Things You'll Need
Wire connectors (wire nuts)
How to Install a Timer Switch. The job of a timer switch is pretty much self-explanatory. It is a switch that is controlled by a built-in timer. Timer switches work great in areas where you do not expect to stay very long, like in a storage closet or small basement. They are also great for controlling the power to a heat lamp in a bathroom. The timer works not only as a safety device, but it also helps you save money by preventing certain lights in your home from accidentally being left on. For anyone who has a teenager living at home, you may feel the need to install one in their bedroom! Anyway, here is how to install a timer switch.
Locate the breaker or fuse in your home that is supplying the power to the switch you want to replace. You can do this by positioning someone in the room where you are performing the installation and have them watch for the lights to go out while you toggle the breakers or remove the fuses. When you find the breaker or fuse, leave a note on the panel box stating that you are working on the electric to prevent anyone else in the home from accidentally giving you the shock of a lifetime.
With the circuit OFF, use your screwdriver to remove the screw holding the existing switch's faceplate. Remove the faceplate. Then loosen and remove the two screws securing the existing switch to the wall box.
Gently pull the existing switch out of the wall box. Use your voltage tester to check the switch for power. If the voltage tester reads no power, then you can loosen the side screws on the switch and remove the wires that are connected to them.
Take your wire strippers and cut away the exposed wire. Then use the wire strippers to strip away about 3/4 inches of new insulation off of the wires.
When you open your new timer switch, you will notice that it will be a self-contained unit with black, white and green wires coming out of it. Use the wire connectors to connect the black timer switch wire to the black wall box wire. Do the same for white wires and also for the green wires. If the wall box features a non-insulated ground, that is OK, just connect that to the green switch wire or secure it around the ground screw on the switch if it does not include a green wire tail.
In the event that your timer switch does not have the wire tails, you will connect the wall box wires to the timer switch exactly as you would a traditional switch--the black wire gets secured around the copper screw and the white wire gets secured around the silver screw.
Take a length of electrical tape and tightly wrap it around each wire connector where the wire meets the connector. This is to prevent any stray strands of wire from causing a dead short.
Now you can gently push the wires back into the box and secure the timer switch to the box with the two longer screws that were included in the packaging.
Once the timer switch is installed, use the two smaller screws that came with it to secure the new faceplate to the switch.
Lastly, if you purchased a timer switch that features a dial timer, then you will slide the dial over the shaft of the timer switch. Some dials require a lock not to be screwed into place, while others do not.
Return to the panel box and toggle the breaker back on or replace the fuse to restore power to the circuit. Back in the room with the new timer switch, turn the timer on and you should hear the seconds ticking away as the light illuminates. If this occurs, then your job is a success! Now just clean up any leftover mess and you are all finished.
If the wall box is filled with wires, you may have to reposition some of them to get the timer switch to fit comfortably. Timer switches are much larger than regular single-pole switches, so keep that in mind.