Wiring a Light Fixture

If you are wiring a light, first plan out where the fixture will be located as well as the position of the switch box. A diagram can generally help out in clarifying the procedure for you. It can be a little confusing at first because there are a number of things to keep track of. In the room where you will be installing the light and switch, there should be a junction box which provides the power from the individual circuit. Through this junction box run a combination of three wires: black, white and either bare or green. This is your starting point. The first thing to do is to turn off the power to the individual circuit. Make sure you know which circuit you are working with so you don’t inadvertently trip the wrong breaker. 

Position the Boxes and Prep the Cables

Affix the switch box along a stud where the switch will go. Where the light fixture will sit, position another wiring box. From the junction box or power supply, run the three-wire cable through the bottom of the switch box, leaving yourself several inches of wire to work with. Run a second length of three-wire cable from the light fixture wire box through the top of the switch box. Strip off about 6 inches of insulation from the three-wire cable from both feeds. From each of the six individual wires (3 from the top, 3 from the bottom), strip off about 1 inch of insulation. At the wiring box for the light fixture, strip off 6 inches of insulation from the large cable and an inch off of each of the individual wires. 

Wire the Switch

At the switch box, connect the bottom black wire to the lower of the two brass screws on the switch. Make a loop with the wire and wrap it over the thread in the direction you will tighten the screw. Tighten it. Twist the exposed ends of the two white wires together and twist a wire nut over them. Assuming the boxes are plastic, twist the two ends of the green wires together and fasten a wire nut over them as well. Now connect the top black wire to the second, upper screw on the switch in the same way as the first. 

Wire the Light

At the light wire box, connect the exposed black wire to either the black wire or the brass screw on the light fixture. Connect the white wire to the white wire or the silver screw on the fixture. Connect the green wire to the green screw on the box. Again, if you twist wires together, use a wire nut. 

Turn the power back on to the circuit and test the switch. It should turn the light on and off. Once you are confident the connection is solid, screw the switch into the wall and attach the light fixture to the wall or ceiling. If there is a problem, turn the circuit back off and test all of the connections to make sure nothing is loose.