Electrical Safety in the Workplace Refresher 30Dec08

Electrical Safety in the Electrical Safety in the WorkplaceWorkplace

FN000385/CRFN000385/CR

FN000385/CR, Electrical Safety in the WorkplaceFN000385/CR, Electrical Safety in the Workplace 22

OverviewOverview

NFPA 70E ObjectivesNFPA 70E Objectives

Electrical HazardsElectrical Hazards

Mitigation of HazardsMitigation of Hazards

Electrical Work ActivitiesElectrical Work Activities– Diagnostic vs. ManipulativeDiagnostic vs. Manipulative


OverviewOverview

Fermilab Electrical Safety PolicyFermilab Electrical Safety Policy

Electrical Hazard AnalysisElectrical Hazard Analysis– Shock Hazard AnalysisShock Hazard Analysis– Arc Flash Hazard AnalysisArc Flash Hazard Analysis

Establishing an Electrically Safe Work Establishing an Electrically Safe Work ConditionCondition

Additional ResourcesAdditional Resources


NFPA 70E ObjectivesNFPA 70E Objectives

Protect workers from electrical shock and Protect workers from electrical shock and arc-flash hazardsarc-flash hazards

Understand the work and associated Understand the work and associated electrical hazardselectrical hazards

Understand the PPE requirements for Understand the PPE requirements for electrical shock protection and electrical shock protection and arc-flash protectionarc-flash protection



Three Main HazardsThree Main Hazards

– Electric ShockElectric Shock

– Arc-FlashArc-Flash

– Arc BlastArc Blast



Electric ShockElectric Shock– Electric current passes through the bodyElectric current passes through the body– 1 milliamp can feel the current1 milliamp can feel the current– 15 milliamps can’t let go of electrical source15 milliamps can’t let go of electrical source– 100 milliamps through chest can result in 100 milliamps through chest can result in

ventricular fibrillation which is usually fatalventricular fibrillation which is usually fatal– Automatic External Defibrillator (AED) Automatic External Defibrillator (AED)

only practical way to return heart to normal only practical way to return heart to normal rhythmrhythm

– Deep tissue burnsDeep tissue burns

FN000385/CR, Electrical Safety in the WorkplaceFN000385/CR, Electrical Safety in the Workplace



Arc FlashArc Flash– Electric current passes through air, Electric current passes through air,

between a “Hot” conductor and ground, between a “Hot” conductor and ground, or between “Hot” conductorsor between “Hot” conductors

– Severity is determined bySeverity is determined byAvailable fault currentAvailable fault currentConductor sizeConductor sizeTime or durationTime or duration

– Temperatures can reach 35,000 Degrees FTemperatures can reach 35,000 Degrees Froughly three times the surface temperature of roughly three times the surface temperature of the sunthe sun



Arc FlashArc Flash– Clothing or PPE that burns and melts to the Clothing or PPE that burns and melts to the

body is the most serious concernbody is the most serious concern– 203 Degrees F for 0.1 seconds results in third 203 Degrees F for 0.1 seconds results in third

degree burndegree burn– The incident energy threshold for the onset of a The incident energy threshold for the onset of a

second degree burn is 1.2 cal/cmsecond degree burn is 1.2 cal/cm22..– Exposure can easily cause skin burns and Exposure can easily cause skin burns and

ignite clothingignite clothing



Arc BlastArc Blast– Rapid expansion of air caused by an electrical Rapid expansion of air caused by an electrical

arcarcCaused by two sourcesCaused by two sources– Metal boiling and vaporizingMetal boiling and vaporizing– Heating of air from the arcHeating of air from the arc

Copper expands by a factor of 67,000 times when Copper expands by a factor of 67,000 times when vaporizedvaporizedBest categorized as an explosionBest categorized as an explosion– Hearing loss due to blast explosionHearing loss due to blast explosion– Lacerations/Punctures from blast debrisLacerations/Punctures from blast debris– Trauma from percussion forceTrauma from percussion force



1997 F0 Compressor Room 480 volt MCC Arc Flash Event1997 F0 Compressor Room 480 volt MCC Arc Flash Event


Mitigation of HazardsMitigation of Hazards

Arc BlastArc Blast– Work De-Energized Work De-Energized – Engineer Out the Hazard Engineer Out the Hazard – Follow Safe Work Practices Follow Safe Work Practices

Electrical Hazard AnalysisElectrical Hazard Analysis

Employ Lockout/Tagout of Hazardous Electrical Employ Lockout/Tagout of Hazardous Electrical Energy SourcesEnergy Sources

Use Voltage Insulating PPE and EquipmentUse Voltage Insulating PPE and Equipment

Use PPE for Arc-Flash ProtectionUse PPE for Arc-Flash Protection

Use Ground Fault Circuit InterruptersUse Ground Fault Circuit Interrupters


Diagnostic vs. Manipulative WorkDiagnostic vs. Manipulative Work

DiagnosticDiagnostic– Inspection, testing, voltage and/or current Inspection, testing, voltage and/or current

measurements, phase alignment, measurements, phase alignment, troubleshooting, circuit and signal tracing, troubleshooting, circuit and signal tracing, thermal imaging, etc. that are performed on or thermal imaging, etc. that are performed on or near exposed live parts within the Limited near exposed live parts within the Limited Approach BoundaryApproach Boundary

– Verification Associated with LOTO Verification Associated with LOTO – Performed by Performed by Qualified PersonsQualified Persons utilizing utilizing

appropriately rated measurement equipment appropriately rated measurement equipment and required PPE.and required PPE.


Diagnostic vs. Manipulative WorkDiagnostic vs. Manipulative Work

ManipulativeManipulative– Making, tightening or breaking of energized Making, tightening or breaking of energized

electrical connections or the replacement, electrical connections or the replacement, removal, or addition of electrical or mechanical removal, or addition of electrical or mechanical componentscomponents

– Examples include: Examples include: Replacing a duplex outlet, light switch, fluorescent Replacing a duplex outlet, light switch, fluorescent fixture ballast, fuses, circuit breakersfixture ballast, fuses, circuit breakers

Drilling or punching holes in a live panelboardDrilling or punching holes in a live panelboard

Pulling conductors into a live panelboardPulling conductors into a live panelboard


Fermilab PolicyFermilab Policy

Do NotDo Not work on energized electrical work on energized electrical equipment unless absolutely necessary.equipment unless absolutely necessary.Diagnostic Energized Work is allowed only Diagnostic Energized Work is allowed only when the diagnostic activity is not feasible when the diagnostic activity is not feasible with the circuit de-energized.with the circuit de-energized.Manipulative Energized Work is prohibited Manipulative Energized Work is prohibited at Fermilab unless it can be demonstrated at Fermilab unless it can be demonstrated that de-energization introduces additional or that de-energization introduces additional or increased hazards or is infeasible due to increased hazards or is infeasible due to equipment design or operational limitationsequipment design or operational limitations


Fermilab PolicyFermilab Policy

Infeasible does not include InconvenientInfeasible does not include Inconvenient

Directorate Approval Required for Directorate Approval Required for Manipulative Energized WorkManipulative Energized Work

Fermilab policies and NFPA 70E apply to Fermilab policies and NFPA 70E apply to both the AC Power Distribution system and both the AC Power Distribution system and to Utilization Equipmentto Utilization Equipment


Electrical Hazard AnalysisElectrical Hazard Analysis

Shock Hazard AnalysisShock Hazard Analysis

Arc-Flash Hazard AnalysisArc-Flash Hazard Analysis



Shock Hazard AnalysisShock Hazard Analysis– Limited Approach BoundaryLimited Approach Boundary

Distance from an exposed live part within which a Distance from an exposed live part within which a shock hazard existsshock hazard existsOnly Qualified persons and escorted unqualified Only Qualified persons and escorted unqualified persons are allowed within the Limited Approach persons are allowed within the Limited Approach Boundary.Boundary.

– Restricted Approach BoundaryRestricted Approach BoundaryDistance from an exposed live part within which there Distance from an exposed live part within which there is an increased risk of shock due to electrical arc-over is an increased risk of shock due to electrical arc-over that may result from inadvertent movement of that may result from inadvertent movement of personnel working in close proximity to the live part .personnel working in close proximity to the live part .



Shock Hazard AnalysisShock Hazard Analysis– Prohibited Approach BoundaryProhibited Approach Boundary

Distance from an exposed live part within which work Distance from an exposed live part within which work is considered the same as making contact with the is considered the same as making contact with the live part.live part.




Shock Protection BoundariesShock Protection BoundariesTable 130.2(C) Approach Boundaries to Live Parts for Shock Protection. (All dimensionsare distance from live part to employee.)

Restricted Approach

Nominal System --------------------------------------------------- Boundary; Includes

Voltage Range, Phase to Phase

Exposed Movable Conductor

Exposed Fixed Circuit Part

Inadvertent Movement Adder

Prohibited Approach Boundary

Less than 50 Not specified Not specified Not specified Not specified

50 to 300 10 ft 0 in. 3 ft 6 in. Avoid contact Avoid contact

301 to 750 10 ft 0 in. 3 ft 6 in. 1 ft 0 in. 0 ft 1 in.

751 to 15 kV 10 ft 0 in. 5 ft 0 in. 2 ft 2 in. 0 ft 7 in.

15.1 kV to 36 kV 10 ft 0 in. 6 ft 0 in. 2 ft 7 in. 0ft 10 in.

36.1 kV to 46 kV 10 ft 0 in. 8 ft 0 in. 2 ft 9 in. 1 ft 5 in.

46.1 kV to 72.5 kV 10 ft 0 in. 8 ft 0 in. 3 ft 2 in. 2 ft 1 in.


138 kV to 145 kV 11 ft 0 in. 10 ft 0 in. 3 ft 7 in. 3 ft 1 in.


230 kV to 242 kV 13 ft 0 in. 13 ft 0 in. 5 ft 3 in. 4 ft 9 in.345 kV to 362 kV 15 ft 4 in. 15 ft 4 in. 8 ft 6 in. 8 ft 0 in.



Note: For Flash Protection Boundary, see 130.3(A).See definition in Article 100 and text in 130.2(D)(2) and Annex C for elaboration.

Limited Approach Boundary

Table 130.2(C) Approach Boundaries to Live Parts for Shock Protection. (All dimensionsare distance from live part to employee.)

Restricted Approach























Restricted Approach























Restricted Approach























Restricted Approach























Restricted Approach























Restricted Approach























Restricted Approach







Less than 50 Not specified Not specified Not specified Not specified50 to 300 10 ft 0 in. 3 ft 6 in. Avoid contact Avoid contact301 to 750 10 ft 0 in. 3 ft 6 in. 1 ft 0 in. 0 ft 1 in.














Restricted Approach








50 to 300 10 ft 0 in. 3 ft 6 in. Avoid contact Avoid contact301 to 750 10 ft 0 in. 3 ft 6 in. 1 ft 0 in. 0 ft 1 in.














Restricted Approach










751 to 15 kV 10 ft 0 in. 5 ft 0 in. 2 ft 2 in. 0 ft 7 in.15.1 kV to 36 kV 10 ft 0 in. 6 ft 0 in. 2 ft 7 in. 0ft 10 in.












Restricted Approach























Shock Protection BoundariesShock Protection BoundariesSystem Voltage Range

Phase to Phase

LimitedApproachBoundary

(Fixed Parts)

RestrictedApproachBoundary

ProhibitedApproachBoundary

Shock ProtectionInsulating PPE

50 to 300Including 120, 277 and 120/208

3 Ft 6 InAvoid

ContactAvoid

Contact

LAB - NoneRAB - Wear/Use if Contact LikelyPAB - Wear/Use if Contact Likely

301 to 750Including 480/277

3 Ft 6 In 1 Foot 1 InchLAB - None

RAB - Must WearPAB - Must Wear

751 to 15KIncluding 13.8K

5 Feet 2 Ft 2 In 7 InchesLAB - None


345K to 362K 15 Ft 4 In 8 Ft 6 In 8 FeetLAB - None


Within theLimited Approach Boundary

Within theRestricted Approach Boundary

Within theProhibited Approach Boundary

Shock Protection Boundaries and PPEFermilab Summary for NFPA 70E

Non-Qualified Worker Allowed Within Only if Advised and Escorted by a QW.Insulated Equipment/Tools if Contact Likely.

Only Qualified Worker Allowed Within.May Not Enter with Conductive Objects.

Body Parts Must be Insulated.

Consider Activity as Same as Working On.


Electrically Insulating GlovesElectrically Insulating GlovesGlove Classes by Use VoltageGlove Classes by Use Voltage

Procure Through Your Local D/S ES&H DepartmentProcure Through Your Local D/S ES&H Department

Gloves must be tested after every 6 months of use Gloves must be tested after every 6 months of use through Fermilab’s program (April 1 and October 1 are through Fermilab’s program (April 1 and October 1 are Scheduled Exchange Dates)Scheduled Exchange Dates)

Inspect gloves before each useInspect gloves before each use

Use Leather Protectors with Electrically Insulating Gloves Use Leather Protectors with Electrically Insulating Gloves

Class 00 500 voltsClass 00 500 volts Class 0 1,000 voltsClass 0 1,000 volts

Class 1 7,500 voltsClass 1 7,500 volts Class 2 17,000 voltsClass 2 17,000 volts

Class 3 26,500 voltsClass 3 26,500 volts Class 4 36,000 voltsClass 4 36,000 volts


Arc Flash Hazard AnalysisArc Flash Hazard Analysis

Determines if thermal hazard existsDetermines if thermal hazard exists– Identifies required protective equipmentIdentifies required protective equipment

Flash Protection BoundaryFlash Protection Boundary– Distance from an exposed live part within which Distance from an exposed live part within which

a person could receive a 2nd degree burn from a person could receive a 2nd degree burn from an arc-flashan arc-flash

– For systems 600 volts or less, the default For systems 600 volts or less, the default boundary is 4 feetboundary is 4 feet



– For voltages above 600 volts, the Flash For voltages above 600 volts, the Flash Protection boundary can be calculated with the Protection boundary can be calculated with the general equationsgeneral equations

– DistanceDistancecircuit componentcircuit component = [2.65 x MVA = [2.65 x MVAbfbf x t] x t]1/21/2

– DistanceDistancetransformertransformer = [53 x MVA x t] = [53 x MVA x t]1/21/2

MVAMVAbfbf = bolted fault capacity available at point involved in mega = bolted fault capacity available at point involved in mega

volt-ampsvolt-amps

MVA = capacity rating of transformer in mega volt-ampsMVA = capacity rating of transformer in mega volt-amps



Incident Energy Exposure CalculationIncident Energy Exposure Calculation– Requires Single Line Electrical Drawing (SLED)Requires Single Line Electrical Drawing (SLED)

available fault currentavailable fault current

conductor wire sizesconductor wire sizes

conductor distancesconductor distances

operating voltage of the systemoperating voltage of the system

trip time for fuses or circuit breakerstrip time for fuses or circuit breakers

arc fault is in open air or in a box arc fault is in open air or in a box


Table 130.7 (C)(9)(a)Table 130.7 (C)(9)(a)

Table 130.7(C)(9)(a) Hazard/Risk Category Classifications

Task (Assumes Equipment Is Energized, and Work Hazard/ Risk V-rated V-ratedIs Done Within the Flash Protection Boundary) Category Gloves Tools

Panelboards Rated 240 V and Below — Notes 1 and 3

Circuit breaker (CB) or fused switch operation with covers on 0 N N

CB or fused switch operation with covers off 0 N N

Work on energized parts, including voltage testing (LOTO) 1 Y Y

Remove/install CBs or fused switches 1 Y Y

Removal of bolted covers (to expose bare, energized parts) 1 N N

Opening hinged covers (to expose bare, energized parts) 0 N N

Panelboards or Switchboards Rated >240 V and upto 600 V (with molded case or insulated casecircuit breakers) — Notes 1 and 3



Work on energized parts, including voltage testing (LOTO) 2* Y Y



Panelboards Rated 240 V and Below — Notes 1 and 3Circuit breaker (CB) or fused switch operation with covers on 0 N N













Circuit breaker (CB) or fused switch operation with covers on 0 N NCB or fused switch operation with covers off 0 N N


















Panelboards or Switchboards Rated >240 V and upto 600 V (with molded case or insulated casecircuit breakers) — Notes 1 and 3Circuit breaker (CB) or fused switch operation with covers on 0 N N












Panelboards or Switchboards Rated >240 V and upto 600 V (with molded case or insulated casecircuit breakers) — Notes 1 and 3Circuit breaker (CB) or fused switch operation with covers on 0 N N

CB or fused switch operation with covers off 1 N NWork on energized parts, including voltage testing (LOTO) 2* Y Y



Panelboards Rated 240 V and Below — Notes 1 and 3Circuit breaker (CB) or fused switch operation with covers on 0 N N






Panelboards or Switchboards Rated >240 V and upto 600 V (with molded case or insulated case

circuit breakers) — Notes 1 and 3Circuit breaker (CB) or fused switch operation with covers on 0 N N




Table 130.7 (C)(9)(a)Table 130.7 (C)(9)(a)

Footnotes 1 and 3Footnotes 1 and 3

– Footnote #1 Footnote #1 25 kA short circuit current available, 0.03 25 kA short circuit current available, 0.03 second (2 cycle) fault clearing time.second (2 cycle) fault clearing time.

– Footnote #3Footnote #3For < 10 kA short circuit current available, the For < 10 kA short circuit current available, the hazard/risk category required may be reduced hazard/risk category required may be reduced by one number.by one number.


Table 130.7 (C)(9)(a)Table 130.7 (C)(9)(a)



600 V Class Motor Control Centers (MCC) -Notes 2 (except as indicated) and 3

CB or fused switch or starter operation with enclosure doors closed 0 N N

Reading a panel meter while operating a meter switch 0 N N

CB or fused switch or starter operation with enclosure doors open 1 N N


Work on control circuits with energized parts 120 V or below, exposed 0 Y Y

Work on control circuits with energized parts >120 V, exposed 2* Y Y

Insertion or removal of individual starter “buckets” from MCC - Note 4 3 Y N

Application of safety grounds, after voltage test 2* Y N

Removal of bolted covers (to expose bare, energized parts) 2* N N




600 V Class Motor Control Centers (MCC) -Notes 2 (except as indicated) and 3

CB or fused switch or starter operation with enclosure doors closed 0 N N

Reading a panel meter while operating a meter switch 0 N N

CB or fused switch or starter operation with enclosure doors open 1 N N

Work on energized parts, including voltage testing (LOTO) 2* Y YWork on control circuits with energized parts 120 V or below, exposed 0 Y Y

Work on control circuits with energized parts >120 V, exposed 2* Y Y

Insertion or removal of individual starter “buckets” from MCC - Note 4 3 Y N

Application of safety grounds, after voltage test 2* Y N

Removal of bolted covers (to expose bare, energized parts) 2* N N



Hazard Risk ClasificationHazard Risk ClasificationEquipment Voltage

Rated Full Load

Current

Hazard/RiskCategory

Conditions or Qualifications

Primary PanelboardsSWBD DHP

480/277 VACMore than

1,200 Amps 3

Primary Transformer Larger than 1000 KVA(Assuming More Than 25,000 ISC Available

with Fault Clearing Time >2 Cycles)Take Advantage of Installed Panelboard Meter for LOTO

Verification if Present.

Motor Control CentersMCC

480 VACTypical 600 Amps and

Above2* Take Advantage of Installed Central Monitoring Unit for LOTO

Verification if Present

Primary or Secondary PanelboardsDHP PHP LP

480/277 VAC400 to 1,200

Amps 2* Proximity to Transformer Power Source Presumed

Operating 13.8 KV Disconnectswith Doors Closed

13.8 KV NA 2 Booster Brentford or RF Anode Power Suppliesare Examples

Secondary PanelboardsPHP LP

480/277 VAC100 to 225

Amps 1Assuming Less Than 10,000 ISC Available

More Than 200 Feet from Panelboard Sourcing Power

Lighting PanelboardsLP

480/277 VAC 100 Amps 1Assuming Less Than 10,000 ISC Available

More Than 100 Feet from Secondary Panelboard Sourcing Power

Utility Panelboards120/208 VAC120/240 VAC

Below 400 Amps 0

No Known Fault Currents Above 10,000 Amps.Knowing Transformer KVA and %IZ, Apply Formula for

Suspect Installations

480/277 VAC NA 0 Requirement Direct from NFPA 70E C9 Table

120/208 VAC120/240 VAC

NA -1No Known Fault Currents Above 10,000 Amps.

Knowing Transformer KVA and %IZ, Apply Formula for Suspect Installations

Simplified Guidance for Electrical Work on Fermilab AC POWER DISTRIBUTION EquipmentDiagnostic Work Including LOTO Voltage Testing Unless Otherwise Noted, Plus Some Additional Operations

This Simplified Table for AC Power Distribution Equipment Has Been Approved by the Electrical Safety Subcommittee. Guidance Assumes the Transformer Powering the AC Power Distribution System Has an Impedance in the Range of 4.5 to 6 %IZ.

If Stated Conditions or Qualifications Are Not Met or the Circumstances of the Work Activity Appear Unique, Refer to NFPA 70E Table 130.7(C)(9)(a) or Consult with Your D/S Electrical Coordinator.

Operating Circuit Breakersand Disconnect Switcheswith Covers On or Closed

Equipment VoltageRated Full

Load Current

Hazard/RiskCategory


Primary PanelboardsSWBD DHP

480/277 VACMore than

1,200 Amps 3

Primary Transformer Larger than 1000 KVA(Assuming More Than 25,000 ISC Available

with Fault Clearing Time >2 Cycles)Take Advantage of Installed Panelboard Meter for LOTO

Verification if Present.

Motor Control CentersMCC

480 VACTypical 600 Amps and

Above2* Take Advantage of Installed Central Monitoring Unit for LOTO

Verification if Present

Primary or Secondary PanelboardsDHP PHP LP

480/277 VAC400 to 1,200

Amps 2* Proximity to Transformer Power Source Presumed

Operating 13.8 KV Disconnectswith Doors Closed

13.8 KV NA 2 Booster Brentford or RF Anode Power Suppliesare Examples

Secondary PanelboardsPHP LP

480/277 VAC100 to 225

Amps 1Assuming Less Than 10,000 ISC Available

More Than 200 Feet from Panelboard Sourcing Power

Lighting PanelboardsLP

480/277 VAC 100 Amps 1Assuming Less Than 10,000 ISC Available

More Than 100 Feet from Secondary Panelboard Sourcing Power

Utility Panelboards120/208 VAC120/240 VAC

Below 400 Amps 0

No Known Fault Currents Above 10,000 Amps.Knowing Transformer KVA and %IZ, Apply Formula for

Suspect Installations

480/277 VAC NA 0 Requirement Direct from NFPA 70E C9 Table

120/208 VAC120/240 VAC

NA -1No Known Fault Currents Above 10,000 Amps.

Knowing Transformer KVA and %IZ, Apply Formula for Suspect Installations

Simplified Guidance for Electrical Work on Fermilab AC POWER DISTRIBUTION EquipmentDiagnostic Work Including LOTO Voltage Testing Unless Otherwise Noted, Plus Some Additional Operations

This Simplified Table for AC Power Distribution Equipment Has Been Approved by the Electrical Safety Subcommittee. Guidance Assumes the Transformer Powering the AC Power Distribution System Has an Impedance in the Range of 4.5 to 6 %IZ.


Operating Circuit Breakersand Disconnect Switcheswith Covers On or Closed


Hazard Risk ClasificationHazard Risk ClasificationEquipment Voltage

Sourcing Branch CB

Hazard/RiskCategory


Power Supplies 480 VAC VariousCan Range from

0 to 3

Ask Your Department for an Assessment.Take Advantage of Installed Panel Meters for LOTO

Verification.

Various Equipment480 VAC or

480/277 VAC100 to Less

than 400 Amps 2 Distance from Primary Panelboards and Feed Conductors Limit Available Fault Currents


480/277 VACLess Than 100

Amps 1 Distance from Primary Panelboards and Feed Conductors Limit Available Fault Currents

Sump Pump Controllers Motor ControllersHVAC Equipment

480 VAC60 Amps and

Below 1 Distance from Primary Panelboards and Feed Conductors Limit Available Fault Currents

Ballasts and Light Fixtures 277 VAC30 Amps and

Below 0 Typical Lighting Ballast

Power Supplies 208 VAC225 Amps and

Below 0No Known Fault Currents Above 10,000 Amps. Knowing Transformer KVA and %IZ, Apply Formula for Suspect

Installations

Various Equipment 120/208 VAC225 Amps and


Installations

Various Equipment 120 VAC30 Amps and

Below -1 Bench Testing.No Known Fault Currents Above 10,000 Amps.

Simplified Guidance for Electrical Work on Fermilab UTILIZATION EquipmentDiagnostic Work Including LOTO Voltage Testing Unless Otherwise Noted

This Simplified Table for Utilization Equipment Has Been Approved by the Electrical Safety Subcommittee. Guidance Assumes the Transformer Powering the AC Power Distribution System Has an Impedance in the Range of 4.5 to 6 %IZ.


Equipment VoltageSourcing

Branch CBHazard/Risk

CategoryConditions or Qualifications

Power Supplies 480 VAC VariousCan Range from

0 to 3

Ask Your Department for an Assessment.Take Advantage of Installed Panel Meters for LOTO

Verification.


480/277 VAC100 to Less

than 400 Amps 2 Distance from Primary Panelboards and Feed Conductors Limit Available Fault Currents


480/277 VACLess Than 100

Amps 1 Distance from Primary Panelboards and Feed Conductors Limit Available Fault Currents

Sump Pump Controllers Motor ControllersHVAC Equipment

480 VAC60 Amps and

Below 1 Distance from Primary Panelboards and Feed Conductors Limit Available Fault Currents

Ballasts and Light Fixtures 277 VAC30 Amps and

Below 0 Typical Lighting Ballast

Power Supplies 208 VAC225 Amps and

Below 0No Known Fault Currents Above 10,000 Amps. Knowing

Transformer KVA and %IZ, Apply Formula for Suspect Installations

Various Equipment 120/208 VAC225 Amps and


Installations

Various Equipment 120 VAC30 Amps and

Below -1 Bench Testing.No Known Fault Currents Above 10,000 Amps.

Simplified Guidance for Electrical Work on Fermilab UTILIZATION EquipmentDiagnostic Work Including LOTO Voltage Testing Unless Otherwise Noted

This Simplified Table for Utilization Equipment Has Been Approved by the Electrical Safety Subcommittee. Guidance Assumes the Transformer Powering the AC Power Distribution System Has an Impedance in the Range of 4.5 to 6 %IZ.



Arc-Flash Protective ClothingArc-Flash Protective Clothing

Hazard Category defines required PPEHazard Category defines required PPE

NFPA 70E Table 130.7(C)(10)NFPA 70E Table 130.7(C)(10)

Fermilab Summary for NFPA 70E Arc-Flash Fermilab Summary for NFPA 70E Arc-Flash Hazard/Risk CategoriesHazard/Risk Categories


Arc-Flash Protective ClothingArc-Flash Protective Clothing

Table 130.7(C)(10) Protective Clothing and Personal Protective Equipment (PPE) Matrix

Protective Clothing and Equipment

Hazard/Risk Category Number —1 0 1 2 3 4(Note 3)

Non-melting (according to ASTM F1506-00) or Untreated Natural Fiber

a. T-shirt (short-sleeve) X X X Xb. Shirt (long-sleeve) Xc. Pants (long) X X X X X X

(Note 4) (Note 6)

FR Clothing (Note 1)

a. Long-sleeve shirt X X X X(Note 9)

b. Pants X X X X(Note 4) (Note 6) (Note 9)

c. Coverall (Note 5) (Note 7) X (Note 5)(Note 9)

d. Jacket, parka, or rainwear AN AN AN AN

FR Protective Equipmenta. Flash suit jacket (multilayer) Xb. Flash suit pants (multilayer) Xc. Head protection

1. Hardhat X X X X2. FR hard hat liner AR AR

d. Eye protection - - - - -1. Safety glasses X X X AL AL AL2. Safety goggles AL AL AL

e. Face and head area protection - - - -1. Arc-rated face shield, or flash suit hood X

(Note 8)2. Flash suit hood X X3. Hearing protection (ear canal inserts) X X X

(Note 8)f. Hand protection - - - -

Leather gloves (Note 2) AN X X Xg. Foot protection

Leather work shoes AN X X X

AN = As neededAL = Select one in groupAR = As requiredX = Minimum required

Protective Systems for Hazard/Risk Category

Table 130.7(C)(10) Protective Clothing and Personal Protective Equipment (PPE) Matrix

Protective Clothing and Equipment

Hazard/Risk Category Number —1 0 1 2 3 4(Note 3)

Non-melting (according to ASTM F1506-00) or Untreated Natural Fiber

a. T-shirt (short-sleeve) X X X Xb. Shirt (long-sleeve) Xc. Pants (long) X X X X X X

(Note 4) (Note 6)

FR Clothing (Note 1)

a. Long-sleeve shirt X X X X(Note 9)

b. Pants X X X X(Note 4) (Note 6) (Note 9)

c. Coverall (Note 5) (Note 7) X (Note 5)(Note 9)

d. Jacket, parka, or rainwear AN AN AN AN

FR Protective Equipmenta. Flash suit jacket (multilayer) Xb. Flash suit pants (multilayer) Xc. Head protection

1. Hardhat X X X X2. FR hard hat liner AR AR

d. Eye protection - - - - -1. Safety glasses X X X AL AL AL2. Safety goggles AL AL AL

e. Face and head area protection - - - -1. Arc-rated face shield, or flash suit hood X

(Note 8)2. Flash suit hood X X3. Hearing protection (ear canal inserts) X X X

(Note 8)f. Hand protection - - - -

Leather gloves (Note 2) AN X X Xg. Foot protection

Leather work shoes AN X X X

AN = As neededAL = Select one in groupAR = As requiredX = Minimum required

Protective Systems for Hazard/Risk Category


Arc-Flash Protective ClothingArc-Flash Protective ClothingCalculated Exposure

from Prospective Arc-FlashHazard/Risk

Category

MinimumRequired

ATPVClothing Requirements Additional PPE

Zero up to 1.2 cal/cm2 -1 NA Cotton Tee Shirt and Pants Safety Glasses

Zero up to 1.2 cal/cm2 0 NA Long Sleeve Cotton Shirt and Pants Safety Glasses

More than 1.2 and up to 4 cal/cm2 1 4 cal/cm2 FR Coverall* Hard Hat, Safety Glasses

More than 4 and up to 8 cal/cm2 2 8 cal/cm2 Cotton Clothing Under FR Coverall*

Hard Hat, Safety Glasses,Face Shield,

Hearing Protection, Leather Gloves,Leather Work Shoes

More than 4 and up to 8 cal/cm2 2* 8 cal/cm2 Cotton Clothing Under FR Coverall*

Hard Hat, Safety Glasses,Double-Layer Switching Hood,


More than 8 and up to 25 cal/cm2 3 25 cal/cm2 Cotton Clothing Under 2 x FR Coveralls*

Hard Hat, Safety Glasses,Flash Suit Hood,


More than 25 and up tp 40 cal/cm2 4 40 cal/cm2 Cotton Clothing Under FR Coverall*plus Multilayer Flash Suit Jacket & Pants



Arc-Flash Hazard/Risk Categories - Required Clothing - Required PPEFermilab Summary for NFPA 70E

* Coverall Rated at 8 cal/cm2 Available from Fermilab Stockroom

Calculated Exposurefrom Prospective Arc-Flash

Hazard/RiskCategory

MinimumRequired



















Calculated Exposurefrom Prospective Arc-Flash

Hazard/RiskCategory

MinimumRequired




















Arc-Flash PPEArc-Flash PPE

All Hazard Risk Categories Require All Hazard Risk Categories Require Eye ProtectionEye Protection

Hazard Risk Categories 1 and up requireHazard Risk Categories 1 and up require– Hard Hats, Leather Gloves, Leather Shoes, andHard Hats, Leather Gloves, Leather Shoes, and

Fire Resistant rated protective clothing Fire Resistant rated protective clothing

Hazard Risk Categories 2 and up requireHazard Risk Categories 2 and up require– Arc-rated face shield or flash suit hood andArc-rated face shield or flash suit hood and

Hearing ProtectionHearing Protection


Fire Resistant (FR) ClothingFire Resistant (FR) Clothing

Hazard/Risk Category 1 or above, fire Hazard/Risk Category 1 or above, fire resistant or FR clothing is requiredresistant or FR clothing is requiredArc Thermal Protection Value (ATPV) Arc Thermal Protection Value (ATPV)

– Identifies maximum thermal protection the Identifies maximum thermal protection the clothing can provide.clothing can provide.

– PPE such as face shields, hoods, jackets, PPE such as face shields, hoods, jackets, coats, and coveralls have an ATPV ratingcoats, and coveralls have an ATPV rating

Select clothing and equipment that meets or Select clothing and equipment that meets or exceeds minimum ATPV required for the exceeds minimum ATPV required for the Hazard/Risk Category Hazard/Risk Category


Fire Resistant (FR) ClothingFire Resistant (FR) Clothing

Wear and care of PPEWear and care of PPE– Wear cotton or natural fiber non melting Wear cotton or natural fiber non melting

clothingclothing– Wear PPE that satisfies the minimum ATPV Wear PPE that satisfies the minimum ATPV

requiredrequired– Layering clothing increases protectionLayering clothing increases protection– Wear clothing loose rather than tightWear clothing loose rather than tight

Do not use bleach or fabric softeners on Do not use bleach or fabric softeners on ATPV rated PPEATPV rated PPE


Electrical Safe Work ConditionElectrical Safe Work ConditionDetermine all possible power sourcesDetermine all possible power sources

Electrical Hazard AnalysisElectrical Hazard Analysis– Shock Hazard AnalysisShock Hazard Analysis

Limited, Restricted, and ProhibitedLimited, Restricted, and ProhibitedApproach BoundariesApproach Boundaries

Shock protection PPEShock protection PPE

– Arc-Flash Hazard AnalysisArc-Flash Hazard AnalysisHazard Risk CategoryHazard Risk Category

Arc-Flash PPEArc-Flash PPE

Flash Protection BoundaryFlash Protection Boundary


Electrical Safe Work ConditionElectrical Safe Work ConditionPlan for EmergenciesPlan for Emergencies

– Know how to de-energize quicklyKnow how to de-energize quickly– Be prepared to pull employee free with an Be prepared to pull employee free with an

insulated rescue hookinsulated rescue hook– Means available to call 3131Means available to call 3131– Know CPR and where AED’s are locatedKnow CPR and where AED’s are located

Protect unqualified persons from work areaProtect unqualified persons from work area

Don the appropriate PPEDon the appropriate PPE


Electrical Safe Work ConditionElectrical Safe Work Condition

Open disconnect deviceOpen disconnect device

Perform LOTO Perform LOTO – Verification is the most important stepVerification is the most important step

F4 Service Building 13.8 KV Disconnect F4 Service Building 13.8 KV Disconnect switch failure occurred on Wed Oct 1, 2008switch failure occurred on Wed Oct 1, 2008


Electrical Safe Work ConditionElectrical Safe Work Condition– Voltage Testing (LOTO)Voltage Testing (LOTO)

Use a meter rated for the taskUse a meter rated for the task– Test meter both before and after use when performing Test meter both before and after use when performing

LOTOLOTO– Common observation –Common observation –

People don’t check their meter after performing LOTOPeople don’t check their meter after performing LOTO– Proximity sensors are not to be used for LOTOProximity sensors are not to be used for LOTO

– Ground stored energy devices and potential Ground stored energy devices and potential induced voltage sourcesinduced voltage sources


QuestionsQuestionsResourcesResources

– Fermilab Electrical Safety SubcommitteeFermilab Electrical Safety Subcommittee– Division/Section Senior Safety OfficerDivision/Section Senior Safety Officer– Division/Section Electrical CoordinatorDivision/Section Electrical Coordinator– Line ManagementLine Management

Fermilab Summary Guidance SheetsFermilab Summary Guidance Sheets– http://www-esh.fnal.gov/pls/default/esh_home_page.page?this_page=22152http://www-esh.fnal.gov/pls/default/esh_home_page.page?this_page=22152

Enroll in the challenge examEnroll in the challenge exam– http://www-esh.fnal.gov/pls/default/esh_tests.htmlhttp://www-esh.fnal.gov/pls/default/esh_tests.html

Documents

Electrical Safety in the Workplace Refresher 30Dec08