Abstract: A heating, ventilation, and air-conditioning mechanic was working alone on a roof on a clear day. He was removing fan blades and a single-phase condenser motor from a 480-volt, three-phase Westinghouse heating and air conditioning unit. Without deenergizing the air conditioning circuit, the employee had removed the screen from above the fan motor. He removed the fan blades with a screwdriver and laid them on top of the unit. The employee used a crescent wrench to remove the band securing the motor and lifted the motor from unit with the conductors still attached. The employee was electrocuted when he contacted energized parts of the motor. The mechanic had 4 years of experience as a journeyman with his employer, and he had received continued training with his employer through the insurance carrier and various other companies. The air conditioning unit had a warning on its side reading, "Warning: Disconnect Power From Unit Before Opening." The unit was about 25 to 30 years old and required frequent repairs. The last service call was a month earlier, and the same employee had responded. The main panelboard was located in a closet on the first floor of the building. There was also an electrical box on the air conditioning unit to deenergize it and enable it to be locked out.