How to Install Conduit to Protect Wiring in Your Home?

Metal conduit helps protect wires and keep you safe—here's how to install it.

Conduit offers superior protection and safety for wires. Even if local codes permit NM (non-metallic) or armored cable in a basement, garage, attic, or crawlspace, consider installing conduit to protect wiring.

There are many different types and thicknesses of conduit. EMT (electric metallic tube, also called thin-wall) is strong enough for most interior home installations. Outdoors, use IMC (intermediate metal conduit) or PVC conduit. Codes have detailed rules regarding conduit size, but generally, 1/2-inch conduit is large enough for five or fewer wires; 3/4-inch conduit is used for more than five wires. When in doubt or if you might run more wire in the future, buy the larger size—it doesn't cost much more.

Metal conduit may serve as the path for grounding, or local codes may require you to run a green-insulated ground wire. If you use PVC pipe, you need ground wire, either green-insulated or bare copper. If there's no ground wire, make sure all the metal conduit connections are firm; a loose joint could break the ground path.

Save time by buying prebent fittings for your conduit. A coupling joins two pieces of conduit end to end. A sweep makes a slow turn, allowing wires to slide easily, while a pulling elbow makes a sharper turn. Setscrew fittings are commonly used with EMT conduit; they provide strong but not waterproof joints. For weathertight joints, use IMC conduit and compression fittings.

Often, it's easiest to make a drawing of your proposed installation and have a salesperson help you assemble all the parts you need—conduit, sweeps, elbows, boxes, and clamps. And make sure to buy plenty of wire.