Thomas & Betts T-Type Conduit Body, Aluminum

Two trade sizes: 3/4 inch (T29SA) and 1 inch (T37SA). Both are threaded aluminum Type T bodies, so the hubs take rigid or IMC conduit of the matching trade size.

Order the cover and gasket separately. The T29SA (3/4 inch) and T37SA (1 inch) are the bodies only, so you also need a cover sized to the body and, for damp or wet locations, the matching gasket to make the closure up.

A Type T gives you three openings on the run plus the cover opening, so use it where a branch has to leave the run or where you need a pull point with a tee. An LB, LL or LR turns the run 90 degrees with one inlet and one outlet; a C body is a straight-through pull point. If you only need a bend or a straight pull, the T is more body than the job needs.

Threads are standard, so it will thread onto rigid or IMC of the same trade size, but pairing aluminum with galvanized steel in a damp or outdoor location invites galvanic corrosion at the joint. For all-steel runs in wet locations, spec a malleable iron or steel body instead; aluminum is the usual choice on aluminum conduit or dry interior work.

Only if the body is marked with a volume large enough for the conductors, per NEC rules on conduit bodies with splices. Many small trade size bodies are pull and routing points only. For a 3/4 or 1 inch T, count your conductors first; if the fill and volume do not work out, use a junction box with a marked cubic inch capacity.

Match the body to the conduit already in the wall, not to the other way round. Most branch circuit runs in commercial and multi-family work land on 3/4 inch, which is the T29SA; feeders and larger home run pipe go 1 inch, the T37SA. Both are the same aluminum Type T design, so mixing the two sizes across a site keeps one part family with one cover style.