An employee had a team working on a new conduit feeder to a substation switchgear. The 480-volt side of the switchgear where the work was taking place was locked out, tagged out, and verified with a meter to not have power. At the entrance point of the conduit into the substation, another employee was using a knock-out set to punch a hole into the gear. He was having trouble getting the knock-out started, so the injured employee attempted to help him. The injured employee was standing on a two-step riser working with his hands over his head. He was trying to adjust and move some existing wires out of the location of the new knock-out location to thread on the cutting die. As he was moving and pulling, he pushed against the side wall of the switchgear. The side wall flexed into the adjacent compartment, touching a buss that caused an arc flash. The injured employee suffered burns to the hands, left arm, and midsection of his body.