GFI Breakers tripping

[hudscorp]

i have an interesting problem on a job.

i have a single family home with a standard single phase 200amp service.
i wired the house 4 years ago. the kitchen has GFI breakers, not receptacles.
The house also has NuHeat radiant floor heating mats.
The past two months i have been back there a few times to reset the kitchen GFI breakers and theradiant heat thermostats
have been tripping the internal GFI. all at random times a few times even when noone was home.

i have tightened the neutrals, cleaned up the grounds, changed the breakers, tried all i can think of.

any suggestions as to how to fix this? and even more important, WHY its happening?

any suggestions are appreciated. please email me directly at hudscorp@yahoo.com

thank you so much, Hudi

 

[Dennis Alwon]

If a gfci is tripping then my guess is there is a break in the mat and the current is going elsewhere. You can try a new gfci but you might want to ohm out the leads to the resistant heat and see if there is some leakage. I don't mean a break as a separation but as in leakage between conductor and ground

 

[GoldDigger]

i have an interesting problem on a job.

i have a single family home with a standard single phase 200amp service.
i wired the house 4 years ago. the kitchen has GFI breakers, not receptacles.
The house also has NuHeat radiant floor heating mats.
The past two months i have been back there a few times to reset the kitchen GFI breakers and theradiant heat thermostats
have been tripping the internal GFI. all at random times a few times even when noone was home.

i have tightened the neutrals, cleaned up the grounds, changed the breakers, tried all i can think of.

any suggestions as to how to fix this? and even more important, WHY its happening?

any suggestions are appreciated. please email me directly at hudscorp@yahoo.com

thank you so much, Hudi

If there is a lot of stray capacitance (which I might expect to find in some radiant heat mat designs) then a high frequency spike or other transient on the incoming AC might trigger the GFCI (Not speaking from experience, just a theoretical speculation.) What sort of loads are left plugged into the kitchen outlets?
Am I correct that they (sometimes?) leave the radiant heat turned on when they are not home?

Dennis's idea of leakage in the heat panels could be something that conducts for a short time after the thermostat applies power rather than continuously. Or something that is sensitive to temperature.

 

[hudscorp]

If a gfci is tripping then my guess is there is a break in the mat and the current is going elsewhere. You can try a new gfci but you might want to ohm out the leads to the resistant heat and see if there is some leakage. I don't mean a break as a separation but as in leakage between conductor and ground

the GFI are tripping randomly. no relevance to each other and the kitchen GFI breakers have tripped under no load.
My theory is that there is some sort of ground fault from the utility that is back feeding into the house and causing only GFI type equipment to trip.
I was pondering a whole house surge protector but i dont think it would help for a ground fault.

 

[GoldDigger]

there is some sort of ground fault from the utility that is back feeding into the house and causing only GFI type equipment to trip.

Basic electrical theory does not allow that to happen unless there are neutral to ground connections in your wiring somewhere downstream of the GFI. All sorts of other strange things can happen when POCO has a high resistance ground where they count on a low resistance ground, but tripping GFIs is not one of them.
Some GFCI receptacles and breakers are subject to false tripping from RFI, but that has to be more than just a cell phone or cordless phone unless it is parked right next to a GFCI receptacle.
Again, under some circumstances surges or spikes on the line can trip GFIs.

 

[PetrosA]

If these things are all in the same area of the house, or if the home runs run together back to the panel, I'd be asking whether the people had any work done recently that may have cause some pinched romexes along the home runs. Maybe a plumbing leak was repaired, or some flooring was redone, or something was added or basement finished? Is a rodent infestation possible? I would probably start by isolating the wiring and meggering it.

 

[Warmsmeallup]

If your client is still having issues, try disconnecting the Nuheat mats for awhile. Doing this test during the summer is more convenient than mid-winter.

 

[kwired]

Since you mentioned other GFCI are tripping I don't think the radiant floor heat is the source of the problem, it simply has ground fault protection (probably at a 30 mA level) in the controller and is responding to the same incident.

Is the incoming power by chance experiencing surges, brown outs, etc. There may be some inductive kickback issues somewhere causing the tripping, could even be from outside the home.

Are electronics not on GFCI's indicating power failure after such incidents?

 

[newservice]

Sounds like yu are saying you have 2 separate problems, one -that the kitchen small appliance circuit breaker(s?) are tripping, and that separately the built in gfi on the thermostat is tripping.? Assuming the mats aren't wired in to the small appliance circuits.

 

[meternerd]

Basic electrical theory does not allow that to happen unless there are neutral to ground connections in your wiring somewhere downstream of the GFI. All sorts of other strange things can happen when POCO has a high resistance ground where they count on a low resistance ground, but tripping GFIs is not one of them.
Some GFCI receptacles and breakers are subject to false tripping from RFI, but that has to be more than just a cell phone or cordless phone unless it is parked right next to a GFCI receptacle.
Again, under some circumstances surges or spikes on the line can trip GFIs.

Two things you might check. Have you lifted the main bonding jumper and isolated the panel neutral from the POCO and made sure there are no neutral grounds anywhere but at the service disconnect? If that seems OK, you can request the POCO to do a test with a "Beast of Burden". If you don't know what that is, it's a load box connected to the meter socket which loads each hot leg and measures voltage on each leg to neutral. A neutral problem will cause the loaded side to drop voltage and the unloaded side to rise in voltage. If they won't help, you can do the same thing by watching voltage at the main breaker as you turn on 120V loads on one phase and then the other. Sounds like some sort of neutral issue to me.

 

[growler]

The past two months i have been back there a few times to reset the kitchen GFI breakers and theradiant heat thermostats
have been tripping the internal GFI. all at random times a few times even when noone was home.

Kitchen GFCI tripping at random times? See if the refrigertator is plugged in the small appliance circuit. I have seen those go a couple of weeks and not trip.

Heat mats? You just have to test those.

 

[kwired]

Two things you might check. Have you lifted the main bonding jumper and isolated the panel neutral from the POCO and made sure there are no neutral grounds anywhere but at the service disconnect? If that seems OK, you can request the POCO to do a test with a "Beast of Burden". If you don't know what that is, it's a load box connected to the meter socket which loads each hot leg and measures voltage on each leg to neutral. A neutral problem will cause the loaded side to drop voltage and the unloaded side to rise in voltage. If they won't help, you can do the same thing by watching voltage at the main breaker as you turn on 120V loads on one phase and then the other. Sounds like some sort of neutral issue to me.

GFCI doesn't care if neutral is lost or how many times it may be bonded as long as this bonding is not on the load side of the GFCI.

If you have lost service or feeder neutral you will have voltage problems, but you will not have a trip condition for a GFCI supplied by that circuit.

 

[meternerd]

Oh....guess I'm just used to everybody blaming the evil power company first.

 

[TonyEEINC]

May be the service meter?

May be the service meter?

I have had seen similar issues with GFI breakers, when the service provider uses a smart meter, they transmit a RF signal to the provider, the amount of wattage output can be adjusted.
My local electric company did not want to admit it was there issue for a while, but when I got to the right person they adjusted the output of the RF and the trouble went away.
You could change to GFCI outlets which may be far enough away to not be effected.
As for the floor heater sounds like a different problem to me, and this stuff usually ends with you busting up tile...........

 

[Barbqranch]

Nuheat controller

Nuheat controller

I also have a NuHeat heated floor in my bathroom (love it!) and the controller seems to just randomly trip the internal GFI. It is on a GFI circuit, which never trips. I believe the heat blanket is just acting as a big antenna and noise is tripping it. It never seems to trip when on, it appears to be tripping either when changing state or when off.

 

[p real]

i think first of all, you have to determine if the two issues are related to eachother or separate. This will at least tell you whether its likely a poco or service problem, or if it is related to the gfis themselves and their associated wiring. i know i have chased such troubleshooting problems and thought the problem was one big issue when actually it was two unrelated small issues. That being said, i have also seen gfis that share the line side of a circuit cause problemz between each other. Have you tried putting it on a normal brkr and seeing if that still llets the internal gfis on the controllers trip? how about all the other gfis in the house? If they are not tripping intermittenly too then i would say the problems are most likely not related to the power co or service.