3 Way Switch Wiring Diagram

Make Your Own Three-Way Switch Wiring Diagram

There are several kinds of switches used to control light and other fixtures in your house. One of the most common switches is the single pole switch that allows you to control a light from one location in the house. Another very common type of switch is the three-way switch.

A three-way switch is quite helpful if you want to control a light from multiple locations around your house. It can also be used in combination with four-way switches to multiply the locations from where you can control the lights or appliances. Before diving in too deep, let’s see what three-way switches are.

What is a 3-Way Switch?

A three-way switch allows you to turn lights or appliances on or off from two different locations. Three-way switches are essential, especially for stairs or long hallways, so you can turn the lights on when you approach from one side. You can then turn off the lights when leaving from the other side of the hallway.

basic 3-way switch

A three-way switch is constructed differently than a normal switch. For starters, there is no particular on or off toggle. If both the switches are up or both are down, the circuit is complete, and the light turns on. But, when both switches are in opposite directions, the circuit is open, and the light is off.

The 3-way switch has four screws. One is the grounding screw that is green, and the other three are part of the circuit. Two of them are traveler terminals, and one of them, which is a bit darker, is called common. To learn more about a three-way switch, let's look at how a three-way switch works.

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How does a 3-Way Switch Work?

To understand how a three-way switch works, you need to pay attention to which wire goes to which screw. The green or grounding screw is attached to the bare copper or green wires. They are the grounding wires. The grounding screws are a new addition to the three-way switches. That is why you may not find them on older 3-way switches.

How does a 3-Way Switch Work?

Then there are the traveler screws that are connected to the hot or charged wire. These screws will provide two different paths for the electricity to travel to the fixture.

Lastly, there is a common terminal that is darker in color than the traveler terminals. It either connects to the hot wire that leads to the fixture or accepts the hot wire coming from the power source.

If the circuit’s power is on, any of these may be hot depending on how the switches are toggled. The 3-way switch is designed to interrupt the hot wire when it's turned off. The white wire coming straight from the power source goes uninterrupted into the light fixture while the hot wires are routed through the switches.

How to Wire 3-Way Switches

There are three significant ways in which 3-way switches can be set up depending on the position of the switches and lights and where the power enters the circuit.

Case 1

In the first case, we see if the wires from the power source enter one switch box at first, then go towards the light fixture and then to the other switch box. The white wire from the power source goes into the switch box first and then the light fixture. It terminates there without going to the second switch box. The diagram below shows how we can wire the switch in a case like this.

How to Wire 3-Way Switches

Case 2

In another case, the wires from the power source may enter the light fixture box first, then it goes into one switch box and then the other. In this type of wiring, the inbound white wire connects to the light fixture without any interruption. The black wire then connects to the taped white wire that goes from switch one and then connects to the common terminal in switch two. Red and black travelers then connect paired traveler terminals on both switches.

How to Wire 3-Way Switches

Case 3

In the third case, the wires from the power source go from one switch to another, then the fixture. The white wire connected through the wire nuts moves uninterrupted from the source to the light fixture. The hot black wire is connected to the common terminal of the first switch, and then it is carried by paired travelers to traveler terminals in the second switch. Lastly, the common terminal of the second switch sends the black wire into the light fixture.

How to Wire 3-Way Switches

3 Way Switch Wiring Diagrams

If you are an electrical expert and want to create a three-way switch wiring diagram for a place, you may want to look through the multiple types of diagrams you can make. There are many wiring diagram templates available online or in EdrawMax that can be modified a bit to suit your needs.

3-Way Switch Wiring Diagram, NM Cable

A very common type of 3-way electrical diagram is when the power supply wire moves from one switch to the second switch and finally terminates at the fixture. This wiring diagram shows both switches aligned together with the fixture at the end. You can use tools or colors to label the different types of wires used and used different line styles to show charged or uncharged wires.

3-Way Switch Wiring Diagram, NM Cable

3-Way Switch Wiring Diagram Light Fixture Between Switches

Another way to wire a three-way switch is when supply comes at the switch, goes to the fixture, and terminates at the other switch. In this wiring diagram, the fixture is connected to the switches with three-wire cables. You can create a detailed diagram like this one or create a simple outline of the layout.

3-Way Switch Wiring Diagram Light Fixture Between Switches

3-Way Switch Wiring Diagram Line to Light Fixture

In another configuration, the power supply enters the fixture first, goes into one switch, and finally terminates at the other switch closing the circuit. This wiring diagram helps you understand the type of cables you will require for this configuration.

3-Way Switch Wiring Diagram Line to Light Fixture

Use EdrawMax for Wiring Diagram Creation

Three-way switches are extremely helpful around the house. You can install the switches at both ends of a long hallway or a flight of stairs so you can turn off the lights when you are at the other end. This will prevent you from coming back to turn off the light and reduce your electricity bills. It is a very efficient way of monitoring lights and other fixtures from anywhere around the house. You can also combine multiple three-way switches to control a single fixture through 2 or more places.

If you are planning to wire a three-way switch in your house or are designing an electrical plan for your house, EdrawMax is an excellent tool to help you design it. With an array of tools and symbols to create the diagram, beginners and experts can easily use it. If you do not have time to create a wiring diagram from scratch, you can choose from the thousands of professional templates available in the software. Create your own wiring configuration and experiment with ideas using EdrawMax.


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