Abstract: An experienced electrician was working in a motor control center at a chemical plant where potash was manufactured. He was working on three 480-volt, three-phase, pump-motor circuit breakers. The process involved deenergizing one of the circuit breakers while keeping the remaining two pumps running and maintaining production. After returning from lunch, the electrician had completed work on the circuit breaker for pump #1. Pump #1 was deenergized, and pump #2 and pump #3 were running. The employee then racked out the circuit breaker for pump #3, which was still under load. He radioed the control room operator that he had racked out the wrong circuit breaker and that he was going to rack it back in. While the electrician was racking the circuit breaker back into position, the pump control circuit received a start signal; and the circuit breaker closed and faulted. The ensuing electric arc burned the electrician. He sustained first- and second-degree burns on both his hands and his arms up to the elbows. He was hospitalized for his injuries.