NFPA 70E 2015 Article 120 Establishing an Electrically Safe Work Condition provides the requirements and specifications of an employer provided lockout/tagout procedure to safely de-energize and re-energize electrical as well as other sources of energy. It also requires that all stored energy which is outlined in the requirements for the released of stored electrical or mechanical energy that might endanger personnel, includes the requirement that before the equipment is touched or worked on, all capacitors be discharged, and that high capacitance elements are short-circuited and grounded. A key element to the lockout/tagout procedure is to verify that the energy source, stored or otherwise, is dissipated.
Proper method to operate electrical panel disconnect:
View Video 1 to see an electrical Lockout/Tagout procedure performed.
June 8, 2014 - Taconite mine – A mine electrician did not lock out a 4160-volt starter/disconnect when testing a circuit with a 600-volt meter. The safety device that prevents the starter door from being opened when the system is energized had been defeated. The electrician was burned from the arc flash that occurred when he contacted bare metal conductors inside, and the meter "blew up" in his hands. The electrician, who was not wearing proper protective gear, was hospitalized with burns to this hands and face.
Video 1: Electrical Lockout/Tagout Procedure
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