Black wire: This is a hot wire that carries electricity from the power source to the first switch in a typical 3-way setup. Its also called the “common wire” or the “line wire.” Unless the breaker is off, this black wire is always hot.

What is the common terminal on a 3-way switch?

The single dark-colored screw is known as the common terminal. The ground screw is usually green. The arrangement of these screws varies depending on the switch manufacturer. On some 3-way switches, the two traveler screws are on one side of the switch body, with the common screw isolated on the other side.

What is the common wire on a switch?

A one way light switch has two terminals which is a common marked as COM or C. The common is for the live wire that supplies the input voltage to the switch. The other terminal is marked as L1 and is the output to the light fixture.

Which wires go to the common screws on the 3-way switch?

When wiring a 3-way switch, first screw the terminal screws of the new switch until they are difficult to turn. Connect the ground wire to the green screw. Connect the wire marked common to the black or dark colored screw. Connect the two remaining traveler wires to the two brass or light colored screws.