October 10, 2003, Newsletter Issue #77: 3-way switches

Tip of the Week

It is tough without graphics, but I`ll try.
When you look at a 3-way switch you will notice 3 screws. At one end (call it the bottom) is a single screw. At the other end (top) are two screws. The single screw at the bottom is the common terminal. The two screws on the top are traveller terminals.
A 3-way circuit requires 2 switches. At switch #1, the power from the panel goes on the common terminal. The traveller wires go on the traveller terminals. The traveller wires then go to the traveller terminals on switch #2. The common terminal on switch #2 goes to the light fixture. This wire is called the light leg.
Switch #1 common terminal is always hot. One of the travellers is also always hot. When you flip switch #1, you are moving power from 1 traveller to the other.
At switch #2, one of the travellers is also always hot. When you flip switch #2, you move power from one traveller or the other to the light leg.
At switch #1, let`s say you have the left traveller wired to the black wire, and the right traveller wired to the red wire. At switch #2, you must reverse the travellers so that the left traveller is red and the right traveller is black.
There are about a jillion different ways to wire a 3-way, but the principle is always the same: power to the common on switch #1, travellers reversed between the switches, and the light leg on the common at switch #2.
Keep in mind that there will also be a neutral wire going through the circuit, and probably a ground wire. The neutral wire should always be white, but all white wires are not necessarily neutral. The ground wire is always either bare or green.
Home Improvement Guru

About LifeTips

Now one of the top on-line publishers in the world, LifeTips offers tips to millions of monthly visitors. Our mission mission is to make your life smarter, better, faster and wiser. Expert writers earn dough for what they know. And exclusive sponsors in each niche topic help us make-it-all happen.