Abstract: An operation-maintenance manager and a shift manager of a cogeneration plant were preparing to reconnect the system to the transmission grid after the system had been down for 6 months. The connection was performed automatically from the control room. During the connection process, indicators in the control room showed that a circuit breaker was not closing. The two employees went to the circuit breaker room to see if they could determine the cause of the problem. They racked out the 13.8-kilovolt vacuum circuit breaker to see if there were any apparent problems. They did not see any problems, so they began to rack the circuit breaker back in. An electrical fault occurred, and the ensuing electric arc burned the two employees. Employee #1 sustained third-degree burns on both forearms and his right hand. He was hospitalized for his injuries. Employee #2 sustained a minor burn on his left arm. Both employees had been wearing regular street clothing.