At my request a few years ago an electrician pulled a 30amp 2 pole breaker out of the panel and replaced it with two single pole 15 amp breakers and connected them to the existing 10/3 cable.

10/3 runs from the two 15amp breakers to a jbox. Is it still code (NEC) to construct two separate 15 amp circuits from the jbox in this scenario? if so any suggestions for labeling the jbox?



1 Answer 1


Under current (and quite a few years back, now) code, the handles of the two 15A breakers should be tied together, so when you shut off one half of the MultiWire Branch Circuit you shut off both halves of it.

Otherwise, yes, you can split that out into two separate 15's from a junction box.

Labeling? The numbers of the slots for the breakers that feed it, and MWBC, I suppose. No label is required by code there. But I'm quite fond of disambiguating what breaker(s) feeds what box.

  • Common shutoff for maintenance safety is only half the picture. It is also absolutely critical (for “not burning down your house” purposes) to ensure that the breakers are on separate phases when there is a shared neutral, so that the neutral doesn’t get overloaded. Generally a listed handle tie ensures proper phasing, but it’s important to be aware.
    – nobody
    Sep 23 at 1:34
  • Question states that a two pole breaker was removed and replaced with two single poles, so that's a given here. Me, I prefer dual pole breakers for MWBCs, but that's me, not a code requirement, unless it serves 240 as well as 120V loads.
    – Ecnerwal
    Sep 23 at 1:43
  • "so that's a given here" - what is?
    – nobody
    Sep 23 at 2:09
  • Check your reading comprehension. You take out a two pole, you insert two one poles in the same place, you have two one poles on opposite phases so your original comment is inappliacable in this case. That's a given.
    – Ecnerwal
    Sep 23 at 2:13
  • additionally, here in florida I have an outdoor breaker box and I was trying to avoid adding another conduit up the wall. otherwise it would be more user friendly to add 2 14/2 w/g cables if the panel was inside. the electrician validated the breakers were on different phases.
    – Eddie57
    Sep 23 at 19:06

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