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3 Way & 4 Way Switch Wiring Diagram

3 way switch

3-way switch diagram requires you to look for this all-important black screw. Copyright 2018 Tim Carter

"A 3-way switch has three screws plus the green grounding screw. The most important screw is the black one."

3 Way Switch Diagram TIPS

  • continuous hot and light feed wire goes on black screw
  • traveler wires go on the brass screws
  • 14/3 with ground or 12/3 with ground wire best to use between switches
  • WATCH all videos below for easy steps

Watch this very short 11-second video to see exactly WHAT a 3-Way switch is. Then watch the longer video below to see how to connect all the wires.

3 Way Switch Wiring Video

What is a 3 Way Switch Wiring Diagram?

A 3-way switch wiring diagram is a simple drawing showing how to connect the wires to each of the four screws on the 3-way switch.

The diagram below is based on the video you watched above.

What is the Black Screw For on a 3-Way Switch Diagram?

The black screw on a 3-way switch diagram is for the continuous hot wire that comes from the circuit panel or for the feed wire that runs up to the light fixture.

Electricians call the continuous hot wire the line wire. They often call the other black wire that goes from the other 3-way switch to the light fixture the load wire as the light bulb(s) are the actual load or thing that's using the electricity.

What Wires Go On the Brass Screws?

The traveler wires go on the brass screws. Watch the video above to see how easy it is to connect them. It makes no difference what wire goes on what screw at each switch. That's the best part.

Connecting the traveler wires is caveman simple and idiotproof.

It's important to realize you must put the line wire on the single black screw on the one 3-way switch.

The line wire is the one that is hot all the time. The black feed wire that goes to the light fixture is connected to the single black screw on the other 3-way switch.

I show all of this in the above video. WATCH IT.

3-Way Wiring Diagram

Here's a 3-way wiring diagram I made back in the 1990s on a very crude version of Microsoft Publishing software. It's much better to watch the video above to have a realistic 3-way wiring diagram.

3-Way Switch Wiring Diagram

3-Way Switch Wiring Diagram

A point often overlooked is the traveler wires. These wires connect to the brass screws on the switch. It doesn't make any difference how you connect them at each switch.

The white neutral wires are wire-nutted together and do not connect to the switch. The same is true for the bare or green grounding wires.

Related Links

3 Way Switch Quick Start Guide

3 Way Switch Troubleshooting Video - For Existing Switches

4 Way Switch Basics

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4-Way Switch Wring Diagram

A 4-way switch is always placed in between two 3-way switches. Watch the 4-Way Switch video below and pay attention.

If you understand how to wire a 3-way switch, you'll have no issues with a 4-way switch.

You can have an indefinite number of 4-way switches in a circuit. They all must be between the two 3-way switches.

The last house I built for my family in Amberley Village, Ohio had four switches in the kitchen controlling a few lights. You can see me operate all four switches in the video below.

4-Way Switch Wring Diagram

4-Way Switch Wring Diagram


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12 Responses to 3 Way & 4 Way Switch Wiring Diagram

  1. I have A single receptical with two switches one at the top and one at the bottom with a single wall plug in the middle the switches are cross way not up and down so is the wall plug the top switch is for the sealing fan the wall plug is for the TV and the bottom switch is for the doorbell how do you wire so they all work?

  2. Hi there.. I need to wire two double pole switches..The first two pole switch is located in the porch and turn on the porch light and the outside wall lights, separately. This switch has a tubbing connection with a second two pole switch inside the house. This inside switch turn on a light in the roof for this area and from this switch I want to turn on/off the porch light. The power entrance is from this switch . Please help me with the wiring schematic for this situation. thanks.

  3. I have a stairwell that isco controlled by 3 way occupancy sensor switch at the garage door entry and a 4 way switch at the front door and a 3 way switch at the top of the stairwell. I have to leave the 4 way switch to the down position so that the occupancy sensor and 3 way function correctly. Whenever I flip the 4 way, the light acts like a short, meaning it flicks on then off instantly & none of the switches function. I can't figure what wiring configuration is required for all switches to function correctly. Is there a 4 way occupancy sensor out there or a companion switch I need? I'm using a Maestro occupancy sensor switch. Thank you.

  4. I have 2 3-way switches. The power comes in at the 1st switch. At the 2nd switch there is a constant hot duplex. I am installing a 4-way switch so I rewired the switches to allow for the 4-way. Now I cannot get the duplex to work because it is connected from one of the travelers.
    How do I wire this to make the duplex constant hot and allow for the 4-way switch?

  5. Hi Tim ,
    I have 2 3way switches that control 3 fixtures .
    (outside my garage , and 2 by the front door ) .
    I put a dawn to dusk sensor on the garage fixture , but this leaves the 2 lights by the front door on continuously . So I was thinking of trying to change the 2 3way switches to 2 single pole switches . Any suggestions , or other choices ? Thank you - love your news letters

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