GFCI breaker trips with no load connected

Question

I installed a 20A GFCI breaker on a circuit of 6 wall & counter outlets in kitchen and it trips instantly. I unplugged everything from the outlets and still trips. Then disconnected load and neutral from the GFCI breaker leaving only the neutral pigtail connected to the neutral bar and it trips instantly as well. The breaker does not trip with the pigtail disconnected and have tried another new breaker with same results. I assume there is a fault on one of the neutral wires on the bar with possibility of a ground wire touching a neutral wire and hoping there is a simple method of testing which one is the cause. I'm probably overlooking other factors but hoping I don't need to trace every circuit back to their loads.

Panel: Square D QOM2200VH MAIN BREAKER 200A
Breaker: GFCI is ‎HOM120GFI

Thanks everyone for your feedback. There is a neutral line on the bus bar causing the issue and not isolated to the 6 kitchen outlets as I have tried on different circuits with same results. No matter what position in the panel I insert the GFCI breaker it will trip without any load just the pigtail connected to either of the two neutral bars. If I remove the pigtail from the bar and use as a regular breaker with a load it will not trip. I have tried three different new breakers from HD & Lowes with same results.

Answer 1

disconnected load and neutral from the GFCI breaker leaving only the neutral pigtail connected to the neutral bar and it trips instantly as well.

So if LOAD hot and LOAD neutral are disconnected, and it still trips, that clinches it - the GFCI is defective. I would search it very carefully to make sure there isn't a pilot-error problem of some kind, but other than that it's a warranty reaplacement.

The breaker does not trip with the pigtail disconnected

Because it has no power. The trip mechanism requires power to operate, and removing the pigtail denies it power. (think about the error where someone wires a light to switch neutral instead of hot: it still switches off the light.)

have tried another new breaker with same results.

That is extremely unlikely unless Square D production was having a really bad day. The strongest indication here is pilot error of some kind. Review your work with utmost care. Also check the panel for any other problems - for instance if this were an Eaton breaker and you had a lost neutral, the Eaton would trip with a "high voltage" error code. I don't know if Square D's can do that, but they do indicate trip reasons via a procedure.

I assume there is a fault on one of the neutral wires on the bar with possibility of a ground wire touching a neutral wire and hoping there is a simple method of testing which one is the cause. I'm probably overlooking other factors but hoping I don't need to trace every circuit back to their loads.

Nothing on the line side of a GFCI can trip a GFCI. If nothing is connected to the Load side, a GFCI cannot trip. (these are not true of AFCIs - but you say this is a GFCI).

If a circuit that was once on a GFCI is wholly disconnected (all hot(s) and neutral, that is - ground doesn't connect through the GFCI) -- the circuit cannot affect the GFCI.

Answer 2

Disconnecting the hot from a GFCI will cause it to trip because the hot & neutral will automatically not be balanced and this is what causes the trip - your testing was invalid. Hook the breaker back up properly. Also, be sure that the ground wire is properly secured to the ground buss (assuming sub-panel, anywhere on neutral/ground buss on a main panel).

To properly test this, go to the first receptacle in the line, pull it from the wall, disconnect the wires (cap them for safety) and turn the breaker back on. If no trip, then the problem is in your wiring at the first receptacle.

If it still trips, then your issue is somewhere in the wall and you're going to have to double check the wiring - somewhere, somehow, there's a short between the breaker & the 1st receptacle.

If your first receptacle doesn't trip the breaker, shut power back off, reconnect wiring to the first receptacle, move to the second in line, disconnect it, cap the wires, turn the breaker on.

Lather. Rinse. Repeat until you find the receptacle with the bad wiring. Simply removing the wiring & redoing it at each receptacle (including properly torquing the screws at the receptacles) may well fix the problem without you ever figuring out exactly what it was.