Abstract: An electrical engineer working for a convention center management firm was in an electrical room, switching a power supply from a truck-mounted generator to a service-supplied system. The handle on the transfer switch had been broken for about 5 months, so he was using a pipe wrench. He was very close to energized parts inside the switch. As he closed the switch, an electrical fault occurred. The ensuing electric arc caused flash burns to the employee's face and minor flash burns to his supervisor. The engineer was hospitalized for 2 weeks. (The supervisor was not listed on an injury line on the original form.)