When a GFCI outlet trips, does it open both the hot and the neutral, or only the hot? An outlet beyond the GFCI outlet has an open neutral and I wonder if that is normal when a GFCI trips?

  • 2
    If your testing device is a 3-light tester, it may not have an open neutral at all. The legends are often laughably wrong. Apr 8, 2019 at 4:54
  • A outlet tester requires power. If the outlet tester has power you have reset the GFCI feeding it so there should not be an open neutral. But I agree with Harper some of those testers are such a joke I think his magic 8 ball comparison is accurate.
    – Ed Beal
    Apr 10, 2019 at 13:52

2 Answers 2


At least three sources indicate that a GFCI outlet interrupts both the hot and the neutral.

The Circuit Detective:

When a GFI outlet trips off, both the hot and neutral "line" terminals become disconnected inside the receptacle from the "load" terminals.


More importantly, a GFCI receptacle switches off both the hot and neutral sides when it trips; making sure that the hot leg is interrupted even if it was mistakenly attached to the neutral side of the receptacle.

PDH Online:

GFCI are generally designed to interrupt both conductors in case someone has mistakenly wired a circuit backwards and is using the white conductor as the hot conductor instead of the black conductor.

And this source indicates that "it depends".


Essentially RCBO's are classified by the number of poles and current paths:

  • 1P+N Single pole RCBO with one overcurrent protected pole and uninterrupted neutral (two current paths)
  • 1P+N Two pole RCBO with one overcurrent protected pole and an unprotected switched neutral pole
  • 2P Two pole RCBO with two overcurrent protected poles

Bottom line:
Probable, but inconclusive. You'd need to find the spec sheet of your particular model to be certain.

  • In the last quote, from Voltimum, the 1P+N is defined twice. I think the first definition is for 1P.
    – Robert Lee
    Dec 14, 2022 at 0:24
  • 1
    I'm just relaying what their site said, so I can't be certain. But I think the first two are two different flavors of 1P+N.
    – Doug Deden
    Dec 14, 2022 at 4:10
  • Indeed, it appears to be describing two flavours of the 1P+N, i.e switched vs not-switched neutral. It's confusing they're named the same.
    – Robert Lee
    Dec 14, 2022 at 12:27

The neutral in a GFCI may not open when it trips. So if you are reading an open neutral, that could very well be part of the reason it tripped.

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  • I would like to know the reason for a down vote (reversed) on a correct answer. There has been a lot of these lately.
    – Ed Beal
    Apr 8, 2019 at 12:59
  • @EdBeal, not the down voter, but it's a very short answer? I don't know, that's all I can think of. (And this still has a down vote - a high rep user like you can click on the number and see the up and down votes)
    – JPhi1618
    Apr 8, 2019 at 18:17
  • @EdBeal -- I'm pretty sure this answer is not correct, actually -- if you look at the reference schematic in any GFCI-chip datasheet, it shows that the breaker breaks both hot and neutral, and that comports with the GFCI/RCD teardowns I've seen as well Apr 8, 2019 at 22:31
  • Try and look a few up and provide a reference. I can start with the NEC exhibit 210.6 it shows the shunt trip on the hot and nothing on the neutral. This plus the one he already posted from the web.
    – Ed Beal
    Apr 9, 2019 at 14:01
  • @EdBeal see page 4 here or page 6 here, as well as the photos from this teardown link Apr 10, 2019 at 0:32

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