A 3 way switch allows you to turn a light on or off from two different switches. It could be there is or once was a three way switch in play. Another use for 4 wires with these colors is for two switches controlling two different devices light and fan in a bathroom for example. In this diagram power enters the fixture box. Other experts could give you. We ll cover the easier scenario first. It does not matter to which terminal screw this wire is connected. Three way switches are always used in pairs and include special wiring connections. Never work on a light switch with the power on. In a hallway or large room for example installing three way switches at both ends lets you turn the light fixture on or off from both locations.
Never work on a light switch with the power on. When wiring a 3 way switch circuit we will be using a 3 wire cable known as romex coming from the source such as the breaker box. When you see a red wire in a light switch box it can mean two things. A 3 way switch allows you to turn a light on or off from two different switches. It could be there is or once was a three way switch in play. Then a 4 wire cable going between the two 3 way switches and then a 3 wire cable going from the switches to the load. Going out of the bottom of the gang box is the following. Other experts could give you. This 3 way light switch wiring diagram shows how to do the light switch wiring and the light when the power is coming to the light fixture. But first let s get my disclaimer out of the way.
Red and blue wires link traveler terminals of both switches. When you see a red wire in a light switch box it can mean two things. Regardless of what 3 way switch wiring diagram you re following you ll need to use a 3 wire cable to connect the two 3 way light switches. The black hot wire connects to the far right switch s common terminal. Connect 3 wire cable in the first switch box. A three way wall switch is a common type of light switch that makes it possible to control a ceiling light or other electrical fixture from two different locations in a room. 3 way switches are useful for large rooms with multiple entrances but require a bit more wiring than a standard single pole switch. Three wire romex red and white to the brass terminals of the three way switch black to the bundle of black wires nutted together two wire romex black to one of the single pole switch and white to neutral bundle. The red insulated wire connects to either one of the 2 unused terminal screws shown in the image above to be on the top left and right sides of both 3 way switches. The wiring method will depend on whether your power goes to the switch first or the light first.
But first let s get my disclaimer out of the way. Then a 4 wire cable going between the two 3 way switches and then a 3 wire cable going from the switches to the load. This is the 3 wire cable which you must have to wire a 3 way light switch. Connect 3 wire cable in the first switch box. And if you don t know which breaker controls the light you have. Three way switches are always used in pairs and include special wiring connections. The 3 wire cable enters through the top of the first switch box. Red and blue wires link traveler terminals of both switches. The 3 wire cable consist of a black wire a white wire and a bare copper wire while the 4 wire cable has an added red wire which is hot as well. It does not matter to which terminal screw this wire is connected.
We ll cover the easier scenario first. When you see a red wire in a light switch box it can mean two things. So what you should see if you have correct 3 wire electrical cable romex is a black power white neutral and now a 3rd red wire. Red and blue wires link traveler terminals of both switches. Regardless of what 3 way switch wiring diagram you re following you ll need to use a 3 wire cable to connect the two 3 way light switches. This is the 3 wire cable which you must have to wire a 3 way light switch. Never work on a light switch with the power on. Then a 4 wire cable going between the two 3 way switches and then a 3 wire cable going from the switches to the load. The red insulated wire connects to either one of the 2 unused terminal screws shown in the image above to be on the top left and right sides of both 3 way switches. Another use for 4 wires with these colors is for two switches controlling two different devices light and fan in a bathroom for example.
