In Class II Division 1 locations, fittings and boxes shall be provided with which feature to permit connection to conduit terminations and maintain dusttightness?

In Class II Division 1 locations, fittings and boxes shall be provided with which feature to permit connection to conduit terminations and maintain dusttightness?

• A. threaded bosses
• B. gasketed covers
• C. sealing fittings
• D. strain relief

Answer: (A)

In Class II Division 1 locations, fittings and boxes must allow a secure conduit connection that stays dusttight. The feature that makes this possible is a threaded boss on the enclosure. A threaded boss provides the threaded surface needed to accept a conduit fitting or hub, so the connection can be tightened against the box and sealed to prevent dust from entering at the termination. Gasketed covers help with sealing the lid but don’t create the conduit termination itself, sealing fittings aren’t universally required for every box, and strain relief secures conductors rather than establishing the conduit-to-box seal. So, threaded bosses are the appropriate feature.

In Class II Division 1 locations, fittings and boxes must allow a secure conduit connection that stays dusttight. The feature that makes this possible is a threaded boss on the enclosure. A threaded boss provides the threaded surface needed to accept a conduit fitting or hub, so the connection can be tightened against the box and sealed to prevent dust from entering at the termination. Gasketed covers help with sealing the lid but don’t create the conduit termination itself, sealing fittings aren’t universally required for every box, and strain relief secures conductors rather than establishing the conduit-to-box seal. So, threaded bosses are the appropriate feature.