How to Wire a 3-Way Switch
Time Required: Under 2 hours
Before replacing any 3-way switches that are broken, turn off the power at the breaker box. A 3-way wall switch controls a common light or set of lights from two separate switch locations. Two, 3-way switches are required in any 3-way application.
This guide highlights the procedures for replacing a broken 3-way electrical switch. Before proceeding, make sure you are comfortable working with electrical wires and switches. If you are not, consider hiring an electrician and check local building codes to ensure it is safe to complete this project yourself.
Safety: Before doing any electrical work, turn off the power at the breaker box.
- Turn off the power for the circuit at the breaker box. Test with a voltage tester to confirm. If the tester shows current, check the service panel and turn off another circuit that powers the switch. Test again and proceed only if the tester shows no current.
- Remove the wall plate.
- Remove mounting screws and gently pull the switch out of the wall box.
- Inspect the wiring. A loose or broken wire could explain why the switch doesn’t work.
- Disconnect the wires. If the wires are stabbed into the back of the switch, insert a small flat head into the slot above the wire to release. If you are having problems, simply cut the wire.
- When disconnecting the wires, mark the wire on the black or dark colored screw as common. Mark the wires on the brass or light colored screws as travelers. Make notes or take a picture to verify connections before removing the old switch.
- Remove insulation so ¾-inch of copper conductor is showing.
- Use long nose pliers to bend the end of each wire into a hook. Make sure the hook is tight enough to fit around the terminal screw.
- When wiring a 3-way switch, first screw the terminal screws of the new switch until they are difficult to turn.
- Connect the ground wire to the green screw.
- Connect the wire marked common to the black or dark colored screw.
- Connect the two remaining traveler wires to the two brass or light colored screws.
- Connect the wires to screw terminals by slipping the looped wire under the head of the screw. The end of the loop should point clockwise.
- Use long nose pliers to squeeze the wire end tight around the screw.
- Tighten the terminal screws.