elec/electronic engineers, techs,

assemblersassemblers Electricians and weldersElectricians and welders Industrial machine operatorsIndustrial machine operators mechanics,repairers, painters, riggers, mechanics,repairers, painters, riggers,

roustabouts,stationary engineersroustabouts,stationary engineers

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Selection and Use of Safety Selection and Use of Safety Related Work PracticesRelated Work Practices Parts must be deenergized before work Parts must be deenergized before work

except as noted in 1910.333(a)(2) and less except as noted in 1910.333(a)(2) and less than 50 volts. than 50 volts. 1910.333(a)(1) 1910.333(a)(1)

Work can be performed on energized parts Work can be performed on energized parts in case of infeasibility or increased hazard in case of infeasibility or increased hazard of deenergized parts. of deenergized parts. 1910.333(a)(2) 1910.333(a)(2)

Deenergized parts must be treated as Deenergized parts must be treated as energized or locked out. energized or locked out. 1910.333(b)(1) 1910.333(b)(1)

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Lockout/Tagout (LOTO)Lockout/Tagout (LOTO) LOTO subject to OSHA review. LOTO subject to OSHA review. 1910.333(b)(2)1910.333(b)(2)

(i) (i) Procedures must be in place before Procedures must be in place before

deenergizing circuits. deenergizing circuits. 1910.333(b)(2)(ii) 1910.333(b)(2)(ii) Rules governing use of locks and tags. Rules governing use of locks and tags.

1910.333(b)(2)(iii) 1910.333(b)(2)(iii) Verification of deenergization required. Verification of deenergization required.

1910.333(b)(2)(iv) 1910.333(b)(2)(iv) Restart procedures. Restart procedures. 1910.333(b)(2)(v) 1910.333(b)(2)(v)

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Safety Related Work Practices Safety Related Work Practices for Exposed Energized Partsfor Exposed Energized Parts

Only qualified personnel may work on Only qualified personnel may work on energized equipment. energized equipment. 1910.333(c)(2) 1910.333(c)(2)

Overhead lines. Deenergize or Overhead lines. Deenergize or protective measures. Minimum protective measures. Minimum approach distances. approach distances. 1910.333(c)(3) 1910.333(c)(3)

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LIVE PARTS

LIVE PARTS

LIVE PARTS LIVE PARTS

INSULATED PARTSOR WALL

GROUNDEDPARTS

Condition a

Condition b

Condition c

3 ft for 0-150 volts3 ft for 151-600 volts

3 ft for 0-150 volts3.5 ft for 151-600 volts

3 ft for 0-150 vollts3.5 ft for 151-600 volts

WORKING CLEARANCES, LIVE PARTS, 0-600 VOLTSFrom Table S-1, 29 CFR 1910

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LimitedSpace

RestrictedSpace

ProhibitedSpace

Exposed LivePart, Fixed

FlashProtectionBoundry

A B C

FlashProtectionRequired

A.Qualified personnel onlyB. Qualified personnel, approved plan, PPE.C. All requirements in B plus specific training & risk assesment.

Adapted from NFPA 70E, Ch. 2-21

APPROACH DISTANCES TO LIVE PARTS

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LimitedSpace

RestrictedSpace

ProhibitedSpace

Exposed LivePart, Fixed

FlashProtectionBoundry

A B C

FlashProtectionRequired

A.Qualified personnel onlyB. Qualified personnel, approved plan, PPE.C. All requirements in B plus specific training & risk assesment.

Distances from live part to outer boundries Flash protection: 3 feet Limited space: 3 1/2 feetRestricted space avoid contact Prohibited space avoid contact

APPROACH DISTANCES TO LIVE PARTS, 300 V & LESS

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LimitedSpace

RestrictedSpace

ProhibitedSpace

Exposed LivePart, Fixed

FlashProtectionBoundry

A B C

FlashProtectionRequired

A.Qualified personnel onlyB. Qualified personnel, approved plan, PPE.C. All requirements in B plus specific training & risk assesment.

Distances from live part to outer boundries Flash protection: 4 feet Limited space: 4 feetRestricted space: 2 feet Prohibited space: 3 inches

APPROACH DISTANCES TO LIVE PARTS, 751 to 2,000V

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Work Practices (Con’t)Work Practices (Con’t)

Procedures required for handling Procedures required for handling all all conductive materials. conductive materials. 1910.333(c)(6) 1910.333(c)(6)

Nonconductive ladders. Nonconductive ladders. 1910.333(c)(7)1910.333(c)(7) Conductive apparel must be insulated. Conductive apparel must be insulated.

1910.333(c)(8)1910.333(c)(8) AdequateAdequate Illumination required. Illumination required.

1910.333(c)(4) and ANSI 11.1 1910.333(c)(4) and ANSI 11.1

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Work Practices (Con’t)Work Practices (Con’t)

Safeguards required for housekeeping Safeguards required for housekeeping duties. duties. 1910.333(c)(9) 1910.333(c)(9)

Interlocks: only qualified personnel may Interlocks: only qualified personnel may defeat and only on a temporary basis. defeat and only on a temporary basis. 1910.333(c)(10) 1910.333(c)(10)

Alerting techniques required in exposed Alerting techniques required in exposed hazardous locations. hazardous locations. 1910.335(b)1910.335(b)

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Electric Power & LightingElectric Power & Lighting

Live load disconnects must be load Live load disconnects must be load rated. Breakers not marked “SWD” rated. Breakers not marked “SWD” cannot be used to make\break live loads!cannot be used to make\break live loads!

Breakers operated under fault conditions Breakers operated under fault conditions must be replaced. Breakers operated must be replaced. Breakers operated under overload should be examined.under overload should be examined.

It is unlawful to degrade overload It is unlawful to degrade overload protection in the workplace! protection in the workplace!

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ungrounded cord

2 wire cord with pigtail

COMMON CORD AND PLUG VIOLATIONS

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WORKING ON OR NEAR EXPOSED LIVE PARTS REQUIRES PERSONALPROTECTIVE EQUIPMENT:29 CFR 1910.333(c)(2). EXPOSED BODY PARTS MUST BE PROTECTED: 29 CFR 1910.335(a)(1).

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Portable Electrical EquipmentPortable Electrical Equipment HANDLINGHANDLING: Tools shall not be handled by : Tools shall not be handled by

connecting cords or unsafely.connecting cords or unsafely. VISUAL INSPECTION FOR DAMAGEVISUAL INSPECTION FOR DAMAGE.. Must have grounding conductor or be Must have grounding conductor or be

double insulated or be battery operated.double insulated or be battery operated. Tools used in damp or wet locations must Tools used in damp or wet locations must

be rated for use in those environments.be rated for use in those environments. Attachment plugs cannot be altered! Attachment plugs cannot be altered!

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Only qualified personnel are permitted Only qualified personnel are permitted to use test equipment on live circuits.to use test equipment on live circuits.

Test equipment must be used within Test equipment must be used within ratings.ratings.

TEST EQUIPMENT

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Safeguards for Personnel Safeguards for Personnel Protection Protection

Protective equipment is required in Protective equipment is required in hazardous locations. hazardous locations. 1910.335(a)(1) 1910.335(a)(1)

General Equipment & Tools. Insulated General Equipment & Tools. Insulated tools required when working near tools required when working near exposed live parts. Includes fuze exposed live parts. Includes fuze pullers/installers,ropes, shields,etc. pullers/installers,ropes, shields,etc. 1910.335(a)(21910.335(a)(2) )

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Are Written Procedures Are Written Procedures Necessary?Necessary?

Written procedures increase training Written procedures increase training effeciency, protect employer and effeciency, protect employer and employee.employee.

Written procedures are required for Written procedures are required for Lockout/Tagout.Lockout/Tagout.

Procedures required for both enclosed Procedures required for both enclosed and and confined work spaces. confined work spaces. 1910.335(c)1910.335(c)(5)(5)

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AcnowledgementsAcnowledgementsRalph H. Lee Ralph H. Lee Electricity and the Human BodyElectricity and the Human Body,,

IEEE TransactionsIEEE Transactions

Accident Facts, National Safety Council, 1996 ed.Accident Facts, National Safety Council, 1996 ed.

Jack McDaniel Jack McDaniel Work Book for ElectricalWork Book for Electrical Safety Safety Related Work Practices and Lockout/TagoutRelated Work Practices and Lockout/Tagoutfor General Industry for General Industry

James G. and James W. Stallcup James G. and James W. Stallcup Electrical Electrical Regulations SimplifiedRegulations Simplified