VFD Pool Pump Trips GFCI Breaker Intermittently After Tesla Solar+PW Install

[yblaser]

Since there are a lot of experts on here I thought I would pose this issue that I am having post install of Tesla Solar and PW.

I have a variable speed Pentair Intelliflo pool pump that had been working well since it was installed 2 years ago. Since the install of my Tesla system it has been tripping the GFCI breaker intermittently (~1-2x/month although in the last two weeks it has tripped twice). I have read that these variable frequency drive pumps can induce noise on the line that causes the GFCI breakers to trip erroneously.

Prior to the Tesla install this pump was on its own Pentair-branded GFCI breaker. It is unclear if the Pentair breaker is just a rebranded Siemens breaker or if it is specially adapted or cherry picked to resist these false trips. With the Tesla install they moved all my loads to new Square D panels (separate panels for backed up and non backed up loads) and replaced the breakers since my old breakers are all Siemens style. Pentair does not sell a Square D breaker. The pump is on its own dedicated GFCI breaker.

Any thoughts on how to resolve this issue? I don't think addressing this with Tesla will be very productive. Would adding a powerline filter between the pump and the breaker help? Is it possible something else Tesla did would cause intermittent tripping like this?

 

[mswlogo]

Change the GFCI breaker. Those pumps are known to false trip GFCI. Could be the system change was just enough to tip the scales. But the pumps are KNOWN to false. I had to change my GFCI for that exact pump. The Electrical supply place knew exactly which GFCI to give me.

 

[yblaser]

Change the GFCI breaker. Those pumps are known to false trip GFCI. Could be the system change was just enough to tip the scales. But the pumps are KNOWN to false. I had to change my GFCI for that exact pump. The Electrical supply place knew exactly which GFCI to give me.

Thanks. To be clear, what is in there now is a new breaker that Tesla installed because the panel type changed. I considered buying a new breaker but given the cost I am hesitant to buy a new one and hope it works but that is what I might have to do.

 

[BGbreeder]

Some GFI circuit breakers are more sensitive than others. I doubt that this has to do with the powerwalls per se, but may be due either to the rewiring that went on to install them, or your new breaker.

If it were me, I would start by checking that the wires are tight in the circuit breaker, (and back at the VFD, and the grounds on the ground bus bar). I would then double check that the wires for the pool pump are not lying adjacent to another circuit, especially one with a big motor on it that might induce a spike in the pool circuit, and that the GFCI itself isn't adjacent to breakers that have big motors. I have seen panels where the electrician had banded all of the circuits together, which looks neat, but that is not such a great idea because of heating effects and EMF noise. If you find that wires are adjacent, you might see if you can swap a few breakers to help with the separation.

If that search doesn't turn up anything actionable, or if you still have problems, I would consider adding a snubber, like this one;

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back at the VFD, on the side towards the main panel, i.e. the feed side. Try to get it as close as you can to the VFD, as this makes the snubber more effective. (Short wires keep the harmonics high, and more readily filtered.)

If that doesn't work, I would replace the GFCI.

VFDs are well known for putting harmonics back on to the rest of the house.

I think fundamentally pairing GFI and VFDs is a challenge because since VFDs store energy, they can be legitimately creating an imbalance in the current flow from the perspective of the ground fault interrupter. As it is a pool, GFI is a must.

Unless you have a fancy power quality monitor ($$$$), solving something like this is often an exercise in trying solutions sequentially to see what works.

Does this make sense?

Good luck.

All the best,

BG

 

[mswlogo]

Thanks. To be clear, what is in there now is a new breaker that Tesla installed because the panel type changed. I considered buying a new breaker but given the cost I am hesitant to buy a new one and hope it works but that is what I might have to do.

Ahhh, that’s even more likely the problem. Some breakers just will not work with those variable speed pumps. It’s a very common issue. Find someone that knows the issue and they will know the breaker to use. If they are guessing find someone else. Easy fix. What kind of panel is it? Some panels don’t have choices for breakers. Like Square D.

Replacing it with the same breaker will very unlikely work. It will need a different breaker.

 

[DHevey]

I had the same problem with the same pump. I replaced the breaker with one from Home Depot and haven't had a problem since. My house is about four years old, and I've had to replace multiple GFI's in the last six months. I think they're just getting old and they were probably a bad batch anyway.

 

[mswlogo]

I had the same problem with the same pump. I replaced the breaker with one from Home Depot and haven't had a problem since. My house is about four years old, and I've had to replace multiple GFI's in the last six months. I think they're just getting old and they were probably a bad batch anyway.

Keep in mind, it’s not a defective breaker. It’s just incompatible. Just guessing and picking one at Home Depot is dumb luck. A good electrical supply place might know exactly what you need. Mine did. My Panel was a Bryant and can take Siemens breakers. Siemens owns Bryant and the breakers looks absolutely identical. But internally they are different. I think it’s just a difference on the Milliwatts of leakage that is allowed between the Bryant and the Siemens.

 

[yblaser]

Thank @mswlogo and @DHevey. Good to know that you were able to resolve by just replacing the breaker. It's a Square D panel that Tesla installed. I'll see if the pool company that installed the pump has any particular recommendation for a breaker that is compatible with this panel.

Thanks @BGbreeder. It makes sense. At a previous house with the same type of pump I did have to install a noise filter to prevent the pump from interfering with the power line communication of my TED energy monitor. I think I still have the filter and it would be a few minutes to install temporarily at the breaker (understanding that is not an ideal location). Long term I like the product you linked to that I could install at the pool equipment pad much closer to the pump. If it works it is a much better solution than trying to find just the right breaker that works.

 

[mswlogo]

Thank @mswlogo and @DHevey. Good to know that you were able to resolve by just replacing the breaker. It's a Square D panel that Tesla installed. I'll see if the pool company that installed the pump has any particular recommendation for a breaker that is compatible with this panel.

Thanks @BGbreeder. It makes sense. At a previous house with the same type of pump I did have to install a noise filter to prevent the pump from interfering with the power line communication of my TED energy monitor. I think I still have the filter and it would be a few minutes to install temporarily at the breaker (understanding that is not an ideal location). Long term I like the product you linked to that I could install at the pool equipment pad much closer to the pump. If it works it is a much better solution than trying to find just the right breaker that works.

I was a afraid it was a Square D. I’m not sure there are choices for large 240V GFCI on Square D. You might call the pool pump company. In absolute worst case you might have to add a Subpanel with a different brand GFCI breaker.

 

[yblaser]

Just wanted to post a follow up to this thread... I haven't had much time to troubleshoot this issue but I was able to observe that at least in one case the breaker tripped overnight while the pump was not running and only providing housekeeping power to the integrated controller. This led me to believe it is not a noise issue with the VFD. I decided to bite the bullet and order a new breaker. While researching the breaker types and learning what the various part numbers mean I realized that Tesla installed a combination arc/ground fault breaker. I'm assuming now that it is the arc fault portion causing the breaker to trip as they are known to cause issues. I have ordered a regular GFI breaker and hopefully this will fix the issue once I replace the breaker.

Thanks all for the help.

 

[BGbreeder]

That's a great data point.

On a completely personal level, arc fault breaker trips always make me a little nervous. If it were me, I would take a bright flashlight and examine every wire terminal and junction box that the wires pass through, looking for loose connections, insulation rubs or scores, especially where wires enter or leave a box, loose splices, and any signs of arcing. You might have a faulty breaker, but what if you don't?

Three other thoughts; I wondered if it might be worth checking if there is a neutral at the pool pump junction box that it isn't grounded. Second, you don't have a cell or radio tower nearby, or a home handheld radio, do you? Third, what might be on the adjacent breakers that might be surging current over to the pool circuit? (Vacuum, TV, motor...)

Square D had a bad batch of arc fault breakers a few years ago, so it definitely happens.

All the best,

BG

 

[wwhitney]

Seems to me that Tesla caused a regression in the functionality of your electrical system with their work, and is liable to fix it. And that the proper fix is to set a small panel that accepts the approved Pentair breaker, and to supply it with a regular Square D (QO or HOM?) breaker that your new panel accepts.

Actually the best solution is for Pentair to fix their pumps so they play nicely with a wider variety of breakers.

Cheers, Wayne

 

[yblaser]

That's a great data point.

On a completely personal level, arc fault breaker trips always make me a little nervous. If it were me, I would take a bright flashlight and examine every wire terminal and junction box that the wires pass through, looking for loose connections, insulation rubs or scores, especially where wires enter or leave a box, loose splices, and any signs of arcing. You might have a faulty breaker, but what if you don't?

Three other thoughts; I wondered if it might be worth checking if there is a neutral at the pool pump junction box that it isn't grounded. Second, you don't have a cell or radio tower nearby, or a home handheld radio, do you? Third, what might be on the adjacent breakers that might be surging current over to the pool circuit? (Vacuum, TV, motor...)

Square D had a bad batch of arc fault breakers a few years ago, so it definitely happens.

All the best,

BG

Thanks! The circuit run is completely outdoors so I am a little less concerned about the potential for an arc starting a house fire. I'll take a look at the wires where I can access them although it is about a 30-40 ft run in metal conduit with the last 10 ft or so underground. If I recall correctly it is a direct run with no splices in between the MSP and the pump. There is of course where Tesla spliced in the circuit in the MSP when they relocated the load but I believe the splices are wrapped up pretty well and I would be hesitant to unwrap them.

You did mention earlier the potential for interference from adjacent circuits/wires. The conduit to the pool pad also has the power for our pool cover motor but since your previous post I have been checking every time I use the pool cover to ensure the pump is still powered and I have not seen the breaker trip. The only other circuit in the conduit is for the automation controller which should be benign. If it is always tripping at night time then I might suspect a condensation issue since all the equipment is outdoors and we are a few miles from the ocean.

 

[yblaser]

Seems to me that Tesla caused a regression in the functionality of your electrical system with their work, and is liable to fix it. And that the proper fix is to set a small panel that accepts the approved Pentair breaker, and to supply it with a regular Square D (QO or HOM?) breaker that your new panel accepts.

Actually the best solution is for Pentair to fix their pumps so they play nicely with a wider variety of breakers.

Cheers, Wayne

Thanks Wayne. I do agree that it seems to be a Tesla caused issue and that they should remedy it but I'm just imagining all the time I would have to spend on the phone with them to get them out, the day off work to meet them at the house, and then the inevitable finger pointing between what Tesla installed and the pool equipment.

There does seem to be hundreds of threads on the internet about this problem so I definitely agree Pentair should fix their pumps. I have seen the recommendend solution is just what you suggested, installing a small panel to accept the Pentair breaker.

 

[mswlogo]

Just wanted to post a follow up to this thread... I haven't had much time to troubleshoot this issue but I was able to observe that at least in one case the breaker tripped overnight while the pump was not running and only providing housekeeping power to the integrated controller. This led me to believe it is not a noise issue with the VFD. I decided to bite the bullet and order a new breaker. While researching the breaker types and learning what the various part numbers mean I realized that Tesla installed a combination arc/ground fault breaker. I'm assuming now that it is the arc fault portion causing the breaker to trip as they are known to cause issues. I have ordered a regular GFI breaker and hopefully this will fix the issue once I replace the breaker.

Thanks all for the help.

Good catch. The Arc faults are great, but I doubt it’s required there.

Thanks for sharing. Good info to know.

Is it only the pool pump that’s on it?

 

[BGbreeder]

@yblaser There is always the snubber...

 

[yblaser]

Good catch. The Arc faults are great, but I doubt it’s required there.

Thanks for sharing. Good info to know.

Is it only the pool pump that’s on it?

Yes the breaker that is tripping goes directly to the pool pump and there are no other loads on that breaker.

 

[mswlogo]

Yes the breaker that is tripping goes directly to the pool pump and there are no other loads on that breaker.

BTW my Arc fault breakers tell you why they tripped with blink codes (I forget details). Tells if it was arc fault or load. Yours might tell you if it saw arc fault vs ground fault vs load.

 

[wwhitney]

But regardless of what the breaker says is the reason for tripping, it may be a false positive trip due to the electrical noise that the VFD in the Pentair puts on the conductors.

Cheers, Wayne

 

[yblaser]

BTW my Arc fault breakers tell you why they tripped with blink codes (I forget details). Tells if it was arc fault or load. Yours might tell you if it saw arc fault vs ground fault vs load.

Thanks! I did not know that. I looked up the data sheet and you have to turn the breaker off, hold down the test button, and then turn the breaker back on. If it trips immediately it was a ground fault, if it trips in 2 seconds it was an arc fault, and if it trips in 5 seconds it is either no fault, a thermal overload, or a short circuit. I'll have to try that.