Run your wires
- PANEL to switch 1 (14/2)
- LIGHT to switch 2 (14/2)
- Switch 1 to switch 2 (TRAVELER) (14/3)
Make your connections
- Connect all the grounds, including to each switch.
- Connect all the neutrals. If any of your switches are “smart” devices, they may also need a neutral connection.
- Connect the PANEL hot wire to the common terminal on switch 1.
- Connect the LIGHT hot wire to the common terminal of switch 2.
- Connect the switches using the TRAVELER (14/3) black and red wires (in any order).
That’s it, you’re done. The black/red wires in the TRAVELER ensure that no matter which orientation switch 1 is in, power is able to reach switch 2 (for it to also have a say in the matter). The neutral provides the normal return path to the panel, and the ground provides a fault path.
But if you’re like me, you’re probably adding a 3-way switch into an existing circuit, which probably looks like this (or wants to):
- PANEL to switch 1 (existing)
- LIGHT to switch 1 (existing)
- Switch 1 to switch 2 (TRAVELER) (14/3)
The trick is remembering “common in, common out”. Power should go IN one of the switches and OUT the other one. This is the same principle regardless of how your switches/wires are physically arranged.
Run your 14/3 traveler over to the new switch box and sharpie or tape the remaining white wire at both ends (so you don’t accidentally bundle it in with the neutrals). Connect the blacks/reds/grounds as normal on both switches, and connect the sharpied/taped white to the common terminal on the switch 2. Back at switch 1, take note of whether its common terminal is connected to the panel or the light, and connect the sharpied/taped white to the opposite. I.e. if switch 1 common feeds the light, connect the white traveler to the panel hot by itself (your new switch is now “switch 1” in the original layout). If switch 1 common is connected to the panel wire, then connect the white traveler to the light hot by itself.