View Full Version : Power from a 3-way switch
kikib757
Sep 18, 2010, 07:02 PM
I am wiring my new kitchen and I have a mutiple switches in boxes and my question is on a 3-way switch can I get power off it to work another switch in the same box, same circuit?
stanfortyman
Sep 18, 2010, 07:04 PM
Depends on how the circuit is wired. If the feed is in this box then yes.
kikib757
Sep 18, 2010, 11:13 PM
No the feed is not in the box. It is actually a 4-way switch and this is the last switch in the run. So it goes source (or feed I guess you call it)-switch-switch-switch - lights and then I want to power off this last switch to the other switch in the box which runs to an island where a switch for the island lights are and then I also have a switch for under cabinet lights.
If it was a single pole switch could I do it since it is only has 2-wire?
If the feed is in that box then you would you just pigtail the wires out of the feed line to each switch?? Or could you tell me how you would do it?
So if I can't use the 3-way switch to get power, then I guess I need to get power from another switch that is a single pole that is possibly located on the same wall or something? Any suggestions would be appreciated.
Thanks.
stanfortyman
Sep 19, 2010, 04:47 AM
It doesn't matter if it is a single pole, 3-way or 4-way.
You need a feed in the box to take power for another load.
A single pole switch is more likely to have a constant feed available yes, but it is not at all certain. Many times a single pole switch is wired as a switch loop. This is where the feed comes down on the white and goes back up on the black. There is no neutral available in this case.
The only way is to test the wiring in the box to check for a proper feed and neutral.
kikib757
Sep 19, 2010, 08:03 AM
I guess my husband and I are confused when you say feed. He thinks that means there has to be a separate wire coming in supplying power (not from a switch). Can you tell me what you mean by feed? So you are saying it is possible to get power from a 3-way switch (that is the last switch on the run) to another switch in the box? So you know we have only ran the wire and are getting ready for pre-cover inspection, so there is no power going to any of them, everything is open. We are building a new house and doing all the wiring ourselves. Thanks
tkrussell
Sep 19, 2010, 08:08 AM
Feed, power, source, all the same meaning.
If your doing all the wiring yourself, I suggest you have someone knowledgeable to check all the wiring to be sure something is not missing. Now is the time before it is covered to make any corrections.
Do not rely on the inspector to pick up what might be missing, he does not check to be sure circuits are wired properly he only will check to be sure the installation follows code.
Stratmando
Sep 19, 2010, 08:31 AM
If the wiring is in conduit and additional wire(s) can be pulled or pushed, this should not be a problem.
With 3 ways, 1 has a constant hot, as mentioned, a Neutral may not be present.
Here are a couple of diagrams:
http://www.thecircuitdetective.com/3and4wyinfo.htm
kikib757
Sep 19, 2010, 08:35 AM
We have an electrician wiring the panels and he has been out and gone over things with us but we didn't go over pigtailing from switch to switch as we assumed I was doing it correctly. Now I need go back and make sure each box has a source of feed coming in. Sounds like we cannot get power from a 3-way switch unless it is at the beginning of the run with a feed coming into the box. I guess I have a some rewiring to do. Sounds like you can get power from a single pole switch just not a 3-way or 4-way, is that correct? I guess I will just have to have the electrician come back out and go over each box where I have a question. I was hoping to work on it today, but it may have to wait. Thanks again.
Stratmando
Sep 19, 2010, 09:16 AM
May not be as bad as you think, Just run a cable(hot, neutral and ground to switchbox. Whatever switch and fixture this is supplying power to, needs to use this new neutral. Keep neutrals from separate circuits separated.
kikib757
Sep 19, 2010, 09:27 PM
Thanks for all your help. I think we have solved the problem and you are right it wasn't as big as I thought it would be. I only had to run about 3 extra wires for different locations that I did the same thing at. Thanks again.