3-Way Switch Installation – Power Source Through a Switch Box, Fixture Between Switches

 by Dave Donovan

Wiring a three-way switch circuit is one of the most daunting tasks for the do-it-yourself home electrician. With so many wires going this way and that, it can be very easy to become confused. And confused is the last thing you want to be when working on electricity.

In this scenario, we take a look at how to wire a three-way lighting circuit when the power source enters one of the switch boxes first and the light fixture is located between the two switches. For these instructions, the switch box that has the feed from the panel will be called Switch #1 and the other one, Switch #2.

Wiring Switch #1

This is the box that has the feed from the panel, so the first thing you’ll want to do is turn off the power to the circuit. In this box, you have a black, white and ground coming in from the electrical panel and a black, white, red and ground leaving the box. Let’s start with the wires coming from the panel.

• Take the BLACK wire coming from the panel and connect it to the DARK colored screw on the side of the switch that has two terminals.
• Connect the WHITE wire coming from the panel with the WHITE wire leaving the box.
• Connect one end of a length of ground wire to the switch’s ground screw and the other end with the other ground wires in the box.

Now, for the remaining wires which are leaving the box.

• Connect the BLACK wire that leaves the box to the screw directly underneath the other black wire.
• Connect the RED wire to the remaining screw (the one by itself on the other side of the switch).

Now, let’s move on to the light fixture.

Wiring the Light Fixture

Inside the light fixture box, you should see two sets of black, white, red and ground wires (one set coming from Switch #1 and the other set going to Switch #2).

• Connect all of the ground wires together, including the ground wire from the fixture.
• Connect the two RED wires together.
• Connect the WHITE wire from Switch #1 to the WHITE wire on the FIXTURE.
• Wrap electrical tape around the WHITE wire going to Switch #2 and connect it to the BLACK wire coming from Switch #1. (The tape on the white wire identifies it as a current-carrying line)
• Take the BLACK wire from Switch #2 and connect it to the BLACK wire on the FIXTURE.

You’re almost finished!

Inside the box for Switch #2, you should have a black, white, red and ground wire. You will wrap electrical tape around the white wire in this box as well.

• Connect the ground wire to the ground screw on the switch.
• Connect the RED wire to the single screw on the side of the switch.
• Connect the BLACK wire to the DARK colored screw on the side of the switch with two screws.
• Connect the WHITE wire (with electrical tape wrapped around it) to the screw directly under the BLACK wire.

Close up all the boxes, secure the light fixture to the ceiling and turn the circuit back on. Your three-way circuit should now work perfectly!

Dave Donovan is a freelance copywriter living in Atco, N.J. An electrician for 15 years, an injury forced him to pursue his true passion - writing.