Abstract: An employee of a plumbing and heating contractor was working from a 6-foot-high aluminum ladder, assembling a gas pipe to an overhead gas heater. As he was working, he received an electric shock. The aluminum ladder was sitting on top of a 100-foot extension cord set that was connected to a four-way outlet not protected by a ground-fault circuit interrupter. He had been using an electric drill earlier that day, and it was still connected to the cord set. The employee was transported to a hospital and was released the same day. His only remaining symptoms of the electric shock were soreness in most of the muscles in his body.