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Electrical SafetyARC FLASH ANALYSIS

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Electrical Safety

ARC EXPOSURE ENERGY BASICS

Exposure Energy is Expressed in cal/cm 2

1 cal/cm 2 Equals the Exposure on the tip of a finger by a Cigarette Lighter in One Second

An Expos ure Energy of Only One or Two c al /cm 2 Wil l Caus e a 2nd Degree Bu rn on Hum an Skin

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Electrical SafetyIndustry Standards and Regulations

OSHA 29 CFR 1910 Subpart S OSHA Enforces NEC2002 110.16 & NFPA70E

NFPA 70E-2000 Requirements for shock and arc flash boundaries Requirements for personal protective equipment

NEC 110.16-2002

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Electrical SafetyNEC 2002110.16 Flash Protection. Switchboards, panel boards, industrial control

panels, and motor control centers in other than dwelling occupancies,that are likely to require examination, adjustment, servicing, or maintenance while energized, shall be field marked to warn qualified

persons of potential electric arc flash hazards. The marking shall belocated so as to be clearly visible to qualified persons beforeexamination, adjustment, servicing, or maintenance of the equipment.

FPN No. 1: NFPA 70E-2000, Electrical Safety Requirements for Employee Workplaces , provides assistance in determining severity of potential exposure, planning safe work practices, and selecting personal protective equipment.

FPN No. 2: ANSI Z535.4-1998, Product Safety Signs and Labels , provides guidelines for the design of safety signs and labels for application to products.

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Electrical Safety

Sample NEC Warning Article 110.16

!

WARNING

Arc Flash and Shock HazardAppropriate PPE Required

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Electrical SafetyARC Flash Analysis OSHA 1910.132(d) Where work will be performed within the

flash protection boundary, the flash hazard analysis shalldetermine, and the employer shall document, the incident energyexposure to the worker (in cal/cm 2)

OSHA 1910.269(I)(6) Flame resistant (FR) clothing and PPE

shall be used by the employee based upon the incident energyexposure associated with the specific task.

As an alternative, PPE requirements of NFPA 70E Part II 3-3.9may be used in lieu of a detailed flash hazard analysis.

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Electrical Safety

Sample NEC Warning Article 110.16

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Electrical Safety

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Electrical SafetyApproach Boundaries

Nominal System Voltage Range

Limited Approach Boundary Restricted Approach Boundary

Prohibited ApproachBoundary

Phase-to-Phase Exposed MoveableConductor

Exposed Fixed CircuitPart

Includes InadvertentMovement Adder

0 - 50 Not specified Not specified Not specified Not specified

51 - 300 10 ft. 0 in. 3 ft.6 in. Avoid contact Avoid contact

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

751V - 15 kV

10 ft. 0 in.

5 ft.0 in.

2 ft. 2 in.

0 ft. 7 in.

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

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

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

72.6 121 kV 10 ft. 8 in. 8 ft.0 in. 3 ft. 3 in. 2 ft. 8 in.

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

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Electrical Safety

NFPA 70E provides two choices for PPEselection:

Do an arc flash hazard analysis, and documentthe incident energy exposure IEEE 1584 SKM (Arc Flash Evaluation Module)

ArcPro Software Duke Power Cal/Flux Software

As an alternate, use the Hazard Risk CategoryClassifications table to choose the PPE levelrequired for the task

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Electrical SafetyHazard Risk Category Tables

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Electrical SafetyHazard Risk Category Classification

NFPA 70E Hazard Risk 0 This hazard risk category poses minimal risk.

NFPA 70E Hazard Risk 1 This hazard risk category poses some risk.

NFPA 70E Hazard Risk 2 This hazard risk category involves tasks that pose a

moderate risk. NFPA 70E Hazard Risk 3

This hazard risk category involves tasks that pose ahigh risk.

NFPA 70E Hazard Risk 4 This hazard risk category represents tasks that pose

the greatest risk.

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Electrical SafetyMethods of Reducing Hazard Risk

Specifying Current Limiting Fuses on Low VoltageSwitchgear Breakers

Specifying ARC Resistance Medium VoltageSwitchgear

Remote Control of Switchgear Breakers

High Resistance Grounding on Low Voltage andMedium Voltage (15kV and below) Systems

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Electrical SafetyWhat We Offer Our Clients

Design of safer power systems while insuringcompliance with OSHA NFPA 70E standards and IEEE1584

Save time with the fully integrated Short Circuit, TimeCurrent Coordination, Equipment Evaluation and ArcFlash Evaluation

Offer alternatives to reduce exposure to ARC FlashEnergy.