How to replace a light switch
Swapping a basic wall switch is one of the more doable electrical jobs, as long as you shut off the power, confirm it's off and know the signs that mean stop.
- DifficultyModerate
- Time30–60 minutes
- If you need helpElectrician
Light switches wear out. The toggle gets loose, it crackles, it only works if you press it just right, or it stops working at all. Replacing a standard switch is a common homeowner job, and a new switch is inexpensive.
This is still electrical work, so it's rated Moderate. The steps aren't hard, but the safety steps are not optional. You'll shut off the breaker, prove the power is off with a tester, and stop if you find anything on the list below. Give yourself 30 to 60 minutes the first time.
What you'll need
- Non-contact voltage tester Shop for Non-contact voltage tester (opens in a new tab)
- Replacement switch, same type as the old one (single-pole or 3-way) Shop for Replacement switch, same type as the old one (single-pole or 3-way) (opens in a new tab)
- Insulated screwdrivers, flat and Phillips Shop for Insulated screwdrivers, flat and Phillips (opens in a new tab)
- Wire stripper Shop for Wire stripper (opens in a new tab)
- Needle-nose pliers Shop for Needle-nose pliers (opens in a new tab)
- Masking or painter's tape, to label wires Shop for Masking or painter's tape, to label wires (opens in a new tab)
- A flashlight and your phone for photos
Shopping links may earn us a small commission at no cost to you. Disclosure.
Know which switch you have
| Type | What it does | How to spot it |
|---|---|---|
| Single-pole | Controls a light from one spot | On and off printed on the toggle. Two brass screws plus a green ground screw. |
| 3-way | Works with a second switch, like at the top and bottom of stairs | No on or off markings. Three screws plus ground. Leviton marks the common screw in black and the two traveler screws in brass. |
| 4-way | The middle switch when three or more switches control one light | Four screws plus ground. Call an electrician for these. |
Buy the same type you're replacing. A dimmer or smart switch has its own wiring needs, so follow that product's instructions or have an electrician install it.
Shut off and confirm the power
- Turn the light on. That way you'll see it go out when you hit the right breaker.
- Turn off the breaker. Find the circuit in your panel and switch it off. See how to read your breaker panel. Put tape over it and tell everyone at home not to touch it.
- Test your tester. Hold the voltage tester near an outlet you know is live. It should beep or light up.
- Test the switch. Remove the cover plate. Hold the tester tip near each screw and wire on the switch. It should stay silent.
- Test again after pulling it out. Once the switch is out of the box, test every wire in the box. Some boxes carry more than one circuit.
Check for stop signs
Before you disconnect anything, look closely at the wires. Stop and call an electrician if you see any of these:
- Silver-colored wire, or a jacket marked "Al" or "Aluminum." The CPSC warns that aluminum branch wiring connections can loosen and overheat, which can lead to fires, and says repairs should be done by a qualified electrician. Leviton's standard switch instructions say to use copper or copper-clad wire only.
- No ground wire, meaning no bare copper or green wire in the box and no ground screw connection.
- Scorched, melted, brittle or cracked insulation.
- More wires than you expected, or wires bundled together in ways you don't understand.
- The tester still beeps with the breaker off.
Replace a single-pole switch
- Remove the switch. Take out the two mounting screws and gently pull the switch out of the box.
- Take a photo. Snap a clear picture of where each wire connects.
- Disconnect one wire at a time. Loosen a screw, move that wire to the same spot on the new switch, then do the next one. This keeps you from mixing them up.
- Use the screws, not the push-in holes. Bend each wire into a hook and wrap it clockwise around the screw, about three quarters of the way around, as Leviton describes. Tighten firmly. If the wire end is nicked or blackened, trim it and strip a fresh end using the strip gauge on the switch.
- Connect the ground. Attach the bare copper or green wire to the green screw on the switch.
- Tuck and mount. Fold the wires neatly into the box, screw the switch in place with on at the top, and attach the cover plate.
- Restore power and test. Turn the breaker on and try the switch.
Replace a 3-way switch
- Find the common wire. On the old switch, find the darker screw. Wrap a piece of tape around the wire attached to it.
- Move the common wire. Connect the taped wire to the black or darker common screw on the new switch.
- Move the travelers. Connect the other two wires to the two brass screws. On most 3-way switches, these two can go on either brass screw.
- Connect the ground, mount and test. Attach the ground to the green screw, mount the switch and test it from both switch locations.
If the light only works from one spot or acts strangely, turn the breaker back off and check that the common wire is on the common screw. If it still doesn't work, call an electrician.
When to call a pro
Call a licensed electrician if:
- You find aluminum wiring, no ground, or damaged insulation.
- You're replacing a 4-way switch, or the box has wires from more than one circuit.
- The new switch doesn't work or the breaker trips when you turn it on.
- A switch or cover plate gets hot, smells like burning plastic or the lights flicker. The CPSC lists these as warning signs.
- Your city or county requires a permit or a licensed electrician for this work.
Renters: don't replace switches without the landlord's okay. Not sure? Try our fix it or call a pro quiz.
Keep it from happening again
- Flip switches with normal pressure. Slamming them wears out the mechanism faster.
- Pay attention to switches that crackle, buzz or feel warm, and get them checked early.
- Label the breakers in your panel so the next repair starts faster.
- If your home was built from 1965 to the mid-1970s, the CPSC says it may have aluminum branch wiring. Have an electrician check if you're not sure.
Common questions
How do I know if I have a single-pole or 3-way switch?
A single-pole switch controls a light from one place and has on and off printed on the toggle. A 3-way switch works with a second switch elsewhere, has no on or off markings, and has three wire screws plus a ground. Leviton marks the common screw on its 3-way switches in black.
Do I need a permit to replace a light switch?
It depends on where you live. Some cities and counties allow homeowners to replace a switch like for like without a permit, and others require one or require a licensed electrician. Check with your local building department first.
What if there's no ground wire in the box?
Older homes sometimes have no ground wire. Don't guess at a workaround. Have a licensed electrician look at it, since the right fix depends on your wiring and local code.
Why is my light switch warm?
A dimmer can feel slightly warm in normal use. A regular switch or faceplate that's hot to the touch is a warning sign, which the CPSC lists among the signs of a failing aluminum wiring connection. Turn off that circuit and call an electrician.