A three way switch is a circuit commonly found in residential buildings and some businesses. They are used when multiple switches operate one or more lights at opposite ends of a large room, hallway, or staircase. Three way switches are similar to single pole switches, but have two connections on one side of the switch and one on the other, whereas a standard switch has two single connections. Three way switches have a “common” terminal, which usually has a different color from the other two, and is the lower screw on the side of the switch that has two screws. The other terminals on the switch are referred to as the traveller terminals. One is connected to the common screw depending on how the switch is used.

How to Wire a Three Way Switch

Step 1 – Run the power supply to one of the switch boxes (include a single neutral and hot wire) with a #14/2 wire cable.

Step 2 – Run another #14/3 wire to the other switch location.

Step 3 – Run a #14/2 wire from the second switch to the light box.

Step 4 – Splice the neutral wire on the first box from the power supply to the white wire on the 3-wire cable leading to the other switch.

Step 5 – Affix the hot wire (usually black) to the common screw located on the three way switch.

Step 6 – Connect the red and black connector on the #14/3 cable to the remaining screws on the switch. These are referred to as the “traveller” connections.

 

 

Step 7 – Connect the white wire from the #14/3 to the white wire leading to the light at the alternate switch location.

Step 8 – Affix the black and red travellers from the #14/3 to the same screws as previously done on the other switch, and tie the black wire on the common screw.

Precautions to Take When Working With Electricity

Generally, the white wire is grounded at the main electrical panel in a home. Sometimes, however, it is used as a hot feed. Never assume that a wire is dead. Turn off the circuit breakers and test all wires before installing a three way switch.