What is a Three-Way Switch? How is it wired?
Function and Common Uses
A 3-way switch controls a light from two locations, often used on stairways or in rooms with2 entries. Unlike single-pole switches, these lack ON-OFF markings because either switch can control the light.
A 3-way switch controls a light from two locations, often used on stairways or in rooms with2 entries. Unlike single-pole switches, these lack ON-OFF markings because either switch can control the light.
Physical and Terminal Differences
3-way switches are bulkier, featuring three screw terminals plus a ground screw, rather than the two on a single-pole switch.
3-way switches are bulkier, featuring three screw terminals plus a ground screw, rather than the two on a single-pole switch.
The Common Connection
A dark-colored “common” terminal acts as the input from the power source or output to the light fixture.
A dark-colored “common” terminal acts as the input from the power source or output to the light fixture.
Traveler Terminals and Wires
Two brass-colored “traveler” terminals connect the switches using wires (often black and red) that allow current to flow between them to turn the fixture on or off.
Two brass-colored “traveler” terminals connect the switches using wires (often black and red) that allow current to flow between them to turn the fixture on or off.
Connection Methods
While some switches allow for push-fit connections, using the screw terminals is recommended for a more secure installation.
While some switches allow for push-fit connections, using the screw terminals is recommended for a more secure installation.
Installation Tips
Labeling wires before removal, especially the common wire, is essential to avoid improper wiring during replacement.
Labeling wires before removal, especially the common wire, is essential to avoid improper wiring during replacement.
It’s also a good idea remove and reconnect one wire at a time when replacing switches. By doing this one wire at a time, you can ensure you are connecting the new switch correctly. This can sometimes be difficult, though, if the circuit wires in the wall box are too short—in this case, marking the wires is essential.
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