Use these light switch wiring diagrams to wire or fix standard, 3-way, 4-way, and dimmer switches safely and correctly.
Light switch wiring diagrams help you understand how electrical circuits connect switches and lights. Whether you’re installing a new switch, troubleshooting a problem, or trying to identify wires, these diagrams show how power flows through different setups.
This guide includes diagrams for standard (single-pole), 3-way, 4-way, and dimmer switches, along with links to step-by-step instructions for each type.
Quick Answer
Light switch wiring diagrams illustrate how hot, neutral, and ground wires connect to switches and fixtures. A standard single-pole” switch controls one location, a 3-way switch lets you control one or more lights from two locations, and a 4-way switch controls lights from three or more locations. Dimmers, sold as both single-pole and 3-way switches, allow you to set light levels with ease.
Bottom line: The correct wiring diagram depends on how many switches control the light—identify that first before making any connections.
Which Light Switch Wiring Diagram Do You Need?
- One switch controls one light: Use a standard (single-pole) diagram
- Two switches control one light: Use a 3-way switch diagram
- Three or more switches control one light: Use a 4-way switch setup
- You want adjustable lighting: Use a dimmer switch
Tip: Always confirm how many switches control the light before choosing a wiring diagram.
Types of Light Switch Wiring
Light switches are wired differently depending on how many locations control the light. The diagrams below show the most common configurations used in homes.
How to Read a Light Switch Wiring Diagram
- Black wires: Hot (carry power)
- White wires: Neutral (return path)
- Red wires: Secondary hot or traveler wires
- Green or bare: Ground (safety)
Follow the path of the hot wire to see how power flows through the switch to the light.
👉 See What the Red Wire Means
Standard Light Switch Wiring Diagram
A standard (single-pole) switch controls a light from one location by interrupting the hot wire.
This is the most common type of switch used in homes for controlling a light from one location.
See full guide: Standard Light Switch Wiring
👉 Troubleshooting this setup? See Light Switch Not Working
3-Way Switch Wiring Diagram
A 3-way switch setup uses two switches and “traveler” wires to control one or more lights from two locations. There are actually several different setups, depending on where the switches are located in relation to the lights. All of these are shown in the guide linked to:
See full guide: 3-Way Switch Wiring
4-Way Switch Wiring Diagram
A 4-way switch works with two 3-way switches to control a light from three or more locations.
See full guide: 4-Way Switch Wiring
👉 Troubleshooting this setup? See Light Switch Not Working
Dimmer Switch Wiring Diagram
A dimmer switch replaces a standard switch and allows you to adjust light levels. Most dimmers are wired the same way as a single-pole switch, though some also support 3-way configurations using a traveler wire.
A dimmer switch allows you to adjust light levels for both comfort and energy savings.
Three-way dimmer switches have an extra red wire that serves as a “traveller.” Wire them the same way you wire a standard 3-way switch, as shown in the 3-way Switch Wiring Diagram toward the top of this page.
👉 Troubleshooting this setup? See Light Switch Not Working
See full guide: Install a Dimmer Switch
Common Light Switch Wiring Mistakes
- Connecting wires to the wrong terminals
- Confusing neutral and hot wires
- Using backstab connections instead of screw terminals
- Not turning off power before working
👉 See Light Switch Not Working for troubleshooting.
For more, see Complete Light Switch Wiring and Repair Guide.
Important Safety Note: Always turn off power at the circuit breaker before working with electrical wiring.
