How to Wire a Three-Way Light Switch

How to Wire a Three-Way Light Switch


Wiring a three-way light switch allows you to control a light fixture from two separate locations, like the top and bottom of a staircase. While it may seem daunting, installing a three-way switch is not much more difficult than wiring a standard single-pole switch. By following some basic wiring principles and safety precautions, you can successfully wire your three-way switch.

What You Will Need

Before beginning, make sure you have the following materials:

How a Three-Way Switch Works

Before wiring, it helps to understand how a three-way switch operates. A three-way switch has three terminals:

Power flows from the common terminal through one traveler terminal to the light fixture. The traveler terminals alternate which one receives power when you flip the switch. The common terminal remains constant.

One three-way switch will have the common terminal wired to the hot source. The other three-way will have the common terminal wired to the light fixture. The traveler wires connect between the pair of switches.

This allows flipping either switch to control the light fixture, because power can flow through two possible paths using one traveler or the other.

Step-by-Step Wiring

Follow these steps to wire a three-way light switch:

1. Turn Off Power

The first step is to turn off power to the circuit you are working on at the main breaker panel. Verify power is off using a voltage tester on the wires inside the electrical box before touching them.

2. Install First Three-Way Switch

3. Install Second Three-Way Switch

4. Connect Traveler Wires

5. Test Operation & Install Covers

Three-Way Switch Wiring Diagram

Use this diagram as a visual reference for wiring two three-way switches:

Three-way switch wiring diagram

The power source and light fixture are at opposite ends, with a three-wire NM cable running between the switches. The traveler wires allow the switches to communicate to control the light.


Installing three-way light switches is a great DIY home wiring project. Make sure to take proper safety precautions like turning off power at the breaker before beginning work. Following basic wiring principles allows you to wire three-way switches to control lights from multiple locations. Take it slow and double-check your switch wiring before restoring power.