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.
How do I find the common wire on a 3-way switch?
0:182:06Find the correct wiring for a 3-way switch in 2-minutes! - YouTubeYouTubeStart of suggested clipEnd of suggested clipIf no house current is found on any of the three wires. Go to the other switch. And do the sameMoreIf no house current is found on any of the three wires. Go to the other switch. And do the same thing one of the wires will have house current and that wire is the hot wire mark.
What is the red wire in a three-way switch?
Figure A: 3-Way Switch Wire Diagram — Power to Light Fixture The black hot wire connects to the far right switchs common terminal. Red and blue wires link traveler terminals of both switches. The red wire, which is connected to the first switchs common terminal, leads back to the fixture.