# Troubleshooting an intermittently tripping GFI



## Bob Badger (Apr 19, 2009)

The GFCI can not be tripped by ground faults on the secondary side of the transformer.


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## azsparky (Nov 3, 2008)

Any ideas? Can something wired in parallel on the line side of the GFI cause it to trip? Maybe a voltage spike or drop? However, I believe this circuit is a house panel circuit serving only 120 volt site lighting. they utilize a lot of CFL's.


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## Dennis Alwon (May 9, 2009)

Just unplug the trany and see what happens. I am with Bob not on the load side of the trany. Could moisture be getting in the outdoor receptacle?

BTW, I would like to introduce myself....... We can play a game called Guess who I am.


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## brian john (Mar 11, 2007)

How long is the primary run? (from the GFCI to transformer)

Did you megger the primary feeder and the primary of the transformer, primary to secondary?


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## azsparky (Nov 3, 2008)

Transformer plugged directly into single gang GFI receptacle with an in use cover. It is very well sealed against moisture. Caulked, KO's sealed. etc. The GFI receptacle is about 100' from the house panel feeding it. This is at a condominium/townhome development. This is a transformer providing lighting for a common area. I swapped out the transformer and the problem persists. Can never get it trip while I am there, so it is frustrating to troubleshoot.


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## Dennis Alwon (May 9, 2009)

Please explain what else is on the circuit. Obviously there are many possibilities. There can be a bad wire out to the recep. feeding the trany that only shows it face when the ground is moist but since are from AZ that may not be the issue.


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## brian john (Mar 11, 2007)

AZ

Distance from GFCI to transformer?

Megger the circuit from the GFCI to the transformer.

Transformer primary to secondary.

Primary to ground.

If you did what you said you did this is the issue.


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## azsparky (Nov 3, 2008)

I believe the circuit feeds only site lighting. 120 volt bullet floods in landscape areas, 8x8 recessed lighting above individual garage entrances. This lighting circuit including the GFI is controlled by a photocell. This photocell also energizes two other circuit's loads thru a three pole contactor.


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## Bob Badger (Apr 19, 2009)

Dennis Alwon said:


> We can play a game called Guess who I am.


Roger, Don, Larry or Ken?


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## Dennis Alwon (May 9, 2009)

If you have the ability to do as Brian says then go for it otherwise start disconnecting a portion at a time and see what happens. That can be time consuming and a royal pain.
Good luck.


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## Dennis Alwon (May 9, 2009)

Bob Badger said:


> Roger, Don, Larry or Ken?



You are getting close. :laughing: Hey Mr. Badger-- you don't have enough to do at MH's you have to come here and play.


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## brian john (Mar 11, 2007)

Dennis Alwon said:


> You are getting close. :laughing: Hey Mr. Badger-- you don't have enough to do at MH's you have to come here and play.


 
Knock it off Dennis, we enjoy Bob's company over here.


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## azsparky (Nov 3, 2008)

I don't have a megger. But it seems like maybe I need to get one now.


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## Dennis Alwon (May 9, 2009)

brian john said:


> Knock it off Dennis, we enjoy Bob's company over here.


I'll try and behave. But you know that will be hard.


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## brian john (Mar 11, 2007)

azsparky said:


> I don't have a megger. But it seems like maybe I need to get one now.


 
Meggers can be had for a fairly reasonable price.

http://search.ebay.com/search/search.dll?from=R40&_trksid=p3907.m37.l1313&satitle=megger&category0=

Oh and Dennis a bit different here?


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## azsparky (Nov 3, 2008)

*Introducing me, Mr. "can't solve a tripping GFI"*

BTW, my name is Bob and I have 17 year's experience as an electrician in AZ. I have had my own small licensed electrical business since 2005. I am licensed only for residential, but have more than half of my experience in commercial work. (Didn't want to mess with Commercial GC's)

I want to thank everyone for their input and I hope to be of help for someone else on this forum one day.


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## Dennis Alwon (May 9, 2009)

brian john said:


> Oh and Dennis a bit different here?


Yes I have noticed. I have been lurking, on and off, for some time.


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## brian john (Mar 11, 2007)

azsparky said:


> BTW, my name is Bob and I have 17 year's experience as an electrician in AZ. I have had my own small licensed electrical business since 2005. I am licensed only for residential, but have more than half of my experience in commercial work. (Didn't want to mess with Commercial GC's)
> 
> I want to thank everyone for their input and I hope to be of help for someone else on this forum one day.


 
I was just in AZ, was in LA for a few days and had a couple days off hit Death Valley, Hoover Dam, then around the canyon and back to LA.

Great place.


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## 220/221 (Sep 25, 2007)

You just missed the summer here.

It's officially freakin hot @ 105


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## MDShunk (Jan 7, 2007)

As much as I like point-of-use GFCI protection, I've never really had very good success with outdoor mounted GFCI's. You mention that you're replaced the transformer, but did you happen to replace the GFCI? That's an easy 10-dollar thing to try if you don't happen to have a megger just yet.


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## brian john (Mar 11, 2007)

I had a white out at the Grand Canyon while I was there.
Dust storm at Death Valley.
And damn near blown off the dam at Lake Meade.


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## user4818 (Jan 15, 2009)

220/221 said:


> You just missed the summer here.
> 
> It's officially freakin hot @ 105


It's a dry heat though. :jester:


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## 220/221 (Sep 25, 2007)

BTW, landscape light transformers are notorious for tripping GFCI's. I hate chasing intermittant issues so I just unplug them and tell them to get a new one if it stops tripping.


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## Joefixit2 (Nov 16, 2007)

220/221 said:


> You just missed the summer here.
> 
> It's officially freakin hot @ 105


We actually have 2 seasons, first we have the hot weather then summer.


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## drsparky (Nov 13, 2008)

brian john said:


> I had a white out at the Grand Canyon while I was there.
> Dust storm at Death Valley.
> And damn near blown off the dam at Lake Meade.


Hows the bypass progress, the internet updates don't seem to update.
Chuck


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## brian john (Mar 11, 2007)

drsparky said:


> Hows the bypass progress, the internet updates don't seem to update.
> Chuck


 
Check my flickr account I posted some pictures I took.

http://www.flickr.com/photos/[email protected]/sets/72157617665846334/show/


Sure will make it faster but take some of the fun out of the trip.


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## randomkiller (Sep 28, 2007)

Peter D said:


> It's a dry heat though. :jester:


 
A pizza oven is dry heat and I have plans on being comfortable in one.


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## user4818 (Jan 15, 2009)

randomkiller said:


> A pizza oven is dry heat and I have plans on being comfortable in one.



Not sure I follow...are you planning on retiring in Arizona?


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## brian john (Mar 11, 2007)

I do not plan on retiring but if I did it would be to the middle of no where ME, ME ONLY, no electricity, no nothing.


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## Fredman (Dec 2, 2008)

azsparky said:


> I believe the circuit feeds only site lighting. 120 volt bullet floods in landscape areas, 8x8 recessed lighting above individual garage entrances. *This lighting circuit including the GFI is controlled by a photocell. This photocell also energizes two other circuit's loads thru a three pole contactor*.


 
So the GFI in question is being fed from the contactors load contacts and not directly from the photocells load wire right?


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## 76nemo (Aug 13, 2008)

brian john said:


> Check my flickr account I posted some pictures I took.
> 
> http://www.flickr.com/photos/[email protected]/sets/72157617665846334/show/
> 
> ...


 

Brian, those pictures are stunning. I can not get over the quality of them. What type of camera do you have??? Thanks for sharing the link with us!!!


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## drsparky (Nov 13, 2008)

Brian, the photos were cool.


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## brian john (Mar 11, 2007)

I use a Nikon.


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## Fredman (Dec 2, 2008)

Intelligent people have more zinc and copper in their hair 







:blink:


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## BuzzKill (Oct 27, 2008)

Nice work, brian.


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## brian john (Mar 11, 2007)

Fredman said:


> Intelligent people have more zinc and copper in their hair :blink:


What about those with no hair?


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## LGLS (Nov 10, 2007)

brian john said:


> What about those with no hair?


They go for the pubes, or the eyebrow / eyelashes.


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## 220/221 (Sep 25, 2007)

After like two years, I finally figured out your name just now^:laughing:

I always thought, "WTF is lawn guy..... land sparky".


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## hogsmoss (Apr 30, 2009)

maybe someone is messing around and manually tripping the GFI when your not there.:devil2:


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## LGLS (Nov 10, 2007)

220/221 said:


> After like two years, I finally figured out your name just now^:laughing:
> 
> I always thought, "WTF is lawn guy..... land sparky".


It's easier if you're from here...


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## drsparky (Nov 13, 2008)

LawnGuyLandSparky said:


> It's easier if you're from here...


I don't have a clue what LGLS means, but I'm not very bright.

Chuck


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## drsparky (Nov 13, 2008)

:laughing:I got it.


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## Benaround (May 5, 2009)

Those in use covers are useless, I wonder if during the day there is an

automatic sprinkler system near by and the GFCI gets a little damp ?


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## azsparky (Nov 3, 2008)

Fredman said:


> So the GFI in question is being fed from the contactors load contacts and not directly from the photocells load wire right?


Yes the Lighting transformer GFI is fed directly from one of the load contacts of a three pole lighting contactor. The coil is energized by a photocell.


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## azsparky (Nov 3, 2008)

Benaround said:


> Those in use covers are useless, I wonder if during the day there is an
> 
> automatic sprinkler system near by and the GFCI gets a little damp ?


I don't believe moisture is the problem. I replaced the GFI, totally re-did the makeup, examined all the wiring in the box for nicks, etc, sealed around the in-use cover with Caulk. I even swapped the Lighting transformer out with one from another building. The problem persisted only at the same building. The GFI will trip about every two days or so, but no exact time of trip can be established. The maintenance guy just notifies me that it has tripped again.

Hey, maybe the maintenance guy is a serial GFI tripper............? Watching me from his lair and having a good laugh as I troubleshoot the crime scene?


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## azsparky (Nov 3, 2008)

azsparky said:


> Yes the Lighting transformer GFI is fed directly from one of the load contacts of a three pole lighting contactor. The coil is energized by a photocell.


There is a large fountain about 30 feet away, but the entire community has the same setup with no other issues reported. I notice no signs of moisture at the GFI. With 10% humidity here, moisture has to have some real cohungas to travel 30 feet.


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## Noe (Apr 7, 2009)

I seem to recall a problem like this once. Outside GFCI tripped with lawn lighting...always in the a.m. Turned out that outside GFCI load side fed restroom recept and the HO using hair dryer and outside lighting was overloading GFCI.
Does GFCI feed anything else on load side?


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## azsparky (Nov 3, 2008)

Noe said:


> I seem to recall a problem like this once. Outside GFCI tripped with lawn lighting...always in the a.m. Turned out that outside GFCI load side fed restroom recept and the HO using hair dryer and outside lighting was overloading GFCI.
> Does GFCI feed anything else on load side?


No. The GFI is wired in parallel at the outlet box. It has no load wiring at all. It's only load is the Lighting transformer which is plugged into it. The line side comes from a seperately metered house panel which also feeds other site lighting.


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## LGLS (Nov 10, 2007)

If the LV transformer has a built-in clock, smart money is on the made in China motor driving that cheap-o clock. Since the whole transformer is controlled from a contactor-switched receptacle, open the x-former and disconnect that clock motor.

Also, add a 4.99 analog electric alarm clock to the receptacle and set the time properly. So if it trips again, you'll know EXACTLY what time it happened.


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## azsparky (Nov 3, 2008)

LawnGuyLandSparky said:


> If the LV transformer has a built-in clock, smart money is on the made in China motor driving that cheap-o clock. Since the whole transformer is controlled from a contactor-switched receptacle, open the x-former and disconnect that clock motor.
> 
> Also, add a 4.99 analog electric alarm clock to the receptacle and set the time properly. So if it trips again, you'll know EXACTLY what time it happened.


No controller at all at the transformer. The controller is a remote photocell which energizes a three pole contactor, one pole of which energizes the GFI feeding the Lighting transformer. The other poles of the contactor energize other site lighting


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## azsparky (Nov 3, 2008)

azsparky said:


> No controller at all at the transformer. The controller is a remote photocell which energizes a three pole contactor, one pole of which energizes the GFI feeding the Lighting transformer. The other poles of the contactor energize other site lighting


good idea on the timer to see approximately when it tripped.


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## jrhelectrical (May 12, 2009)

AZSPARKY, I, would not inergize a GFIC with a contactor this item is to sensitive , a very small arc could at random times cause it to trip. The site lighting on the other poles are probably causing this occurance.Look at how you have it wired and also refer to the low voltage lighting in the other areas of the complex to see if they were wired differently. jrhelectrical


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## brian john (Mar 11, 2007)

Megger


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## brian john (Mar 11, 2007)

jrhelectrical said:


> AZSPARKY, I, would not inergize a GFIC with a contactor this item is to sensitive , a very small arc could at random times cause it to trip. The site lighting on the other poles are probably causing this occurance.Look at how you have it wired and also refer to the low voltage lighting in the other areas of the complex to see if they were wired differently. jrhelectrical


GFCI are not suseptible to arcs, they work on a zero sequence reading through a CT. Current.

How can site lighting from another pole affect conductors on the LOAD of an GFCI.


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## jrhelectrical (May 12, 2009)

Why use a lighting contactor powersource to feed a GFI rec at all? Temporarily replace the source of power with an another feed (preferably another phase for a couple of weeks and see what happens),I, understand you said it works perfectly most of the time if that is correct I, would not lean to much on broken or damaged cables not to say that could'nt be the problem but change the obvious first. Go with the simple cures first. jrhelectrical


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## brian john (Mar 11, 2007)

Pee in the wind or get a megger.
Trouble shooting is about resolving issues methodically, why would you constantly guess at something when the answer is possibly right in front of you.


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## waco (Dec 10, 2007)

I'm not sure I see the reasoning behind "getting a megger." What should a megger read on such a circuit and since the problem is intermittent, when should the megger be used?

The GFCI is already telling you the circuit has a material or design flaw. In my experience, there ought to be an exception to GFCIs on outdoor feeds to LV transformers. I go to the extreme of hardwiring LV transormers or keeping them inside the house so they don't have to be associated with any GFCI.


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## Bob Badger (Apr 19, 2009)

waco said:


> I'm not sure I see the reasoning behind "getting a megger." What should a megger read on such a circuit and since the problem is intermittent, when should the megger be used?


With an experienced operator you can use a mega to find which part of the circuit has a problem even though the problem is intermittent.

I have recently got a mega and have been trying it out on various good circuits to try to learn the results.

But beyond that if you meg each section of conductors of a circuit and only one section comes out with a really different reading I think it is a safe bet you found the problem.



> In my experience, there ought to be an exception to GFCIs on outdoor feeds to LV transformers.


I don't think adding an exception is the correct response to a GFCI working as it should.



> I go to the extreme of hardwiring LV transformers or keeping them inside the house so they don't have to be associated with any GFCI.


That is a great way to deal with it.


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## brian john (Mar 11, 2007)

waco said:


> I'm not sure I see the reasoning behind "getting a megger." What should a megger read on such a circuit and since the problem is intermittent, when should the megger be used?
> 
> The GFCI is already telling you the circuit has a material or design flaw. In my experience, there ought to be an exception to GFCIs on outdoor feeds to LV transformers. I go to the extreme of hardwiring LV transormers or keeping them inside the house so they don't have to be associated with any GFCI.


 The cable may be marginally usable, the 1000 VDC can locate possible insualtion issues, based on the results you can make a determination if it is the insulation or if it is the insulation in the transformer.

As I understand it he has replaced the GFCI device, replaced the XMFR, what's left? The conductors (assuming no wiring errors). Before replacing the underground cable I would megg the distribution and resolve the issue.

In my opinon this is a one trip fix.


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## Fletcher76 (Mar 16, 2011)

Just curious if you figured out your problem, I have a similar problem.


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## 220/221 (Sep 25, 2007)

I think he quit the business because of it because it was two years ago and he hasn't been back :jester:


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## azsparky (Nov 3, 2008)

No, I'm still here 220/221. Working on my reply to Fletcher. I just got my email notification


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## 220/221 (Sep 25, 2007)

azsparky said:


> No, I'm still here 220/221. Working on my reply to Fletcher. I just got my email notification


 
Cool. I thought you abandoned us :thumbup:


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## Fletcher76 (Mar 16, 2011)

Hey azsparky you didn't forget about me did you?


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