Totally enclosed motors shall have no external surface with an operating temperature that exceeds _____ when operating in Class I, Division 1 locations.
a) absolute zero
b) 80% of ignition temperature of the gas or liquid involved
See answer and applicable Code reference
The correct answer is: b) 80% of ignition temperature of the gas or liquid involved
Code requirements for equipment placed in Class I locations can be found in Part III of Art. 501. As noted in Sec. 501.125(A), in Class I, Division 1 locations, motors, generators, and other rotating electrical machinery shall conform to one of the four options shown. "Totally enclosed motors of the types specified in 501.125(A)(2) or (A)(3) shall have no external surface with an operating temperature in degrees Celsius in excess of 80% of the ignition temperature of the gas or vapor involved."