Abstract: A power line worker with 18 years of experience with an electric utility was a crew leader for an electrical construction crew. The crew was installing additional transformers and a 13-kilovolt feeder at a secured substation. The modifications were necessary to upgrade the capacity of the substation because of growth in the area. During the installation process, the crew used a Westinghouse mobile transformer to meet the demand on the substation. The crew leader was absent from the jobsite the morning of the accident. During his absence, problems developed with the mobile unit. The problem was handled by distribution personnel within the utility company. Upon his return, the crew leader observed the troubleshooting activity and offered his assistance. When the mobile unit was reactivated, a problem arose with the grounding apparatus on the unit. The crew leader climbed the structure of the unit and apparently slipped. He came too close to an energized insulator at the 33-kilovolt end of the unit and caused an electrical fault. The employee received an electric shock and suffered burns to both arms and to his left ear from the ensuing electric arc. He was hospitalized for his injuries and had to undergo mental and physical therapy. The employee did not remember the accident afterwards.