Arc Flash 101presented by Arc Flash Blaster LLC

ARC FLASH?

ARC FLASH INCIDENT

STANDARDS AND REGULATIONS

Pressure Waves

Copper Vapour:(Solid to vapor expands by 67,000 times)

Molten Metal

Intense Light

Hot Air-Rapid Expansion

35,000°F

Shrapnel

Sound Waves

Arc flash accidents ...

Serious injuries can result.Serious injuries can result.

HAZARD?

• EVERY DAY... a USA worker is killed, 13 suffer lost time injuries due to electric shock or burns

• EVERY DAY... 1 in 20 on-the-job fatalities are due to electric injuries, 75% by electrical arcs

ONLY 240V

LESSONS LEARNED

GOVERNMENT FACILITY

LOW VOLTAGE PANEL

BACK OF SHIRT

POLYESTER SHIRT BUTGOOD GLOVES

SHERMCO INCIDENT

• ON FEB 13 2005 WORKERS RACKED IN A BREAKER

• 2 WORKERS OBSERVING

• DURING RACKING FELT RESISTANCE

• THINKING STIFFNESS IN RACKING SCREW HE BACKED BREAKER OUT

SHERMCO INCIDENT

• ACTUALLY IT WAS BROKEN CABLE TIES WITH LOOSE WIRING

• NO PRE-INSPECTION MADE

• CONTINUED RACKING IT PULLED WIRING DOWN ONTO 4160V BUS

What do the standards say?

Wiringnot runneatly

Relaysdamagedby heat

What do the standards say?

What do the standards say?

What do the standards say?

Other cubicles were damaged byfault current flowing in the control

wiring

What do the standards say?

INSTALLATION AFTER REPAIR

Notewiringis heldout ofharm’s

way

RESULTS

• ESTIMATED INCIDENT ENERGY 33CAL/CM2

• MAIN BREAKER CLEARED ON OVERCURRENT, 1.7 SECONDS @ 15,000 AMPS

• LOWER DOOR SHIELDED WORKER, DOOR HANDLE HIT WORKER IN SIDE OF HEAD AND HE FRACTURED SKULL (NO HARD HAT)

THE SOLUTION?

ARC FLASH PROGRAM & ARC FLASH LABELS

WARNING

Arc Flash and Shock Hazard

Appropriate PPE Required

_____________ Flash Protection Boundary ( _____feet or _____ inches )

_____________ cal/cm 2 Flash Hazard at ( _____feet or _____ inches)

(N/A = Not Calculated)

_____________ 18Q -2, Table 1 applies for Arc Flash PPE Determination

_____________ Short Circuit Current Available (Amps)

_____________ Reduction by one H azard Category in Table 1 Allowed

_____________ Nominal Phase to Ground Voltage (18Q -2, Table 2)

Date: ________________ ___ Calculation # _______________________ ________

Bldg. __________ Equip. Name / CLI # _________________________

!

Brady Solutions

PERSONAL PROTECTIVE EQUIPMENT (PPE)

PPE (will be changing)

PPE Category Clothing Requirements

Calorie Rating

0 Long sleeve shirt & pants (non-melting), safety glasses, EARPLUGS

1.2 cal/cm2

1FR shirt & pants (or coveralls), hard hat

and glasses, EARPLUGS, LEATHER GLOVES, FACESHIELD

4.0 cal/cm2

2T-shirt, FR shirt & pants (or coveralls),

face shield, leather gloves, earplugs, hard hat, glasses, leather shoes

8.0 cal/cm2

4 Everything in “2” plus “Bee Suit” & Flash Suit Hood (instead of face shield) 40 cal/cm2

HOW DO WE GET THERE?

• UNDERSTAND THE ARC FLASH HAZARD REQUIREMENTS ON A LABEL

• TRAIN YOUR WORKERS AND PROVIDE GEAR

• REQUIRE JOB HAZARD ANALYSIS AND SET ELECTRICAL SAFETY STANDARDS/RULES

• SELF-AUDIT

• CREATE LABLES (STUDY WORK)

Arc Flash– Incident Energy– Arc Flash Boundary

MCC

Incident Energy at the Working

Distance

DO I UNDERSTAND THE FLASH PROTECTION BOUNDARY?

DE-ENERGIZE!

LOTO?LOTO?

How is itHow is itsupposedsupposed

to getto getrepairedrepairedsafely?safely?

SMART UPFRONT DESIGN

• EQUIPMENT SELECTION

• ELIMINATE PARALLELING OF SOURCES

• DIFFERENTIAL OR FAST PROTECTION

• DO NOT OVERSIZE PANEL BREAKERS

• LOW SETTINGS ON PROTECTIVE DEVICES

• GROUND FAULT PROTECTION (90% FAULTS BEGIN AS SLG)

• ISOLATE CONTROL CIRCUITS

USE NEW TECHNOLOGY

H

L

Note... Install per Manufacturer Requirements!

Use the right tools for the job

• Proper PPE

• Hot Sticks

• Properly rated hand held meters

• Insulated tools

Protect Yourself & Others

• That includes assessing other’s abilities

• Make sure everyone knows the hazards

• Wear clothes properly

• You can always STOP work and ASK

NFPA 70E - 2009 Changes

110.7 Electrical Safety Program

• (A) General. The employer shall implement and document an overall electrical safety program...

130.3

• New last sentence and exception

• The flash hazard analysis shall be updated when a major modification or renovation takes place. It shall be reviewed periodically, not to exceed five years to account for changes in the electrical distribution system that could affect the results of the analysis.

130.3 Continued

• Exception: The requirements of Sections 130.7(c)(9); 130.7(c)(10) and 130.7(c)(11) shall be permitted to be used in lieu of a detailed Flash Hazard Analysis.

130.3 Exception [New]

• A flash hazard analysis is not required for circuits of 240 volts and below unless the circuit includes at least one 125kVA or larger transformer.

130.3 FPN [New]

• FPN: Improper or inadequate maintenance can result in increased opening time of the overcurrent protective device, thus increasing the incident energy.

130.3(A)

• Changed the 4 foot flash protection boundary to be based on a 2 cycle clearing time and 50kA fault current or 100kA cycles.

• Existing is 6 cycles and 50kA, or 300kA cycles.

130.3(B)

• The language is modified so that when work is performed within the Flash Protection Boundary, one of two methods are to be used for selecting protective clothing and other PPE.

• --1) Incident Energy Analysis

• --2) Hazard Risk Categories (Tables)

130.3(C) [New]

• Equipment Labeling. Equipment shall be field marked with a label containing the available incident energy or required level of PPE.

• (if required by 110.16 in NEC)

• laminate all the tasks if using the tables

Table 130.7(C)(9)

• added “Performing infrared thermography inspection” task to tables.

130.7(C)(9)

• Deleted NOTES 3 and 6.

• Notes permitted an automatic reduction of one hazard risk category for lower short circuit currents.

130.7(C)(9)

• The 2* designation means that a flash suit hood or alternatively a face shield used in combination with a balaclava (sock hood) is required for this task...

Table 130.7(C)(10)

• Hearing Protection added to HRC 0 and 1.

130.7(C)(10)

• Requires the use of leather gloves for HRC 1.

Table 130.7(C)(10)

• Added a requirement to use either face shield or flash hood for HRC 1 with a minimum arc rating of 4.

210.5 FPN [New]

• Failure to properly maintain protective devices can have an adverse effect on the flash hazard analysis incident energy values.

Michelle Murphymnmurphy@usit.net