I always took light switches for granted: flip the switch, and the lights go on or off – until the day one didn’t.
Fortunately, I learned how to replace a light switch, which is a straightforward DIY job: Turn off the power, remove the old switch, and install the new one by connecting wires in the proper spots.
In this article, I’ll talk about my experiences replacing a light switch, and we’ll go through the steps so you can do it, too.
| Project difficulty: Intermediate Estimated time to complete: 30 minutes Project cost: Less than $1 to $20; tools not included in cost. |
Types of Light Switches
Your malfunctioning light switch may be any of the following types, which all serve different purposes in your home’s electrical system:.
Single pole switch: This common type of switch manages one electrical circuit (pole). It can be the on/off switch for, say, a bedroom light (which is what I replaced).
Single pole switches aren’t always a single switch and switch plate. For example, the two-switch setup for the bathroom lights and fan in my house consists of two single pole switches.
Double light switch: This switch controls two separate fixtures — either on one circuit or two. You’ll find it in a bathroom, living room, or controlling your outdoor lights.
Double pole switch: This switch controls two separate circuits simultaneously, and offers safeguards against excess power loads. In the home, it may control a light switch/fan combination or outdoor lighting.
Double-pole switches also are used to control appliances (dryer, water heater) that use a 240-volt circuit. If you’re going that route, be sure to check the replacement’s amperage rating, make sure it’s the correct voltage and is compatible with the appliance
Three-way switches: You’ll find these at both ends of a staircase or hallway, or any place where two switches control one light fixture.
Four-way switches: These aren’t commonly used, but they can control a light fixture from three or more locations. You may find them in long hallways or rooms with several entrances.
Dimmer switch: These switches may have a rotary knob or a slider that allows you to lower or increase the brightness of a room.
What You Need
- Screwdrivers (standard and Phillips)
- Voltage tester
- Wire cutter and stripper
- Needlenose pliers
- Flashlight
- Electrical tape
Steps to Replace a Light Switch
Switch replacements tend to follow the same process, though there are some differences depending on the switch:
Turn Off the Power
Stay safe: Don’t touch the switch until the power is off: Cut the power to the circuit (or room) by pulling the corresponding circuit breaker, unscrewing the fuse, or if necessary, cutting power to the house.
You may discover at this point that your breaker or fuse box isn’t well labeled. (Something I’ve learned the hard way.) If you need to use the trial-and-error method to find the correct circuit, here’s how:
Get a helper to plug in and manually turn on a lamp in the room you’ll be working in. From there, your helper babysits the lamp while you pull breaker switches or unscrew fuses. Your helper will let you know (by phone, or a good yell) when the light goes out.
Give the switch a final check with a voltage tester. And be sure to label the circuit.
Pull Out the Switch
Start by removing the switch plate. I suggest putting the plate and screws in a container or a pocket. It will save you a game of “find the screws” later. (Ask me how I know). Then, use a voltage tester to determine that the circuit doesn’t have power.
When the power is off, remove the switch. Unscrew it from the electrical box and gently pull it out with the wires attached. (BTW: Keep those screws: the new switch may not have them.)
Wire the New Switch
When you look at the old switch, your first thoughts may be — Which wire is which? And where do they go? Generally:
Black or red wire: This is the hot wire that carries electrical current. It attaches to the brass-colored screw.
White wire: This is the neutral wire, which completes the electrical circuit. It attaches to the silver screws.
Green or copper wires: These are ground wires, and attach to the green screw at the bottom of the outlet. Depending on building codes, the wiring for your switch may not include a ground wire.
In case you’re wondering: Many switches have “Top” marked on the mounting bracket. And switches are marked, too. If the toggle is up, you should see the “on” mark, and vice versa.
Once you’re comfortable with the setup, it’s time to remove the wires from the old switch and attach them to the new one. Here are a couple of ways to do it:
- Remove all the wires from the old switch first. Be sure to label the wires or take pictures of the setup before you attach them to the new switch.
- Take it one wire at a time: Remove a wire from the old switch and hook it to the corresponding spot on the new switch. Repeat with the other wires.
Exceptions
Some switches deviate a bit from the usual process:
Dimmer switches: While some of these have screw terminals, others just have wiring. You’ll need a connector to join the new and old wires. Generally, these come with the switch, or perhaps you can reuse the old ones.
Connectors come in different sizes, so if you have to buy them, check the directions for the new switch to get the proper size. To connect, match the wire by colors: black to black, white to white, and so on.
Double switches: You’ll notice a brass tab ( jumper) on one side between two black screws. If you want both fixtures to run off the same circuit, don’t remove the tab — a common setup, but check the old switch. Only break it off if you want (and the wiring allows) each fixture to run off a different circuit.
The line attached to that side is the hot wire. For a single circuit, it doesn’t matter which terminal you attach it to. The other side has the ground terminal, plus two others — these connect the wires from the fixtures to the switches.
Your last step will be to wrap electrical tape around the switch, covering the terminals. This prevents the ground wire from coming in contact with the hot wire.
How to Connect a Wire to a Terminal
If needed, use a wire stripper to take off about 1/2 inch of insulation. Using pliers, twist the bare wire into a clockwise loop. Hook the wire clockwise and wrap the loop about two-thirds around the terminal screw. Tighten with a screwdriver.
Some switches will have plug-in connectors (or both screws and plug-ins). There is a difference of opinion on which to use. Some DIY sites are fine with plug-ins, while others say that screw terminals provide a better connection.
If your old switch has plug-ins, and you can’t pull the wires out, just cut them close to the switch and strip a little insulation for a new connection.
Finish the Job
When you’re done, gently push the newly wired switch into the electrical box, screw it back into place, and replace the switch plate. (Be careful with the switch plate; it can crack if you screw it in too tightly.) Then turn on the power and flip the switch.
If the light comes on, pat yourself on the back — the job’s done.
For all you visual learners, here’s a video tutorial that explains the process we just covered:
A Few Safety Tips
Let’s put it this way: electricity demands our respect. A misstep can damage the electrical system, your home, or you. So, to stay safe, make sure to do these things:
Turn off the power: Flip the breaker switch (or unscrew the fuse) to the circuit. (Breakers can be labeled by device, or by room.) Can’t figure it out? Your best option is to cut power to the entire house.
Check the wiring: Once the switch plate is off, take a look at the wiring around the switch. Make sure everything is intact: Frayed or damaged insulation can expose bare wiring, which can cause an electrical shock or a fire.
Be careful when wiring the switch: If you miswire a switch, it may not work properly. Worse, it could shock you, or cause a short-circuit or a fire.
When to Call an Electrician
Sometimes, a balky light switch can signal more serious problems with your home’s electrical wiring. In these cases, turn off the power and call an electrician:
- Warm switch plate
- Burning smell
- Problems with multiple switches
- Sparking, popping, or buzzing
- Frayed or exposed wiring
Should your situation call for an electrician, Home Gnome can match you with a local service that can perform any needed repairs.
FAQ About Replacing a Light Switch
There are a few signs that point to a bad switch. The obvious one is that it doesn’t work. Nothing happens when you flip the switch (which is what happened at my house), or it takes several tries to turn the light on.
There could also be a delay.The lights should go on and off consistently. If they don’t, it could be a worn switch. Or, the switchmay be wobbly, or it sticks. These also may be signs of a worn mechanism.
Yes, you can. First, make sure the light bulbs you’ll use can be dimmed. The dimmer switch should match the type of switch you’re replacing ( single pole or 3-way). The wiring of most dimmer switches is designed to replace a standard switch with the same configuration.
However, there are dimmer switches on the market that can replace either a single pole or a 3-way switch. Follow manufacturer’s instructions on installing them.
Light switches are fairly inexpensive. Prices depend on where you live, brands, and retailers, but the more complicated the switch or the higher the amp, the more it will cost. A single pole 15 amp switch costs less than $1; a single pole 20 amp switch costs less than $10. A single pole dimmer switch can cost $10, but one that can be used as a single pole or 3-way switch can be found in the $20 range.
If You Need Help to Replace That Light Switch
I hope this tutorial will help guide you when you’re ready to tackle that light switch replacement. However, if you’d prefer to have an electrician handle the job, Home Gnome delivers the best home service experience at the click of a button. Book reliable, skilled electricians in seconds and leave the rest to us.
Main Photo Credit: Daniel M. Hendricks / Flickr / CC BY-ND 2.0
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