Three-way switches require a three-wire cable: the power wire, the neutral wire, and the traveller or switch wire.
The cable should even have a ground wire, or a complete of four wires within the cable. The system also requires three-way switches. The switches are wider than regular single-pole switches and they have three terminal screws on the side (sometimes back) of the switch housing. Two terminals will likely be on one side of the switch housing; one terminal on the other side.
Four-way switches have four terminals. This switch works together with two three-way switches to manage electricity to lights and receptacles from three locations. The entire four terminals are brass colored. They support hot conductors (traveller wires), which receive and transfer electricity from each of the three-way switches. The toggle on a four-way switch is not marked “OFF” and “ON. ” These markings are the one way to tell the difference between it and a double-pole switch, which is labeled “OFF” and “ON.”
It is advisable to use No. 12 wire for residential, indoor wiring. No. 14 wire is acceptable if the circuit is protected at 15 amperes. (Canadian code requires using #14 wire for interior application.)
WORKING WITH WIRE
To make wire connections, the wire should be pulled through boxes no less than 6 inches, cut, after which stripped of insulation. Here is the procedure to follow:
1. Cut the cable to the correct length using lineman’s pliers or a hacksaw.
2. With a sharp knife or slitting tool, slit the outer sheathing, being very careful not to chop the insulation covering the wires contained in the cable. If possible, lay the cable on a flat, firm surface to slit it properly. You may additionally use a cable ripper.
3. Peel back the sheathing and trim it square.
4. With wire strippers, put single wires in the correct size groove in the handle (12 for No. 12 gauge wire). Twist the stripper or rotate it 360 degrees, sliding the insulation off the wire as it breaks loose under the cutting blades. Remove 3/4 to 1 inch of insulation.
5. Splice wires together and top with a wire connector.
In wiring three-way switches, the facility wire is connected to the COMMON terminal, usually marked “COM. ” The placement of this common terminal may vary in response to the manufacturer of the switch. Check the switch. If not marked, the common terminal could also be color-coded black or brass.
In the following illustrations, track each wire with a finger or pencil to its conclusion on the fixture. This manner, you will ensure all connections are made properly.
Note that the shadings of the wires in the illustrations represent actual color. See color key in each figure.
Tip:The traveller wire is connected in the sunshine ceiling boxes, with a length of neutral wire taped black to point a hot wire. The ground wire is pigtailed throughout. Neutral wire bypasses first three-way switch.