Explosionproof requirements apply to fixed boxes and joints in which locations?

Explosionproof requirements apply to fixed boxes and joints in which locations?

• A. Class I, Division 1 locations
• B. Class II, Division 2 locations
• C. Class II, Division 1 locations
• D. Class III, Division 1 locations

Answer: (A)

Explosionproof enclosures are designed to contain any internal ignition so it cannot ignite the surrounding atmosphere. This level of protection is required where flammable gases or vapors are present during normal operation, which is Class I, Division 1 locations. In these locations, fixed boxes and wiring joints can be potential ignition sources, so they must be built to keep sparks or flames from escaping. Division 2 hazards are not normally present, only under abnormal conditions, so the universal explosionproof requirement is not applied the same way there. Other classifications, like Class II for dusts or Class III for fibers, use different protection schemes appropriate to those hazards. So the most correct setting for explosionproof requirements on fixed boxes and joints is Class I, Division 1 locations.

Explosionproof enclosures are designed to contain any internal ignition so it cannot ignite the surrounding atmosphere. This level of protection is required where flammable gases or vapors are present during normal operation, which is Class I, Division 1 locations. In these locations, fixed boxes and wiring joints can be potential ignition sources, so they must be built to keep sparks or flames from escaping. Division 2 hazards are not normally present, only under abnormal conditions, so the universal explosionproof requirement is not applied the same way there. Other classifications, like Class II for dusts or Class III for fibers, use different protection schemes appropriate to those hazards. So the most correct setting for explosionproof requirements on fixed boxes and joints is Class I, Division 1 locations.