3-Way Switch Wiring

3-Way Switch Wire Colors

There is no standard for wire colors on 3-way switch travelers. The colors will vary depending on whether NM cable or conduit was used.

With NM cable, the wire colors for travelers will be black and red using 3-wire cable.

With conduit, the wire colors for travelers could be any color.

3-Way Switch Wiring, NM Cable

In the 1st diagram below, a 2-wire NM cable supplies power from the panel to the first switch box. The black (line) wire connects to the common terminal of the first 3-way switch. A 3-wire NM connects the traveler terminals of the first and second 3-way switch together. Traveler wires are interchangeable on each switch.

The common terminal of the second 3-way switch connects to the light fixture(s).

The white neutral wires are connected together in each switch box.

Diagrams shown on this page are simplified for clarity. Electrical outlet boxes can have numerous NM cables going in and out. See Actual Switch Box Wiring Diagram.

Ground connection diagram is shown separately.

Placing Black Tape on the White Wire of NM Cable

In a lighting circuit a 2-wire NM cable may carry line voltage on one wire and switched hot on the other.

Line is usually connected to the white wire, and black electrical tape is wrapped around it. Black tape is also wrapped around the white wires of other NM cables that connect to it.

The black wire on this cable is usually used as a switched hot for the lights.

3-Way Decora Switch Wiring Diagram

3-Way Toggle Switch Wiring Diagram

With conventional wiring, line voltage enters the first 3-way switch box.

Black common wire is usually wrapped around the two traveler wires on a 3-way switch.

Common wire wrapped around traveler wires

3-Way Switch Wiring Page 2

3-Way Toggle Switches

3-Way Decora Switches

3-Way Switch Wiring

Troubleshoot 3-Way Switches