How to Wire a Three-Way Switch
A three-way switch is the most common system installed in residential areas. This system is used to control a light and receptacle or more from two different switches and locations. A good example of this is light in a bathroom that can be turned-off and on from the master bedroom or a child’s room.
There are many ways to wire a three-way circuit. We will just cover the basic wiring styles and methods. To start with, you need to prepare three-way switch cable wires with a ground wire. The other wires are the neutral wire, the power cable wire, and the switch or traveller wire.
This means that your cable should have a total of four wires. Four wires in the cable will appear that you will have four-way switches for your terminals that are also equivalent to having four terminals. Switches will work in combination with the two three-way switches to operate electricity to the lights and receptacles from three different locations.
For the switches, this system will require three-way switches. These switches are broader than regular single-pole switch mechanisms. Switches consist of three terminal screws. These screws are oftentimes found on the back of the housing switch or on its side.
One of three terminals can be easily marked and identified by a different color. It is commonly at the bottom screw on one side of other two screws. Marked terminals are usually tagged as the “common terminal” while the other two are called travellers. Names of the terminals simply show how they work. For this reason, electrical connection goes from one common screw that goes to one or the other travellers. This depends on the switch position.
These 4 terminals are brass in color. Support for traveller wires or hot conductors are provided by these 4 terminals. These wires act as recipients and transferrence of electricity that comes from other functional three-way switches. The four-way switch toggle is not marked with “on” and “off”. Markings are important because it is the only way to know the difference between the four-way and double-pole switch.
Usually, double-pole switches are marked with “on” and “off”. Thus, it is best to use #12 wires for indoor residential wiring. Check also your local electrical codes. Some countries like Canada require #14 wires for interior use. #14 wires are suggested to be used for protected circuits at 15 amperes.