7.2KW ProPower for Off-Grid Cabin

[OT66]

Perfect. I don't know if you have notice but several of us are retired....so a few pictures may help to understand better

LOL, once I get up there this evening I'll include pictures. The following are from the Magnum 4024PAE inverter manual. Does any of this lead you to believe that my cable that comes from my generator (the L14-30 plug) and goes into this Magnum inverter would not have the ground connected to in the inverter? That's what the Magnum tech suspects. I can't make sense of that because when I first started on this hunt for solutions, people said that an unsafe way to make it work would be to disconnect the ground from the cable that plugs into the truck.

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[Yves]

It may take a little bit longer to find a solution and little bit more expensive but you have to do it right. It doesn't make sense to risk life or damage equipment to cut the corner to make it work. I believe that you understand this already. If you have a multimeter, you could take the resistance (ohm) reading between the white (neutral ) and the ground. If you have 0 ohm as reading, it will mean the neutral is bonded to the ground. Which is normal for a house's electrical panel. The problem the 7.2KW also have a neutral bonded to ground. So when you do the connection the 7.2KW sees that as a problem and will trip. The solution for my house was to install a transfer switch. The transfer switch is typically a breaker panel where your main power and generator will connect via their own triple breaker (red/black/white). Only one source of power will be used at the time to feed the specific breakers you have relocated to the transfer switch. In that configuration you only have the bonded neutral from one or the other.

 

[OT66]

It may take a little bit longer to find a solution and little bit more expensive but you have to do it right. It doesn't make sense to risk life or damage equipment to cut the corner to make it work. I believe that you understand this already. If you have a multimeter, you could take the resistance (ohm) reading between the white (neutral ) and the ground. If you have 0 ohm as reading, it will mean the neutral is bonded to the ground. Which is normal for a house's electrical panel. The problem the 7.2KW also have a neutral bonded to ground. So when you do the connection the 7.2KW sees that as a problem and will trip. The solution for my house was to install a transfer switch. The transfer switch is typically a breaker panel where your main power and generator will connect via their own triple breaker (red/black/white). Only one source of power will be used at the time to feed the specific breakers you have relocated to the transfer switch. In that configuration you only have the bonded neutral from one or the other.

Yves, thanks. I’m not going to cut corners or be unsafe that’s why I am looking around so much on here and appreciate all the feedback. I was just confused when talking to the company that makes my solar inverter that he seemed quite confident that I’m going to need to hook up the ground from my plug at the inverter. But why that ground would ever be disconnected in the first place is beyond me. I won’t know anything until I get to the cabin and by the time I get to look Ill have no power obviously and no cell service so was just trying to make some sense of it. If the ground is in fact disconnected like he thinks then why wouldn’t the plug work now since that’s what people have said will work albeit unsafely. OR if it is not connected and I ground it at the inverter like he is saying how will that help me? Id still be bonded at the truck and panel would I not?

 

[Yves]

Yves, thanks. I’m not going to cut corners or be unsafe that’s why I am looking around so much on here and appreciate all the feedback. I was just confused when talking to the company that makes my solar inverter that he seemed quite confident that I’m going to need to hook up the ground from my plug at the inverter. But why that ground would ever be disconnected in the first place is beyond me. I won’t know anything until I get to the cabin and by the time I get to look Ill have no power obviously and no cell service so was just trying to make some sense of it. If the ground is in fact disconnected like he thinks then why wouldn’t the plug work now since that’s what people have said will work albeit unsafely. OR if it is not connected and I ground it at the inverter like he is saying how will that help me? Id still be bonded at the truck and panel would I not?

If something is not wired properly it could potentially trip the 7.2 KW as the GFI could detect problem. The company may be right. We have seen so many time problems caused by the bonded neutral that we believe this could be your problem but we could be wrong.....

 

[daemonic3]

It may take a little bit longer to find a solution and little bit more expensive but you have to do it right. It doesn't make sense to risk life or damage equipment to cut the corner to make it work. I believe that you understand this already. If you have a multimeter, you could take the resistance (ohm) reading between the white (neutral ) and the ground. If you have 0 ohm as reading, it will mean the neutral is bonded to the ground. Which is normal for a house's electrical panel. The problem the 7.2KW also have a neutral bonded to ground. So when you do the connection the 7.2KW sees that as a problem and will trip. The solution for my house was to install a transfer switch. The transfer switch is typically a breaker panel where your main power and generator will connect via their own triple breaker (red/black/white). Only one source of power will be used at the time to feed the specific breakers you have relocated to the transfer switch. In that configuration you only have the bonded neutral from one or the other.

This makes complete sense but the only place on his to tap in with a 3 (or 4) pole breaker is past the inverter at the subpanel, but that would completely defeat the purpose.

I'm still thinking he needs just a single pole switch that unbonds his green ground wire inside the subpanel when planning to use the propower genny with the neutral bond. Like a knife or blade switch or something. I just don't know how this would work with the order of operation required (i.e. can you unbond the green ground temporarily for a few seconds with the inverter still live, then fire up propower using Fordpass? You obviously can't do it the other order as propower will trip before you can unbond the ground)

Perhaps this order:
1. Flip subpanel main breaker off
2. Unbond green from neutral bus inside subpanel
3. Fire up propower connected to inverter, make sure it is not tripping
4. Flip subpanel main breaker back on, make sure propower still not tripping
?

 

[OT66]

This makes complete sense but the only place on his to tap in with a 3 (or 4) pole breaker is past the inverter at the subpanel, but that would completely defeat the purpose.

I'm still thinking he needs just a single pole switch that unbonds his green ground wire inside the subpanel when planning to use the propower genny with the neutral bond. Like a knife or blade switch or something. I just don't know how this would work with the order of operation required (i.e. can you unbond the green ground temporarily for a few seconds with the inverter still live, then fire up propower using Fordpass? You obviously can't do it the other order as propower will trip before you can unbond the ground)

Perhaps this order:
1. Flip subpanel main breaker off
2. Unbond green from neutral bus inside subpanel
3. Fire up propower connected to inverter, make sure it is not tripping
4. Flip subpanel main breaker back on, make sure propower still not tripping
?

Made it to cabin tonight. I tried a few things that people had suggested throughout the week but still ground fault every time at the truck. Here’s a picture of my inverter where my generator L14 plug wires into and then wires out to my ac panel in the cabin. Panel picture as well.

 

[daemonic3]

Made it to cabin tonight. I tried a few things that people had suggested throughout the week but still ground fault every time at the truck. Here’s a picture of my inverter where my generator L14 plug wires into and then wires out to my ac panel in the cabin. Panel picture as well.

What a rats nest! Well here is my guess:

According to the labels in the inverter box, the blue is neutral, black and red must be hots.
In the subpanel the blue goes to the neutral bus bar on the right. All the neutrals are now white.
The bare grounds all tie and jump on the left.
The screw in the top right appears to bond the bare copper grounds to the neutral bus bar.

So maybe install a switch inline to cut that connection? At least you could test it out first by undoing that screw. The top breaker appears to be the "main" to temporarily cut off the inverter for safety. Then I would test my ordered procedure.

When I say "I" I mean literally ME. I'd say you do what YOU feel is safe after reviewing with more advice here or an electrician!

 

[daemonic3]

I have a better guess! Stared at the pic more and I think that top right screw has a black (hot) going to it as well. I think it's feeding a 120v circuit in the house, and the screw is just a casing screw.

I see now i think the bonding screw I drew a cyan arrow to. I think unscrewing that and removing the copper bridge will unbond it. The sub panel user manual probably would confirm or disprove it.

Keep us posted on findings! Would love to see this work without anything frying.

 

[HammaMan]

Made it to cabin tonight. I tried a few things that people had suggested throughout the week but still ground fault every time at the truck. Here’s a picture of my inverter where my generator L14 plug wires into and then wires out to my ac panel in the cabin. Panel picture as well.

You need to remove the ground wire from your L14 plug connected in the box, it's not used for this installation. It's just that simple. Inverters, the truck, and generators are all neutral bonded. The reason you're having an issue is because the GFCI circuit in the truck is tripping due to the inverter's neutral bonding. Can't recall another post mentioning this. There's no other way around it. With your generator connected, you're creating a ground loop that's for the most part inconsequential. The ground on the truck isn't used for this application. The truck feeds directly into the inverter (as most installs would have it done).


The cord from the truck itself will still be GFCI protected in case it gets cut or wet, but your cabin's power system will function just as it should which is...
1 - feeding your cabin's loads through its AC out
2 - using the 'excess' current from the truck to charge the batteries on its AC in


Neither the truck nor the generator are operating in independent mode, as in you're not plugging devices in to them directly. You're connecting to your cabin's panel as a utility. People are looking at the problem backwards. The utility does not feed customers a ground. It feeds L1, L2, and neutral which carries the delta of L1 and L2 with 120v appliances.

If there's no ground for your L14 plug in that inverter interconnection box (hard to see if one of those strands actually go to it or if it's split from the panel), someone may have neutral bonded it elsewhere (not likely, and it's wrong, but never assume).

 

[Hullguy]

I wouldn’t remove ANY ground from your system!!! The ground is the most important wire in any electrical system as this stabilizes and on a short circuit causes a massive amount of current that trips the breaker saving you from harm. The only safe way is to install a neutral switching transfer switch

 

[Yves]

You need to remove the ground wire from your L14 plug connected in the box, it's not used for this installation. It's just that simple. Inverters, the truck, and generators are all neutral bonded. The reason you're having an issue is because the GFCI circuit in the truck is tripping due to the inverter's neutral bonding. Can't recall another post mentioning this. There's no other way around it. With your generator connected, you're creating a ground loop that's for the most part inconsequential. The ground on the truck isn't used for this application. The truck feeds directly into the inverter (as most installs would have it done).


The cord from the truck itself will still be GFCI protected in case it gets cut or wet, but your cabin's power system will function just as it should which is...
1 - feeding your cabin's loads through its AC out
2 - using the 'excess' current from the truck to charge the batteries on its AC in


Neither the truck nor the generator are operating in independent mode, as in you're not plugging devices in to them directly. You're connecting to your cabin's panel as a utility. People are looking at the problem backwards. The utility does not feed customers a ground. It feeds L1, L2, and neutral which carries the delta of L1 and L2 with 120v appliances.

If there's no ground for your L14 plug in that inverter interconnection box (hard to see if one of those strands actually go to it or if it's split from the panel), someone may have neutral bonded it elsewhere (not likely, and it's wrong, but never assume).

I agree with the power cord going to the plug from the truck would still be protected but what do you do from the plug to the breaker panel? I agree with @Hullguy the grounds have to be connected.

 

[Yves]

I have a better guess! Stared at the pic more and I think that top right screw has a black (hot) going to it as well. I think it's feeding a 120v circuit in the house, and the screw is just a casing screw.

I see now i think the bonding screw I drew a cyan arrow to. I think unscrewing that and removing the copper bridge will unbond it. The sub panel user manual probably would confirm or disprove it.

Keep us posted on findings! Would love to see this work without anything frying.

I think the black wire that you see on the right is the shadow of the white wire when @OT66 took the picture

 

[mj1angier]

Did you check your generator outlets to see if you are sending 120 or 240 from them?

 

[HammaMan]

I wouldn’t remove ANY ground from your system!!! The ground is the most important wire in any electrical system as this stabilizes and on a short circuit causes a massive amount of current that trips the breaker saving you from harm. The only safe way is to install a neutral switching transfer switch

The grounds ARE already connected as they're bonded at the main panel to the neutral. People are looking at the problem inverse. Everywhere the neutral and ground connect at the primary power source, and it's only needed ONCE else you have a loop (as in what's already occurring in this installation when using the generator). If you believe that a truck sitting on 6" of rubber is actually providing a ground, I've got a bridge to sell ya.

Stop looking at the generator as a tool connected to a plug. IT IS UTILITY, UTILITY DOESN'T PROVIDE GROUND.

I'm not getting into the theory of why this is, just understand that what I've directed to do is precisely how systems are wired. I've designed several power systems. This is safe -- the neutral is the return of power to the source of generation where bonding occurs. The inverter is where the primary neutral bonding occurs, this cord's ground serves no purpose, at all, period, when connected to either the truck, or the generator with neutral bond.

 

[OT66]

I think the black wire that you see on the right is the shadow of the white wire when @OT66 took the picture

Better pictures. From the inverter my two hots go into the main 60 amp breaker, neutral (blue) into the neutral bus and ground into ground screw. Is that screw on the right by my neutral bar the bond screw? How can I unbound temporarily to see if pro power will work. The ground attached to the bottom of the neutral bar going out the panel, is that what would be grounded Outside?

I have a better guess! Stared at the pic more and I think that top right screw has a black (hot) going to it as well. I think it's feeding a 120v circuit in the house, and the screw is just a casing screw.

I see now i think the bonding screw I drew a cyan arrow to. I think unscrewing that and removing the copper bridge will unbond it. The sub panel user manual probably would confirm or disprove it.

Keep us posted on findings! Would love to see this work without anything frying.

That screw your pointing to has no wire in it. Does that mean it’s not bonded?

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