Ground fault using manual transfer switch

[doans]

I had an Ioniq 5 previously and used their V2L adapter to power part of my house, it worked well, now when trying to do the same using pro power onboard from my lightning I am getting a ground fault.

My setup is a manual generator transfer switch and connect a Power Cord Plug Adapter 15Amp 5-15P Male to 30Amp L5-30R Female with Twist Lock to the transfer switch and then just an extension cord to one of the 120v outlets in the bed. As soon as I flip the transfer switch to generator mode I get the ground fault error.

I had an electrician install this box and it worked fine before, what exactly do I need to do to get it working on the lightning?

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[bmwhitetx]

The Lightning ProPower has GFI protection. The bonded ground at your panel between neutral and ground allows current to flow through ground, thus tripping the GFI on the truck. There are LOTS of threads on this that give solutions, some of which are not to be discussed/banned. Suggest you read those and discuss with electrician. Start with the threads that have the most replies.

 

[Runaway Tractor]

There is no code compliant, 100% perfect way to do what you are trying to do with the F150 Lightning's Pro Power and that kind of MTS. First, the truck has it's own ground-neutral bond, which cannot be disabled to make it a floating neutral. Second the truck has GFCI protection which cannot be disabled, which sees the ground-neutral bond in your house panel as a fault and trips immediately.

The ground wire from the truck would have to be disconnected from the plug on the female twist-lock end of the cord to prevent the truck's ground fault from tripping and break the parallel pathways created by two bonding points. This is of course a hack that no electrician could or would suggest you do and would recommend against doing it. The only code compliant 100% safe perfect way to do it is literally rewiring the entire main electrical service entrance to your house with a transfer switch configured to accommodate this.

Those solar battery generators have the same bonded neutral issue, but they don't have built in GFCI protection, so you'd be none the wiser using it and "it would work". Just like most portable gas/lpg generators.

 

[doans]

Thank you for the great responses, so if I am understanding this correctly I would have to install a different manual transfer switch such as a Generac 6852 to make this work and be compliant? Or possibly another option would be this post where he used a similar MTS and a EZ transfer switch? The EZ transfer switch says it works with floating and bonded neutrals and assuming the Generac does also.

Trying to make sure I even understand this issue enough to talk to the electrician and tell him what is needed.

 

[Runaway Tractor]

I would have to install a different manual transfer switch such as a Generac 6852 to make this work and be compliant? Or possibly another option would be this post where he used a similar MTS and a EZ transfer switch? The EZ transfer switch says it works with floating and bonded neutrals and assuming the Generac does also.

Both of those break and transfer both the hot and neutral. Doing so allows your truck's bonded neutral to be the only bond in the system (and the system is just that subpanel). So yes, that would be the safe and correct way to have a critical loads panel powered by the F150 Pro Power.

 

[Hammick]

It's most likely you transfer switch but once you get a new one make sure your EVSE is not plugged in to the lightning when you turn on the pro power. My truck will throw a ground fault if my Autel charger is plugged in.

 

[intensifi]

If you live in PG&E territory request the generator adapter collar for your meter. I read that the Pro power plugs in with no issues.

 

[Newton]

I installed the 6852 and it seems to work fine and passed inspection. If you do this you need to add a label to indicate that any generator installed must also have a neutral+ground bond (the wording is in the most recent NEC.)

I did notice that although the 6852 is advertised as being auto transfer ready the wiring diagram for the upgrade kit shows that if you do that it will no longer switch neutral (it is designed to work with a permanently wired generac.)

Also note that even though it is wired correctly, no lights will show on the unit unless you have the truck plugged in -- even the light marked "utility power."

 

[doans]

Thanks again everyone, I will talk with the electrician and see how to proceed. Definitely not in PG&E land.

The EZ transfer switch would appear to be the much more cost friendly approach. A new MTS and rewiring it sounds expensive. We don't often have power outages anyways.

I only used my MTS once and here I am having to change it already

 

[doans]

Actually, sorry one more question @Runaway Tractor , if I make this change to get the F150 lightning pro power working will I have to make another change when I sell the F150 and get another vehicle?

I mean nobody knows exactly what vehicle I will get next and what technology will be in the future. But is this the "correct" way to do it and should work with new vehicles and/or generators in the future? Obviously I don't want to have to keep making changes to this.

 

[Runaway Tractor]

Nope. Any generator or vehicle 240 inverter system with a bonded neutral will hook right up to that without a problem.

 

[Henry Ford]

Both of those break and transfer both the hot and neutral. Doing so allows your truck's bonded neutral to be the only bond in the system (and the system is just that subpanel). So yes, that would be the safe and correct way to have a critical loads panel powered by the F150 Pro Power.

Per code, any generator attached to a Generac 6852 should be grounded as well.

 

[ryun]

The ground wire from the truck would have to be disconnected from the plug on the female twist-lock end of the cord to prevent the truck's ground fault from tripping and break the parallel pathways created by two bonding points. This is of course a hack that no electrician could or would suggest you do and would recommend against doing it. The only code compliant 100% safe perfect way to do it is literally rewiring the entire main electrical service entrance to your house with a transfer switch configured to accommodate this.

I just had a discussion with my electrician on this very thing and he said basically the same. It would work but he wouldn't do it personally. I pressed but he couldn't say why other than he couldn't even come close to endorsing it otherwise he'd be liable.

I'd love to understand the reasoning behind it -- I'm in no way trying to defeat it (in fact, I already plan on using the EZ Generator Switch talked about above for cost and safety). But here's my hang up: If the truck is neutral-ground bonded and the panel is neutral-ground bonded then the Lightning is safer than most portable generators even with the ground removed from the plug; it already has a path to ground along the neutral line. Most people I know with portable generators and no GFCI protection never ground them while in use.

But okay, I already admit that I don't understand it all so maybe there's still a way for the truck to become energized or something. Or maybe the worry is that the neutral line could be so overloaded with extra current that it could fail and/or cause a fire. But then the GFCI protection would kick in and stop it all, no?

Another reason for my hang up is I've heard from multiple electricians that if I don't have a ground connection in my house at an outlet then it's no big deal. Just slap a GFCI outlet downstream of the rest of the branch and you're good to go. Code compliant. How is Pro Power without a ground any different? Does it come down to the energy potential being way higher in a generator than a 20 amp, 120V circuit?

 

[Galactus55]

It's most likely you transfer switch but once you get a new on make sure your EVSE is not plugged in to the lightning when you turn on the pro power. My truck will throw a ground fault if my Autel charger is plugged in.

Hammick has hit the nail on the head.
Try using your system as is.
Just unplug your charger from the Lightning and all should be good.

 

[Runaway Tractor]

If the truck is neutral-ground bonded and the panel is neutral-ground bonded then the Lightning is safer than most portable generators even with the ground removed from the plug; it already has a path to ground along the neutral line. Most people I know with portable generators and no GFCI protection never ground them while in use.

I know. It took me a long time to wrap my head around the whole thing. But once it clicks, it's like "oh, duh, of course."

With the bond in the panel and the generator, you now have two parallel pathways for neutral current to flow from the house back to the generator (this is where it clicked for me). Whatever split-phase imbalance current exists flows back to the generator on the neutral and the ground. It turns the ground from the panel to the generator into a current carrying conductor, which it is not rated or sized to do. Worse, if the neutral fails (which is a thing that happens), you now have all the current on the ground conductor.

Being realistic, will it work and is it generally safe if everything is intact? Sure. Do thousands of people do this every day not even knowing about it? Yep. Overloads and ground faults still trip the breakers. It's not going to kill linemen or kittens.

Floating neutral generators don't have that bond. The bond in the panel is the only bond. A short to ground on the generator frame or cable trips by way of the grounding bond in the house panel like everything else.

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