An electrical contractor was installing a 480 volt electrical panel at a customer location. The employee pulled wires to the panel the day before the accident, but did not finish the job. When he returned to the facility the next day, he got on a ladder and touched the panel that he thought was cold. At some point between the time he left the panel and returned to finish the job the wires were energized. The employee was shocked and thrown from the ladder. He received burns on his hands and was admitted to the hospital.