Intelligent Power Today Magazine

Advanced approaches to addressing direct-current arcing faults

BY MICHAEL FURTAK & LEW SILECKY, Mersen

Let’s face it: there is not very much information available about direct current (DC) arc flashes. And, if you have searched in vain, well hopefully this feature will give you some insight into arc flash with relevance to DC circuits. Essentially, we want customers to be armed with information so that they can accurately determine the necessary level of protection required when working around these circuits.

In this feature, direct-current arcing fault incident energy calculations are presented to assess the level of risk involved when working...

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...