Intelligent Power Today Magazine

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...

Absence of voltage testing is a vital step in the process of verifying and establishing a de-energized state of any electrical system. As detailed in NFPA 70E clause 4.2.5., there is a specific and approved approach to establishing an electrical safe work condition with the following steps:

• determine all possible source of electrical supply
• interrupt the load current, open the disconnecting device for each possible source
• verify where possible that all blades of the disconnecting devices are open
• release or block any stored energy
• apply lockout device in accordance with documented and established work procedures
• using an adequately rated portable...