Ground Fault tripping on house related to pool pump turn-on - how to fix?

[kwired]

What is it that you are calling "3 way breakers?"

Only thing that comes to mind is what is typically called "dual function" breakers.

1 thermal magnetic trip function
2 GFCI function
3 AFCI function

Certainly not a plug on circuit breaker product I am aware of that functions similar to a "three way switch", manual transfer switch with overcurrent protection is possible though.

 

[dns718]

Agree. +1




Could it be the freq drive controller for the pump motor causing the problem?

I have reread the OPs original posted message over at least a couple more times and I can't find where he definitively says the 60 amp GFCI breaker, for "variable speed pump", is tripping out on ground fault.

OP said:

The problem could be a defective freq drive or just a poorly designed freq drive.

That's right - the 60A main breaker (at the house/garage area, *non-GFCI*) has never tripped; nor has the 20A pool pump breaker (GFCI, junction panel at pool equipment pad location on opposite side of house ~60' away).

I couldn't find a reference to VFD/frequency drive on the Hayward site or owner's manual, but I did see it referred to elsewhere on the web so apparently yes, apparently this is a frequency drive (correct me if I'm wrong please). Hayward and others do admit to its "noisiness" but offer precious little by way of filter/conditioning circuits. Speaking of which, does anyone offer "after market" / 3rd-party filtering solutions to help offset a temporary inrush surge current from things like these VFD motors? (Big capacitor, etc.) Thanks -

 

[dns718]

What is it that you are calling "3 way breakers?"

Only thing that comes to mind is what is typically called "dual function" breakers.

1 thermal magnetic trip function
2 GFCI function
3 AFCI function

Certainly not a plug on circuit breaker product I am aware of that functions similar to a "three way switch", manual transfer switch with overcurrent protection is possible though.

Sorry if 3-way is confusing terminology with switch topology - yes it is meant in this thread to refer to the new code breakers that protect not only against overload condition (high-current), but also GFCI and AFCI. So three types of "protection" (and tripping conditions). Yes, I think I've heard of them called "dual-function" breakers (though I think of them as "three-function" breakers).

 

[dns718]

I believe he further clarified that by using the diagnostic function that Square D has on the latest generation AFCI's:

press and hold test button while resetting breaker, if it trips in less then one second that means it has been tripping on GFCI function, if it trips in two seconds it means it has been tripping on AFCI function, If it trips in five seconds there is no fault, or it has been tripping on short circuit or overload functions.

I believe all he was saying was after talking to Schneider, they determined the breakers in question are tripping on GFCI function. Problem is they are breakers not associated with the circuit that is causing the trips, tells me there is probably some sort of interference going on causing this trip condition, like maybe RF interference. RF from non associated circuit has been something that gets brought up on this forum from time to time causing tripping GFCI's and AFCI's.

Thanks for helping clarify, yes that is what I meant to say. Interesting about mentions elsewhere of frequency drives and RF interference that you bring up and causing other tripping GFCIs (and AFCIs but apparently my dataset is these other breakers are tripping based upon erroneously-sensed ground fault condition).

I haven't heard much as yet on whether the SyCom whole house surge suppressor might also be contributing to these nuisance trips (as a secondary cause in a cascading-fault scenario)? I did see elsewhere how surge suppression can cause ground faults...

 

[dns718]

This happens enough that it’s beginnig to be not news at all. Just different circumstances.

We also know that while, according to SQ D, there is nothing wrong with older models the newer ones are less apt to randomly trip.

This is an interesting mention. Square D did ask for my nuisance tripper date codes, 2017s mostly but a couple of 2015s mixed in - and said while there has been no special problem reported for these (e.g., that would say have been a quality issue batch for recall etc.), he nonetheless has sent a replacement set of breakers my way... which I will try down the road -

 

[kwired]

Thanks for helping clarify, yes that is what I meant to say. Interesting about mentions elsewhere of frequency drives and RF interference that you bring up and causing other tripping GFCIs (and AFCIs but apparently my dataset is these other breakers are tripping based upon erroneously-sensed ground fault condition).

I haven't heard much as yet on whether the SyCom whole house surge suppressor might also be contributing to these nuisance trips (as a secondary cause in a cascading-fault scenario)? I did see elsewhere how surge suppression can cause ground faults...

I didn't really say they caused interference with GFCI/AFCI in industrial settings but have caused RF interference in industrial settings for many years. Also so happens many more GFCI were required in dwellings then in industrial applications until more recent years. AFCI is still mostly only required in dwellings - a place where VFD's aren't so common. Now that we are putting more of mentinoed items in same facilities we are finding more these kinds of compatability issues.

 

[Jamesco]

This is an interesting mention. Square D did ask for my nuisance tripper date codes, 2017s mostly but a couple of 2015s mixed in - and said while there has been no special problem reported for these (e.g., that would say have been a quality issue batch for recall etc.), he nonetheless has sent a replacement set of breakers my way... which I will try down the road -

I would suggest you have an electrician replace the breakers soon after you receive them.

Just out of curiosity, how many breakers are affected? Are they all located next to one another and or across from one another? What are the loads, type of, the GFCI/AFCI breakers serve? Any idea of the total connected load to each one of them?

 

[dns718]

I would suggest you have an electrician replace the breakers soon after you receive them.

Just out of curiosity, how many breakers are affected? Are they all located next to one another and or across from one another? What are the loads, type of, the GFCI/AFCI breakers serve? Any idea of the total connected load to each one of them?

OK, will plan on replacing. Day 2 results of current experiment (reduction of variable frequency drive Hayward EcoStar pool pump prime start up from 3450 rpm to 3000 rpm) has for 2nd straight day avoided any nuisance trips of home breakers. Good news and meaningful given this was fairly predictable to have trips at the higher rpm... will need additional data over coming days to see if this has definitely changed behavior but encouraging that we have some direct cause and effect forming, even if shy of the exact failure scenario (e.g., since the home panel breakers are tripping via ground fault condition, how is this ground fault forming? Via noisy high inrush current requirement at start up coupled with whole house surge protector or ???)

There are about 6 breakers or so that have tripped at one time or another (again, all separate from pool breakers). 4 are on one side of panel and 2 across, all combination GFCI/AFCI Square D, near each other but not perfectly adjacent in all cases. 15A or 20A breakers. Example service for dining nook (nothing plugged in!) to bathroom + electrical bidet (Toto rated 1300W) to security closet including DVR. At the time of trip, discovered to be almost always aligned with the time the pool pump turns on, there is usually little else going on in terms of load on these other home circuits (besides what I mention in the latter). That's what has made it odd and perplexing - but of late seems like we are zero-ing on the pool pump start-up (2 minute high-speed prime) that is somehow causing a ground shift, perhaps exacerbated by clamping behavior on surge (or overly-sensitive or defective breakers). The other experiment I have queued up is to bring the pool pump back to full speed and turn-off (switch off the 35A breaker for) the surge protector.

Thanks all for the insights to date in this apparently unusual and mystifying case!

 

[Jamesco]

OK, will plan on replacing. Day 2 results of current experiment (reduction of variable frequency drive Hayward EcoStar pool pump prime start up from 3450 rpm to 3000 rpm) has for 2nd straight day avoided any nuisance trips of home breakers. Good news and meaningful given this was fairly predictable to have trips at the higher rpm... will need additional data over coming days to see if this has definitely changed behavior but encouraging that we have some direct cause and effect forming, even if shy of the exact failure scenario (e.g., since the home panel breakers are tripping via ground fault condition, how is this ground fault forming? Via noisy high inrush current requirement at start up coupled with whole house surge protector or ???)

There are about 6 breakers or so that have tripped at one time or another (again, all separate from pool breakers). 4 are on one side of panel and 2 across, all combination GFCI/AFCI Square D, near each other but not perfectly adjacent in all cases. 15A or 20A breakers. Example service for dining nook (nothing plugged in!) to bathroom + electrical bidet (Toto rated 1300W) to security closet including DVR. At the time of trip, discovered to be almost always aligned with the time the pool pump turns on, there is usually little else going on in terms of load on these other home circuits (besides what I mention in the latter). That's what has made it odd and perplexing - but of late seems like we are zero-ing on the pool pump start-up (2 minute high-speed prime) that is somehow causing a ground shift, perhaps exacerbated by clamping behavior on surge (or overly-sensitive or defective breakers). The other experiment I have queued up is to bring the pool pump back to full speed and turn-off (switch off the 35A breaker for) the surge protector.

Thanks all for the insights to date in this apparently unusual and mystifying case!

.

I find it odd the 20 amp GFCI breaker at the pool pump, that supplies power to the VFD, has never tripped. I assume somewhere in trouble shooting the problem you pushed the TEST button on the GFCI breaker to make sure the device is working properly.

I read up on the SPD you are using for surge protection at the electrical panel. From what I read it uses multiple MOVs. I don't think the SPD is causing the problem. I'm not sure I would disconnect it from the panel either as you suggested. One thing I did notice is how cheap, price wise the thing is.

I think you need to find someone that has good power analyzer and connect it at the electrical panel and monitor the Lines when the pool pump is started. I still think it's harmonics distortion/noise the pool pump VFD is sending back out on the AC mains that is screwing with the breakers in the electrical panel. I would think a power analyzer would show for sure if it harmonics, or if it is something else.

Just me, I don't think the pool pump's inrush current alone is the problem. I would bet the Central air unit compressor pulls as much inrush current as the pool pump does.

One other question. Is the electrical service main breaker, for the house electrical panel, mounted in the electrical panel, or is it outside on the house? If outside, approximately how far would you say the main breaker is from the electrical panel in the house?

Here is some reading material for you on harmonics.

http://apps.geindustrial.com/publib...TNR=Application and Technical|DEE-500|generic

https://www.vfds.com/blog/vfd-harmonic-mitigation

http://www.fluke.com/fluke/uses/comunidad/fluke-news-plus/articlecategories/pq/vfdharmonics

http://ewh.ieee.org/conf/tdc/Eliminating_harmonic_problems_APQ_T_D.pdf


.

 

[kwired]

OK, will plan on replacing. Day 2 results of current experiment (reduction of variable frequency drive Hayward EcoStar pool pump prime start up from 3450 rpm to 3000 rpm) has for 2nd straight day avoided any nuisance trips of home breakers. Good news and meaningful given this was fairly predictable to have trips at the higher rpm... will need additional data over coming days to see if this has definitely changed behavior but encouraging that we have some direct cause and effect forming, even if shy of the exact failure scenario (e.g., since the home panel breakers are tripping via ground fault condition, how is this ground fault forming? Via noisy high inrush current requirement at start up coupled with whole house surge protector or ???)

There are about 6 breakers or so that have tripped at one time or another (again, all separate from pool breakers). 4 are on one side of panel and 2 across, all combination GFCI/AFCI Square D, near each other but not perfectly adjacent in all cases. 15A or 20A breakers. Example service for dining nook (nothing plugged in!) to bathroom + electrical bidet (Toto rated 1300W) to security closet including DVR. At the time of trip, discovered to be almost always aligned with the time the pool pump turns on, there is usually little else going on in terms of load on these other home circuits (besides what I mention in the latter). That's what has made it odd and perplexing - but of late seems like we are zero-ing on the pool pump start-up (2 minute high-speed prime) that is somehow causing a ground shift, perhaps exacerbated by clamping behavior on surge (or overly-sensitive or defective breakers). The other experiment I have queued up is to bring the pool pump back to full speed and turn-off (switch off the 35A breaker for) the surge protector.

Thanks all for the insights to date in this apparently unusual and mystifying case!

That diagnostic test you ran on the breaker itself isn't telling you you actually have a ground fault - it is only telling you the ground fault function of the breaker is what is triggering the trip. Whatever interference is going on here is effecting the ground fault detection feature of the breaker.

.

I find it odd the 20 amp GFCI breaker at the pool pump, that supplies power to the VFD, has never tripped. I assume somewhere in trouble shooting the problem you pushed the TEST button on the GFCI breaker to make sure the device is working properly.

I don't know that OP mentioned what brand that breaker was, if not Square D might not be effected by whatever is tripping the Square D breakers. From reading other threads here and there Siemens has an GFCI that seems to work with certain pool pumps that give other brand GFCI's fits, don't know why.

 

[Jamesco]

That diagnostic test you ran on the breaker itself isn't telling you you actually have a ground fault - it is only telling you the ground fault function of the breaker is what is triggering the trip. Whatever interference is going on here is effecting the ground fault detection feature of the breaker.

I don't know that OP mentioned what brand that breaker was, if not Square D might not be effected by whatever is tripping the Square D breakers. From reading other threads here and there Siemens has an GFCI that seems to work with certain pool pumps that give other brand GFCI's fits, don't know why.

Post #20
dns718 said:

Thanks for the breaker suggestion... to clarify, I've not seen any trips either at the pump 20A GFCI breaker (believe this to be Square D as everything else is, but strangely no identifying marks as with all other breakers and box) or the 60 non-GFCI main house panel breaker. But are you suggesting that the Siemens is better at filtering out noise that might affect other main panel 3-way breakers? Hayward did tend to like the Siemens QF220 as tested across a wide range of frequencies, though Schneider Electric (Square D) also claimed testing well into GHz range.

The Square "D" logo is clearly marked on the front of their breakers.

Just a guess it is not a square D breaker.

 

[kwired]

Post #20
dns718 said:


The Square "D" logo is clearly marked on the front of their breakers.

Just a guess it is not a square D breaker.

Stuff in there I may have missed, but yes I have to agree it likely isn't a Square D breaker.

 

[dns718]

.

I find it odd the 20 amp GFCI breaker at the pool pump, that supplies power to the VFD, has never tripped. I assume somewhere in trouble shooting the problem you pushed the TEST button on the GFCI breaker to make sure the device is working properly.

I read up on the SPD you are using for surge protection at the electrical panel. From what I read it uses multiple MOVs. I don't think the SPD is causing the problem. I'm not sure I would disconnect it from the panel either as you suggested. One thing I did notice is how cheap, price wise the thing is.

I think you need to find someone that has good power analyzer and connect it at the electrical panel and monitor the Lines when the pool pump is started. I still think it's harmonics distortion/noise the pool pump VFD is sending back out on the AC mains that is screwing with the breakers in the electrical panel. I would think a power analyzer would show for sure if it harmonics, or if it is something else.

Just me, I don't think the pool pump's inrush current alone is the problem. I would bet the Central air unit compressor pulls as much inrush current as the pool pump does.

One other question. Is the electrical service main breaker, for the house electrical panel, mounted in the electrical panel, or is it outside on the house? If outside, approximately how far would you say the main breaker is from the electrical panel in the house?

Here is some reading material for you on harmonics.

http://apps.geindustrial.com/publib...TNR=Application and Technical|DEE-500|generic

https://www.vfds.com/blog/vfd-harmonic-mitigation

http://www.fluke.com/fluke/uses/comunidad/fluke-news-plus/articlecategories/pq/vfdharmonics

http://ewh.ieee.org/conf/tdc/Eliminating_harmonic_problems_APQ_T_D.pdf


.

I did just check out the pool pump dual common-trip 20A GFCI (unmarked company; sticker says "Interrupting Rating 10 000 A / 60 Hz / 120/240 V-A nom. I/AIR"). It did trip when pressing the test button (on the left side breaker; no button on right side but both trip through interlocking device).

Good point about the surge current not likely being the issue (at least by itself) and for another contributor's thoughts on the breaker tripping as not necessarily ground related (even if it reflects that).

Main house breaker is 200A and in the same "main" house panel, which is on the inside wall of the garage. Meter is mounted on the outside of the garage wall just opposite, and runs underground to a nearby pole with transformer from utility (FPL), maybe 30'.

The VFD harmonics does seem suspect. As an update, today was Day 4 of the experiment to see if lowering the initial 2 minute Hayward priming cycle from 3450 rpm to 3000 rpm was sufficient to avoid trips; unfortunately, today did result in one main panel 3-way/dual-function AFCI/GFCI breaker trip. It does appear that the problem has been affected, however, as we went 3 days/tries without any trips which was almost never seen at the higher 3450 rpm setting. Based upon today's results, I have lowered the prime further to 2800 rpm to see if that helps further, but it seems this will be short of a "rock solid" approach - in fact, in the process of establishing the new setting the pump restarted and tripped (at 2800 rpm) another main panel breaker.

If I were to find someone to measure the electrical panel power with a power analyzer to see the harmonics, what would be a possible next step for solution? This might be a way to convince the pool electrician at least of cause and effect.

The articles/pointers are good (extrapolating from industrial VFD applications to my residential setting). Are there any filters that I should consider that are not too expensive?

I will reach out to the pool company and Hayward (pool pump manufacturer) again with the added info to see if they can offer further options.

Thanks for the thoughts and guidance!

 

[FionaZuppa]

put wires around a ferrite ring to squash high freq harmonics from reaching the gfi.

a few posts on this has come up before, use of ferrites was discussed, but i have not seen anyone post back any results.

 

[Jamesco]

dns718 said:
Post #33

I did just check out the pool pump dual common-trip 20A GFCI (unmarked company; sticker says "Interrupting Rating 10 000 A / 60 Hz / 120/240 V-A nom. I/AIR"). It did trip when pressing the test button (on the left side breaker; no button on right side but both trip through interlocking device).

Manufacture's name should be on the breaker somewhere.

dns718 said:
Post #33

If I were to find someone to measure the electrical panel power with a power analyzer to see the harmonics, what would be a possible next step for solution? This might be a way to convince the pool electrician at least of cause and effect.

Any Power Quality company will have the equipment needed. You may even find a commercial/industrial electrical contractor that has the equipment. Or at least he/she will give you the name of a Power Quality testing company they use or recommend.

Just curious, how long have you been living in the new house?
Did you hire the pool Company or did the home builder?
If the home builder, then the Pool Company was a sub contractor and paid by the home builder. Correct?

I don't know how it works in your state but in mine there is a law or an unwritten law that says a home builder must warrant the house for one year. That includes his sub contractors as well. Have you contacted the home builder and discussed with him the problems you are having?

Just an outsider looking in, the odds are good the Pool Company knew the pump they installed has had problems with nuisance tripping GFCI/AFCI breakers. (Just do a search on the internet)
If the Pool Company was/is a sub contractor of the builder's, and the builder paid the company for the work done on your house, then the builder should be responsible for solving the problem.

If you haven't talked with the Home builder you should. He should set up a meeting, with him or his representative, the pool company owner, the pool company's electrician, the electrical contractor that wired your house, the lead electrician that wired the house, and finally you.
Get everybody together at one time, one place. Let the finger pointing and blaming start there.

What do you know 100% for sure? The VFD/pool pump is causing nuisance tripping of breakers in the main electrical panel in the house.
Turn off the pump and leave it off, no problems.
Turn on the pump, problems.


.

 

[going_commando]

I ran into a similar problem a year ago or so. It was a new house that we had wired and we used square D dual function breakers for the kitchen circuits and the laundry. The GC called us complaining of breakers tripping and the lights flickering. It was only the dual function breakers tripping. Turns out it was the Dewalt 120v cordless miter saw (uses 2 60V dewalt batteries) using a plug in converter so you dont have to use batteries. The power supply must have been pumping some serious harmonics. The LED bulbs in the house would dim and pulse when the saw was run, and you could watch the dual function breakers trip showing a ground fault in a cascading fashion, one after the other. We called square-d and they were aware of the problem. Apparently this isnt a new phenomenon with square D dual function breakers being sensitive to harmonics. Once the GC stopped using that plug in converter the problems went away.

Its odd that square-d tech support would tell you they didnt know of nuisance tripping problems recently when last year they told us they knew of problems.

 

[dns718]

put wires around a ferrite ring to squash high freq harmonics from reaching the gfi.

a few posts on this has come up before, use of ferrites was discussed, but i have not seen anyone post back any results.

This is an intriguing prospect as I was looking at a way to filter these harmonics. Any idea of the spec/size for such a ferrite ring? The wires are in conduit of course (being outside) to the junction box, so I would need to figure out where would be a suitable space for this (probably at the source right at pump would be best in theory (?) though as a practical matter given limitations, maybe inside the junction box next best assuming I could fit it).

 

[dns718]

I ran into a similar problem a year ago or so. It was a new house that we had wired and we used square D dual function breakers for the kitchen circuits and the laundry. The GC called us complaining of breakers tripping and the lights flickering. It was only the dual function breakers tripping. Turns out it was the Dewalt 120v cordless miter saw (uses 2 60V dewalt batteries) using a plug in converter so you dont have to use batteries. The power supply must have been pumping some serious harmonics. The LED bulbs in the house would dim and pulse when the saw was run, and you could watch the dual function breakers trip showing a ground fault in a cascading fashion, one after the other. We called square-d and they were aware of the problem. Apparently this isnt a new phenomenon with square D dual function breakers being sensitive to harmonics. Once the GC stopped using that plug in converter the problems went away.

Its odd that square-d tech support would tell you they didnt know of nuisance tripping problems recently when last year they told us they knew of problems.

Interesting. While our house was being built, I was aware of occasional trips that indeed seemed to correlate with the use of various power tools. Schneider did acknowledge this much (as did others). Did you happen to confirm whether the dual-function breakers were tripping based upon arc or ground fault signature detection? (In our pool pump case, the trips are uniformly ground fault related, but I have formerly suspected - though not confirmed - that the power tools' induced trips might have been arc related.) Schneider engineer Craig coincidently checked in with me today, curious about whether I had swapped out for the breakers he sent. I did just recently receive these though still doing some characterization/experiments before I likely call a licensed electrician to help me change these out.

Latest update is that changing pool priming speed from 3450 rpm to a lesser value does affect the problem - though it is apparently not "linear" - in that we are presently seeing less failures at 2900 rpm than either 2800 rpm or 3000 rpm (no trips for 4/4 tries to date). One theory was that the added load of the heat pump might exacerbate the trips - which I remembered as independent but did not carefully check for this possibility just yet. I am not really surprised given the hypothesized noisy harmonics from the variable VFD drive pool pump controller that there might be values that are noisier than others (though I still expect some lesser effect as the rpms are reduced). This experimentation is to better understand the cause and effects plus see if there might be a suitable workaround, though this speed change by itself feels less than rock solid given the intermittent nature of random noise (maybe a full moon will make worse!).

I did revisit Hayward tech support and my local pool installer, and the installer agreed to schedule a visit to check the pump. I suppose another avenue could be to replace the VFD drive with a less featured, more conventional back-generation 2-fixed-speed pump.

 

[kwired]

Interesting. While our house was being built, I was aware of occasional trips that indeed seemed to correlate with the use of various power tools. Schneider did acknowledge this much (as did others). Did you happen to confirm whether the dual-function breakers were tripping based upon arc or ground fault signature detection? (In our pool pump case, the trips are uniformly ground fault related, but I have formerly suspected - though not confirmed - that the power tools' induced trips might have been arc related.) Schneider engineer Craig coincidently checked in with me today, curious about whether I had swapped out for the breakers he sent. I did just recently receive these though still doing some characterization/experiments before I likely call a licensed electrician to help me change these out.

Latest update is that changing pool priming speed from 3450 rpm to a lesser value does affect the problem - though it is apparently not "linear" - in that we are presently seeing less failures at 2900 rpm than either 2800 rpm or 3000 rpm (no trips for 4/4 tries to date). One theory was that the added load of the heat pump might exacerbate the trips - which I remembered as independent but did not carefully check for this possibility just yet. I am not really surprised given the hypothesized noisy harmonics from the variable VFD drive pool pump controller that there might be values that are noisier than others (though I still expect some lesser effect as the rpms are reduced). This experimentation is to better understand the cause and effects plus see if there might be a suitable workaround, though this speed change by itself feels less than rock solid given the intermittent nature of random noise (maybe a full moon will make worse!).

I did revisit Hayward tech support and my local pool installer, and the installer agreed to schedule a visit to check the pump. I suppose another avenue could be to replace the VFD drive with a less featured, more conventional back-generation 2-fixed-speed pump.

With newer units if the diagnostic feature tells you ground fault - it only means the device trip was triggered by the ground fault detection components. If you have say RF interference causing this trip, then you don't actually have a ground fault, but it is still the GF circuitry of the device that is initiating the trip.

 

[FionaZuppa]

i finally got to look a tad more at the siemens gfi i cracked open, the one that was/is recommended by Pentair.

i thought the 8pin soic that was on the internal pc board was a small op-amp, but its not that simple, its a "GFI" IC 8pin by Fairchild, and the ckt i see looks about identical to page 6 of the Fairchild datasheet.
see https://www.mouser.com/ds/2/149/RV4141A-1012110.pdf

the scr being used in this ocpd is UTC MCR100L http://www.unisonic.com.tw/datasheet/MCR100.pdf

i am not sure why this specific ocpd is less susceptible to tripping than others. maybe the others have more crude circuitry and as such the hi freq overlay from the VFD on the pump causes those other breakers to trip.