Changing a Light Switch
Homeowners may choose to replace or upgrade a light switch for functional or for aesthetic reasons. Changing the light switch is a simple and inexpensive DIY project.
Understanding how the switch is wired is the most important part. When you turn on a light switch, power goes to the light through the “hot” (black) wire and then back through the neutral (white) wire to the ground. The bare or green-wrapped ground wires serve as a backup to divert the power safely away in case of an electrical fault.
In most cases, two black wires will be attached to the switch’s two terminal screws. The white wires will be connected to each other but not to the switch itself; this connection is typically secured by a plastic wire nut. The ground wires will be connected to each other and attached to the grounding screw on the switch.
Turn Off Power
Turn off the power to the circuit at the circuit breaker or fuse box. You can double check to ensure that it was turned off by flipping the switch in an attempt to operate a light, and by using a voltage tester once the switch plate is removed to confirm that the wires are not charged.
Remove the Switchplate and Existing Switch
Use a flathead screwdriver to remove the switch cover, and a Phillips head screwdriver to remove the existing switch from the box.
Remove the Wires from the Old Switch
Use a screw driver to loosen the screws holding the electrical wires on the side of the switch, and then disconnect the wires from the switch itself. Pay attention to the wire colors and where they had been attached on the old switch, as you will be duplicating their placement on the new switch. Using needle nose pliers will be helpful while working in this small space. Keep the wires separated by bending them to opposite corners of the box. If the switch is grounded, remove the grounding wire last.
Attach the Dimmer Switch
There will be three wires: one black, one white, and a separate ground wire that may be bare copper or is sometimes wrapped in green. Inspect the quality of the wires. If any of the wires seem weakened, trim and re-strip the end of the wire to meet your needs.
Identify the three different colored wires, and attach the new light switch to the wires in the same way they had been attached to the old switch. If your wires are solid copper, create a loop in the end of the wire with the pliers and guide it around the screw on the side of the switch. Tighten the screw, ensuring that the wire is securely held beneath the screw and is not splaying to the perimeter of the screw. If your wall wire is composed of a group of smaller wires, use the pliers to gently twist the ends of the wires together to make them “whole,” and then follow the same direction.
Attach the Switch to the Box and Reinstall the Switch Plate
Once the wires are attached, you can gently fold any excess wire and compress the dimmer into the electrical box. Move slowly to ensure the wires don’t loosen or break if you have to force the switch into position. Tighten the screws to secure the switch to the box, and fit the switch plate. You may find that tightening or loosening the switch in the box by a few small twists of the screw driver makes a difference with how well the plate fits over the box. Once the cover is in place, turn the breaker or fuse back on, and check your handiwork.