In Class II Division 1 locations, fittings and boxes shall be provided with ___ for connection to conduit or cable terminations and shall be dusttight.

In Class II Division 1 locations, fittings and boxes shall be provided with ___ for connection to conduit or cable terminations and shall be dusttight.

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

Answer: (B)

In Class II Division 1 locations, enclosures must keep dust out while providing a secure, sealed entry for conduits or cables. A threaded boss is a built‑in, raised thread on the enclosure that accepts conduit fittings or cable glands. By screwing the connector into this boss and tightening it against a gasket or the enclosure, you create a tight, dust‑tight seal for the termination and a solid electrical connection. This is why threaded bosses are specified—they give a proper, sealable entry point that maintains the enclosure’s dusttight integrity. Gasketed covers seal only the lid, sealing fittings refer to the connectors themselves, and strain relief secures the cable but doesn’t establish the threaded entry point needed for a dust-tight connection.

In Class II Division 1 locations, enclosures must keep dust out while providing a secure, sealed entry for conduits or cables. A threaded boss is a built‑in, raised thread on the enclosure that accepts conduit fittings or cable glands. By screwing the connector into this boss and tightening it against a gasket or the enclosure, you create a tight, dust‑tight seal for the termination and a solid electrical connection. This is why threaded bosses are specified—they give a proper, sealable entry point that maintains the enclosure’s dusttight integrity. Gasketed covers seal only the lid, sealing fittings refer to the connectors themselves, and strain relief secures the cable but doesn’t establish the threaded entry point needed for a dust-tight connection.