An Arc Flash is very simply, an electrical short circuit through air. Whether it occurs from phase to ground or phase to phase doesn't matter. What does matter is that enough energy is present to perpetuate the arc. Lightning is an example of arc flash as is an electric arc welding machine. The difference between them is that lightning discharges itself in a very short period of time whereas an arc welding machine sustains the arc indefinitely. Either way, you don't want to get too near either of them. Arc flashes, like lightning, can cause electrical equipment to vaporize, resulting in an arc-plasma fireball. Temperatures may exceed 35,000° F (the surface of the sun is 9000° F). These high temperatures also cause rapid heating of surrounding air and extreme pressures joining together to produce the arc blast. The arc blast will further vaporize electrical equipment including solid copper conductors which will expand up to 67,000 times their original volume. The result of this violent event is usually destruction of the equipment involved, fire, and severe injury or death to any people who are unfortunate enough to be nearby.


   There are a number of reasons why an Arc Flash event can occur, but the ones involving people are usually preventable. Most arc flashes occur when maintenance workers are manipulating live equipment for testing or repair and accidentally cause a fault. Improper tools, improper electrical equipment, corrosion of equipment, improper work techniques and lack of training are just some of the events that can lead to a devastating arc flash / arc blast event.


OSHA (the Occupational Safety and Health Administration) has issued a set of regulation meant to address in general, electrical on the job safety and has included arc flash training as part of the overall electrical safety training requirements.

   OSHA Standards 29-CFR, Part 1910. Occupational Safety and Health Standards. 1910 sub part S (electrical) Standard number 1910.333 specifically addresses Standards for Work Practices and references the National Fire Prevention Association publication, NFPA 70E.
   OSHA 29CFR 1910.335 (a) (1)(i) requires the use of protective equipment when working where a potential electrical hazard exists and 29CFR 1910.132(d)(1) requires that employers assess the workplace for hazards and the need for personal protective equipment. OSHA compliance is required by any plant, building or facility.

   The National Fire Protection Association (NFPA) Standard 70 - 2002 “The National Electrical Code” (NEC) contains requirements for warning labels. Each panel must be marked with an approved Arc Flash Warning Label.

   NFPA 70E Standard for Electrical Safety in the Workplace, provides guidance on implementing appropriate work practices that are required to safeguard workers from injury while working on or near exposed electrical conductors or circuit parts that could become energized. The standard requires that a "Flash Hazard Analysis shall be done before a person approaches any exposed electrical conductor or circuit part that has not been placed in an electrical safe work condition". This Arc Flash Hazard Analysis must be done to determine the level of Personal Protection Equipment PPE that a worker must use, and the Arc Flash Boundary in inches along with the incident energy found at each location.

An Arc Flash Analysis is a calculation performed by Professional Engineer to determine the incident energy found at each location that determines the various arc flash boundaries as well as determining what personal protective equipment (PPE) must be used in approaching each boundary.  An Arc Flash Analysis should only be performed by experienced and qualified electricians and engineers.


The National Electrical Code requires labeling of equipment to warn of potential arc flash hazards. Each panel must be marked with an ANSI approved Arc Flash Warning Label. These labels are used to warn and instruct workers of the arc flash hazard, voltage, arc flash boundary and required PPE (Personal Protective Equipment). Subject to the requirements of the facility and arc flash analysis, labels are provided and attached for each analyzed point of concern.


OSHA Standard 1910.332 states: "Employees shall be trained in and familiar with the safety-related work practices required by 1910.331 through 1910.335 that pertain to their respective job assignments."

Our online training course is a method of instructing and informing your employees about the hazards of arc flash. This 4 hour tool employs the latest software and techniques to drive home the point that electrical safety is not an option and that compliance is required. We hope you will consider making this tool a part of your company's electrical safety training program.