Arc Flash Presentation 2.1 MB PPT - ece.iit.edu

							Electrical Safety




           ARC FLASH
            ANALYSIS
Electrical ARC
           Safety   FLASH ANALYSIS
 ARC-FLASH
Electrical Safety

  • As much as 80% of all electrical injuries are
    burns resulting from an arc-flash and ignition
    of flammable clothing.

  • Arc temperature can reach 35,000°F - this is
    four times hotter than the surface of the sun
    Fatal burns can occur at distances over 10 ft.
 ARC EXPOSURE ENERGY BASICS
Electrical Safety

 • 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
 Industry Standards and Regulations
Electrical Safety
 • 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
 NEC 2002
Electrical Safety
 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.
     Sample NEC Warning Article 110.16
Electrical Safety

                    WARNING

          !
         Arc Flash and Shock Hazard
          Appropriate PPE Required
 ARC Flash Analysis
Electrical Safety
 • 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.
     Sample NEC Warning Article 110.16
Electrical Safety
Electrical Safety
                       Approach Boundaries
Electrical Safety
Nominal System
 Voltage Range
                            Limited Approach Boundary              Restricted Approach
                                                                        Boundary
                                                                                          Prohibited Approach
                                                                                               Boundary


Phase-to-Phase    Exposed Moveable         Exposed Fixed Circuit   Includes Inadvertent
                     Conductor                    Part               Movement 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.
  NFPA 70E provides two choices for PPE
               selection:
Electrical Safety
 • 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
 Hazard Risk Category Tables
Electrical Safety
 Hazard Risk Category Classification
Electrical Safety
 • 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.
 Methods of Reducing Hazard Risk
Electrical Safety
 • 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
 What We Offer Our Clients
Electrical Safety
 • Design of safer power systems while insuring
   compliance with OSHA NFPA 70E standards and IEEE
   1584

 • Save time with the fully integrated Short Circuit, Time
   Current Coordination, Equipment Evaluation and Arc
   Flash Evaluation

 • Offer alternatives to reduce exposure to ARC Flash
   Energy.