Generac 6852 Transfer Switch installed (to power my house from the Pro Power 240V plug)

[Thunder1809]

I spent yesterday putting in one of these Generac 6852 with an electrician so I did it correctly. We put in a couple of tandem breakers to get to 10 circuits like I had on my previous transfer switch. But it is not working correctly while using ProPower from the truck. I don’t get the bonded neutral fault like I did when I plugged into my other transfer switch last week.

When I switch over from line to generator with the truck plugged in I get a ground fault. What is odd is that it does not occur immediately, but sometimes after minutes, sometimes after a few seconds and sometimes when I turn on one additional breaker. We did a lot of trouble shooting and checked that each circuit was wired correctly and the neutrals were pulled off the neutral bar in the main panel.

I brought out my gas generator and hooked it up and it works fine. So we were both wondering if there is a problem with the GFCI or the inverter with the truck. Is there a way the dealer can check this? If the ground fault occurred immediately I would think it was our installation, but there were times when we had it running with about 500 watts on each leg and it would run for a while and then would fault.

Any ideas are appreciated.

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[Maquis]

I spent yesterday putting in one of these Generac 6852 with an electrician so I did it correctly. We put in a couple of tandem breakers to get to 10 circuits like I had on my previous transfer switch. But it is not working correctly while using ProPower from the truck. I don’t get the bonded neutral fault like I did when I plugged into my other transfer switch last week.

When I switch over from line to generator with the truck plugged in I get a ground fault. What is odd is that it does not occur immediately, but sometimes after minutes, sometimes after a few seconds and sometimes when I turn on one additional breaker. We did a lot of trouble shooting and checked that each circuit was wired correctly and the neutrals were pulled off the neutral bar in the main panel.

I brought out my gas generator and hooked it up and it works fine. So we were both wondering if there is a problem with the GFCI or the inverter with the truck. Is there a way the dealer can check this? If the ground fault occurred immediately I would think it was our installation, but there were times when we had it running with about 500 watts on each leg and it would run for a while and then would fault.

Any ideas are appreciated.

The GFCI on the truck has class A protection. It must trip before the current imbalance (current to “ground”) exceeds 6mA. That’s not much - it’s the same as the protection on a single GFCI-protected branch circuit in your house. If there is slight leakage current on some of your circuits, once you energize enough of them to reach the threshold, it will trip. It often requires some sophisticated troubleshooting to figure out what is causing the leakage current. It’s often caused by older appliances, or modern ones that use inverter technology.

 

[Henry Ford]

@Maquis is correct. You need to isolate circuits in the panel until you figure out which circuit it's on then start troubleshooting the offending circuit(s). I had a similar issue that turned out to be a fireplace fan I had wired wrong years ago.

If you haven't read this whole thread it's worth spending the time.

 

[Thunder1809]

Thanks for the advice and I will do more troubleshooting.

It seemed random as the electrician and I tried different circuits and worked to keep things balanced between the legs, but it would seem it could be a number of different circuits on the 6852 that caused it to have a ground fault. We thought it was the one in my office and when the printer kicked on it faulted, but I unplugged it and it still did the same. So we turned other things off and it did the same. I also suspected an old freezer that I wanted to power, but I unplugged it and there was still a fault. Hopefully it is not in too many places.

If I plug the old freezer into the 120 outlet in the bed, and if that is the issue it should trip that too?

 

[Maquis]

Thanks for the advice and I will do more troubleshooting.

It seemed random as the electrician and I tried different circuits and worked to keep things balanced between the legs, but it would seem it could be a number of different circuits on the 6852 that caused it to have a ground fault. We thought it was the one in my office and when the printer kicked on it faulted, but I unplugged it and it still did the same. So we turned other things off and it did the same. I also suspected an old freezer that I wanted to power, but I unplugged it and there was still a fault. Hopefully it is not in too many places.

If I plug the old freezer into the 120 outlet in the bed, and if that is the issue it should trip that too?

If your electrician has a quality multimeter (Fluke 87, for example) he should try measuring the current on each circuits‘s EGC. It should be zero or very close to it.

Dumb question - Are you absolutely you have all the neutrals and EGCs isolated from each other?

 

[Thunder1809]

We did double check that and found there was one neutral that did not get pulled out of the neutral bar. Even with that isolated it faulted.

I have a Fluke meter (my son works there and gets me all kinds of stuff) and if I know what to check I could do that.

 

[BhamDCam]

Thanks for the advice and I will do more troubleshooting.

It seemed random as the electrician and I tried different circuits and worked to keep things balanced between the legs, but it would seem it could be a number of different circuits on the 6852 that caused it to have a ground fault. We thought it was the one in my office and when the printer kicked on it faulted, but I unplugged it and it still did the same. So we turned other things off and it did the same. I also suspected an old freezer that I wanted to power, but I unplugged it and there was still a fault. Hopefully it is not in too many places.

If I plug the old freezer into the 120 outlet in the bed, and if that is the issue it should trip that too?

I had a similar issue when I was troubleshooting my setup. I narrowed it down to one circuit that was making the truck fault. I unplugged everything from the circuit and turned on the PPO/Transfer Switch and it did NOT fault. As soon as I plugged in anything (I mean anything) to any of the outlets then it would fault. I concluded that there is an issue with how the outlets were wired (old house and all), not necessarily any one device/appliance.

 

[Henry Ford]

I've had this exact issue. I'm going to do my best to go through the steps to identify the problem below but it's possible I miss a step since I'm going by memory, which is not good. Be safe. Don't test a hot panel. Assume it's hot until you confirm it's not. You are testing for continuity, not current. Anyway...

The problem is there's a neutral touching ground somewhere when the switch is in the Generator Power position. It's that simple. You need to figure out where that is happening.

1. Make sure you lifted the correct neutral wires from your main panel. It would be an easy mistake to make to reroute the wrong wire, especially if your panel was full, like mine was.

2. Test continuity between the neutral bus and the ground bus in the switch panel with the switch in the Generator Power position. There should be no continuity.

3. If there's continuity between the ground bus and neutral bus in the switch panel, lift individual neutral wires from the neutral bus and test continuity between the individual neutral wire and the ground bus. There should be no continuity.

4. If you identify a circuit with continuity to the ground bus you have isolated the circuit where neutral and ground are touching. Figure out exactly what outlets/lights/etc. are on that circuit and start investigating. Unplug everything on the circuit and test again. If you still can't find it start inspecting outlets, light hookups, and whatever else is hooked up to that circuit. That's how I discovered a miswired fireplace fan.

If you are brave enough to face internet scrutiny, post photos of your installation here. If there's something that's screwed up it will be identified and you can address it.

Good luck! It's frustrating but if you are methodical, thorough, and safe you'll figure it out and be happy with the switch when it's put back together.

I wrote this is post 92.

 

[Lilburnedbear]

Copy that. Appreciate the prompt reply. Generac limits the number of tandem circuits (total of 10 circuits in 8 slots)…from my view it seems the limiting factor may be the conduit as there are a significant number of wires traveling in that conduit (conduit fill). What say you?

Yes, you can add tandem breakers to increase the number of circuits. It does mean you need to add two wires to the conduit for each additional circuit.

Can I ask if you can use breakers that aren’t Siemens in the panel? I have some Square D Homeline tandem breakers I’d like to use to expand the capacity to 10 circuits total. . And some Eaton AFCIs for the bedrooms. Can I switch the existing breakers in the TS for those ore won’t they be compatible?

thanks!!

 

[rio]

I'm about to to this install and have a question: The manual instructs for a 50A breaker in the main panel to power the transfer switch; however, the power wires that come pre-wired are 8 AWG (or so I've read - my switch hasn't arrived yet). Shouldnt a 50A breaker use 6 AWG? Feels like I should either use a 40A breaker or replace the wires with 6AWG. Am I missing something?

 

[Maquis]

Can I ask if you can use breakers that aren’t Siemens in the panel? I have some Square D Homeline tandem breakers I’d like to use to expand the capacity to 10 circuits total. . And some Eaton AFCIs for the bedrooms. Can I switch the existing breakers in the TS for those ore won’t they be compatible?

thanks!!

The list of compatible breakers should be listed on the label in the panel.

 

[Maquis]

I'm about to to this install and have a question: The manual instructs for a 50A breaker in the main panel to power the transfer switch; however, the power wires that come pre-wired are 8 AWG (or so I've read - my switch hasn't arrived yet). Shouldnt a 50A breaker use 6 AWG? Feels like I should either use a 40A breaker or replace the wires with 6AWG. Am I missing something?

If the supplied wires are THHN in conduit, they’re good for 50A.
You‘re thinking of NM cable.

 

[Thunder1809]

Can I ask if you can use breakers that aren’t Siemens in the panel? I have some Square D Homeline tandem breakers I’d like to use to expand the capacity to 10 circuits total. . And some Eaton AFCIs for the bedrooms. Can I switch the existing breakers in the TS for those ore won’t they be compatible?

thanks!!

I used Square D tandem breakers and single breakers when I expanded to 10 circuits. The electrician recommended that I get these.

 

[rio]

If the supplied wires are THHN in conduit, they’re good for 50A.
You‘re thinking of NM cable.

Oh I see. They are. Thanks!

 

[Lilburnedbear]

I used Square D tandem breakers and single breakers when I expanded to 10 circuits. The electrician recommended that I get these.

Thanks. Did you switch all breakers over to Square D to be uniform or just mix the Square D and Siemens for ones you wanted to replace/ swap out?

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