How to Wire a Light Switch: Step-By-Step Guide

Learning how to wire a light switch is a basic skill that every homeowner should learn. Even without electrical expertise, light switch wiring is straightforward and simple to accomplish – as long as you are safe and careful about it. Here are a few easy steps to wiring a switch so that you don't need to call on an electrician for this small project.

How to Wire a Light Switch

A single pole light switch is the standard model that you're probably most familiar with – you flip the switch up and down to turn the lights on and off. Wiring single pole light switches is usually the same across the board, but it is a good idea to read the directions that come with your switch just in case any instructions differ.

Tools:

• New single pole light switch
• Phillips head screw driver
• Electrician pliers/needle-nose pliers
• Current detector (if needed)
• Electrical tape
• Wire nuts (if needed)

Note the Wires

Before you learn how to wire a light switch, you should familiarize yourself with the different wires you are going to encounter and what they each do.

Black Wire: This is a "hot" wire, which serves to cut off power from reaching the light switch when you turn it off.

White Wire:This is a neutral wire, which bypasses the switch and leads directly to the lights. The white wires are required to complete the circuit.

Green/Bare Copper Wire:This is the ground wire and should be connected to both the switch and the light. (Note that some older homes may not have the copper wire)

Red Wire: This wire is only found with three-way switches. It connects all the switches together and allows the individual function of each light switch.

Tip!

When wiring an electrical switch, try to take note of the wire locations and connections, as you will want to replicate them when you install the new switch.

Steps to Wire a Light Switch

Step 1: Disconnect the Power

Before you begin your light switch wiring, make sure to shut off the power to the light switch – do not start before this step. Working with electricity is dangerous, so you need to turn the power off at the breaker. If you aren't sure which switch leads to the light, turn it on and test each breaker until you find the one that turns the lights off. Make sure to double-check just in case anything is mislabeled.

Step 2: Remove the Cover Plate

Use your Phillips-head screw driver to remove the cover plate. There will likely be two flathead screws that are simple to take off. At this point you can use a current detector to ensure no live power is running through the wires. From there, loosen the old light switch and pull it from the wall – do be aware that it will still be attached to the wires, so be careful when doing so.

Step 3: Detach the Wire

Now you can begin your light switch wiring. Take note of the wires and their layout before detaching them to make things a little simpler for you. The black and white wires are usually attached using brass screws, while the copper wire uses a green screw. Loosen all the screws to free the wires and remove the old switch from the wall entirely.

Step 4: Prep the Wires

Before you begin wiring up the switch, first examine all the wires. They should have at least a half-inch of exposed wire that is intact and bent into a U-shape. If there are any damaged or frayed portions, use your pliers to remove them and then leave that half-inch of exposed wire. If there is no wire exposed, you can strip away a small section of insulation using the pliers. Note that it is possible that your light switch might have slots to push the wires in instead of screws.

Step 5: Wire the New Switch

Using your new switch, wrap the black wire around one of the brass screws in a clockwise direction. This will ensure the connection tightens as you turn the screw. Do the same with the white wire – wrap it clockwise around the brass screw. Finally, wrap the copper wire clockwise around the green grounding screw and tighten.

Step 6: Replace the Cover

To complete the light switch wiring, use the provided screw to attach the new cover back to the electrical box, making sure it is level. Try not to over-tighten the screws. We suggest covering the switch in electrical tape to cover the connections and make it safer.

Step 7: Switch on the Power

You can finally switch the breaker back on and the light should come on when you flip the switch. If it doesn't, the problem is likely a loose connection. Switch off the power again and inspect the switch to check that all the wires are tightly connected.

With your new knowledge of how to wire a light switch, you can replace your own and update your home in no time.