Abstract: An electrician was installing the neutral conductor for an emergency lighting system onto the neutral bus of an 800-ampere cabinet. An 800-ampere, three-phase main circuit breaker, which had been previously installed in the cabinet, was open. However, the conductors feeding this circuit breaker were energized. Because an excessive amount of insulation had been stripped from the six conductors that were connected to the circuit breaker, about 20 millimeters of conductor was exposed on each of the six conductors. As the electrician was routing the neutral conductor behind other conductors in the cabinet, an electrical fault occurred. The ensuing electric arc burned the employee on both hands. He was hospitalized for his injuries. Representatives of the company believed that the neutral conductor contacted the exposed portion of one of the supply conductors. However, there was no evidence of burning or damage to the neutral conductor.