Overcoming bonded neutral issues in the setting of a GFI protected Ford Lighting 7.4kw inverter.....

[hammick]

Is neutral bonded to the frame?

I have no idea. The PPOB has neutral bonded to ground. Logic would dictate that the frame is grounded. Later tonight or tomorrow I will check for continuity at the PPOB ground to frame.

Right now I'm powering our house with the PPOB because we are in the 4-8 pm .36kwh peak rate period.

 

[cdherman]

Based on concerns raised here about people using a patch cord or outlet with delete ground, I am thinking of doing the following:

The current generator sits in a covered lean-to. The 200A transfer switch is outside, on the meter pole after the meter and a 200A breaker. I do not know if the ground and neutral are bonded in either the 200A breaker or the transfer switch. Regardless, the 50A generator input runs in conduit, underground into the leanto, up the wall and into a electrical enclosure. Front there, it terminates in a 6-6-6-8 length of equipment cord, ending with a 5-14 50A plug.

From the truck I will make a basic 30A twist lock to 50A 5-14R adaptor. Grounded as usual. Maybe I can even find an already made up one.

But I want to do the following at the enclosure on the wall: Install a 30A rated 3 way switch -- ground wire from cord to the common terminal of the switch. One traveler to ground on the premises (running to the transfer switch). Other traveler to a new ground rod below the enclosure, inside the leanto. I intend to paint the switch green, and label clearly:

Up: Generator lead cord grounded to premises ground. (generator w/o GFI)

Down: Generator lead cord grounded to earth (generator with GFI)

This will effectively ground the earth and truck as well, so that if there were a fault in any of the Loads or N of the cord, the GFI would detect if someone touched it,

No way anyone can run off with the cord and misuse it, since its hard wired. Clearly labeled.

I am open to suggestions, comments about this idea and how to label. Except non-productive "its not code" discussions. I think that's been discussed ad nauseum.

 

[Checkthisout]

Based on concerns raised here about people using a patch cord or outlet with delete ground, I am thinking of doing the following:

The current generator sits in a covered lean-to. The 200A transfer switch is outside, on the meter pole after the meter and a 200A breaker. I do not know if the ground and neutral are bonded in either the 200A breaker or the transfer switch. Regardless, the 50A generator input runs in conduit, underground into the leanto, up the wall and into a electrical enclosure. Front there, it terminates in a 6-6-6-8 length of equipment cord, ending with a 5-14 50A plug.

From the truck I will make a basic 30A twist lock to 50A 5-14R adaptor. Grounded as usual. Maybe I can even find an already made up one.

But I want to do the following at the enclosure on the wall: Install a 30A rated 3 way switch -- ground wire from cord to the common terminal of the switch. One traveler to ground on the premises (running to the transfer switch). Other traveler to a new ground rod below the enclosure, inside the leanto. I intend to paint the switch green, and label clearly:

Up: Generator lead cord grounded to premises ground. (generator w/o GFI)

Down: Generator lead cord grounded to earth (generator with GFI)

This will effectively ground the earth and truck as well, so that if there were a fault in any of the Loads or N of the cord, the GFI would detect if someone touched it,

No way anyone can run off with the cord and misuse it, since its hard wired. Clearly labeled.

I am open to suggestions, comments about this idea and how to label. Except non-productive "its not code" discussions. I think that's been discussed ad nauseum.

Just make 1 foot long whip cord that you plug-in between the end of the truck cord and house.

Defeat the EGC in this cord.

Put cord in safe deposit box at bank when not in use.

 

[Hedges]

The 200A transfer switch is outside, on the meter pole after the meter and a 200A breaker. I do not know if the ground and neutral are bonded in either the 200A breaker or the transfer switch. .

I am open to suggestions, comments about this idea and how to label. Except non-productive "its not code" discussions. I think that's been discussed ad nauseum.

Where in the house electrical system did you feed the Lightning's output when its GFCI tripped?

I think the house neutral-ground bond should be at the first disconnect, the 200A breaker. That means a 3-pole 200A transfer switch would isolate neutral from ground, so feeding it with GFCI might work. ("Might", because things like leakage from line to ground will trip it, and some equipment including EMI filter capacitors can be sufficiently leaky.) Of course you could try shutting off all loads, then connect them until you find the offending leakage, and just keep those off.

If you put in a 3-pole switch, you would then want to put a neutral-ground bond in your generator.

 

[hammick]

Where in the house electrical system did you feed the Lightning's output when its GFCI tripped?

I think the house neutral-ground bond should be at the first disconnect, the 200A breaker. That means a 3-pole 200A transfer switch would isolate neutral from ground, so feeding it with GFCI might work. ("Might", because things like leakage from line to ground will trip it, and some equipment including EMI filter capacitors can be sufficiently leaky.) Of course you could try shutting off all loads, then connect them until you find the offending leakage, and just keep those off.

If you put in a 3-pole switch, you would then want to put a neutral-ground bond in your generator.

This 3-pole automatic transfer switch works perfect for me but requires my subpanel (now critical load panel) to be completely isolated from the main panel except the ground wire of course. Every once in a while the Lightning will throw a ground fault if my 30a 240v AC breaker is on. Not sure if the Lightning is just overly sensitive or if I need to clean the cobwebs and bugs out of the outside AC disconnect box.

I know it is not UL listed but it's very robust (ignore 3lb spec; it weights 9lbs) and does exactly what I need it to do. It's as simple as going to the Lightning and Turning on my Pro Power. All automatic from there. I haven't seen anything remotely like it for the price.

So if your subpanel is fine with just 50a when on grid power it's a great option if you don't need a UL listing.

https://www.amazon.com/dp/B0B63WXZYZ?psc=1&ref=ppx_yo2ov_dt_b_product_details

 

[hammick]

Based on concerns raised here about people using a patch cord or outlet with delete ground, I am thinking of doing the following:

The current generator sits in a covered lean-to. The 200A transfer switch is outside, on the meter pole after the meter and a 200A breaker. I do not know if the ground and neutral are bonded in either the 200A breaker or the transfer switch. Regardless, the 50A generator input runs in conduit, underground into the leanto, up the wall and into a electrical enclosure. Front there, it terminates in a 6-6-6-8 length of equipment cord, ending with a 5-14 50A plug.

From the truck I will make a basic 30A twist lock to 50A 5-14R adaptor. Grounded as usual. Maybe I can even find an already made up one.

But I want to do the following at the enclosure on the wall: Install a 30A rated 3 way switch -- ground wire from cord to the common terminal of the switch. One traveler to ground on the premises (running to the transfer switch). Other traveler to a new ground rod below the enclosure, inside the leanto. I intend to paint the switch green, and label clearly:

Up: Generator lead cord grounded to premises ground. (generator w/o GFI)

Down: Generator lead cord grounded to earth (generator with GFI)

This will effectively ground the earth and truck as well, so that if there were a fault in any of the Loads or N of the cord, the GFI would detect if someone touched it,

No way anyone can run off with the cord and misuse it, since its hard wired. Clearly labeled.

I am open to suggestions, comments about this idea and how to label. Except non-productive "its not code" discussions. I think that's been discussed ad nauseum.

I think your plan is solid. But if your gas/propane generator is already bonded with GFI why go through the hassle of the switch? You would still label that there is a ground rod as the shed. Even if someone used an un-bonded generator is having the extra ground rod really a safety issue. Depending on how far away the shed is code might even require it.

Nobody touches our home electrical system except me. My wife will throw breakers if I tell her exactly what to do. That being said I put labels on everything for the inevitable day that I can no longer remember what the hell I have done. For example when we had our first EV (Tesla MYLR) I converted our 30 amp 120v RV plug that was in the garage to a 30a 240v receptacle. The Tesla mobile charge didn't use the neutral so I converted the neutral to L2 and swapped out the 120v breaker for a 240v breaker. So L1 L2 & G. Labeled the inlet box in the garage: "No neutral connected - 24a Tesla EV charger only" Now I believe this was a code violation but even if something was plugged in requiring the neutral it wasn't a safety issue; it just wouldn't work.

Went through a similar issue this summer with a new solar ground mount array at our off grid place. 4.3kw array had 10 gauge wiring from array to solar disconnect inside the garage. Was getting conflicting info on whether to include a ground wire so it would ground at our main panel UFER ground. We are off grid with no inspections so I couldn't get an official answer. Decided to put in an 8ft ground rod next to the schedule 80 pipe and grounded the panels (Iron Ridge ground mounts ground all panels and hardware) to it. So the array is not grounded to the 600v disconnect. The metal disconnect does have a 10awg EGC to the solar charge controller and of course all the solar equipment has EGC to the main panel which is bonded. Works for me and I have it all labeled for when I forget.

My thought process was I didn't want an easy path for a lightning strike to enter the building even though I installed a Midnight Solar OCP at the charge controller).

 

[Hedges]

Every once in a while the Lightning will throw a ground fault if my 30a 240v AC breaker is on. Not sure if the Lightning is just overly sensitive or if I need to clean the cobwebs and bugs out of the outside AC disconnect box.

Capacitors in EMI filters cause a bit of ground current. There may be some leakage.
If you had a clamp microammeter you might be able to track it down.

 

[CoolWill]

Just make 1 foot long whip cord that you plug-in between the end of the truck cord and house.

Defeat the EGC in this cord.

Put cord in safe deposit box at bank when not in use.

Someone could rob the bank and still end up with the cord.

 

[Supervstech]

As I understand it, the lightning has its own N-G bond, so it legally cannot be connected to a house with its own N-G bond.

Opening the egc on the cord to the house would not present any issues in the house, because the house does have a N-G bond, BUT the truck itself would be ungrounded. The truck is gfci protected, so this shouldn't present any issues for the truck itself.

Ideally, the HOUSE needs to have the N-G bond removed, and all neutrals and grounds separated.

I have a customer with a lightning, and he wants me to tie into his condo panelboard and provide a simple way to power the house...

So far I have declined to take that on...

I think, from reading this thread I have made the right decision.

 

[hammick]

Capacitors in EMI filters cause a bit of ground current. There may be some leakage.
If you had a clamp microammeter you might be able to track it down.

Thanks. So would these EMI filters be in the AC inverter? The truck rarely throws the fault. When it does I just head to the breaker box and turn off the AC beaker then turn on the Pro Power. The truck never faults out when I turn the breaker back on. So I can live with it.

 

[hammick]

As I understand it, the lightning has its own N-G bond, so it legally cannot be connected to a house with its own N-G bond.

Opening the egc on the cord to the house would not present any issues in the house, because the house does have a N-G bond, BUT the truck itself would be ungrounded. The truck is gfci protected, so this shouldn't present any issues for the truck itself.

Ideally, the HOUSE needs to have the N-G bond removed, and all neutrals and grounds separated.

I have a customer with a lightning, and he wants me to tie into his condo panelboard and provide a simple way to power the house...

So far I have declined to take that on...

I think, from reading this thread I have made the right decision.

If he can live with a manual transfer switch with 10 critical load circuits the Reliance XR series is probably the cheapest and easiest code compliant way to do it. Generac has one as well but it's more $$$. The 3-pole auto transfer switch I'm using (see post no. 85) works perfect with a critical load subpanel but is not UL listed so I'm guessing it would not pass inspection.

 

[hammick]

Is neutral bonded to the frame?

I can confirm continuity of ground and frame from both the frunk inverter and the bed inverter.

 

[cdherman]

I think your plan is solid. But if your gas/propane generator is already bonded with GFI why go through the hassle of the switch? You would still label that there is a ground rod as the shed. Even if someone used an un-bonded generator is having the extra ground rod really a safety issue. Depending on how far away the shed is code might even require it.

Actually while hiking at today at 9,900 ft I had an epiphany. My plan has a rather glaring/stupid hole. That accessory ground rod that I dreamt up for good measure will nicely link the inverter ground to the premises ground, where ever that is (likely about 200 ft away at the first main panel) via the good ole' earth. And since the neutral and ground are bonded there, I will surly get ground faults from the inverter. To work, the ground from the Inverter must be isolated. Period

Hammick, as you note the chassis of the Lightning and the ground of the inverter are in continuity. I am even worried that if I drive the Lightning into the leanto with muddy wet tires, there may be enough "leakage" of ground via the wet muddy tires to throw ground faults, even with the ground in the generator cable disconnected. We shall see. If it happens, its a nuisance fault, not something dangerous.

But my idea of a switch is still OK I think, but labeled like this:

Up: Generator lead cord grounded to premises ground. (generator/source w/o GFI)

Down: Generator lead cord ungrounded (generator/source with GFI that cannot tolerate neutral/ground bonding)

I would rather be entirely transparent that I am taking liberty with the code, rather than create some "double secret ungrounded dogbone" that could get mis-used down the road by someone who comes along after I am gone.

The relative safety of such a situation was discussed in detail already, and alternatives, either completely fixing all the neutral bonding on the premises, or installing an isolated critical loads panel are just not an option for me. I think those other options are viable and very reasonable for someone who must remain in strict code compliance, so I am not arguing against those solutions in any way.

 

[Supervstech]

Actually while hiking at today at 9,900 ft I had an epiphany. My plan has a rather glaring/stupid hole. That accessory ground rod that I dreamt up for good measure will nicely link the inverter ground to the premises ground, where ever that is (likely about 200 ft away at the first main panel) via the good ole' earth. And since the neutral and ground are bonded there, I will surly get ground faults from the inverter. To work, the ground from the Inverter must be isolated. Period

Hammick, as you note the chassis of the Lightning and the ground of the inverter are in continuity. I am even worried that if I drive the Lightning into the leanto with muddy wet tires, there may be enough "leakage" of ground via the wet muddy tires to throw ground faults, even with the ground in the generator cable disconnected. We shall see. If it happens, its a nuisance fault, not something dangerous.

But my idea of a switch is still OK I think, but labeled like this:

Up: Generator lead cord grounded to premises ground. (generator/source w/o GFI)

Down: Generator lead cord ungrounded (generator/source with GFI that cannot tolerate neutral/ground bonding)

I would rather be entirely transparent that I am taking liberty with the code, rather than create some "double secret ungrounded dogbone" that could get mis-used down the road by someone who comes along after I am gone.

The relative safety of such a situation was discussed in detail already, and alternatives, either completely fixing all the neutral bonding on the premises, or installing an isolated critical loads panel are just not an option for me. I think those other options are viable and very reasonable for someone who must remain in strict code compliance, so I am not arguing against those solutions in any way.

Vehicular grounding wouldn't cause a gfci interrupt.
Unless there is a short to the ground...
So, if you were dragging an extension cord along the ground, AND driving through wet muddy area, and there was some current leakage, then it would trip.

 

[hammick]

Actually while hiking at today at 9,900 ft I had an epiphany. My plan has a rather glaring/stupid hole. That accessory ground rod that I dreamt up for good measure will nicely link the inverter ground to the premises ground, where ever that is (likely about 200 ft away at the first main panel) via the good ole' earth. And since the neutral and ground are bonded there, I will surly get ground faults from the inverter. To work, the ground from the Inverter must be isolated. Period

Hammick, as you note the chassis of the Lightning and the ground of the inverter are in continuity. I am even worried that if I drive the Lightning into the leanto with muddy wet tires, there may be enough "leakage" of ground via the wet muddy tires to throw ground faults, even with the ground in the generator cable disconnected. We shall see. If it happens, its a nuisance fault, not something dangerous.

But my idea of a switch is still OK I think, but labeled like this:

Up: Generator lead cord grounded to premises ground. (generator/source w/o GFI)

Down: Generator lead cord ungrounded (generator/source with GFI that cannot tolerate neutral/ground bonding)

I would rather be entirely transparent that I am taking liberty with the code, rather than create some "double secret ungrounded dogbone" that could get mis-used down the road by someone who comes along after I am gone.

The relative safety of such a situation was discussed in detail already, and alternatives, either completely fixing all the neutral bonding on the premises, or installing an isolated critical loads panel are just not an option for me. I think those other options are viable and very reasonable for someone who must remain in strict code compliance, so I am not arguing against those solutions in any way.

I think it is a good plan. I intend to ditch the Lightning ground when I connect it to my off grid inverter (unless by some miracle the inverter isolates it). Everything is inside an insulated garage so I'm not that worried about it. It would take tons of OSB removal and spray foam removal to add an isolated subpanel there.

I hear a software update is coming to the Lighting to activate the Pro Power without having the truck on. Not sure if it will be as simple as pushing the green button in the bed or frunk or even app based. App based would be great. We can put a sign on the tailgate that reads: "Truck energized with 7,200 watts of electricity - touching could result in serious injury or death"

I'm jealous of your 9.900' adventure. Would love to be doing that today but instead sitting here recovering from knee surgery spending way too much time on the interwebs.

 

[hammick]

Actually just had a epiphany myself. I have a Lester Summit II 1050w 48v golf cart charger connected directly to my battery pack. I installed this so I could use a whisper quiet 1,600 watt inverter generator for absorption charging back when I had lead acid batteries. It's gotten very little use (inverter loads easily trip the little genset)

This would give me 22 amps of nice slow charging and zero ground fault issues or potential damage to the Pro Power. Charger has Bluetooth for IOS app monitoring. No way my inverter loads will trip the lightning with this charger. No more having to run the diesel genset when the wife gets out of control with electric ovens, sous vide machine, etc. Problem solved.

 

[Hedges]

Ideally, the HOUSE needs to have the N-G bond removed, and all neutrals and grounds separated.

I have a customer with a lightning, and he wants me to tie into his condo panelboard and provide a simple way to power the house...

So far I have declined to take that on...

I think, from reading this thread I have made the right decision.

Condo, neutral-ground bond upstream somewhere?
I think if you put a 3-pole transfer switch before his breaker panel, that would work.
It would be GFCI protecting the whole house, so more likely to trip than if just protecting one circuit.

 

[hammick]

Condo, neutral-ground bond upstream somewhere?
I think if you put a 3-pole transfer switch before his breaker panel, that would work.
It would be GFCI protecting the whole house, so more likely to trip than if just protecting one circuit.

The 3-pole transfer switch will only work if it is completely isolated from the main panel when being powered from the Lightning. Was a simple process for me as I already had a subpanel with ground and neutrals separated. It was added when we finished the basement because the main panel was out of room. It's now powered from the xfer switch when the Lightning is connected.

 

[Hedges]

L1, L2, N completely isolated when transfer switch open.
Ground can go to everything, and per NEC all grounds in a building are to be tied together.

So I think installing a 3-pole transfer switch before a condo panel should do the trick. Assuming N-G bond happens at the building's service entrance, where there are breakers to feed each unit.