Re: Two 3-way switches another switch/outlets and a switch for ext light
Jack's right on the money how they are logically wired. But it gets confusing because the power could come in at one of the switches or at the light, the light could be between the switches or one end or the other... you can see that drawing a diagram to fit your specific situation can be quite a guessing game!
A long time ago, I had a "three-way switch" wiring FAQ. It would get between 2,000, and 4,000 hits per month. But then the server that it was on went down, and I still haven't taken the time to put it back up. Oh, well.
You need to know how 3-way switches work internally if you're ever going to figure this out. It helps if you think of the electricity flow like water in a hose. A standard switch is like a faucet, and a three-way switch is like the diverter valve in your bathtub that send the water up to the shower.
So you've got electricity coming in on the hot. It's connected to the "common" terminal on the first switch. This switch diverts the electricity to one or the other of the travelers. The second switch taps into one or the other travelers, directing the electricity to the common terminal which is in turn connected to the light. The neutral is like the drain; you NEVER have a valve in a drain! Oh -- I don't know if you noticed this or not, but you have to have two wires that go just between the switches with no lights or anything else connecting to them. These are the travelers.
Anyway, what I'm getting at is this: if switch 1 is diverting to the black traveler, and switch 2 is tapping into the red traveler, electricity can't flow and the light doesn't come on. When you flip switch 1, now the electricity goes to the red traveler and the light comes on.
Chances are you have a situation where a traveler is connected to the common, and either the hot or the light is connected to a traveler screw. On most 3-way switches, the common is identified by having a black colored screw; the other two are brass.
I hope I've sufficiently confused you.
Last edited by Fencepost; 08-08-2009 at 01:44 AM.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.