GFCI Protected Circuit

[Little Bill]

WARNING.....Very long post. Sorry, I don't know how to explain it other than make it a novel!

I got a call from a customer saying his GFCI breaker is tripping. It is a 120V 20A Siemens GFCI.

Here is what is on the circuit:

Post light with a photo cell

Small pump for a fountain that is plugged in but not running or even turned on.

250W metal halide 120V yard light on a photo cell

Dehumidifier under the house with a cord cap to a duplex recep.

Condensate pump for the dehumidifier

Here is the details concerning when it trips, it doesn't trip immediately:

Post light & yard light come on but don't know which comes on first, dehumidifier is on all the time as well as the condensate pump. The small fountain pump is plugged in but not turned on. Anywhere from 45 mins to 1 hour after the lights come on it trips.

This is what I have done so far but it still trips.
Covered the PC for the post light to allow the light to come on. Let it stay on about 15 minuites.
Disconnected the yard light at the junction box on the pole. The junction box also has a GFCI receptacle in it. I left the GFCI recep and just disconnected the feed to the light/photo cell. Left for the night. Customer called back the next morning saying it still tripped.

Went back today and took the post light off the pole. Checked the connections, sockets, etc. I checked for continuity between hot-ground, neutral ground all good. I decided to go a step farther and checked the light with a megger. That also checked good.

Went under the house and disconnected the feed (UF) wire where it was connected in a junction box. Went back out and meggered the UF with nothing connected at either end.
That checked good with the megger. Connected the feed back in the junction box. Put a pigtail w/lamp socket instead of the post light and let it stay on about 1/2 hour with no trip.

Now I don't know how to check a PC other than to see if it's switching or not so I just changed the PC. Put the light back on the post. The reason I changed the PC is the customer had taped up the eye earlier in the morning to see if it would come on. That's when he said it stayed on for about an hour then tripped. He said the breaker would not reset and that's when he called me. I told him to remove the tape and see if it would reset, which it did. He also said he went under the house and turned the dehumidifier to where it would run. It ran with nothing else running and the breaker held. So I thought I would just eliminate the possibility of a bad PC.

Went back to the yard light and removed the GFCI receptacle & replaced with just a regular duplex since the circuit was already on a GFCI breaker. Connected the yard light back. It came on as soon as the breaker was reset. I think the PC does that when first powered up after the power has been disconnected. It stayed on for about a minute then went off, breaker not tripped. Post light came on and stayed on because I had tape over the eye. I watched the post light for a while and told the customer to leave the tape on until dark then pull it off. I left but told him to let me know if it held. He called me about an hour later and said it tripped again.
I just told him to try one more thing with the post light. I told him to change the bulbs and see if that helps. So I haven't heard back but that doesn't mean anything as he may be waiting to call tomorrow.

I'm confused as to why the breaker only trips when the post light is on but then only after a while. If the dehumidifier is the problem, why doesn't it trip during the day?
I'm sure it has to come on some during the day.
Since the fountain pump hasn't been on during any of the tripping I don't think it is the problem.

Anyone have any suggestions? I may have left something out, so ask away if it seems I left out anything.

 

[readydave8]

WARNING.....Very long post. Sorry, I don't know how to explain it other than make it a novel!

I got a call from a customer saying his GFCI breaker is tripping. It is a 120V 20A Siemens GFCI.

Here is what is on the circuit:

Post light with a photo cell

Small pump for a fountain that is plugged in but not running or even turned on.

250W metal halide 120V yard light on a photo cell

Dehumidifier under the house with a cord cap to a duplex recep.

Condensate pump for the dehumidifier

Here is the details concerning when it trips, it doesn't trip immediately:

Post light & yard light come on but don't know which comes on first, dehumidifier is on all the time as well as the condensate pump. The small fountain pump is plugged in but not turned on. Anywhere from 45 mins to 1 hour after the lights come on it trips.

This is what I have done so far but it still trips.
Covered the PC for the post light to allow the light to come on. Let it stay on about 15 minuites.
Disconnected the yard light at the junction box on the pole. The junction box also has a GFCI receptacle in it. I left the GFCI recep and just disconnected the feed to the light/photo cell. Left for the night. Customer called back the next morning saying it still tripped.

Went back today and took the post light off the pole. Checked the connections, sockets, etc. I checked for continuity between hot-ground, neutral ground all good. I decided to go a step farther and checked the light with a megger. That also checked good.

Went under the house and disconnected the feed (UF) wire where it was connected in a junction box. Went back out and meggered the UF with nothing connected at either end.
That checked good with the megger. Connected the feed back in the junction box. Put a pigtail w/lamp socket instead of the post light and let it stay on about 1/2 hour with no trip.

Now I don't know how to check a PC other than to see if it's switching or not so I just changed the PC. Put the light back on the post. The reason I changed the PC is the customer had taped up the eye earlier in the morning to see if it would come on. That's when he said it stayed on for about an hour then tripped. He said the breaker would not reset and that's when he called me. I told him to remove the tape and see if it would reset, which it did. He also said he went under the house and turned the dehumidifier to where it would run. It ran with nothing else running and the breaker held. So I thought I would just eliminate the possibility of a bad PC.

Went back to the yard light and removed the GFCI receptacle & replaced with just a regular duplex since the circuit was already on a GFCI breaker. Connected the yard light back. It came on as soon as the breaker was reset. I think the PC does that when first powered up after the power has been disconnected. It stayed on for about a minute then went off, breaker not tripped. Post light came on and stayed on because I had tape over the eye. I watched the post light for a while and told the customer to leave the tape on until dark then pull it off. I left but told him to let me know if it held. He called me about an hour later and said it tripped again.
I just told him to try one more thing with the post light. I told him to change the bulbs and see if that helps. So I haven't heard back but that doesn't mean anything as he may be waiting to call tomorrow.

I'm confused as to why the breaker only trips when the post light is on but then only after a while. If the dehumidifier is the problem, why doesn't it trip during the day?
I'm sure it has to come on some during the day.
Since the fountain pump hasn't been on during any of the tripping I don't think it is the problem.

Anyone have any suggestions? I may have left something out, so ask away if it seems I left out anything.

If it consistently trips 45 min-1 hour after lite comes on: something is heating up and touching?

Otherwise I wonder if you could put in non-GFCI breaker, and individual GFCI receptacles or blank-faces to isolate problem?

 

[Little Bill]

If it consistently trips 45 min-1 hour after lite comes on: something is heating up and touching?

Otherwise I wonder if you could put in non-GFCI breaker, and individual GFCI receptacles or blank-faces to isolate problem?

This circuit was not GFCI protected anywhere except the GFCI receptacle on the yard light pole until the dehumidifier was installed. I'm guessing that there were two reasons for this. One, the nearest circuit to get power for the dehumidifier was the circuit for the outside lights, and two, they didn't want to install a GFCI receptacle for the dehumidifier because it would be too hard to crawl under and reset it. That's even if you would know if it had tripped.

Really nothing but the dehumidifier and the fountain pump needs GFCI. It might be easier to just run a circuit for the dehumidifier and put in a GFCI breaker for it, then put a regular breaker for the rest.

 

[electricalist]

The second paragraph says it a gfci breaker circuit then goes on later and says put regular plug in place of gfci Since its on a gfci breaker
The mh May have the short. They sometimes go out after they are on for a while when going bad.
I'd bypass any and every pc unplug any thing with a cord. Reset the breaker if it trips its a light causing it. .
Mh is a hunch. .

 

[Little Bill]

The second paragraph says it a gfci breaker circuit then goes on later and says put regular plug in place of gfci Since its on a gfci breaker
The mh May have the short. They sometimes go out after they are on for a while when going bad.
I'd bypass any and every pc unplug any thing with a cord. Reset the breaker if it trips its a light causing it. .
Mh is a hunch. .

Probably got lost in my long post but I did say that I disconnected the metal halide. I left it disconnected over night. Customer said the breaker tripped some time after dark.
Other than when the PC was taped, all of the tripping has occurred after dark when the outside lights are on. I guess you could also say that's when there is the most load....lights and dehumidifier.

 

[electricalist]

Gotcha I'm terrible at details.
Overall I usually disconnect everything I can and add them back til I find the cause. I'd definitely hook to lights to a different circuit If I could or an extension cord and see which circuit trips.

 

[goldstar]

If it's a GFI breaker that's tripping you don't know whether it's tripping due to a ground fault problem or an over load. Try clamping an amp probe on and see how much current you have flowing in the circuit with everything on.

 

[czars]

When several items are connected to the same GFCI protected circuit, potential current leakage from each will sum together. If each item has an acceptable leakage of 2 ma, then 3 or 4 items will cause the GFCI device to trip. Try to isolate each load on separate, temporary GFCI devices. If one trips, that load is a problem. If none trip, the sum of the leakages is the problem and separate GFCI protection devices will solve the problem.

 

[ritelec]

Probably got lost in my long post but I did say that I disconnected the metal halide. I left it disconnected over night. Customer said the breaker tripped some time after dark.
Other than when the PC was taped, all of the tripping has occurred after dark when the outside lights are on. I guess you could also say that's when there is the most load....lights and dehumidifier.

I don't know. May be out in left field. But night time.
Animal bedding down for the night. Just a thought. How and why ??? Just a thought.

 

[augie47]

I might have missed it in the post, but have you tried a different GF breaker ?
I'm not an advocate of "bad breaker", but it does happen.

 

[Little Bill]

I might have missed it in the post, but have you tried a different GF breaker ?
I'm not an advocate of "bad breaker", but it does happen.

That was going to be my last thing to try. As to why I didn't take everything off the circuit and add each back one at a time. It is because of what the HO said, that it only happens at night. So the most logical things were the outside lights that were both on a photo cell. Seemed to fit, since the lights didn't come on until after dark and that's when I was told the breaker tripped, that one of the lights was the problem.

Now for the "REST OF THE STORY"!
I should know by now to take most of what a customer says with a grain of salt.:happyyes:

I was called this morning by the HO to tell me that he changed the light bulbs but the breaker still tripped. So he crawled under the house and unplugged both the dehumidifier and the condensate pump. Said the breaker held all night.

The dehumidifier was actually my first suspect as to the cause of the tripping. I didn't pursue it because of being told it only tripped at night and the dehumidifier also runs during the day.:rant:
So I'm thinking the GFCI was actually tripping at various times and was only noticed at night. Also that's when he tried to reset it. So it makes sense what another poster mentioned about additive leakage. Perhaps there were other small leakages and the dehumidifier put it over the top. Well either that or the condensate pump, as I don't know which one since he unplugged both.

Moral of the story.......listen to your "gut" and not to the customer!

 

[electricalist]

Some days we beat ourselves. I'm like you, follow my instincts for 2 reasons. 1 it's how our gut feeling is created, the mind realizes its been through those factors but we can't totally recall all the details but we get that feeling. 2. If the customer knew what it was or the sollution then we wouldn't be there.
All in all atleast it's figured out, your approach keeps them calling you.