# New GFCI breaker trips immediately



## mtm179 (May 25, 2018)

Recently installed a sub panel in detached garage. Sub panel fed by 50 amp breaker in main panel with 4 #6 gauge wire (2 hots, 1 neutral, 1 ground). Feeder wires exit house in conduit then buried 18" in conduit to detached garage. Neutral and ground is isolated in sub panel with ground wire from sub panel to 2 grounding rods 6' apart. As per multimeter, 240V between both hots and 120V individually between neutral. A branch circuit that is protected by a GFCI breaker immediately trips once flipped on. Nothing is even plugged into the exterior outlets on that circuit. Breaker is wired correctly with breaker pigtail to neutral bar and load hot and neutral to breaker. Any suggestions?


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## jbfan (Jul 1, 2004)

Removed the hot and reset the breaker.
What is the result?


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## daveb1 (Jan 15, 2010)

Check all connections at receptacles, lights and switches on that circuit. Did you by chance wire in a stitch loop?


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## mtm179 (May 25, 2018)

No switch loop wiring and breaker still trips when hot is disconnected.


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## jbfan (Jul 1, 2004)

Sounds like a bad breaker! Why do you need a gfci breaker?


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## mtm179 (May 25, 2018)

Its protecting 3 outside outlets, outdoor light, and pool light in the future.


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## dmxtothemax (Oct 26, 2010)

What happens when you turn off the breakers at the sub panel ?


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## curiousB (Jan 16, 2012)

Has this circuit ever been used or is it new wiring?

Things to check

- corrupt neutral after the breaker. The gfci load neutral gets tied to another neutral from a different circuit. You can’t commingle gfci load side neutrals with other neutrals from panel.

- moisture in downstream boxes

- shorted neutral to ground in wiring







Sent from my iPhone using Tapatalk


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## Bret86844 (Mar 16, 2016)

I had this problem when I swapped out a standard breaker for GFI/AFI breaker. It turned out to be the ground wire touching the hot terminal in one of the outlets.


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## CodeMatters (Aug 16, 2017)

mtm179 said:


> No switch loop wiring and breaker still trips when hot is disconnected.



Trips without hot connected? Change the breaker (as previously suggested).

EDIT: Other possibility would be that the neutrals of 2 different ccts are connected together.......somewhere.....


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## mtm179 (May 25, 2018)

New wiring. It’s the only active circuit for now. The breaker trips as soon as I flip it on. Never had chance to turn off manually. Not sure if this matters, but at end of circuit after a switch is a low voltage transformer then a junction box with roughed out wiring for pool light. Switch is currently off.


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## rjniles (Feb 5, 2007)

Disconnect both the hot and neutral from the breaker, if it still trips it is a bad breaker. You do have the circuit neutral connected to the breaker and not the neutral bar?


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## MTN REMODEL LLC (Sep 11, 2010)

If the GFI breaker is new.....I guess I'd start breaking that circuit at your best guess... and see if the line or the breaker is bad...

maybe at the first JB...... if the breaker holds, then just working your way down the line......

if the breaker doesn't hold.... than either the breaker or the line to the first jb is leaking.....No..?????


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## CodeMatters (Aug 16, 2017)

Another possibility is that wrong neutral is connected to the breaker. 
I've seen it happen...........


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## MTN REMODEL LLC (Sep 11, 2010)

Or, I guess you could move that breaker to a different garage circuit to determine if it's line leakage or the breaker.


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## mtm179 (May 25, 2018)

Breaker neutral is to neutral bar and circuit neutral to breaker. Gonna replace breaker first and see what happens. That seems to be easiest fix. If not I’ll check wiring down circuit. Thanks to all for suggestions.


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## MTN REMODEL LLC (Sep 11, 2010)

MTM.... Let us know if ya solve........ it's just our (my) curiosity.

(GFI breakers do go bad......and sometimes bad ones do get thru the returns at BB stores)


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## mtm179 (May 25, 2018)

I will update. Thanks again


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## mtm179 (May 25, 2018)

Replaced GFCI breaker. Same issues. Gonna check wiring downstream next. All outlets have weatherproof covers. Could moisture be an issue?


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## CodeMatters (Aug 16, 2017)

Are you sure the neutral and hot on the breaker are from the same cable? 
If you have two cables coming in through the same box conn it's easy mix them up.


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## mpoulton (Jul 23, 2009)

I would almost guarantee there is a neutral-ground fault downstream of the breaker. That's pretty much the only thing that would cause this. Modern GFCI breakers continuously monitor for this and trip when it's detected. It may be a neutral terminal of a device bumping against a bare ground in a box somewhere.


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## mtm179 (May 25, 2018)

Found the problem. Light fixture screw nicked the neutral wire exposing copper. Poorly designed fixture. Screw is as deep as box and sits right above knockout. Thanks again for all the input.


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