I am currently dealing with a little confusion regarding arc fault protection and how it would be enforced by 2016 NEC code. I'm not a licensed electrician, I'm doing an apprenticeship and the guy overseeing my work is unavailable right now, was hoping for some advice. I ran a branch circuit to a shared switch box consisting of 2 - 3 way switches powering independent lighting circuits. I used a 14/3 cable not being aware he was enforcing this code. (I haven't seen it enforced much around here in my experience). I was am now being told that you can not share a common neural and still arc fault protect them. I think I may have found a way if I were to use a 2- pole 15 amp breaker they would only need one neutral, correct? Is this violating any other NEC codes in the process by them having a common trip? Also I am finding GE has discontinued 2 pole afci breakers. I would have to order online to match the load center but does anyone have any idea as to why they stopped making them? Were they having trouble with the functionality? Any advice you guys may have would be a big help. Thanks

  • The local electrical supply house doesn't have double pole AFCI's? If not, why can't you order it?
    – Tester101
    Apr 1, 2017 at 2:56
  • I'm being told ge doesn't make one anymore and I'm worried it was due to safety issues. Have a ge panel
    – Mike
    Apr 1, 2017 at 3:06
  • 1
    @Mike -- this was actually a design revision known as MOD 3 -- see my answer below Apr 1, 2017 at 4:11
  • 1
    @Mike, you should give ThreePhaseEel the best answer check mark. I was wrong, wrong, wrong!
    – Kris
    Apr 1, 2017 at 12:13
  • Multi-wire branch circuits are much more complex than they seem, and are loaded with pitfalls. I have fixed many serious mistakes in them; I seem to know more about them than my town's career electrician I am saying take the time to become very well-read in their various complexities, do your own learning, and have very close attention to detail when working with them. You will become more cautious about using them at all, and will probably stop calling them "shared neutral" :) Apr 1, 2017 at 15:03

2 Answers 2


Unfortunately most AHJ's these days require some form of fault protection... whether it be GFCI, AFCI, CAFCI, or the newer DFCI. DFCI's have class A GFCI protection ( 5mA trip) unlike their former cousins CAFCIs which are more of an equipment GFCI (30mA trip) with Arc fault protection too.

Maybe you can use a discontinued double pole AFCI. Good question on why they discontinued some of the AFCIs. Probably not enough demand and not required by Code.

By the way, the guy overseeing your work should technically be your Boss, legally he cannot sub you out as a independent contractor since you're not liscesned.

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    CAFCI (Combination Arc-fault Circuit-Interrupter). DFCI (Dual Function Circuit-Interrupter). GFCI (Ground-Fault Circuit-Interrupter).
    – Tester101
    Apr 1, 2017 at 2:31
  • Well in this aspect he is, but overall we are partners in a business. I am a general contractor. I recently merged with my brothers electrical contracting company. I am very capable of doing the work just haven't done much with arc fault and the 16 code book. So my question now is short of ripping open walls is there anything I can do too be code compliant off the 1 neutral?
    – Mike
    Apr 1, 2017 at 2:32
  • DFCI would only be required where both AFCI and GFCI were required, right? Should be no need for DFCI in a living room, for example.
    – Tester101
    Apr 1, 2017 at 2:53
  • Yes, living rooms and similar area could be on a plain AFCI...no GFCI protection required.
    – Kris
    Apr 1, 2017 at 2:59
  • Exactly, all I need is afci as it is a billiard room. I didn't realize he was enforcing this code because it isn't enforced in my area yet everywhere. I only have one neutral for 2 separate lighting circuits. Can I carry a common neural some way or do I have to rip walls open to get a second neural to the panel. Everything is 100%finished and I'm looking for an alternative option
    – Mike
    Apr 1, 2017 at 3:04

GE (THQL) AFCIs don't come in two pole any longer -- because they don't need to

Your apparent lack of ability to find two pole THQL AFCIs is actually due to a manufacturing revision to the single pole units. Mod 3 single pole THQL AFCI breakers can be handle-tied for multiple pole applications, as they do not use a CT-based trip for arc-to-ground detection. (You still need to wire the load neutral to one of the AFCIs, but either one will do -- you don't need to connect it to both.)

See this GE handout for details.

  • That's interesting. I'd like to cut one of those open, to see how it works.
    – Tester101
    Apr 1, 2017 at 15:35

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