Abstract: At 9:00 a.m. on April 16, 2007, Employee #1 was changing the electrical service for a tenant in a high rise office building in Los Angeles, CA. The work involved use of a "retail switch gear," which is used in establishments where tenants move in and out frequently. It is designed with empty "pull boxes," or cabinets that allow wire to be pulled from other areas of the building without having to turn off the power to other tenants. At the time of the accident, Employee #1 was pulling 600 ACM wire from a 4 in. conduit located in the floor of the pull box. The rear wall of the pull box was constructed of aluminum and bolted to the sides of the cabinet. On the other side of the aluminum back was another cabinet containing live 480 volt, 5000 amp service. As Employee #1 pulled up the stiff 3/4 in. thick MCM cable, he bent it into a curve and it pushed into the back of the cabinet. This caused the aluminum back panel to flex into a live buss on the other side in the cabinet behind it, resulting in an arc blast. Employee #1 sustained deep second-degree burns to his left forearm.