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I have 12/2 power into first switch, 12/3 through all three split receptacles and to the second switch. I just can't wrap my head around the right connections.

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  • What's your definition of "split receptacles"?
    – JACK
    Aug 28, 2020 at 17:04
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    That's not enough wires if you want half of each outlet to be on full-time. You'd need that many just to have the outlets fully switched.
    – isherwood
    Aug 28, 2020 at 17:57
  • Split meaning 1 at each receptacle being hot all the time and the other being switched by the 3 ways. Aug 28, 2020 at 19:03
  • You can do it in a safe manner with balanced current in every cable, using two parallel 12/3 cables, but not within code because you can't provide a proper neutral at the far switch. Aug 28, 2020 at 20:41
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    @NateS. The OP was pretty adamant about only using what was there. Some of the comments have been deleted.
    – JACK
    Aug 29, 2020 at 1:28

4 Answers 4

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Since OP has indicated that wiring is accessible via an attic crawl space, here is a solution that requires adding another run of 12/3 between the two switch boxes. The currents in each cable are balanced, no box has more than three wire nuts, and neutral is available at one of the switches.

had to redo this one seven times to get it right

Add a 12/3 run from one switch box to the other. This doesn't need to go anywhere near the outlet boxes, and certainly should not add to the outlet box fills by passing through them.

Feed the constant-hot to the far switch via the new cable. In the diagram I used the red wire so that each switch would have three different colors on its terminals. This should be marked with black paint or tape to indicate it is now constant-hot.

Use the other two wires as travelers back to the near switch. These should be marked with yellow paint or tape to indicate they are now travelers. This completes a standard three-way switch loop which is completely independent from the outlet runs.

Now in the near switch box you have neutral, constant-hot, and switched-hot. Distribute these to the outlets via the 12/3 segments in the usual fashion.

The switch loop current is confined to the long 12/3 and is balanced, and the outlets current is confined to the distribution 12/3 segments and is balanced.

Do NOT use the existing last 12/3 segment to provide a neutral connection at the far switch box. Remove that segment (don't just cap it off, rip it out) so that no future maintainer will attempt to use it and accidentally create an unbalanced circuit.

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    The OP was pretty adamant about only using what was there. Some of the comments have been deleted. That's what started "The Rant'.
    – JACK
    Aug 29, 2020 at 1:39
  • OP said in a comment that he needed to use only the materials supplied by the homeowner, not that he needed to leave existing wiring in place. OP said in a comment that the wiring was accessible via the attic. - Comments are gone, I think the rant scared him. Aug 29, 2020 at 1:46
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    What, is OP trying to pass a Hillbilly Electrical Code version of FizzBuzz? It can be done but only by dangerously bootlegging neutral. Aug 30, 2020 at 2:39
  • @Harper - Reinstate Monica: I don't understand this comment. - What "can be done"? What is bootlegged onto neutral? Aug 31, 2020 at 18:15
  • What I mean is, if one followed the Hillbilly Electrical Code (bootlegged neutral), that frees up a wire. Using a California 3-way frees up one more, so that would suffice. The fact that the customer knows this is disturbing, and makes me think we're dealing with either a catty but unethical customer, or an investigative reporter trying to catch OP doing something wrong....... and this is a trick/test (FizzBuzz being a common test for programmers). Sep 1, 2020 at 15:13
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You're not wrapping your head around it because it isn't possible.

For the conventional wiring to work, there'd need to be 5 wires between the receps - 2 travelers, always-hot, neutral and switched-hot. They don't make /5 cable, so the only way to do that is conduit.

You cannot rescue the situation by throwing an additional /2 cable alongside the /3 for a couple reasons: first the 5 need to be in the same cable, and second you can't put that many splices in a typical box.

(It is possible to do with /4 cable using a technique called a "California 3-way", which is legal and works with 1 traveler... but will be quite a surprise to the next person.)

Smart switches save the day again.

You put a smart-switch master at either switch location. A smart-switch remote at the other. The remote must communicate with the master either wireless or with powerline signaling, since there will be no datacomm cables available. We get lucky and the wire function gets to correspond to wire color.

  • White: Neutral
  • Black: always-hot
  • Red: switched-hot

Hook them up according to each point's needs. The remote smart-switch will not use red.

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With the supplies given to you by the homeowner, it can't be done. Here's a simple diagram of what's needed as far as connections are concerned: enter image description here

You're looking at 12/4 which exists and 12/5 NM cable which doesn't. Code doesn't allow parallel cables to be run. If you were able to install conduit from switches to receptacles and receptacles to receptacles, then you could pull the needed wires. Hope this helps explain things.

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  • It's possible to do this with 4C+E. But you need to move to a different type of 3-way wiring. In on 1, out on 2, tie the commons together. Aug 28, 2020 at 21:41
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    Yeah you can get 4/12 NM-B cable and if you use a "California 3-way" that would work. the cable comes with two neutrals one of which would need to be sleeved or painted a live color in this application.
    – Jasen
    Aug 28, 2020 at 21:52
  • @Jasen Didn't want to draw out all the possibilities.... it's Friday and Happy Hour's started...
    – JACK
    Aug 28, 2020 at 22:25
  • @JACK -- 12/4 is a thing, although you're right 12/5 isn't. (You can also use THHN in ENT for this.) Aug 28, 2020 at 23:50
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    Yeah that would make sense, use a California 3-way with traveler being blue in /4 or white-red in /2/2... But that is not what OP has. Aug 29, 2020 at 2:42
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I actually started to write the "smart switch is the solution" myself earlier, but @Harper beat me to it - and well done as usual. Based on additional information from comments:

Watch Out for Inspectors! And Lawyers!

Seriously. The norm for DIY is a homeowner doing work in their own home. That excludes rentals (landlord or tenant) and excludes handyman (or anyone other than a licensed electrician) doing electrical work for someone else.

In many (not all) jurisdictions, a homeowner can make certain changes (varies by jurisdiction how much - from only simple switch & receptacle replacement on up to anything short of a main panel replacement) themselves, either with no or minimal permitting requirements. However, in most places, someone other than the homeowner is not legally allowed to make such changes without (a) being a licensed electrician and (b) permits. I am not going to argue the pros & cons of permits. That gets rather political. But I will tell you that if I, as a homeowner, am relying on someone else to do the work then I expect that they know exactly what to do and won't (of all things) be asking a bunch of strangers on the internet what to do. Not when it comes to health & safety. Conversely, if I, as a homeowner, buy stuff and say to the professional "use this, save a few dollars for me", and the professional does not think this is the right solution then I expect that professional to tell me "no, can't do it" or "you can use that but you are better off with something else", etc.

This particular question about switches & receptacles may not be a big one, but if the professional doesn't know how to wire it up (or indeed that it can't be wired up with the supplied equipment) then I'd seriously worry about workmanship and other things like proper connection of grounds, GFCI where required, etc.

I have done some limited electrical work myself (I am not an electrician) but never on someone else's house. I have hired electricians to do the stuff I can't - and looking back, I can see they really knew what they were doing, to the extent that I am still learning stuff now, many years later, that I can see they did for me properly, without checking with me, just doing what needed to be done. They know I'm not made of money, but when it came to safety they knew not to cut corners.

Rant over.

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    Strongly agree with @manassehkatz -- it's a frame challenge, not an answer, but it had to be said. Aug 28, 2020 at 20:18
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    I didn't realize that it was a response to a comment on that answer. You should link to it (grab the URL from the date stamp) or quote it in your answer for posterity.
    – isherwood
    Aug 28, 2020 at 20:18
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    I love a good rant.
    – JACK
    Aug 28, 2020 at 21:30
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    I must have missed quite a tempest. The comments seem to be deleted and 2 downvotes. Aug 29, 2020 at 2:43
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    @Harper-ReinstateMonica Friday night smackdown.... and upvoted ya..
    – JACK
    Aug 29, 2020 at 12:47

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