According with the NEC NFPA70. For Class I Division 1 locations , motor enclosures shall be: Explosion proof approved for division 1 locations or Totally enclosed supplied with positive-pressure ventilation from a source of clean air with discharge to a safe area and so arranged to prevent energizing the motor until ventilation has been established or Totally Enclosed inert gas-filled or submerged in a flammable liquid type. For Class I Division 2 locations , motor enclosures TEFC or open type are permitted but should not have brushes, switching mechanisms or similar arc producing devices. If such mechanisms exit an Explosion proof approved for division 1 locations is required. For Class II Division 1 locations , motor enclosures shall be: Explosion proof approved for class Í I division 1 locations or Totally enclosed supplied with positive-pressure ventilation from a source of clean air with discharge to a safe area and so arranged to prevent energizing the motor until ventilation has been established. For Class II Division 2 locations , motor enclosures shall be TENV (totally enclosed non ventilated) or Totally enclosed pipe ventilated or TEFC (totally enclosed fan cooled) or Dust ignition Proof and all will have maximum full-load external surface temperature in accordance with section 500-3(d) when operating in free air and shall no have external openings.
