How to Wire a 2-Conductor Switch Leg
If you want to install a light fixture or switched outlet, you will need to know how to properly wire a two-conductor switched leg. The switched leg of a switch simply refers to the wire that is supplied electricity when the switch is turned on. When the switch is on, the switched leg then provides power to the fixture or device to be powered. Wiring the switched leg is an easy DIY project, and this simple how-to guide will show you everything you need to know.
Step 1 - Shut Off Power
Before you start, go to the main breaker box in your home and switch off the circuit that provides power to the switch you will be working on. Once you switch off the breaker, go to the room where the switch is located and check the connection with a multimeter or test light to make sure no power or current is flowing to the switch.
Step 2 - Prepare Wiring from Breaker Box
Clip and strip the wires that lead from the breaker box to the switch. If the wiring was used with an older switch, you should always clip and re-strip the wiring as it may have become frayed or damaged. Freshly clipped bare wire ends will also provide a much better connection when wiring the switch.
Step 3 - Connect Light Switch to Breaker Box Wiring
Connect the wiring from the breaker box to the light switch by attaching the black wire to the brass-colored screw terminal and the white wire to the silver-colored terminal. Also, create a small hook in the bare copper wire, which is used for ground, and attach it to the screw with the green painted surface.
Step 4 - Prepare Wiring for Switched Leg
Strip the ends of the wiring that will lead to the fixture or device that needs to be powered. Strip the ends so that they are about 3/4 inch long.
Step 5 - Connect Leg to Switch
On the rear of the switch, there will be three additional screw terminal leads or three wires that will be used to connect the fixture or device to be powered. Attach the black, white, and ground wires that lead to the fixture in the same manner as you did for the incoming wires from the main breaker box.
Step 6 - Connect Switched Leg to Fixture
Go to the area where the light fixture or other device to be powered is located. Connect the black, white, and ground wires to the corresponding wires of the fixture. Secure the wiring connections with wire nuts to properly shield them.
Step 7 - Turn the Power On
Go back to the main breaker box and switch the circuit breaker for the switch to the 'on' position. Then, use the switch to test the newly installed fixture on the switched leg of the switch.