Breaker Off / 3-way and 4-way switches
3-way and 4-way switches
One light from two places takes two 3-way switches joined by two travelers. From three places, a 4-way switch goes in the middle. Pick where the power comes in.
- 013-way switch wiring, power at the first switch In the first switch box, a 2-wire cable from the panel and a 3-wire cable to the other switch. In the second switch box, that 3-wire cable and a 2-wire cable up to the light.
- 033-way switch wiring, power at the light Two cables in the light box. A 2-wire cable runs to the first switch, and a 3-wire cable runs on to the second switch.
- 053-way dimmer wiring, power at the switch In the first switch box, a 2-wire cable from the panel and a 3-wire cable to the other switch. In the second switch box, that 3-wire cable and a 2-wire cable up to the light.
- 073-way dimmer wiring, power at the light Two cables in the light box. A 2-wire cable runs to the first switch, and a 3-wire cable runs on to the second switch.
- 094-way switch wiring A 3-wire cable on each side of the 4-way switch box. The two 3-way switches sit at the ends of the run.
Questions people ask at the box
What is the common screw on a 3-way switch?
The darker screw, black or copper colored, usually on its own end of the switch. Flipping the switch connects the common to one traveler or the other. At one switch it takes the power in; at the other it sends power on to the light.
Which wires are the travelers?
The two wires that run between the two switches, usually the red and the black in a 3-wire cable. They go on the brass screws, and at each switch it does not matter which traveler goes on which brass screw.
Why does my 3-way only work from one switch?
At one of the switches a traveler and the common are swapped. Find the wire that brings power in (or goes up to the light) and make sure it is the one on the dark common screw.
Can I put a dimmer on a 3-way circuit?
Yes: one 3-way dimmer and one ordinary 3-way switch, or a smart dimmer with its companion switch. Two standard 3-way dimmers on one light will not work.