How to Wire a 3-Way Switch Yourself

When working with electrical, always start by disconnecting the electrical supply to the device you’re working on. Flip the breaker switch at your electrical panel that powers the light fixture and switch you will be wiring. Once off, test the light fixture and existing switch with a voltage tester to ensure there is no active current.

Using a screwdriver, unscrew and remove the old switch’s wall plate. Next, unscrew the mounting screws. Gently remove the entire switch receptacle from the wall, but be careful to leave the wiring attached for now.

Before disconnecting the wires from the back of the switch, it’s important to identify the electrical wires. Doing so makes wiring the new switch much easier. 

Label the wire connected to the black or dark-colored screw as the hot wire. Label the wire connected to the brass or light-colored screw as the traveler wire. Use tape to label each wire or take a picture with your phone.

Once labeled, you can disconnect the wires from the old switch. If the wires are attached to a screw on the back of the switch, loosen the terminal screw to disconnect the wires. If the wires connect to the back of the switch via stab-in connectors, insert a flathead screwdriver into the slot above the wires to disconnect them.

To prepare the existing wires for the new switch, ensure 3/4 inches of the copper conductor is exposed at the end of each wire. If needed, remove some of the insulation coating with a wire stripper to expose the copper.

Bend each wire into a hook with needle-nose pliers. The hook should fit snugly around the screw terminal on the back of the new switch. Skip this step if you will be using the stab-in connectors on the back of the new switch and keep the wires straight.

This process is similar to how you would connect wires to a standard light switch. Grab the new three-way switch and loosen the screw terminals on the back. Attach the hot wire to the black or dark-colored screw on the new switch. 

With needle-nose pliers, tighten the wire hook, so it fits snugly around the screw terminal. Tighten the terminal screw until it’s difficult to turn and firmly holds the wire in place.

Repeat this connection process by attaching the two traveler wires to the brass or light-colored screws and the bare copper wire to the green screw at the bottom of the switch.

If you’re using the stab-in connectors on the back of the new switch, make the wire connections at the same locations, but insert the wires straight into the stab-in slots without bending them.

This step is optional. For added protection and to ensure none of the wires come loose, you can wrap the body of the switch with electrical tape. Be sure to cover the screw terminals and any bare wires.

Insert the switch into the electrical wall box and install the mounting screws. Place the wall plate up against the switch and install the wall plate screws.

With the switch fully installed, turn the circuit breaker back on and test the switch. If the three-way switch is not working as intended, reach out to a professional electrician to finish the job.