Abstract: An employee was on the deck of a tunneling machine in front of an electrical cabinet. The company needed to know the location within the cabinet where more cables were to be added. The employee had the cabinet door open and was looking inside toward the end of the cabinet. He was going to make marks on the end cover to indicate where the cables needed to be run. He contacted live parts energized at 480 volts, received an electric shock, and was knocked unconscious. When he fell back down onto the deck in the prone position, his coworkers responded. They administered cardio-pulmonary resuscitation and called for emergency medical services, which arrived within a few minutes. The emergency medical team restarted the injured employee's heart, and he was soon breathing on his own. He was hospitalized for his injury.