Abstract: An electrical trainer was asked to help troubleshoot a 480-volt circuit breaker at a motor control center at a coker unit. The circuit breaker was in the test position, and the cubicle door was open when the trainer arrived. He tried to close the door, but was not able to do so since some components were in the way. Checking to ensure that the circuit breaker was in the open position, the trainer started to rack in the breaker. An electrical fault occurred, and the trainer was burned by the ensuing electric arc. He was hospitalized with second and third degree burns to his hands and second degree burns to his face.