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How To Wire A Three Way Switch

What wires go where on a 3-way light switch?

With a three-way switch, three wires connect the pair of switches—two black “traveler” wires and a third “common” wire. When the circuit’s power is turned on, any of these may be “hot,” depending upon how the switches are toggled.

What color wire goes to the black screw on a 3-way switch?

The black screw has the black (common) wire that runs up to the light through the yellow cable. The two grounds are connected together and then to the green ground screw on the switch. To summarize, the black screw gets either the wire from the electrical panel or the wire going to the light.

What is the common wire in a 3-way switch?

The black (line) wire connects to the common terminal of the first 3-way switch. A 3-wire NM connects the traveler terminals of the first and second 3-way switch together. Traveler wires are interchangeable on each switch. The common terminal of the second 3-way switch connects to the light fixture(s).

Where does the white wire go on a 3 way switch?

The black “hot” wire enters the switch on the left. Three-way wire(which includes red, black and white wires) runs from the switch on the left to the switch on the right, with the white wire carrying ground and the red and black wires carrying the output from terminals in the left switch.

Does it matter what wire goes where on a light switch?

With a switch loop yes, it should. The hot wire should come down from the ceiling on the white wire and go back up on the black wire. Just think ‘white down, black up’. If you wired it the other way around, hot black down and hot white up, you have a problem.

Does the black wire go to the black screw on a light switch?

The black (hot) wire goes to the brass screw or into the hole in the back of the device on the same side as the brass screw. This wire is sometimes red. The green or bare copper (ground) wire, if the device has one, attaches to the green screw terminal on the switch or to the electrical box.

What wire goes to the black screw on a light switch?

As marked before from the original switch, one wire (either power in, or the wire to the light fixture) goes to the black terminal, two wires go to the brass screws, and the bare copper wire (not visible here) goes to the ground screw.

What wire goes to the black screw on a switch?

The black wire goes up to the light through the yellow cable. The green ground screw on the switch is used to connect the two grounds. The black screw can get either the wire from the electrical panel or the wire going to the light.

Is the common wire the hot wire in a 3-way switch?

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

What is common wire on 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.

Is the red wire common in a 3-way switch?

Figure A: 3-Way Switch Wire Diagram — Power to Light Fixture The black hot wire connects to the far right switch’s common terminal. Red and blue wires link traveler terminals of both switches. The red wire, which is connected to the first switch’s common terminal, leads back to the fixture.

At what terminal of 3-way switch we connect wire going to the load?

The common terminal is the “bridge” between the power supply and the load (typically a light fixture). With this in mind, the wire that attaches to the common terminal is either (1) a hot wire from the main board or (2) leads to the load (fixture).

Does the hot wire go on the top or bottom of a switch?

Attach the white wire from the light fixture, which is now the hot wire, to the nut at the top right of the switch. Attach the red wire from the light fixture to the nut at the top left of the switch. Connect the bare copper wire to the green nut at the bottom left of the switch.

What happens if a 3-way switch is wired wrong?

Finding the common wire: When wiring a 3-way light switch, you’ll need to find the common wire and connect it to the common screw. If you don’t correctly connect this wire, then your lights won’t work from more than one switch.

How do you replace an old outdated 3-way light switch?

To replace a three-way switch, follow these steps: Turn off the power to the switch at the circuit or fuse panel. Unscrew and remove the switch plate; then use a voltage tester to make sure that the circuit is dead. Unscrew the switch from the electrical box and pull it out with the wires still attached.

Do old house have neutral wire?

In most modern homes in the U.S., if you open your light switch box, you’ll find four wires: load, line, neutral, and ground. Without a neutral wire, they don’t work, and that’s a problem because most older homes don’t have neutral wires. Instead, you’ll only find load, line, and (hopefully) ground wires.

What happens if you reverse the wires on a light switch?

But here’s the catch: If you connect the circuit wires to the wrong terminals on an outlet, the outlet will still work but the polarity will be backward. When this happens, a lamp, for example, will have its bulb socket sleeve energized rather than the little tab inside the socket.