What is an Arc Flash?

When a short circuit occurs in an electrical system there is a great amount of heat generated instantly. That heat transforms the associated metal into a gaseous state. This results in the metal expanding to approximately 67,000 times its previous volume. This rapid expansion, along with the associated heat causes a actual explosion, similar to explosives such as C4.

The amount of energy released is proportional to the amount of short circuit current that is present. When the detailed information about the electrical system is known, that short circuit current can be caclulated and the amount of energy present in the arc flash (or blast) can be determined. Once the level of energy is determined the appropriate level of risk, and associated personal protective equipment can be identified.

History of Arc Flash awaredness

In the early 1980's a paper "The Other Electrical Hazard: Electric Arc Blast Burns" by Ralph Lee was published in the IEEE Transactions on Industrial Applications. With the realization of the need to protect people from the hazards of arc flash, four separate industry standards concerning the prevention of arc flash incidents were developed.

OSHA 29 Code of Federal Regulations (CFR) Part 1910 Subpart S.
NFPA 70-2002 National Electrical Code.
NFPA 70E-2000 Standard for Electrical Safety Requirements for Employee Workplaces.
IEEE Standard 1584-2002 Guide for Performing Arc Flash Hazard Calculations.

What will IEI do?

IEI will provide the 3 basic elements necessary, a Short Circuit Study, a Device Coordination Analysis & an Arc Flash Study. This is traditional and typical of what responsible firms will provide. We feel that we do it a little better and at a more reasonable cost.

Please contact us and let us propose on your arc flash study.

David A. Exe, PE,