Pro Power ground fault: I'd like to hear from the experts please

[Hammick]

So I have been using Pro Power for over a month to power our home. I wired in a three-pole (neutral switching) automatic transfer switch to a critical load panel. All has been working great except I am periodically getting a ground fault in the truck when I turn on the Pro Power. Turning off my main AC beaker (located in the critical load panel) seemed to eliminate the ground fault issue. I found this very odd since the AC wiring does not have a neutral. I checked the AC disconnect box for loose connections, insects, etc. and all looked proper. I should mention this is an inverter driven AC unit that is connected to the furnace by 4 communication wires (essentially a canbus connection).

These ground faults have become such an annoyance that I disconnected the truck's ground connection at the transfer switch. I am still getting periodic ground faults. I resolve this by shutting off the truck, disconnecting the cord to my generator inlet box, reconnecting the cord then turning the truck back on.

Just yesterday I had the truck throw a ground fault after it had been powering the house for hours with no issues. It just decided to ground fault and of course the transfer switch went back to grid power.

So my question for the experts is how is it possible for the truck to ground fault if it's ground is not connected?

Is the Pro Power just overly sensitive? Anyone else experiencing ground faults when the truck's ground is not connected?

I can live with these periodic ground faults but I'd much prefer to have the truck's ground connected since I went through all the time and expense of wiring it correctly.

I can't think what else to test.

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[Maquis]

With the ground wire disconnected, there should be no way for it to trip. There are 2 possibilities:
1) There is another path between the truck chassis and your power system ground. This could happen if your EVSE was plugged into the truck, for example.
2) The GFCI is tripping due to high frequency interference. This has been known to happen when powering inverter-driven motors.

Pentair pool pumps are notorious for this issue. Some have solved these types of issues by installing ferrite beads on the conductors.
pentair pool pump gfci site:forums.mikeholt.com

It would be helpful if you could isolate each load to try to determine which one is causing the trip.

 

[cdherman]

The body of the truck is still grounded, even you have removed the ground pin from your cable. Are your tires a little damp?

 

[Hammick]

With the ground wire disconnected, there should be no way for it to trip. There are 2 possibilities:
1) There is another path between the truck chassis and your power system ground. This could happen if your EVSE was plugged into the truck, for example.
2) The GFCI is tripping due to high frequency interference. This has been known to happen when powering inverter-driven motors.

Pentair pool pumps are notorious for this issue. Some have solved these types of issues by installing ferrite beads on the conductors.
pentair pool pump gfci site:forums.mikeholt.com

It would be helpful if you could isolate each load to try to determine which one is causing the trip.

Thanks. I've had the ground fault with and without the EVSE connected. I'll leave it unplugged during my troubleshooting.

My inverter motors are the main floor AC, main fridge, washer (and maybe the dryer). For my troubleshooting is it enough to turn off those breakers or do I need to remove the neutral and grounds from the circuit? I'll put some ferrite rings on the AC L1 and L2.

The Lennox system throws a fit when I turn off the AC breaker. Even if the thermostat is off or in heat mode. It eventually throws a communication fault and sends a maintenance request to Lennox. Luckily my Lennox installer isn't up on the tech and never reaches out. So I can't just leave the breaker off in the winter.

Just had a thought. Any chance having a Noco battery tender connected to the 12v could cause a ground fault? The Noco does not have a grounding plug. It's connected most of the time. For my testing I'll unplug the tender.

 

[Hammick]

The body of the truck is still grounded, even you have removed the ground pin from your cable. Are your tires a little damp?

Thanks. Truck is parked on an epoxy garage floor and hasn't been in the rain for weeks. I did take it for a wash last Tuesday but I'm certain everything is dry as a bone.

 

[Maquis]

Thanks. I've had the ground fault with and without the EVSE connected. I'll leave it unplugged during my troubleshooting.

My inverter motors are the main floor AC, main fridge, washer (and maybe the dryer). For my troubleshooting is it enough to turn off those breakers or do I need to remove the neutral and grounds from the circuit? I'll put some ferrite rings on the AC L1 and L2.

The Lennox system throws a fit when I turn off the AC breaker. Even if the thermostat is off or in heat mode. It eventually throws a communication fault and sends a maintenance request to Lennox. Luckily my Lennox installer isn't up on the tech and never reaches out. So I can't just leave the breaker off in the winter.

Just had a thought. Any chance having a Noco battery tender connected to the 12v could cause a ground fault? The Noco does not have a grounding plug. It's connected most of the time. For my testing I'll unplug the tender.

As long as the inverters aren’t running, they aren‘t generating RF noise. Shutting off the breaker is sufficient. The battery tender is interesting. It could be causing your problem depending on its design. Unhook it during troubleshooting.

 

[Hammick]

As long as the inverters aren’t running, they aren‘t generating RF noise. Shutting off the breaker is sufficient. The battery tender is interesting. It could be causing your problem depending on its design. Unhook it during troubleshooting.

Thanks. The only inverter motor that could have been running in the past few weeks is the Samsung fridge. I'll start with that breaker.

 

[cdherman]

As long as the inverters aren’t running, they aren‘t generating RF noise. Shutting off the breaker is sufficient. The battery tender is interesting. It could be causing your problem depending on its design. Unhook it during troubleshooting.

I'm curious why the 12v battery tender in the first place. To keep the 240v output going, doesn't the Lightning need to remain in some sort of "On" or "Ready" mode? And in that mode, wouldn't the 12v battery be kept charged?

 

[Maquis]

I'm curious why the 12v battery tender in the first place. To keep the 240v output going, doesn't the Lightning need to remain in some sort of "On" or "Ready" mode? And in that mode, wouldn't the 12v battery be kept charged?

It should, but I think a lot of us are trying to maximize the 12V SoC in order to ensure we get updates.

 

[Rcpd34]

I got around this problem by disassembling the plug on the extension cord between the truck in the house and disconnecting one of the grounds. Works flawlessly.

 

[Maquis]

I got around this problem by disassembling the plug on the extension cord between the truck in the house and disconnecting one of the grounds. Works flawlessly.

If you read the original post carefully, you’ll see that he is still experiencing tripping after removing the truck’s ground connection as part of the troubleshooting process. But disconnecting the ground shouldn’t be necessary with a transfer switch that switches the neutral.

 

[Hammick]

I'm curious why the 12v battery tender in the first place. To keep the 240v output going, doesn't the Lightning need to remain in some sort of "On" or "Ready" mode? And in that mode, wouldn't the 12v battery be kept charged?

As Maquis said to make sure the 12v SOC is high enough to allow OTA updates. But more importantly to keep the 12v fully charged for longevity. I'm not sure why manufacturers can't figure out how to keep the 12v batteries fully charged on vehicles that aren't every day drivers. A lead acid battery that is allowed to sit in a partial state of charge will only last a few years.

Hyundai just had a major recall on the Ioniq 5/6 to address vehicles being disabled because their 12v battery is flat. There is a yellow light on the dash of the I5 that indicates when the 12v is charging. Since the recall/software update I have noticed it's charging the 12v a lot more than before.

Hopefully manufacturers switch to Lion 12v batteries at some point so it's less of an issue.

https://www.impactbattery.com/blog/post/battery-desulfators-do-they-work

 

[Hammick]

I got around this problem by disassembling the plug on the extension cord between the truck in the house and disconnecting one of the grounds. Works flawlessly.

Do you have any inverter motor loads?

 

[Hammick]

The battery tender is interesting. It could be causing your problem depending on its design. Unhook it during troubleshooting.

A lot of these big named tenders (NOCO, CTEK, Batteryminder, etc.) use high frequency pulsing to keep the battery from sulphating at a partial SOC and also to remove light sulphation. Maybe somehow that pulsing is being seen by the truck's GFCI.

 

[Maquis]

A lot of these big named tenders (NOCO, CTEK, Batteryminder, etc.) use high frequency pulsing to keep the battery from sulphating at a partial SOC and also to remove light sulphation. Maybe somehow that pulsing is being seen by the truck's GFCI.

That’s certainly possible. I’m also thinking that it could have some components used for surge suppression that could leak a small amount of current between the line and DC side.

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