Hazardous (Classified) Locations Flashcards

Flexible connections in Class I, Division 1 locations must use which type of flexible fitting?

Answer: Listed flexible fittings approved for the location

Flexible connections in Class I, Division 1 locations must use listed flexible fittings specifically approved for use in that classified location.

In a Class II, Division 1 location, motors must be of which type?

Answer: Dust-ignition-proof

Motors in Class II, Division 1 locations must be dust-ignition-proof to prevent ignition of combustible dust accumulations.

What is the maximum distance from a Class I, Division 1 or 2 enclosure that a conduit seal must be installed?

Answer: 18 inches

NEC Section 501.15 requires conduit seals to be installed within 18 inches of a Class I, Division 1 or 2 enclosure.

Which Group classification covers acetylene in Class I hazardous locations?

Answer: Group A

Acetylene is classified in Group A, which represents the most sensitive and dangerous gas group in Class I locations.

Intrinsically safe equipment is defined as equipment that:

Answer: Cannot produce sparks or thermal effects capable of igniting a hazardous mixture

Intrinsically safe equipment is incapable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a specific hazardous atmospheric mixture.

A grain elevator storage area with combustible grain dust would be classified under which Class and Group?

Answer: Class II, Group G

Grain dust is classified as Class II, Group G, which covers agricultural dusts including grain, flour, and starch.

In a Class I hazardous location, which type of luminaire (light fixture) is required in Division 1 areas?

Answer: Explosion-proof luminaire listed for Class I, Division 1

Luminaires in Class I, Division 1 locations must be explosion-proof and specifically listed for Class I, Division 1 use.