Intelligent Power Today Magazine

While the threat of shock and electrocution from inadvertent contact with energized parts has long been recognized, the arc flash and arc blast hazards have only fairly recently been incorporated into the electrical safety standards.

The U.S. federal agency the Occupational Safety and Health Administration (OSHA) enforces electrical workplace safety standards outlined in the National Fire Protection Association’s NFPA 70E: “Standard for Electrical Safety in the Workplace”. Basic compliance with guidelines in the NFPA 70E 2015 Edition, can be established with a five-step process.

I recently viewed a destroyed 600-volt electrical panel board that had exploded when an operator reset an 800-ampere (A) breaker. His leather-palmed gloves had synthetic backs that ignited and seriously burned the back of his hands. His flame-resistant (FR) shirt was untucked and he was burned on his right side.

It is unfortunate that he was not following Canadian Standards Association’s CSA Z462 standard: “Workplace Electrical Safety” clause 4.3.7.3.10 (d). It is incredibly fortunate that his employer provided arc-rated clothing, as only a few years ago, he would have been wearing cotton coveralls.

Consequently, this incident would have resulted...