Abstract: A five-person power line crew was assigned to install a three-phase service from a pad-mounted transformer to a new meter cabinet. The 480/277-volt circuit remained energized while the employees were working, despite the limited working space for the bolts they were to install. They covered energized parts with a rubber insulating blanket. However, they left the terminal on which they were working and the back plate of the terminals uncovered. The employees connected the first terminal without incident. On the second terminal, the supervisor on the crew dropped a bolt he was inserting. The bolt caused an electrical fault between the terminal and the back plate. The ensuing electric arc burned the supervisor on the face. He was hospitalized for his injuries.