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mflagler 08-27-2008 08:46 PM

How do I wire two separate SETS of 3-way switches together?
Ok. I want to wire two separate SETS of 3-way switches together and then continue the circuit beyond that.

Here's the scenario: I have a 120V power source (14/2 direct from the panel) coming into a 2-gang box. From there it is to power a 3-way switch to the 2nd 3-way switch to the light. I already know how do do that and have strung wire like this: 14/2-S3-14/3-S3-14/2-light.

The second item in the 2-gang box is ANOTHER 3-way switch, and I have strung wire from it as follows: S3-14/3-S3-14/2-light.

These are two separate components. The first set of 3-ways allows the overhead light to be turned on/off from 2 locations. The second set allows an outside light to be turned on/off from 2 locations. For convenience, I have put the both sets in boxes together, so that one could turn on either the overhead light OR the outdoor light from the same spot, and then turn them either off from another spot.

The 2nd set of 3-way switches are in a 3-gang box that will also house a single pole switch to a light, and that is unrelated to the first 2 sets of 3-ways. From that location, one could turn on/off the overhead light, the outdoor light, or a single wall sconce if additional light is needed in the room. I hope I haven't lost anyone yet.

So my question is this: how do I take power from one 3-way switch in the 2-gang box (that which is operating the 1st 3-way set) and enable it to also power the 2nd 3-way set in that same 2-gang box AND THEN how do I join the accompanying 3-ways switch sets with the single pole switch in the 3-gang box.

I am a very visual person, so if anyone has a diagram I can look at, or could make one, that would be ideal. Of course, text is ok if it is simply written, and not too technical. I have had quite a bit of experience with simpler wiring projects, but this one has me stymied.

Any help would be appreciated. Thanks.


Super33 08-27-2008 09:34 PM

14/2 from the panel to the first 2 gang box.
14/3 from the first 3 way to the 3 gang box.
two of them are travellers and one is a neutral.
14/3 from the second 3 way switch to the 2 gang box.
two of them are travellers and one is a hot.
That hot in the 3 gang will feed the single pole switch and nothing more.
The first two 3 way switches in the first two gang box are fed hot as well.
The second 3 way switches in the 3 gang box will be the switch leg side.
switchlegs go from the second 3 way switches to the lights.
neutrals also go to the lights.
Travellers go between 3 way switches.

This is very vague and there are other ways to wire this. Let me know if you need more.

mflagler 08-27-2008 09:53 PM

Clarification, please?

Thanks for the quick reply. No, it's not as vague as you might think. I am with you for all but a few points. As I said, I'm a visual person, and I'm having trouble visualizing a part of this.

First: what do you mean when you say "fed hot"? On which of the screws do I put which coloured wire to achieve this?

Second: what do you mean when you say "the switch leg side" or "switchlegs"? I'm not familiar with that term.

Third (and I'm out of order here): what do you mean when you say that "two of them are travellers and one is a neutral"? Like, I get that I three wire has the red, black, and white. The white is the neutral, and I presume the red and black are travellers. But how do I wire that?

Are you saying this: I take the 14/2 to the 2-gang box, and connect it to the first 3-way switch; then take 14-3 from there to the related 3-way switch in the 3-gang box, then another 14-3 back from the 3-gang box via the 2nd set of 3-ways to the 2-gang to connect to the second 3-way related to it; use the red from the one 3-way to power to single pole, then tie all the neutrals and ground together, sending the neutrals to the two lights? And which of the hots goes to the lights, then, the reds or the blacks?

Thanks again for your quick reply and your help. It is appreciated.


SD515 08-27-2008 10:06 PM

One part I wasn't sure of...does the 2 gang and the 3 gang each have a 14/2 going to a light...or are the 2 14/2's both in the same box (and if so, which) ??

Matthew, you sound like a pretty capable fellow, so maybe this will help:

3 way switch wiring:

White form the source goes directly to the load.

Black from the source goes to the common terminal of one of the 3 way switches.

Black of the load goes to the common terminal of the other 3 way switch.

The travelers get hooked to the remaining terminals.

There can be a few ways to do it...depends where the load and/or source is in relation to the switches.

If you have to use a white as 'hot', it has to feed a switch and be taped black at both ends.

Super33 08-27-2008 10:11 PM

the 14/2 from the panel is the hot and the neutral. In that first 2 gang box that black from the 14/2 is going to go on the black screw on each of the first two 3 way switches. The White is a neutral and it will not be terminated to either of those two switches.

From that 2 gang box you will run two sets of 14/3.
The first set will be black-traveller, red-traveller, and white-neutral.
The second set will be black-traveller, red-traveller, and white-hot(wrap some black tape on that hot(white) wire so it is not to be confused with any neutrals.
So now looking at the back of the 3 way switch you have 4 screws, one ground screw, two matching screws, and one other screw.(not too sure of the colors of screws). two matching screws are for the travellers and the other is for the hot or switchleg depending on what side of the 3 way that switch is on.

Now we're at the 3 gang. Put one pair of travellers on each of the 2 3 way switches, at this point it doesn't matter what pair goes on what switch. you now have a hot and neutral, the hot is going on the top screw of the single pole switch and ending there. the neutrals will splice with the neutrals from the 14/2 from the lights. The black from the 14/2 from the lights will go on the other screw on the 3 way switches(same screw the hot is on from the 2 gang 3 ways). Same goes for the single pole, put that black on that bottom screw.

Splice all grounds and pigtail them to the switches' grounds screws.

jbfan 08-27-2008 10:27 PM

Super. I know what you have described will work, but is it not a code violation to have the hot and neutral in different cables?

220/221 08-28-2008 01:29 AM

In the manner in which you described it, you have no constant power at the 3 gang box.

What I would do is run the 14/2 feed from the panel to the THREE gang box.

Put your 14/2 power in at the 3 gang box with 3 pigtails from the black wire pigtailed, feeding the "common" terminals of the 3w switches and one pole of the single pole switch.

You run two 14/3's to the 2 gang box and run your 14/2 "switch legs" to the fixtures. In the 2 gang box, the black wires of the switch leg 14/2's go to the common terminals.

The black and red wires in the 3wire cable between the boxes will connect in any order to the two remaining terminals on each switch.

All whites are neutrals and tie together. Grounds tie together with pigtails if boxes are plastic.

DAmn...I could have done it by now

Super33 08-28-2008 04:26 PM


Originally Posted by jbfan (Post 152491)
Super. I know what you have described will work, but is it not a code violation to have the hot and neutral in different cables?

It's possible, I'm used to my wires being in pipes. So that might be a code violation I'm not aware of.:huh:

mflagler 08-28-2008 09:58 PM


Thanks a TON for all your help. I am confident that I now have a handle on how that will go, and it seems clear to me at least at first read through.

SD515: Thank you for the compliment, I have gained a lot of experience in the past year, and am actually now considering becoming a licenced electrician, I enjoy the work. Specifically regarding your request for a clarification: right now (I haven't completed the work yet, just strung the wire), there is the 14/2 coming in from source to the 2-gang box. Then a 14/3 to the 3-gang box for the switch there, then a 14/2 going out to the light, just as would be needed to properly wire a 3-way switch. Next, I took another 14/3 out from the 2-gang box to the 3-gang box for the 2nd set of 3-way switches, and another 14/2 out to the 2nd light. I knew I would need that to properly wire two speparate sets of 3-ways. What I didn't know was how to take the power from the first set of 3-ways to the second set of 3-ways, and then to the single pole switch/light to continue the circuit. I've never done that before and never seen a drawing showing how. If what you explained has now changed in light of this information, I'd appreciate hearing about it. However, it seems that 220/221 has the best description, though all of you have been really helpful, thank you again!


SD515 08-29-2008 10:10 PM

You're welcome Matthew. I agree about elect work being fun. I usually have a pun intended.

If you take the source cable to the 3 gang box, you'll find things will go smoothly.

When I first started I couldn't find anyone that would just explain the basics of 3 way wiring. One day I read it it a book, nearly word for word like I mentioned before, and boom it clicked. It works on any 3 way and 4 way. The only difference is a 4 way has an extra switch(s) (a 4 way switch) inline between the 3 way switches. You might consider printing those steps for reference until you remember it, if you need to.

The monkey wrench your project caused was that single pole switch, and not being in the box where the source was.

Good luck with your project...and your future career as an electrician !!:thumbsup:

220/221 08-30-2008 10:39 AM


However, it seems that 220/221 has the best description
:thumbup: What do I win?

Super33 08-30-2008 08:47 PM


Originally Posted by 220/221 (Post 153244)
:thumbup: What do I win?

OMG that's no fair, he said he was feeding the 2 gang with the 14/2 so I went from there and gave one possible way of doing it.:huh:

I demand a rematch!

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