Changing a Light Switch: Step-By-Step Instructions

But can you change a light switch yourself? Or do you need an electrician? The answer depends on your skills or willingness to do the work. You don’t legally need to call an electrician to change or replace light switches unless it’s a new home build, so if you’re motivated to DIY replace the light switch, it’s simple enough for most people to learn.

Light switch replacement is generally pretty straightforward. You'll connect two hot wires in the switch box from the old switch and reconnect them to the new one. It can get a bit more complicated if you're switching out a dimmer switch. If you're replacing a regular switch with a dimmer switch, most dimmer switches already have the wires attached, making it fairly simple. However, we won't discuss this type of replacement in this article.

First, let’s gather the tools you’ll need. Then, we’ll go over the replacement process step by step and discuss everything you’ll need to know to make the job successful.

Step-by-Step Instructions to Prepare for a New Light Switch

For the purposes of this article, we’re going to discuss how to replace a single-pole light switch, but that’s not the only light switch type you might encounter.

• A single-pole light switch is a simple on-off switch that takes power from the electrical panel and routes it to a light fixture, appliance, or wall outlet. Most switches in your home are likely this type. A single-pole switch has two brass screw terminals on the switch body plus a single green screw on the strap. This type of switch has three wires: a hot wire, a neutral wire, and a ground wire. Usually, the hot wire is black, the neutral wire is white, and the ground wire is green.
• A three-way light switch controls light fixtures from multiple locations, such as a stairway light with switches at the bottom and top of the stairs. They have three terminal screws, one of which will attach to the panel, while one goes to the other three-way switch, and the third to the light. It will also have a green grounding screw to attach the copper ground wire.
• A four-way switch is sometimes used in long hallways or large rooms that require several switches to control a single light. If you are installing a four-way switch, read the manufacturer’s instructions, as some have the in wire on the top and out on the bottom, and others are in on the left and out on the right.
• A dimmer switch is available in any of the above wiring configurations. Remember that standard dimmer switches don’t work with most fluorescent fixtures. Low-voltage lighting requires low-voltage dimmers to work.

Removing the Old Light Switch

Once you’ve determined the switch is off, you’re ready to remove the old switch.

• Remove the mounting screws that hold the original switch in the box.
• Pull the switch and attached wires out from the electrical box slightly by the straps (the tabs that you just removed the screws from), taking care not to damage any wiring.
• Document how the wires are attached to the switch. Take a photo on your phone if needed.
• You are only concerned with the wires directly connected to the switch.
• Depending on how old the existing switch is, you might see:
• Two wires: They will be different colors to indicate the function of each wire. The black wire is the incoming “hot” wire, while the outgoing wire is usually white but could be any color.
• If there are two same-colored wires, the hot wire will be marked with electrical tape.
• Three Wires: One wire will be the grounding wire. Grounding wires are either green or bare copper.
• Older switches might be covered with cloth or rubber insulation and not color-coded.
• Black wires go to brass screws (sometimes black screws), green/copper ground wires to green/copper screws, and white wires (usually neutral) go to a silver screw.
• If a wire is marked with electrical tape, it is not neutral, regardless of the color.
• Document (first) and unscrew every wire nut and all switch wiring, keeping track of which wire goes where.

After you've wired the new switch, before replacing the switch plate, switch your breaker on and test the light to ensure it works. If it's working, screw on the switch plate, and you're good to go.

Final Thoughts on Replacing Light Switches

Hopefully, your light switch replacement project went well. If your wiring looks dodgy, you may need to call an electrician to rewire the switch to ensure it’s safe. Some switches might be more complicated, so consult a professional if necessary.

Most household light switches are not hard to replace, but safety always comes first.