We have a two-pole 15amp GFCI breaker in the breaker panel. It feeds the AC (summer), the furnace (winter), two room outlets and the lightning in three rooms.

At random times we loose power in some of the points. GFCI will not trip (verified) but furnace, one outlet, and some of the lights are de-energized. Resetting the breaker (pushing to off position, and then back on) does not help and still partially energized. GFCI breaker yellow test button not tripping (failed).

This circuit was working for many years with no change in electrical load, and problem begun recently.

Any help to why this may happen? and if replacing the breaker is only option?

Thank you in advance!

  • 2
    That's way too much stuff for one circuit. Quite likely you have overloaded the circuit from time to time, and caused a loose connection somewhere (probably a backstab). Note it is a code violation to have the furnace sharing a circuit with anything else. Also note a built-in A/C uses the furnace's air handler to distribute cool, and that uses the same amount of power as the furnace in heat mode. (minus the gas solenoid valve, that is like 2 watts lol). Mar 3, 2022 at 7:24
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    Do any outlets, lights, or devices stay on when the furnace loses power? Also, can you post a photo of the air conditioner's nameplate please? Mar 3, 2022 at 12:42

1 Answer 1


If NEC applies, the furnace is supposed to have its own breaker, though sharing with the A/C is allowed. But there should not be other outlets/lights on the circuit feeding those. NEC 422.12 See: https://diy.stackexchange.com/a/236395/18078

Regardless, you appear to have an intermittent connection. Somewhere, a wire (or possibly something else, like the bus-to-breaker connection) is not making solid contact, so sometimes it connects and sometimes it does not. If part of the circuit remains powered, the bad connection is between there and the part that loses power. This can be a large problem because there are generally sparks every time it connects/disconnects, and that can lead to fires - so you need to track down where the bad connection is and fix it.

You appear to say that parts of the circuit remain powered, so it's probably not the GFCI-to-Breaker-Panel connection - a common cause of problems there is using "alien" breakers that might physically fit, but are not actually compatible with your breaker panel and don't connect well as a result.

The GFCI won't trip if the connection is only to wires that should be connected, rather than from them to ground. An AFCI would very likely be tripping, as that's exactly the sort of failure those are supposed to catch.

However, you appear to be saying that the GFCI breaker has failed and does not trip on test, so for that alone it needs to be replaced - as well as finding the bad connection and fixing it. While you are at it, might as well split the circuit so it no longer violates code.

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