Article
Electrical fittings are everywhere in home and business distribution systems – so much so, you might think they’re all interchangeable. But for contractors working in multiple indoor and outdoor locations, that’s not the case. Not all connectors or other fittings offer the same level of protection for the cabling running through them, which is why matching this hardware to its specific applications is so important.

Connector and Coupling Options to Keep Conductors Dry

Chuck Ross
Electrical fittings are everywhere in home and business distribution systems – so much so, you might think they’re all interchangeable. But for contractors working in multiple indoor and outdoor locations, that’s not the case. Not all connectors or other fittings offer the same level of protection for the cabling running through them, which is why matching this hardware to its specific applications is so important.

This is certainly true in areas where moisture is likely to be present. That’s why the National Electrical code requires fittings installed in wet or damp locations be explicitly listed for such use, along with use in concrete. That listing comes with assurance that the fittings have been designed to keep moisture away from live wires for safer operations. Of course, wet, damp and in-concrete applications each come with other stresses, which define what kind of cable or conduit is allowed. As a result, manufacturers have designed products for each of the code-defined installation options allowed in such locations: jacketed metal-clad (MC) cable, electrical metallic tubing (EMT), and rigid and intermediate metal conduit (IMC).

Specific adaptations have been developed each of these cabling and conduit types and can include:

  • Jacketed MC cable – Knockout gaskets to ensure water doesn’t seep into junction boxes, tapered threads to make attachment to threaded boxes easier. In some cases, contractors have the option of an insulated connector throat to minimize the risk of electrical hazards that could occur from stripped-back connectors having direct contact with interior metal surfaces.

  • EMT – For EMT-to-EMT couplings, internal sealing rings on either side of the connections can maintain watertightness. These rings also can be a part of connector-to-box products, along with knockout gaskets.

  • Rigid/IMC couplings – For these couplings, internal O-rings can keep moisture out.
Photo courtesy of Bridgeport Fittings
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