# Why is GFCI being tripped?



## skymaster (Jun 6, 2007)

BC; IF you are capable, kill the power to the gfci and replace it. Then if the problem remains call an electrician, the best solution is to call an electrician now, let him check it out and if the gfci is bad he will replace it. Sometimes paying a pro is cheaper than messin with serious stuff and making things worse. At the moment the gfci is doing its job by kicking off because of a "fault" it is detecting.


----------



## BigJimmy (Jun 30, 2006)

bcfallar said:


> I wouldn't think a standard sprinkler system, which is used in many garage outlets, would exceed the threshold of the GFCI.


A GFCI is protecting against ground faults. It measures the difference between the current going "out" on the hot/ungrounded conductor and the current "returning" thru the neutral. Under normal circumstances, in=out, i.e. what current is going out is equal to what is returning. If you get a ground fault, the amount of current returning will be less than that being supplied and if the amount is in excess of 5mA, the GFCI will trip. As Joba pointed out, it is designed to protect you in the event that _you_ become the path to ground. All this being said, you cannot really compare a GFCI to a normal circuit breaker in terms of what causes it to trip.

It sounds like the sprinkler system controller is suffering some sort of a ground fault which is tripping the GFCI. The magnitude of the fault does not need to be much to do so.

Is this under warranty? If not, the controller likely needs to be replaced unless there is an actual ground fault within the wiring connected to the load side of the GFCI receptacle. Has anything changed recently, has any work been done to the garage, wife smashed the car into the back of it?

Another thing you may want to do is reset the GFCI and then manually start the sprinkler system and see what happens. Does the GFCI trip immediately? Is there a program for watering? Does the GFCI trip when the controller selects a certain zone?

Think about it/try it and let us know.

Take care,
Jimmy


----------



## BigJimmy (Jun 30, 2006)

skymaster said:


> BC; IF you are capable, kill the power to the gfci and replace it.


Sorry, but I disagree. The GFCI is more than likely the _symptom_ of this issue, not the cause. I have shot trouble on many GFCI-related problems and although I will concede that they can fail, in my experience, it was always an external issue that caused the trip.

Take care,
Jimmy


----------



## chris75 (Aug 25, 2007)

BigJimmy said:


> Sorry, but I disagree. The GFCI is more than likely the _symptom_ of this issue, not the cause. I have shot trouble on many GFCI-related problems and although I will concede that they can fail, in my experience, it was always an external issue that caused the trip.
> 
> Take care,
> Jimmy



But its always the GFCI's fault... :laughing: Damn nuisance tripping...


----------



## Silk (Feb 8, 2008)

chris75 said:


> But its always the GFCI's fault... :laughing: Damn nuisance tripping...


 
I read an article withing the last year that discussed a study done on GFCI's. It concluded that approxiamately 10% of the GFCI's right out of the box were defective. The defect was that the GFCI's would fail to trip at the required levels (between 4 and 6 milliamps), or when they were supposed to trip they would trip but remain energized, failed closed. So with these kind of defects, they are not noticed and are installed.

I believe in GFCI protection, but I don't believe they are foolproof and never fail, even after they have been around for whatever, 20----30 years?

I have changed out multitudes of GFCI's that would refuse to reset, but what about all those that fail to trip, or trip at the wrong levels.

By my own experience I cannot say that it is never the GFCI's fault.

That's all I have to say about that.


----------



## BigJimmy (Jun 30, 2006)

Silk said:


> By my own experience I cannot say that it is never the GFCI's fault.


I totally agree. I was really pushing against replacement _as the first step_ because that's probably much more difficult for the OP than doing some experimentation to see if the problem is external. I'd hate to see the forum coach him through replacing the GFCI only to hear back following its installation that it won't reset. But as you say, it's not impossible that the root of the problem lies within the GF device itself!


----------



## BigJimmy (Jun 30, 2006)

bcfallar said:


> I have a GFCI outlet in my garage with just one thing plugged into it - my sprinkler system.


I just thought of another possibility. In addition to the GFCI protecting the plug-connected device, it is more than likely protecting other receptacles in the garage as well (the GFCI receptacle is often installed as the first device in the circuit and others downstream are wired from the LOAD terminals on it). Now, this could very well include for instance a garage door opener and if the motor insulation is breaking down due to age, it could be faulting enough current to trip the GFCI.

So, do the following:
1. Check your garage to see if there are any other receptacles in it. If so, you can trip the GFCI or turn off the circuit breaker that is powering the GF. Or you can simply kill the power at the main panel and pull the GFCI out to see if there's anything wired to it other than the source.

2. If there are other recepts, check to see if there's anything plugged into them that could be causing the problem.

3. If your garage door opener receptacle is wired from the GFCI, think about possibly unplugging it and operating the door manually for a few weeks to see if the problem goes away.


----------



## skymaster (Jun 6, 2007)

BigJimmy; If you re-read my original post, you will see that I really advocated he call an electrician unless he was really well versed in changing components :}:}:}. Just from many years in this biz I have seen many many gfci's go bad. So much so that I now automatically change them when a problem is going on, at least you now now that the gfci is NEW when troubleshooting. Yes I know they can be bad outta the box, however a new one versus one that has been in use for years seems less likely to be bad.:whistling2::yes:


----------



## BigJimmy (Jun 30, 2006)

NP, Sky! I totally respect your experience on this. I just like to rule out external factors before pulling recepts, etc., or having the OP call in an electrician and paying him $100 to find something stupid.

My next door neighbors were getting ready to have a party on one particular Saturday this winter and they came over in a panic because the lights in a long hallway suddenly stopped working. The only electrician my neighbor could find wanted to charge him $250 just to make the call. So I go over there with my meter and a couple of tools. Sure enough, lights no worky. As I'm walking to the panel to check the breaker, I suddenly realize that these lights are 3-way controlled. When I find the second switch, I notice that it's mid-position. Now, that would have REALLY sucked to pay someone $250 to say "Duuuuh. The switch wasn't fully thrown!"

Karma has paybacks though as they got me pretty liquored!

Take care!


----------



## skymaster (Jun 6, 2007)

ROFLMAO yeah but thats the gravy money we get for all the unreal BS we put up with in our regular life:laughing::yes::thumbup:. Upteen hours chasing a damn loose connection and then hearing" Why so much all you did was tighten a screw?????? ):whistling2: Or "my light doesnt work, all I did was change to bulb. Ya ask if the bulb was good OH YEAH I checked it uh huh LOL upteen hours later, damn let me check the bulb YUP yeah he checked it. Same question all ya did was change the bulb :laughing:


----------



## BigJimmy (Jun 30, 2006)

If it hadn't been my neighbor, I would have gone back to the panel and made a whole bunch of ruckus to give the impression that I was actually doing something!:laughing:


----------



## FlyingHammer (Jun 22, 2009)

Silk said:


> I read an article withing the last year that discussed a study done on GFCI's. It concluded that approxiamately 10% of the GFCI's right out of the box were defective. The defect was that the GFCI's would fail to trip at the required levels (between 4 and 6 milliamps), or when they were supposed to trip they would trip but remain energized, failed closed. So with these kind of defects, they are not noticed and are installed.


Interesting information. I had always assumed pushing the test button was a valid test. Is there a reliable way to test GFCIs for the FTT (failure to trip) or FTD (failure to deenergize) conditions?


----------



## PoleCat (Sep 2, 2009)

Inductive loads will often cause a GFCI to trip when they turn off at the wrong time and the collapsing field induces its own voltage. I have seen many freezer disasters due to this.


----------

