Abstract: A machine operator was working for a large company that exported hay. The hay was processed and packed in a system of conveyors and mixer and extruder machines. The hay often jammed the mixer. The company's practice for freeing the conveyor was for the operator to open the door of a 480-volt electrical cabinet and reverse the polarity of mixer motor's supply conductors. This would reverse the motor's rotation and consequently free the mixer. On the day of the accident, with the mixer jammed, the operator knelt in front of the energized cabinet and crossed the conductors with a screwdriver. This caused an electrical fault, and the ensuing electric arc burned the employee. He suffered second- and third-degree burns on his face, neck, forearms, and legs. He was hospitalized for his injuries.