3-Way Switch Wiring Diagrams
Also see:A 3-way switch allows for controlling a light fixture from two locations. These are usually used at the top and bottom of a flight of stairs or at two different entrances to a room. Below are several options for wiring a three way switch depending on the location of the light fixture and switches in relationship to the electricity source. Also included are alternate wiring diagrams for different switch configurations and a 3-way dimmer wiring diagram.
Another option for controlling a fixture from three or more locations is to use one or more 4-way switches between two 3-way switches. Several wiring diagrams for a 4-way switch circuit are shown at this link. For more about 3-way switch circuits and troubleshooting tips see below.
This wiring diagram features the source for the circuit at the light fixture and the two 3-way switches after. An alternate wiring scheme for this circuit, where the traveler terminals are on the same side of the switches, appears lower on this page. As with all 3-way switches, the traveler wires may be reversed and the circuit will still work fine in most cases.
This 3-way switch diagram illustrates proper wiring when the source is at a light located between the two switches.
This 3-way diagram illustrates wiring when the electrical source is at the first switch and the light is located at the end of the circuit.
This circuit diagram features the source at the first switch and the light fixture located between the two 3-way switches.
This diagram illustrates a specially made dimmer that can be used in a 3-way circuit in place of either of the two switches. The 3-way dimmer has a fourth wire that is connected to one of the traveler wires to allow for dimming the lights once they are on. The other 3-way switch will turn the lights off and on at the level set by the dimmer. This device can be used in place of any of the 3-way switches in these diagrams as well as to dim the lights in a 4-way switch circuit.
About 3-Way Switch Circuits
Modern three way switches have 3 terminals to carry circuit electricity and one terminal for a ground wire. Older 3-way switches will not have a ground terminal. Of the three circuit terminals on the switch, one is called the common and the other two are known as travelers. The common terminal is usually black and the travelers are silver. The ground terminal will usually be green. In any case the common terminal will always be a different color than the traveler terminals to distinquish it. Depending on the manufacturer, the travelers will be on opposite sides of the switch or the two terminals will be on the same side. Included below are diagrams for the second type of switch.
Troubleshooting 3-Way Switch Circuits
All the diagrams on this page have been tested in real life circuits but because of variable factors in existing wiring the examples displayed here may not work in every instance. To avoid problems make sure the hot wire from the source is connect to the common on one of the 3-way switches and the hot wire to the fixture is connected to the common terminal on the other switch. If after wiring, you experience problems with the circuit, reversing the traveler wires on one or both of the switches will most likely resolve the issue.
To connect these circuits use 14/3 cable between the switches and 14/2 cable to the light fixture in these diagrams. To avoid confusion the white wire should be marked with black electrical tape when splicing it to carry current in the circuit.
