How to Wire Four-Way Switches for a House

A light fixture operated by switches at three or more locations requires four-way switches. The installer will need two three-way switches for either end of the switch series with as many intermediate four-way switches as desired.

Difficulty: Moderate

Instructions

Things You'll Need:

• 2-wire cable
• 3-wire cable
• Two 3-way light switches
• One or more 4-way light switches
• Philips head screwdriver
• Light fixture
• Insulated twist-on wire nut connectors
• Electrical tape

Wire Four-Way Switches for a House

1. 
    
   Four-Way Switch Wiring Diagram

   Diagram the installation pattern for light fixtures, three-way switches and four-way switches.

2. 
    
   Determine How Many 3-Way and 4-Way Switches Are Required

   Count how many switches will be required. Two three-way switches start and finish the wiring series. All switches wired in between should be four-way switches.

3. Measure the lengths of two and three-wire electrical cable required. Two-wire cable runs between the power source and three-way switches, the power source and light fixture, and the light fixture and three-way switches. Three-wire electrical cable runs between three-way switches and four-way switches. Two four-way switches in a row also require three-wire electrical cable connections.

4. Purchase all necessary supplies for four-way switch installation including electrical cable, switches, and fixtures.

Wiring a Four Switch with the Light Fixture Wired to the Power Source

5. 
    
   Connect Fixture to Power Source and Wires from 3-Way Switch

   Using wire nuts, connect the black wire from the power source to the white wire in the two-wire electrical cable going to the first three-way switch using. Connect the white wire from the power source to the white wire from the light fixture. Connect the black wire from the fixture to the black wire in the 2-wire electrical cable to the first three-way switch.

6. 
    
   Connect 3-Way Switch to Wires from Fixture and 4-Way Switch

   Connect the white wire from the two-wire electrical cable coming from the light fixture to the dark colored screw on the three-way switch. Connect the white wire from a three-wire cable to a light colored screw on the three-way switch. Connect the red wire from the three-wire electrical cable to the other light colored screw on the switch. Connect the black wire from the two-wire cable to the black wire on the three-wire electrical cable using a wire nut.

7. 
    
   Connect 4-Way Switch Wires to Additional Light Switches

   Connect the white wire from the three-wire cable coming from a three-way switch (or additional four-way) to the top right dark colored screw on the four-way switch. Connect the red wire from the three-wire cable coming from the previous switch to the top left dark screw on the 4-way switch. Connect the white wire from the three-wire cable going to the final three-way switch (or additional 4 way switch) to the bottom right light colored screw on the four-way switch. Connect the red wire from the three-way cable going to the final three-way switch (or additional four-way switch) to the bottom left light colored screw. Connect the black wire from each of the two three-wire cables directly to each other using a wire nut.

8. Repeat step three if using more than one four-way switch.

9. 
    
   Wiring to a Final 3-Way Switch Completes 4-Way Switch Installation

   Finish the switch series with a three-way switch. Connect the red wire from the three-wire cable coming from the four-way switch to the bottom left light colored screw on the final three-way switch. Connect the white wire from the electrical cable to the bottom right light colored screw. Attach the black wire to the dark screw.

Tips & Warnings

• Purchase properly rated wire nuts. Yellow wire nuts with a 600 V rating work well for light fixture and switch installation. Use electrical tape as necessary to properly secure wire nuts. Ensure wiring complies with local codes. Obtain all necessary permits and inspections.
• Turn off power source at the breaker box before attempting any electrical work. Double check all wiring connections before turning power back on again. Wear proper safety gear.