New Fixtures: How to Install a New Electrical Fixture

Man Installing Bathroom Light Fixture

Any wiring project should beginwith a detailed plan. The section "Planning New Electrical Service" helps you prepare a thorough, easy-to-read description. Make sure existing or new circuits can handle the new installation. Present your plans to the local building department and receive a permit before beginning work.

Projects in Installing New Fixtures

Getting ready
Your inspector may approve NM cable, or you might have to install conduit or armored cable. Metal boxes may be required; plastic may be allowed. Determine how ground wires should be connected and how cable should be clamped to the boxes.

Most projects call for two-wire cable, but some require three-wire cable or even four wires running in conduit or Greenfield. Buy plenty of cable; it's easy to underestimate how much you need.

Unless you face special circumstances, use 12-gauge wire for 20-amp circuits and 14-gauge wire for 15-amp circuits. If your existing service uses armored cable or conduit, you can usually switch to NM cable if the cable runs into a box and the ground wire is connected according to code.

Test all new receptacles with a receptacle analyzer. It tells you instantly whether the receptacle is properly grounded and polarized.

Some building departments require that lights be on dedicated lighting circuits rather than share a circuit with receptacles. Other departments allow circuits to combine the two.

Planning a remodeling project
If a wiring project is part of a larger job, plan the work so different tasks and contractors do not collide. The first order of business is removing wall surfaces and any framing. Then comes rough plumbing, then rough electrical -- installing boxes and running cable. If you install receptacles and switches at this point, protect them with tape. Better yet wait until after the walls and ceilings are drywalled (with openings cut) and painted before installing receptacles, switches, and fixtures.

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