Successfully tested powering my home with 30A ProPower and a generator interlock

[ericpullen]

I’ve had the setup ready for a while, but finally got around to testing it all just to make sure it all works before this winter storm arrives.

A little about my setup, I am all electric and have 400A service and had a full panel upgrade done a little over a year ago. I now have 2 - 200A panels, one with most of the critical loads and the other with my large loads (like heat pump, water heater, heat strips, etc). Both of them have generator interlocks, 30A on the primary loads and 50A for the large loads. I have a portable 10k generator I can use for the 50A large loads (AC mainly).

I should also mention I have a new meter base with disconnects on the outside for each panel.

Talked to the electrician and we did remove the ground from the 30A inlet to prevent the fault, but he felt that was still acceptable. Here is the 30A inlet used:

So here is what the truck saw with most of my critical loads running. Plenty of power left!

Ask me anything about the setup, but be easy on the looks of the panels, I had to tear out a stupid closet the previous owner put around the main panel and haven’t gotten around to making it look nice yet.

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[skyak]

What type of cord/cable are you running to connect the truck to the generator inlet?

 

[ericpullen]

This is the cord that I purchased. It’s long enough to reach from the inlet to my truck parked in the detached garage.
RVGuard Generator Extension Cable

 

[Walle1jm]

This is the cord that I purchased. It’s long enough to reach from the inlet to my truck parked in the detached garage.
RVGuard Generator Extension Cable

I just bought one like this too at 100ft! Thankfully haven’t tested it yet as we still have power but good to have just in case.

 

[SilverBrewer]

I love the white panel I gotta say lol

 

[lakeguy55]

How have you handled the bonded neutral issue? Do your transfer switches also transfer the neutral? If so, I assume your generator is bonded neutral also?

 

[ericpullen]

How have you handled the bonded neutral issue? Do your transfer switches also transfer the neutral? If so, I assume your generator is bonded neutral also?

The generator is a DuroMax and I believe has a floating neutral, and I have no transfer switches in the setup, only an interlock breaker for each panel.

I'm not an electrician, but what I understand is that because the two panels are technically sub-panels (the outside meter socket has the "primary" panel and has disconnect breakers for each panel), then the inside panels are not bonded per code.

Whenever the weather gets nice again, I'm going to do a whole video that shows how my setup is used and do a full test-run of both interlock outlets powering the house (one with my Lightning and the other with the generator). I figured others would be interested plus it will serve as an example for my wife if anything ever happens to me

 

[wiffleballpractice]

I'm not an electrician, but what I understand is that because the two panels are technically sub-panels (the outside meter socket has the "primary" panel and has disconnect breakers for each panel), then the inside panels are not bonded per code.

This just means that your neutral ground bond is at the service entrance. If you put a multimeter to the ground and neutral in either panel, they should show as a short (or approximately a short).

The way you got around the truck ground fault is by disconnecting the truck's ground from your house at the plug; your truck thinks everything is fine because there is never any current returned on its ground. I'm not certain of all the consequences of this, but it does mean your truck won't cut power in the event of an actual ground fault, which means this isn't the safest possible solution.

 

[Nick Gerteis]

This just means that your neutral ground bond is at the service entrance. If you put a multimeter to the ground and neutral in either panel, they should show as a short (or approximately a short).

The way you got around the truck ground fault is by disconnecting the truck's ground from your house at the plug; your truck thinks everything is fine because there is never any current returned on its ground. I'm not certain of all the consequences of this, but it does mean your truck won't cut power in the event of an actual ground fault, which means this isn't the safest possible solution.

Correct, but neither would the utility company. The GF critical spots in the house, like a kitchen counter outlet, are still protected by either the GFCI outlet itself or the GFCI breaker in the breaker box that feeds them.

 

[wiffleballpractice]

Correct, but neither would the utility company. The GF critical spots in the house, like a kitchen counter outlet, are still protected by either the GFCI outlet itself or the GFCI breaker in the breaker box that feeds them.

That's true.

Here's my theory on why it's bad that I don't necessarily have the expertise to claim:

The truck's neutral is tied to ground at the truck and the house's neutral is tied to the house ground, which are not necessarily the same. This voltage difference can mean a couple of things, including that current can be flowing on the neutral in either direction and that the 120V may not actually be 120V in reference to the house neutral or house ground.

There's a video out there where a powerboost is set up to backup a house the same way OP's is and most things work fine except the lights behave a little funky, which I think can be attributed to the above. I'd get a multimeter out and look at the voltage of the hot and neutral vs each other and vs ground when on truck power and utility power and see how they differ.

 

[MBM]

That's true.

Here's my theory on why it's bad that I don't necessarily have the expertise to claim:

The truck's neutral is tied to ground at the truck and the house's neutral is tied to the house ground, which are not necessarily the same. This voltage difference can mean a couple of things, including that current can be flowing on the neutral in either direction and that the 120V may not actually be 120V in reference to the house neutral or house ground.

There's a video out there where a powerboost is set up to backup a house the same way yours is and most things work fine except the lights behave a little funky, which I think can be attributed to the above. I'd get a multimeter out and look at the voltage of the hot and neutral vs each other and vs ground when on truck power and utility power and see how they differ.

The truck GFI should trip in the event a ground fault occurs, even without the ground connected.

Yes, a ground to neutral bond at both locations creates multiple issues:
Ground/neutral bond at two locations essentially creates a single conductor, therefore, the ground wire would also be carrying/sharing current that should only be on the neutral.

This is where the issue lies with a GFI tripping at the truck. The truck GFI, or any GFI, works by monitoring all the hot conductors, as well as the neutral, in a scenario where the house and truck are bonded all the current that should be on the neutral isn’t there and the GFI senses that and trips.

 

[biers]

Got my Generac transfer switch up and running. Got the water heater (hybrid, very low draw 98% of the time), fridge, freezer and half the house outlets and lights. Was no problem installing. Took me about 2 hours.

 

[d2blake]

I was testing out my setup and it's nice to have a spare security camera to put on the truck's screen. Then you can instantly monitor your draw with your phone. The app sucks at updating propower info.

 

[capt_ramius]

Unfortunately, this solution seems like it’s only applicable to your panel installation… and may not be the best option, anyways, because it just bypasses and doesn’t actually switch off the neautral-to-ground bond. Glad it works for you, though.

 

[chillaban]

Just wanted to chime in and say I got something very similar to the OP’s setup and it works great. Instead of 30A I opted to get a 50A SS2-50 inlet for future proofing. Requires an adapter you can find off Amazon to L14-30P to SS2-50R.

Similarly, the GFCI trips on the truck end and the electrician disconnected the ground from the inlet to the panel, at the panel side. He felt comfortable doing it since the house side ground still keeps everything inside safe, and the truck GFCI still protects the cable run (he was more concerned about accidental damage to the outdoor cabling run).

I had wanted to do it the “official” way with the Generac GFCI sub panel but it was way too impractical. For some reason just lighting and appliance and bedroom outlets were spread across 15 different breakers so even with tandem ones it was a stretch.

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