Arc Flash Basics

8/4/2019 Arc Flash Basics

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Arc Flash AwarenessArc Flash AwarenessNFPA 70ENFPA 70E

Michael WhiteMichael White

Shermco Industries, Inc.Shermco Industries, Inc.



Hazards of ElectricityHazards of Electricity



An Illustrative StoryAn Illustrative Story

A 400 Amp, 480A 400 Amp, 480--volt Automaticvolt Automatic

Transfer SwitchTransfer Switch

A Critical Hospital LifeA Critical Hospital Life--Safety CircuitSafety Circuit

A Simple Task to Modify the ControlsA Simple Task to Modify the Controls

An Experienced Electrical WorkerAn Experienced Electrical Worker

July 18, 1984July 18, 1984



Typical Transfer SwitchTypical Transfer Switch



The ResultThe Result



MoreMore……



Electrical Safety StatisticsElectrical Safety Statistics

Average of 4,000 nonAverage of 4,000 non--disabling anddisabling and

3,600 disabling electrical contact3,600 disabling electrical contactinjuries annually in the United Statesinjuries annually in the United States

One person is electrocuted in theOne person is electrocuted in the

workplace every dayworkplace every day Electrocutions are the 4th leading causeElectrocutions are the 4th leading cause

of fatalities.of fatalities. Over 2,000 workers are sent to burnOver 2,000 workers are sent to burn

centers each year with electricalcenters each year with electrical--relatedrelated

burn injuriesburn injuries





Lethal VoltagesLethal Voltages

<100,

5%100 -

250,39%

250 -

600,

45%

>600,

11%



Costs Of An Electrical FatalityCosts Of An Electrical Fatality

$1,300,000 estimated direct costs$1,300,000 estimated direct costs

33RDRD

INTINT’’L CONFERENCE ON ELECTRICAL INJURYL CONFERENCE ON ELECTRICAL INJURY Lost productionLost production

Cost of personnel away from jobCost of personnel away from job

Increases in WorkmanIncreases in Workman’’s Comps Comp

Increases in insurance costsIncreases in insurance costs

OSHA finesOSHA fines LitigationLitigation



Costs Of An Electrical FatalityCosts Of An Electrical Fatality

Add:Add:

Pain and suffering of employeePain and suffering of employee Loss to family dependentsLoss to family dependents

•• Financial and emotionalFinancial and emotional

Total direct and indirect costs estimated atTotal direct and indirect costs estimated at

$3,900,00 to $10,400,00 per incident$3,900,00 to $10,400,00 per incident

•• DR. MARY CAPPELLIDR. MARY CAPPELLI--SCHELLPFEFFERSCHELLPFEFFER



Injury Costs Can Last A LifetimeInjury Costs Can Last A Lifetime

A study of one utility revealed these costs of aA study of one utility revealed these costs of asurvivable serious electrical injurysurvivable serious electrical injury

Immediate direct costsImmediate direct costs………… $250,000$250,000Direct costs after year 1Direct costs after year 1…….... $1.3 million$1.3 millionIndirect costsIndirect costs ……………………………… $11.24 million$11.24 million

TotalTotal ……....$12.8 million*$12.8 million**1991 dollars. Equivalent in 2003 dollars is $17.4 million*1991 dollars. Equivalent in 2003 dollars is $17.4 million – – ““Facts onFacts onElectrical Incident & Injury CostsElectrical Incident & Injury Costs””, Lanny Floyd II, 11, Lanny Floyd II, 11thth Annual IEEEAnnual IEEEElectrical Safety WorkshopElectrical Safety Workshop



ArcArc--Flash FatalityFlash Fatality

On Nov. 24, 1997, employees removed safetyOn Nov. 24, 1997, employees removed safety

guards from energized electrical conductors inguards from energized electrical conductors inthe cubicle.the cubicle.

Physical evidence indicates that it was likely thatPhysical evidence indicates that it was likely that

part of one of the safety guards touched thepart of one of the safety guards touched theenergized conductors, causing an electricalenergized conductors, causing an electrical

explosion with a 26explosion with a 26-- foot fireball.foot fireball.



After The ArcAfter The Arc



ArcArc--Flash FatalityFlash Fatality

Proposed penalties of $455,000 againstProposed penalties of $455,000 against

Western Resources at its Lawrence, Kan.,Western Resources at its Lawrence, Kan.,Energy CenterEnergy Center

““Management showed a lack of concernManagement showed a lack of concernabout taking the required safetyabout taking the required safety

precautions that might have prevented thisprecautions that might have prevented thistriple tragedy,triple tragedy,”” said OSHA Administratorsaid OSHA AdministratorCharles N.Charles N. JeffressJeffress..



Hazards of an Arc FlashHazards of an Arc Flash

Toxic GassesRapidly Expanding Vaporized

Metal and Air

Visible and Invisible LightRadiation



Heat DataHeat Data

Curable burnCurable burn 145145oo FF

Skin cell deathSkin cell death 200200oo FF

TinTin 450450oo FF

GasolineGasoline 800800oo FF

AluminumAluminum 1,2001,200oo FF

CopperCopper 1,9811,981oo FF

Carbon steelCarbon steel 2,7002,700oo FF

SunSun’’s surfaces surface 9,0009,000oo FF

Arc flashArc flash 35,00035,000oo FF



480V Arc Flash in Real Time480V Arc Flash in Real Time



480V Arc Flash Slow Motion480V Arc Flash Slow Motion



>2250C/4370F

500C/1220F

141.5db@2ft.

>2160lbs/sq.ft.

>2250C/

4370F



Components of Hazard AnalysisComponents of Hazard Analysis

Determine the Flash Protection BoundaryDetermine the Flash Protection Boundary

(FPB)(FPB) Shock Approach BoundariesShock Approach Boundaries

LimitedLimited

RestrictedRestricted

ProhibitedProhibited

Calculate incident energyCalculate incident energy Using IEEE 1584 orUsing IEEE 1584 or

NFPA 70E Tables 130.7NFPA 70E Tables 130.7

Perform a PPE AssessmentPerform a PPE Assessment



Approach BoundariesApproach Boundaries – – NFPA 70ENFPA 70E



Flash Protection BoundaryFlash Protection Boundary

Incident energyIncident energy

Total heat from arcTotal heat from arc Arc Flash BoundaryArc Flash Boundary

FPBFPB

MCC

Incident Energy

at the Working

Distance

Equal to onEqual to on--set ofset of

second degreesecond degree

burnburn

Severe andpossible fatalthermal burns

if unprotected





N Thi kN Thi k ““It ill l t kIt ill l t k



Never Think,Never Think, ““It will only take aIt will only take a

secondsecond””



The Six StepsThe Six Steps

1.1. Determine if work is performed within theDetermine if work is performed within the

Flash Protection BoundaryFlash Protection Boundary2.2. Gather the informationGather the information

3.3. Perform an Arc Flash StudyPerform an Arc Flash Study4.4. Choose the proper PPEChoose the proper PPE

5.5. Mark your equipmentMark your equipment6.6. Train your workersTrain your workers



System single lineSystem single line

Utility short circuit dataUtility short circuit data

Study operating conditions, such asStudy operating conditions, such asNormal operation; Loops closed;Normal operation; Loops closed;

Transformers in parallel; Dual FeedsTransformers in parallel; Dual Feeds

Find details on transformers, buses,Find details on transformers, buses,

substations, and feeder cablessubstations, and feeder cables

Modification of Switching ProceduresModification of Switching Procedures

Gathering DataGathering Data

E l i f Si



Evaluation of SiteEvaluation of Site



The NFPA 70EThe NFPA 70E--20042004



OSHA And The NFPAOSHA And The NFPA

The NFPA develops consensus standardsThe NFPA develops consensus standards

NATIONAL ELECTRIC CODENATIONAL ELECTRIC CODE – – NFPA 70NFPA 70 ELECTRICAL EQUIPMENT MAINTENANCEELECTRICAL EQUIPMENT MAINTENANCE – – 70B70B

ELECTRICAL SAFETY REQUIREMENTS FORELECTRICAL SAFETY REQUIREMENTS FOR

EMPLOYEE WORKPLACESEMPLOYEE WORKPLACES – – 70E70E OSHA issues regulationsOSHA issues regulations

They are Federal lawThey are Federal law

29CFR (CODE OF FEDERAL REGULATIONS)191029CFR (CODE OF FEDERAL REGULATIONS)1910



OSHA And The NFPAOSHA And The NFPA

OSHA has members on the NFPA 70EOSHA has members on the NFPA 70E

CommitteeCommittee

Ensures it stays consistent with regulationsEnsures it stays consistent with regulations

70E is updated every three years70E is updated every three years

OSHA tells us what, the 70E tells us howOSHA tells us what, the 70E tells us how OSHA has been citing the 70E in courtOSHA has been citing the 70E in court



The NFPA 70E Hazard / The NFPA 70E Hazard / Risk CategoriesRisk Categories



NFPA 70E TablesNFPA 70E Tables

Use Tables 130.7 in 70E as long asUse Tables 130.7 in 70E as long as

incident energy values are under arcincident energy values are under arcenergy listed in Table notesenergy listed in Table notes <40 cal/cm<40 cal/cm22

Article 130.7(C)(9)(a).Article 130.7(C)(9)(a).

……”……”For tasks not listed or for power systemsFor tasks not listed or for power systemswith greater the assumed shortwith greater the assumed short--circuit currentcircuit currentcapacity or with longer than the assumed faultcapacity or with longer than the assumed faultclearing times, a flash hazard analysis shallclearing times, a flash hazard analysis shallbe requiredbe required……..””



NFPA 70E TablesNFPA 70E Tables

Select Hazard/Risk Category from TableSelect Hazard/Risk Category from Table

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

Select recommended PPE from TableSelect recommended PPE from Table

130.7(C)(10)130.7(C)(10)

Verify choices by reviewing TableVerify choices by reviewing Table130.7(C)(11)130.7(C)(11)

•• ATPV is minimum for Hazard/Risk CategoryATPV is minimum for Hazard/Risk Category

PPE L lPPE Le els NFPA 70E 2004NFPA 70E 2004



PPE LevelsPPE Levels – – NFPA 70E 2004NFPA 70E 2004

0 cal/cm0 cal/cm22 < 1.2< 1.2 Level 0Level 0

1.2 cal/cm1.2 cal/cm22 3.93.9 Level 1Level 1

4.0 cal/cm4.0 cal/cm22 7.97.9 Level 2Level 2 8.0 cal/cm8.0 cal/cm22 24.924.9 Level 3Level 3

25.0 cal/cm25.0 cal/cm22 39.939.9 Level 4Level 4 >40.0 cal/cm>40.0 cal/cm22 NO ACCESSNO ACCESS



Hot Enough?Hot Enough?

••1.0 cal/cm1.0 cal/cm22

is amount ofis amount ofheat produce by a cigaretteheat produce by a cigarette

lighter on finger tip for 1lighter on finger tip for 1secondsecond

Proper PPEProper PPE



Proper PPEProper PPE

This hazard risk categoryThis hazard risk categoryrepresents tasks that poserepresents tasks that pose

the greatest risk. Usethe greatest risk. Use

when incident energy iswhen incident energy isbetween 25.1 and 40between 25.1 and 40

cal/cmcal/cm22 ..

Would you use this on aWould you use this on a

class 0,1,2,3?class 0,1,2,3?

K i h PPE



Knowing how to use your PPEKnowing how to use your PPE



Mark Your EquipmentMark Your Equipment











Eff t W kEffect on Workers



Effect on WorkersEffect on Workers

Two workers had 2Two workers had 2ndnd and 3and 3rdrd degree burnsdegree burnson +60% of their bodies.on +60% of their bodies.

One of the workers was placed in a drugOne of the workers was placed in a drug--induced coma for over 60 days.induced coma for over 60 days.

The supervisor initially had minor injuries.The supervisor initially had minor injuries.He has suffered longHe has suffered long--term effectsterm effectsincluding neurological problems.including neurological problems.

Three families will never be the sameThree families will never be the sameagain.again.

Optional Equipment MarkingOptional Equipment Marking



Optional Equipment MarkingOptional Equipment Marking

Questions?



Michael White

Shermco Industries

Phone: 888-SHERMCO

Questions?

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Arc Flash Basics