An arc flash is a potentially destructive workplace accident, capable of causing severe injury and equipment damage in the space of a few seconds. The National Fire Protection Association offers guidelines for appropriate personal protective equipment for anyone working near electrical equipment where arc flashes represent a safety hazard.

What is an Arc Flash?

An arc flash occurs when the normal path of electrical current is interrupted, causing electricity to discharge into the surrounding air. Air temperature can rise as high as 35,000 Fahrenheit during an arc flash--hotter than the surface of the sun. At such temperatures metal vaporizes, causing an explosive pressure wave.

Individuals caught within the arc flash can suffer severe burns, falls, pressure damage, ruptured eardrums, and wounds caused by flying shrapnel from explosions. Arc flashes can cause combustible material to ignite, creating fire hazards.

Are Employers Legally Obligated to Follow NFPA 70e®?

Some employers have noted they are not legally obligated to provide NFPA 70e® training. This is true, but in order to meet OSHA requirements for proper electrical safety training the standards set by the NFPA® must be met. Failure to meet OSHA requirements can result in fines, citations, and other penalties.

Personal Protective Equipment and NFPA 703®

The NFPA 70e® outlines the personal protective equipment to be worn around arc flash hazards. Note PPE alone will not satisfy OSHA standards. Personal protective equipment is the last line of defense against arc flashes, and not a substitute for performing an arc flash hazard assessment, calculating approach boundaries, and practicing appropriate electrical safety.

The amount of PPE worn depends on the potential force of the arc flash, expressed in calories/cm2. The arc flash PPE chart below displays the NFPA 703® personal protective equipment required based on arc flash flash calculations.

Arc Flash PPE Chart

Category
Personal Protective Equipment

0 (N/a )

  • cotton undergarments
  • long-sleeved shirt and long pants made from natural fiber
  • safety glasses / goggles
  • hearing protection (inserts)
  • leather gloves (as needed), or insulating gloves with protectors.

1 (4 Cal/cm2)

  • cotton undergarments
  • arc rated long-sleeved shirt or  fire resistant coveralls
  • arc rated long pants or fire resistant coveralls
  • hard hat with arc rated face shield
  • hearing protection (inserts)
  • safety glasses or goggles
  • leather gloves or insulating gloves with protectors
  • leather shoes as needed

2 (8 Cal/cm2)

  • cotton undergarments
  • short-sleeved natural fiber T-shirt
  • arc rated long-sleeved shirt and long pants or arc rated coveralls
  • hard hat with arc rated face shield and sock balaclava
  • safety glasses or goggles
  • hearing protection (inserts)
  • leather gloves or insulating gloves with protectors
  • leather shoes as needed

3 (25 Cal/cm2)

  • cotton undergarment
  • short-sleeved natural fiber T-shirt
  • arc rated long-sleeved shirt and arc rated long pants
  • arc rated coveralls worn over the above clothing
  • arc rated (25 cal) arc flash suite jacket
  • arc rated 25 cal arc flash pants
  • arc rated 25 cal arc flash suite hood
  • hard hat
  • safety goggles or glasses
  • hearing protection
  • arc rated leather gloves or insulating gloves with protectors
  • leather shoes

4 (40 Cal/cm2)

  • cotton underwear
  • short-sleeved natural fiber T-shirt
  • arc rated long-sleeved shirt and pants
  • arc rated coveralls over the above clothing
  • arc rated 40 cal arc flash suite jacket
  • arc rated 40 cal arc flash suit pants
  • arc rated 40 cal arc flash suite hood
  • hard hat
  • safety glasses or goggles
  • hearing protection
  • arc rated leather gloves or insulating gloves with protectors
  • leather shoes

Extreme danger (over 40 Cal/cm2)

no pPE available


It’s important to remember the equipment outlined in the NFPA 70e® arc flash PPE chart above does not eliminate the risk of injury. Arc flash personal protective gear is instead intended to limit the severity of injuries to curable burns.

Important though personal protective equipment is, it is no substitute for proper electrical safety training. Well-trained staff, regular equipment maintenance, and careful arc flash analysis are even more important, as they reduce the chances of an arc flash occuring in the first place.

 

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