I have a circuit protected by a GFI circuit breaker that has failed. So far, I eliminated anything plugged in or switched. Also determined that the circuit is fine with a standard breaker and draws no current. So, I left it this way for now.
Its impossible to check the actual wire runs behind the sheetrock. Is there anything else to check as a possible source of the trouble?
If there is really no current, on a meter that registers milliamps, go get a new GFI breaker, as the old one is crap. Or plug in the old one with the wires disconnected and see if it trips. In either of these cases, the breaker is the problem.
If no current is in fact "not quite no current" on a sensitive meter, and the difference in "not quite none" is greater than 5mA when measuring the hot leg .vs. the neutral leg, then there is an actual fault. If nothing is supposed to be drawing current and something is drawing a little, then you'd need to start running down the circuit to see where that's happening (which section of wiring) by disconnecting the wires at each device, moving away from the breaker, until you find a place where no current is being drawn - then the suspects become the device just disconnected, the device before it, and the wire directly between. If things have recently been nailed or screwed in the that section of wall, there's a suspect. If you have rodents, there's a suspect. Etcetera. If you have a bad section of wire, the sheetrock needs to get ripped open - but at least you can find out where it is, if it is.
Not being a gung-ho electrician type, I do a lot of running back and forth to the breaker box when trying to sort out something like this, and suggest you do the same.
Is it possible there is another GFI on the same line? Like a GFI protected outlet? My old shop had 2 GFI outlets on a single 120 circuit plus a GFI breaker on the 220 volt hot tub circuit. If I tripped any of the three, all were tripped! Very frustrating until I discovered the need to reset all of them when one tripped.
The one obvious thing that comes to mind is a short between neutral and safety ground somewhere in the wire run. The GFCI requires all current flowing on the hot must be exactly matched by an equal current flowing oppositely on the neutral. If these currents don't match to within a couple mA, the breaker trips. You can pull the neutral off at the breaker end and use an Ohmmeter to check for continuity between N and gnd. If it still shows connected, pull all outlets and switches along the run and look for a pinched wire. Only a GFCI would complain about such a connection. If nothing shows up in the boxes, then you likely have a romex staple through the cable somewhere! That rates a big :(
What's on the circuit? Is it something that is better protected by a GFCI receptacle?
The long wire run adds a lot of inductance that can give you false trips with big load changes, where it won't if the GFCI is at the receptacle closest to the load.
I have a batch of pedestals on a dock we have to rework - 50 to 250 foot wire run with a photocell and magnetic ballast with a 7W PL lamp. When the PCell /opens/ the inductive kick trips the GFCI breaker.
We're going to try a PF Correction (run) capacitor across the ballast, as soon as someone at Advance figures out what size. If that doesn't work, it's either electronic ballasts or LED lights.
Quite true - but the problem usually lies in a fussy inductive or capacitive load plugged in at the far end of a lot of wire. Or you have an underground segment that has damaged insulation and water in the conduit, and that should be changed out anyway.
When you are working in the Gardening Shed in the backyard and you trip the GFCI receptacle you can reset it right there. You don't have to stop what you are doing, troop a quarter mile back to the house to the breaker panel and reset a GFCI Breaker or a master receptacle, then troop all the way back out to the back fence again.
And the loads that don't need to be on the GFCI like the Malibu Lights transformer (big inductive kick when that turns on and off) or the Sprinkler Controller (transformer isolated too) can be wired in directly.
No GFCI on the sprinkler clock, you hard-wire it ahead of any GFCI. If it trips just as you leave for your vacation, you come back to a lawn and shrubs and flowers and garden beds that have been bone dry for three weeks, and everything is either dead or dying.
And you REALLY do NOT want a Refrigerator or Freezer on a GFCI circuit EVER, no matter how much the fools at the NFPA want you to make all kitchen convenience receptacles in new houses or major remodels GFCI protected - make it a separate "Dedicated Appliance Circuit" with a single receptacle and hold your ground with vigor if they want it changed...
(Or you install a separate GFCI there to make him happy till after the Final Inspection and/or Certificate Of Occupancy is signed. And the minute the inspector is driving away you yank it back out...)
Logic: Not only do you lose the contents of the fridge or freezer if the GFCI false trips, if the power has been off for weeks and you open the door without knowing it's been off ahead of time and take radical protective measures (like stuffing Vicks Vapo-Rub ointment up each nostril) I can guarantee that you WILL lose your lunch.
The term "gag a maggot" is rather accurate. You'll end up buying a new fridge, because that stink will NEVER come out, no matter what.