Abstract: A couple of weeks before the accident, some employees had tried to start up a saw mill. However, they could not get the dust chains to operate. The problem appeared to be electrical in nature, so the street lighting section was notified. On the day of the accident, a three-person crew (an electrical supervisor, an electrician, and a helper) arrived to find and repair the problem. To correct the problem, they started working on a 480-volt, 400-ampere panelboard. They had opened the top fuse on the panelboard, which they thought was the main disconnect. However, this fuse, which was not properly identified, only controlled the circuit to the head saw. The supervisor started switching fuses from one 30-ampere fuse block, which the crew thought was faulty, to another, spare, block. Each of the fuse blocks was equipped with a switch to deenergize the fuse block when the panel door was open. Therefore, when the supervisor tested the fuse block containing the fuses to be moved, he found it to be deenergized. Unfortunately, the interlock switch for the spare fuse block was faulty, and the spare fuse block remained energized. He had switched the lead conductors and was transferring the fuse terminals when his screwdriver contacted an energized screw. This caused an electrical fault, and the ensuing electric arc burned the supervisor. He sustained second degree burns to both hands and first degree burns to his face. He was hospitalized for his injuries.