NFPA 70E

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NFPA 70E

• ARC Flash Analysis

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ARC Flash
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ARC Flash Analysis
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ARC Flash

• As much as 80 of all electrical injuries are
  burns resulting from an arc-flash and ignition of
  flammable clothing.
• Arc temperature can reach 35,000F - this is four
  times hotter than the surface of the sun
• Fatal burns can occur at distances over 10
  ft.

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ARC Exposure Energy Basics

• Exposure Energy is Expressed in cal/cm2
• 1 cal/cm2 Equals the Exposure on the tip of a
  finger by a Cigarette Lighter in One Second
• An Exposure Energy of Only One or Two cal/cm2
  Will Cause a 2nd Degree Burn on Human Skin

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Industry 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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NEC 2002

• 110.16 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 be
  located so as to be clearly visible to qualified
  persons before examination, 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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Sample NEC Warning Article 110.16
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MARKING IDENTIFICATION
Markings required by OSHA
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Electrical Panel
PNL Designation
Circuit Breaker Identification
Circuit Breaker Numbers
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ARC Flash Analysis

• OSHA 1910.132(d) Where work will be performed
  within the flash protection boundary, the flash
  hazard analysis shall determine, and the employer
  shall document, the incident energy exposure to
  the worker (in cal/cm2)
• OSHA 1910.269(I)(6) Flame resistant (FR)
  clothing and PPE shall be used by the employee
  based upon the incident energy exposure
  associated with the specific task.
• As an alternative, PPE requirements of NFPA 70E
  Part II 3-3.9 may be used in lieu of a detailed
  flash hazard analysis.

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Sample NEC Warning Article 110.16
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(No Transcript)
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Workspace-600 V
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Workspace-26 kV
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Approach Boundaries
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NFPA 70E provides two choices for PPE selection

• Do an arc flash hazard analysis, and document the
  incident energy exposure
• IEEE 1584
• SKM (Arc Flash Evaluation Module)
• ArcPro Software
• Duke Power Cal/Flux Software
• As an alternate, use the Hazard Risk Category
  Classifications table to choose the PPE level
  required for the task

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Hazard Risk Category Tables
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Hazard 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 a high risk.
• NFPA 70E Hazard Risk 4
• This hazard risk category represents tasks that
  pose the greatest risk.

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Methods of Reducing Hazard Risk

• Specifying Current Limiting Fuses on Low Voltage
  Switchgear Breakers
• Specifying ARC Resistance Medium Voltage
  Switchgear
• Remote Control of Switchgear Breakers
• High Resistance Grounding on Low Voltage and
  Medium Voltage (15kV and below) Systems

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Compressor Station Panels
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Compressor Station Panel
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Compressor Station
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Compressor Station
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City Gate Station
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City Gate Station
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City Gate Station
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City Gate Station
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City Gate Station
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City Gate Station