A lift cable on a truck crane was being replaced with a new cable. The new cable was attached to the truck crane drum and a truck. The truck was used to stretch and place tension on the cable so it could be rolled onto the truck crane cable drum. An employee was holding a second cable on the crane to keep it from tangling with the new cable. As the cable was being stretched by the truck, the cable rose upward and contacted an overhead power line. The employee received electrical burns and was hospitalized.