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I have a kitchen where I have a 15A receptacle on a split circuit (two hot wires and one neutral). Previously, it was set up with the brass connection cut with one hot wire for the top plug and the second hot wire on the bottom plug on the same receptacle.

I wanted to replace it with a GFCI receptacle for safety reasons (within 6' of a sink), and bring my kitchen up to modern code, but I know this is not possible with a split circuit, so I called an electrician to give me a solution and implement it.

The electrician simply put a wire nut on the red wire and screwed the black wire to the GFCI receptacle. This means that half of the circuit is just never used anymore, and the other half now serves the whole receptacle (which is now a GFCI receptacle).

I tried finding other people having done this on the web but couldn't find it, so I'm starting to worry that the electrician probably took a shortcut rather than do the job right.

Should I be concerned, or is this totally fine and up to code?

Edit: There's a bit more to my kitchen situation, but I only mentioned one receptacle (which is alone on its own circuit). Here is a diagram of the full kitchen situation. The receptacle I was talking about above is the one on the left. The receptacles on the right shared a circuit, but when he split them, the one receptacle (in the middle) is the only one that was not within 6' of a sink and the electrician insisted that we didn't need a GFCI there (even though it's a countertop receptacle and I had a GFCI receptacle handy).

PS: I didn't feel like making the ground in my little diagrams. before after

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    Sounds okay, but now you have one circuit instead of two, but that one circuit is GFCI-protected, as you wished. Do you need two circuits in this location? The main reason I can think of, why it might not be up to code would be (1) maybe there is a rule that unused live wires must be disconnected at both ends (I doubt it) or (2) maybe your kitchen now has less circuits than the code-mandated minimum number. Jan 19, 2023 at 13:31
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    I'd suspect that split circuits are frowned upon in kitchen/non-lighting applications. However, I am not an electrician. Assuming your electrician was licensed for your area, then he's the one that ought to know...
    – Chris Knudsen
    Jan 19, 2023 at 13:48
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    There is no way that he could have used both phases on a single GFCI receptacle. There's nothing he could have done differently without some major "surgery" (such as ripping out the existing single-gang box and replacing it with a double-gang and fitting 2 separate GFCIs).
    – brhans
    Jan 19, 2023 at 15:40
  • Is that the only receptacle on that circuit(breakers)?
    – crip659
    Jan 19, 2023 at 15:55
  • This is as good as it gets and you are now limited to 15A for the total of the dual receptacle. Might not be to code now. Split was required in kitchen. Code today is 20A GFCI using 12/2. See also diy.stackexchange.com/questions/160708/…
    – P2000
    Jan 19, 2023 at 16:06

3 Answers 3

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The basic problem is the mix of:

  • Multi-Wire Branch Circuit (MWBC) to supply two 120V sets of receptacles while only using 3 wires instead of 4 (not counting ground). Which used to be a great way to supply two kitchen 120V circuits using a single MWBC (120V x 2/240V circuit).
  • GFCI requirement for kitchens, which can be satisfied at the breaker (but not necessarily available, depending on the type of breakers you have) or at the receptacle (but receptacle GFCI does not allow for split receptacles as commonly used with MWBC).

The electrician did nothing wrong except that they may have caused a code violation with respect to the number of circuits in the kitchen. A kitchen is supposed to have at least 2 120V circuits feeding the receptacles. That can be satisfied with two totally separate circuits or with a properly installed MWBC. If this MWBC is the only circuit providing power to countertop receptacles in your kitchen then you now have a problem that needs to be fixed. On the other hand, if you have additional circuits powering countertop receptacles (if you turn off the MWBC, do you have any countertop receptacles that still work?) then you are perfectly fine as far as code is concerned.

If you want to fix this, either for convenience (more power!) or code (if there are no other countertop receptacle circuits) then you have two options:

  • Breaker

If the MWBC is connected to a panel that (a) has double-GFCI breakers available for it and (b) it is either in a full double space (as opposed to 2 tandem breakers in the inner or outer pair of a quad) or there is a full double space available, then you can install a double GFCI breaker and install an ordinary split duplex receptacle (the old if you have it or a new one for $ 3) and you're done. Note that because this is an MWBC, you can't use two separate GFCI single breakers, even if handle-tied, as there is only one neutral in an MWBC and it would need to be split to the GFCI breakers, which just won't work.

If a double GFCI breaker is not an option, then you have to solve this at the kitchen end. There are a few ways to do this, including:

  • Two GFCI receptacles side-by-side

Replace the single-gang box with a two-gang box. Install the existing GFCI receptacle and another GFCI receptacle. Pigtail the neutral to the line side neutral of both GFCI receptacles. Black goes to line side hot of one receptacle, red goes to line side hot of the other receptacle.

  • Two separate GFCI receptacles

Electrically the same as side-by-side, but practically a bit different. Pigtail the neutral that is going to the existing GFCI receptacle. Run a 12/2 cable from this box to a new box where it is (a) helpful to have more receptacles and (b) not too hard to run a cable and install a box. Connect red from the MWBC to black of this new cable. Connect white to the MWBC neutral (same wire nut as has the pigtail to the existing GFCI receptacle). In the new box, install a GFCI receptacle.

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  • which version/year of the code would this have to be compliant with, after any of the proposed changes?
    – P2000
    Jan 19, 2023 at 16:21
  • 1987 for near-sink receptacles require GFCI. 1959 (wow! looks like my house just missed that, which explains a bit about my original kitchen) for 2 kitchen receptacle circuits. As far as any much newer requirements, those depend on OP's location - anywhere from 2008 to 2020 based on this page Jan 19, 2023 at 16:31
  • Wait... kitchens have required 2 separate circuits since 1959? I wonder how long it's been since my kitchen was updated, then. (Or, they just skipped code compliance...)
    – FreeMan
    Jan 19, 2023 at 18:10
  • @FreeMan Could be they didn't worry about code. Could also be (based on the range of current NEC versions) that your house is several years newer but your jurisdiction was on an older code. There is also an allowance (not sure of all the details and it may have changed over the years) for sharing the "countertop circuits" with dining room and certain other areas, so that might explain it too, depending on the specifics. Also remember that you don't always have to update to new code, just new stuff has to comply and can't make it worse. For example, my house has plenty of circuits that Jan 19, 2023 at 18:12
  • I don't know that there were building codes when my house was built. There certainly weren't electrical codes back in the mid-1890s. :)
    – FreeMan
    Jan 19, 2023 at 18:15
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The electrician simply put a wire nut on the red wire and screwed the black wire to the GFCI receptacle. This means that half of the circuit is just never used anymore, and the other half now serves the whole receptacle (which is now a GFCI receptacle).

That's perfectly fine and sounds correct to me.

You seem to be assuming that the MWBC (Multi-Wire Branch Circuit aka shared neutral) serves that receptacle only. That's not impossible, but it would be pretty unusual. Most likely the MWBC serves a chain of receptacles, and either they pigtail each one, or that one just happens to be last on the chain. Thus, the red wire is still serving those other receptacles.

Note that on MWBCs they are required to pigtail neutral.

Splitting circuits to a single receptacle is fairly pointless; they only ever did it because it didn't cost anything. When wiring a MWBC it makes just as much sense to alternate phase wires at each receptacle, e.g. receptacle 1 comes off L1, receptacle 2 comes off L2, receptacle 3 comes off L1, 4 comes off L2, etc. That method is compatible with GFCIs.

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  • In my case, my former situation was two split circuits, one circuit serving a single receptacle, and the other serving two receptacles (I added the before and after diagram in my original post above). Jan 20, 2023 at 0:07
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I think you need to get another electrician into this one. I'm not an electrician, but two circuits in a single receptacle box is almost certainly not to code. It's an invitation to electrocution if someone tests one receptacle and finds that it has been disabled, and assumes that the other receptacle is also not live.

As a matter of fact, I'd recommend you get another electrician to look closely at EVERYTHING your first electrician worked on. And by "recommend", I mean "Don't give me no back talk, don't say you'll think about it, just effing do it."

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    The original setup was fine. An MWBC is one circuit that has two hots and a neutral. The new setup is also fine - an MWBC with one part not used. If implemented properly (no indication it is not), an MWBC will be set up with split receptacles (not possible with GFCI/receptacles, that is the OP's problem) it requires common shutoff to deal with exactly the safety problem you described - i.e., it is not an actual problem. Sorry to Down Vote, but this answer is not correct. Jan 19, 2023 at 16:05
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    It doesn’t even have to be an MWBC. Multiple separate circuits in a single box is 100% legal under then NEC. You can even power the two halves of a duplex receptacle with completely separate circuits as long as the breakers are handle-tied.
    – nobody
    Jan 19, 2023 at 16:31

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