Enclosure Requirements in Class III Locations

In Class III locations, switches, circuit breakers, motor controllers, and fuses, including pushbuttons, relays, and similar devices, shall be provided with _____.

a) Class I enclosures
b) general duty enclosures
c) dusttight enclosures
d) seals at each enclosure

See answer and applicable Code reference

The correct answer is: c) dusttight enclosures

Article 503 covers the requirements for electrical and electronic equipment wiring for all voltages in Class III, Division 1 and 2 locations. As per 503.115, "Switches, circuit breakers, motor controllers and fuses, including pushbuttons, relays and similar devices, shall be provided with dusttight enclosures."


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