# GFCI outlet seems to trip several times a week



## rhedayi (Nov 16, 2014)

Hi there everyone.  My name is Rudy, and I wanted to bounce an issue off some of you folks.  

I have a GFCI outlet in the garage.  It has a green LED indicator on it.  When I go to test it, it appears to be operating properly.  Meaning the LED goes off and devices on other outlets in the garage stop working.  The only thing plugged in on other circuits is a sprinkler timer.  

It seems every few days, the GFCI has tripped.  I go press the reset button and its fine again. I thought it may be the sprinkler timer that is somehow causing the issue so I unplugged it and ran it to a different GFCI protected outler via an extension cord.  While the original outlet once again tripped (w/o the sprinkler on it), the other gfci outler did not.  SO that makes me think the GFCI trips for some other reason.  What could it be ??  How do I trouble shoot a GFCI that seems to reset and test fine but keeps tripping ?   Thanks in advance


----------



## nealtw (Nov 16, 2014)

Welcome to the site.
Insects in and outlet or faulty gfi are the cheap things to go after. After that you might be looking for damaged wire, rodents or?? Or other things in the garage that are on that line.


----------



## bud16415 (Nov 16, 2014)

All the above as pointed out. An intermittent electrical problem is the hardest to find as when you check everything is working. I would just start with replacing the GFI outlet. Save the one you take out. If the problem stops then toss it. If you still have it then you need to look at each load outlet one by one. It takes so very little imbalance to trip them is what makes it tricky. 


Sent from my iPhone using Home Repair


----------



## JoeD (Nov 16, 2014)

I suspect water in one of the outside receptacles. Does the sprinkler possible spray water on the receptacle it was plugged into?
As already stated insect inside receptacles are also a common issue.


----------



## rhedayi (Nov 16, 2014)

Fellas thanks the replies.  I would have sworn the sprinkler timer was the culprit but since I moved it to a different circuit the original one still tripped last night.  Seems like moisture is a culprit but where and how a mystery.  From what I can tell the garage circuit it's separate from outside circuit each with own gfci. They can be tested independently.  There is even holiday light outlets also live when this gfci trips.   The garage is finished painted so inspecting is hard.  I can swap the gfci but I bet it's fine, it tripped more recently with more condensation dew whatever at night but why?   I guess I will swap the gfci, it has its own circuit breaker so easy to do, then inspect the other outlets for insects I guess or loose wires.  Thanks


----------



## nealtw (Nov 16, 2014)

Moisture can be fixed by spraying wd40 in the outlets. we use it when extension cord plugs get in the mud. the wd is water displacement.


----------



## JoeD (Nov 16, 2014)

WD40 is also very flammable. Any sparks and you will have a poof.


----------



## rhedayi (Nov 16, 2014)

I was thinking compressed air to clean each outlet once I take the covers of to look


----------



## rhedayi (Nov 16, 2014)

Small update
I reset the GFCI this am and it was already tripped by noon, no sprinklers and very little dew overnight because winds kicked up here in so cal.  I took my trusted old school voltage tester and tested the outlet...as expected NOTHING.  I reset it and tested the top outlets fine, the lower outputs IT TRIPPED, hmmm reset GFCI again and test THIS time 120V, test again trip...does this further point to a GFCI that is faulty ?    BTW after I reset it, I tested the other garage outlets and they were on and they do not trip the GFCI 

this picture is from ebay, I have one of these that is orange


----------



## Kabris (Nov 16, 2014)

Even though most likely, like Joe said, a spark would just cause a poof and done with WD 40, I wouldn't recommend using it on energized parts.

If it's a moisture problem then you will have to investigate what else, if anything, is on that circuit.  If the garage GFI is a dedicated circuit, I would simply start off by replacing the outlet and taking it from there. The fact that it resets suggests that there is not a loose connection somewhere.


----------



## Kabris (Nov 16, 2014)

I just saw your small update after I posted. Is that GFI feeding out to the other garage outlets?  Are they also GFI's?


----------



## nealtw (Nov 16, 2014)

Sounds more like insects all the time..


----------



## Kabris (Nov 16, 2014)

But if the GFI in question is at the beginning of the line and it's connected LINE/LINE then it is simply a bad GFI. If the other outlets are on a different circuit then it could be other things, or it could still be a faulty outlet.

And that old school tester is a good one. It gives an accurate reading every time.


----------



## nealtw (Nov 16, 2014)

The test to see if it is the gfi or other plug is simple just removing the wires from the load side of the gfi and if it still trips, that's the problem. If that isn't the problem just replace the other cheap outlets on the same line.


----------



## CallMeVilla (Nov 16, 2014)

Replace the GFCI.  If it trips again, you know the problem is external to the receptacle.  Double check all exterior receptacles and/or lights which might be on the same circuit.  

Another idea:  Replace the GFCI and turn your sprinkler timer off.  See if you get a trip (doubtful).  If there are other devices on the circuit, this will at least eliminate the timer as the offender.


----------



## rhedayi (Nov 17, 2014)

Thank you all for the inputs, I did not get an email stating there were more posts, so did not get to reply yesterday.



Kabris said:


> I just saw your small update after I posted. Is that GFI feeding out to the other garage outlets? Are they also GFI's?


 
This GFCI feeds all the garage outlets and the other outlets do not have GFCI outlets, just regular 3 prong outlets.



CallMeVilla said:


> Replace the GFCI. If it trips again, you know the problem is external to the receptacle. Double check all exterior receptacles and/or lights which might be on the same circuit.
> 
> Another idea: Replace the GFCI and turn your sprinkler timer off. See if you get a trip (doubtful). If there are other devices on the circuit, this will at least eliminate the timer as the offender.


 

Sprinkler timers is now on another (separate) GFCI outlet from outside of all places by the front door.  I ran a long cord as I initially thought the timer had to be the issue.   Interestingly that other GFCI has not tripped at all with the sprinkle timer atatched to it via a 50 foot extension cord.  But the original GFCI with the issue has tripped with nothing on it.


Today after work I will go to home depot and buy a new GFCI outlet. 

Should I just wire it up without connecting the down stream outlets as a test first ?


----------



## nealtw (Nov 17, 2014)

Should I just wire it up without connecting the down stream outlets as a test first ?
Yes the line side only.


----------



## bud16415 (Nov 17, 2014)

I&#8217;m pretty sure you have a bad GFI outlet but Neal&#8217;s suggestion was excellent. That being to pop your GFI out of the box and take the wires off the load side. That eliminates everything but the GFI. If then it pops you know it&#8217;s bad. Your old voltage tester is the type that puts some load across the voltage and that causing one half the outlet to trigger and not the other sure sounds like there is an internal problem. For a few bucks it&#8217;s worth changing.

If you put a new one in I would wire line and load both but that&#8217;s just me. You have non GFI power coming in as the line there is no reason to think the new GFI is faulty to start with.


----------



## rhedayi (Nov 17, 2014)

Thanks Neal and bud.   I have no idea if something "upstream" - meaning from circuit breaker could be at issue, I will swap it tonight and report back 

I appreciate all you folks' input


----------



## nealtw (Nov 17, 2014)

Nothing between the breaker and the gfi can cause this. It can only deal with itself and other outlets on the load side.


----------



## hornetd (Nov 18, 2014)

Use a meter to test the resistance between the Equipment Grounding Conductor (EGC) and the Grounded Current Carrying Conductor; most call this the neutral.  

If you get any measurable value you may have found the problem.  A fault between the EGC and the energized conductor will trip a GFCI immediately on every attempt to reset it.  A fault in the neutral that allows current to flow to the EGC will only trip the GFCI when a load is applied and current is flowing.  Any load on that circuit that operates somewhat randomly could be the culprit.  Examples include refrigerators and freezers, sump pumps, garage door openers, lighting timers or motion sensers...

--
Tom


----------



## rhedayi (Nov 18, 2014)

hornetd said:


> Use a meter to test the resistance between the Equipment Grounding Conductor (EGC) and the Grounded Current Carrying Conductor; most call this the neutral.
> 
> If you get any measurable value you may have found the problem. A fault between the EGC and the energized conductor will trip a GFCI immediately on every attempt to reset it. A fault in the neutral that allows current to flow to the EGC will only trip the GFCI when a load is applied and current is flowing. Any load on that circuit that operates somewhat randomly could be the culprit. Examples include refrigerators and freezers, sump pumps, garage door openers, lighting timers or motion sensers...
> 
> ...


 
Tom
I looked for a google language translator from smart electrician to english, they did not have one    All kidding aside, not sure what all that means or what to do


Today I went to home depot, bought a 15A GFCI (leviton) and just swapped it in.  Turned the circuit breaker back on and seems to be wired OK.  Green LED is on, and when I press test, it kills the power as it should.  Using my old school tester as before nothing trips which is encouraging.  Old one tripped basically each and every night this week so I will know in the morning if we are good.


----------



## slownsteady (Nov 19, 2014)

hornetd said:


> Use a meter to test the resistance between the Equipment Grounding Conductor (EGC) and the Grounded Current Carrying Conductor; most call this the neutral.
> 
> If you get any measurable value you may have found the problem.  A fault between the EGC and the energized conductor will trip a GFCI immediately on every attempt to reset it.  A fault in the neutral that allows current to flow to the EGC will only trip the GFCI when a load is applied and current is flowing.  Any load on that circuit that operates somewhat randomly could be the culprit.  Examples include refrigerators and freezers, sump pumps, garage door openers, lighting timers or motion sensers...
> 
> ...



Tom: So you're saying (if I read this right) that if there is a current between the neutral and the ground, that the GFCI will allow it; but once there is (downstream) use on the circuit, the GFCI will trip.....?


----------



## bud16415 (Nov 19, 2014)

Rhedayi

I think you are good now.


GFCI does not use the EGC (bare copper equipment ground wire)at all. They can be installed in old wiring where there is no EGC and protect you. They are looking at an imbalance going out to a device and coming back. So if your body or anything else is making a path to earth ground some of the current is going thru you to the earth and not all is returning to the common wire (White). 

I think what Tom is saying is the EGC and the common are connected at the panel so measuring resistance between them should be very low. I understood it that far. I don&#8217;t know what kind of a fault he was talking about that would go between the two and show up as I would think they are the same potential. Maybe he can explain it again. I do know they are set very sensitive and I could see a bug or moisture going to ground triggering it.


----------



## rhedayi (Nov 19, 2014)

OK this morning, it is still working, looks good so far, thanks !!


----------



## bud16415 (Nov 19, 2014)

rhedayi said:


> OK this morning, it is still working, looks good so far, thanks !!


 

We had it figured out in post #3. :beer:

Glad its working. Sledgehammer trouble shooting is often the best.


----------



## rhedayi (Nov 19, 2014)

You guys Rock   Thank alot, hit me up with eye related questions, that is my field of work !


----------



## hornetd (Nov 19, 2014)

slownsteady said:


> Tom: So you're saying (if I read this right) that if there is a current between the neutral and the ground, that the GFCI will allow it; but once there is (downstream) use on the circuit, the GFCI will trip.....?



No!  With no load there will be no current between the neutral and the ground.  Once a load is applied to the circuit the current on the Grounded Current Carrying Conductor (Neutral) will take all available paths back to the source.  If there is a neutral to Equipment Grounding Conductor (EGC) fault that has a low enough impedance then the current that is leaking into the ground, and thus not returning on the neutral, will exceed the trip point of the GFCI and it will open.  

GFCIs respond only to an imbalance of current flow between the energized and neutral conductors.  When that current flow differs by more than five milliamperes the GFCI opens the circuit.  Without current flowing there can be no imbalance.  Current will only flow when a load is applied such as when the garage door opener is activated or a refrigerator gets too warm and it's thermostat connects the compressor to the circuit.  

A common Wiggington type solenoid voltage tester or Wiggy draws about Seven milliamperes of current when applied accross a One Hundred Twenty volt circuit.  Testing between neutral and ground on the receptacle outlets of a GFCI will seldom trip the GFCI open unless the circuit is already under load and current is already flowing.  Test between the energized blade and ground will draw Seven milliamperes of current from the energized conductor that is not flowing through the Neutral of the GFCI mechanism.  That imbalance will trip the GFCI.  

--
Tom


----------



## slownsteady (Nov 20, 2014)

Okay, that explains it better to my ear. thanks


----------



## bud16415 (Nov 20, 2014)

rhedayi said:


> Small update
> I reset the GFCI this am and it was already tripped by noon, no sprinklers and very little dew overnight because winds kicked up here in so cal. I took my trusted old school voltage tester and tested the outlet...as expected NOTHING. I reset it and tested the top outlets fine, the lower outputs IT TRIPPED, hmmm reset GFCI again and test THIS time 120V, test again trip...does this further point to a GFCI that is faulty ? BTW after I reset it, I tested the other garage outlets and they were on and they do not trip the GFCI
> 
> this picture is from ebay, I have one of these that is orange


 
How do you explain what was going on internally in his GFCI to have the top outlet fine and the bottom tripped every time. One would think internally they are in parallel just as the downstream loads are. It almost sounds the interrupter circuit is different for top and bottom but all the loads are off the top.


----------



## rhedayi (Nov 21, 2014)

still working ok !!


----------



## rhedayi (Nov 27, 2014)

we are still good, so I consider it a fix !!!  Thanks everyone and happy thanksgiving


----------



## slownsteady (Nov 27, 2014)

Likewise!! Enjoy.


----------



## hornetd (Jun 30, 2015)

slownsteady said:


> Tom: So you're saying (if I read this right) that if there is a current between the neutral and the ground, that the GFCI will allow it; but once there is (downstream) use on the circuit, the GFCI will trip.....?



A functioning GFCI will not permit any current above Five milliamperes to escape the circuit without opening the supply conductors to that circuit.  When there is a fault between the Load side white wire and the Equipment Grounding Conductor (EGC) but there is no load on the circuit then no current flows and the GFCI does not trip.  When a load is applied to that faulted white wire the current will take all paths back to the source in proportion to the impedance of the paths that are available.  Because of the fault between the white wire and the EGC the current to and from the load will divide at the fault between the white wire and the EGC.  As long as the fault has a low enough impedance to carry Six or more milliamperes the GFCI will trip.  The thing that is different about a fault on the white wire is that there is no current present on the white wire until a load is connected to cause current to flow in the circuit.


----------

