7.2KW ProPower for Off-Grid Cabin

[HammaMan]

UPDATE… I reconnected the ground at the plug and removed the ground wire from the neutral bus in the panel. The system is working. When the truth is on it works which I expected it too and it also works with the truck off, running on batteries. Is there a safety concern with this? From what I can tell there’s no neutral/ground bond when I’m running off the batteries. My magnum inverter doesn’t bond from what I read so … ??

L1 and L2 desperately want to return on the neutral. If a neutral is some how disconnected, the ground is 'insurance' of sorts as now L1 and L2 want to get to the ground (when neutral is bonded). Without the neutral bond, a device whose neutral gets loose could end up making the ground live giving you touch potential electrocution, or in a wet area, step potential.

Treating the truck and generator as utility is the safer option. Both the truck and generator are neutral bonded -- nearly non-existent chance of electrocution when they're operating. The truck's ground is also bonded to the frame which also happens to be your 12v dc negative. Nearly zero risk of shock from it as the pixies it generates are wanting to return to it, combined with the fact that it's also GFCI, any current that comes back on the ground from any of the plugs instantly trips the breaker. Great as a stand alone generator, no utility in a properly wired structure where wet areas will already be on their own GFI breakers.

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[OT66]

Pmd you

 

[Hullguy]

It seems like the work was done by "some electrician". They may have done the bonding in the inverter as in my own opinion the way it is done in your panel it is wrong. So even if you unplug the groung in your panel you may achieve nothing. What I would do if it was my situation is to unplug the ground coming from the L14-30 going to the inverter. At least if this work you would know the 7.2KW can work with your system. At the end I would put the ground back to the inverter.

After bring a multimeter and take some measurement in your panel.

1- Measure between the ground bar and the neutral bar, you should have 0 ohm
2- Unplug the ground between the ground rod and your neutral bus, if you still have 0 ohm then your electrical system is bonded somewhere else.
3- If at step 2 you still have 0 ohm, then I think you should move the ground rod to the ground bar but don't connect the ground to the neutral bar as a system should be bonded at one location.
4-If at step 2 you don't have 0 ohm, then I think you should move the ground rod to the ground bar then run a wire from the ground to the neutral bar.

These are the steps that I would do if I was in your situation. Again I'm not an electrician and I can't take any of the responsibilities. I would like the comments from @Gros Ventre and @Hullguy as they seems to be a lot more knowledgeable about different codes and regulations

Don’t do this!

 

[Hullguy]

Your panel is neutral bonded, but your grounding isn't done to code. Your generator and truck are also neutral bonded. The generator's lack of GFCI means you're double bonded when using it (and it works). Your inverter requires neutral bond in the panel.

99% of people back-feeding their home (that have utility w/ manual gen failover) have double neutral bonded systems without issue. The issue arises when you introduce the GFCI as utility. Your situation is more unique than most due to you NOT having a permanent utility.

Code is written in the blood of lives lost due to improper installation causing fire / electrocution. For your system to work you'd I'd suggest floating the ground inbound from the truck at a separate junction box like the scribble diagram suggests....

Speaking of improper box connection, replace the blues with whites or wrap white tape around them. Neutrals should be marked with double white bands.

Don’t do this! Against National Electrical Code!

 

[Gros Ventre]

I've been fulltiming in RV's for about 7 years. Admittedly I have been spending most of my time at my home base in coastal Texas because of my youngest grandchildren actually like me, for now. And yes, other than weather related power outages, the Powerboost isn't used nearly as much as when I'm galavantin around chasing sunrises and sunsets without an itenerary. The Powerboost is like a gift too good to be true. I no longer have to heft a 150lb Yamaha 3000 inverter into the bed of a truck. (that's empty of fuel. Closer to 175lbs with fuel) No longer have to tote gas cans. And the Powerboost is quieter, as well as fuel efficient.

It's an AMAZING grid on wheels!

...And its a true 7.2 kW generator. When you buy a generator unit the engine is sized to the generator. When at altitude (I live at 7500 feet) you lose output proportional to altitude. In my case I lose 30% since the engine can't produce the power. But... The Powerboost engine is so much larger than the generator, you get all of that 7.2 kW... I specifically considered this when I ordered that 7.2 kW option.

 

[Gros Ventre]

L1 and L2 desperately want to return on the neutral. If a neutral is some how disconnected, the ground is 'insurance' of sorts as now L1 and L2 want to get to the ground (when neutral is bonded). Without the neutral bond, a device whose neutral gets loose could end up making the ground live giving you touch potential electrocution, or in a wet area, step potential.

Treating the truck and generator as utility is the safer option. Both the truck and generator are neutral bonded -- nearly non-existent chance of electrocution when they're operating. The truck's ground is also bonded to the frame which also happens to be your 12v dc negative. Nearly zero risk of shock from it as the pixies it generates are wanting to return to it, combined with the fact that it's also GFCI, any current that comes back on the ground from any of the plugs instantly trips the breaker. Great as a stand alone generator, no utility in a properly wired structure where wet areas will already be on their own GFI breakers.

You didn't even try to understand what I posted.........

 

[Yves]

Don’t do this!

Not that I want to argue with you at you seems to be knowledgeable. But can you provide a little more details as I don't really see where is the problem with the tests that I'm suggesting him to do. If I can learn from this then I win something

 

[Hullguy]

Would be happy to, but when the RV is on shore power (30Amp RV cable), it is grounded in the shore power panel, and the grounding rod that it is wired to. Right?

The grounding rods, (2 are required now), are at the campgrounds main Electrical panel at the meter. The plug you use for an RV is just an oversized receptacle like you use at your house. The electrical ground on the RV is from the grounding system. There shouldn’t be a ground rod the at the shore
power receptacle

 

[Yves]

I've got the remaining parts arriving this week to tap the HV bus of the truck and the goal is to get it to generate 20kWh of emergency power. Why spend this kind of money on a tool and not get the most out of it???

So you are converting the 7.2KW to a 20KW generator? Are you sure that the remaining of the electrical components can handle that much more power? Can you provide more details on how you will be doing this as I find it very interesting.

 

[Gros Ventre]

Not that I want to argue with you at you seems to be knowledgeable. But can you provide a little more details as I don't really see where is the problem with the tests that I'm suggesting him to do. If I can learn from this then I win something

I spoke of where the bonding was in the house. Many breaker panels come with a green bonding screw that connects the neutral to the ground. Some utilities require you to remove that screw because they want the bonding somewhere else. In the case of my utility they want it outside in the metering panel. My point was simple: make sure you understand where that bonding occurs. I said nothing about "the utility providing the ground." In my case the ground is provided as part of the house wiring... of course it is outside with grounding rods and heavy duty cable to those rods. If I read the NEC correctly the utility never provides the ground.

 

[Hullguy]

Not that I want to argue with you at you seems to be knowledgeable. But can you provide a little more details as I don't really see where is the problem with the tests that I'm suggesting him to do. If I can learn from this then I win something

No worries! I hope I have some knowledge of this being a Master Electrician for over 30 years. It’s all based on the National Electrical Code.
the ground provides voltage stabilization and short circuit protection By being bonded or attached to the neutral. By Code, you have to bond the neutral at the service, or utility. It can only be done at one spot. In this case it is the inverter converting 12vdc to 240/120 AC.
It will work by removing the ground. But this removes all of your short circuit and stabilization protections guarding you against electrocution and fire.

 

[Yves]

No worries! I hope I have some knowledge of this being a Master Electrician for over 30 years. It’s all based on the National Electrical Code.
the ground provides voltage stabilization and short circuit protection By being bonded or attached to the neutral. By Code, you have to bond the neutral at the service, or utility. It can only be done at one spot. In this case it is the inverter converting 12vdc to 240/120 AC.
It will work by removing the ground. But this removes all of your short circuit and stabilization protections guarding you against electrocution and fire.

Thanks @Hullguy, if the bonding is already at the inverter then should he not remove the bonding in the panel? That was really the reason that I did recommend the different test

 

[Hullguy]

Thanks @Hullguy, if the bonding is already at the inverter then should he not remove the bonding in the panel? That was really the reason that I did recommend the different test

my mistake. The neutral is bonded at the panel. if you remove any grounds from the inverter it could fry the electronics. And removes the safety factor from the inverter

 

[OT66]

Don’t do this! Against National Electrical Code!

Probably makes very little difference but just so you're aware, I'm in Canada, so not looking at NEC. I don't know if CEC is nearly identical but NEC is referenced so often in these posts. I'm not in the states.

 

[Hullguy]

Probably makes very little difference but just so you're aware, I'm in Canada, so not looking at NEC. I don't know if CEC is nearly identical but NEC is referenced so often in these posts. I'm not in the states.

Different terminology but same method! Don’t remove any grounds from anything! Replace the panel with a neutral switching transfer switch. The existing panel is a shit install and your neutral bar and grounds aren’t installed right.

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