Whether it’s due to repair or renovation, at some point you’ll probably need to replace a light switch. We’re talking about the most basic of switches, a “single pole”, technically, a switch that’s either “on” or “off.” You can save the cost of a repairman by doing it yourself. DIY projects can be fun and cost effective. Fortunately, it’s one of the easiest tasks to complete, armed with some precautions and a little research.
Step One: Turn off the Power Source
For a simple replacement like this you don’t need to be a licensed electrician, but you do need to be careful anytime you’re dealing with electricity. So safety first. The primary step is to turn off the power at the source, the electrical box. The best practice is to shut off all the electricity coming into the house by turning off the main circuit breaker, most often this is the first breaker at the top of the electrical box. You may want to mark the breaker with a sign so no one in the house turns the main circuit back on while you’re working.
Step Two: Test the Wires
With the electricity off, remove the decorative switch plate and the mounting screws holding the current switch in place. Carefully pull the switch out of the wall to get to the wires. Use extra care if you’re working with a dated fixture, since old wire tends to stiffen up. Test the light switch before working on it. Pick up a circuit tester (available at home improvement stores) and follow the instructions to be sure no electricity is reaching the switch. Once you know the switch is dead, there are a couple of ways to work on your replacement switch.
Step Three: Disconnect Wires from Old Switch to New Switch
The old switch has three basic wires (two if your house is older): black wires which conduct electricity (when it’s on), white wires which are neutral, and a bare or green wire which is the grounding wire. Professional domestic electricians are in the habit of disconnecting the grounding wire last, and reconnecting it first in order to prevent electric shock. Electricity flows like water, taking the path of least resistance. The grounding wire is the path of least resistance – an easier path for electricity to travel than through you. This is just another good practice when dealing with electricity.
If you already have a new switch, disconnect each wire from the old switch and transfer it to the same place on the new switch, one at a time. This way, you don’t end up with a handful of wires and no idea what goes where. Alternatively, you may have to remove the old switch and take it with you when buying the new switch so you have exactly the switch you need. If this is the case, use some masking tape and a pen or several colored pens to mark the wires and to indicate where each wire went. In general the black wire gets connected to the black screws, the white to silver screws and the grounding wire on top. Mark your disconnected wires meticulously to avoid confusion later.
Step Four: Mount New Switch to Wall
Once everything is reconnected, gently place the new light switch into the wall, making sure all the wires stay attached. Mount the new switch with the screws you removed previously, and reinstall the switch plate. Restore power to the house, and turn on your light using your new switch. (If it’s not working, check to be sure the wires didn’t get disconnected during the final steps – but be sure to turn the power off before you investigate.)