Inverter grounding

[Lafnbug]

I tried to answer this on my own, but here I am...

My electrical system is 900w solar, 645a/h of batteries, and a 2000w PSW inverter. A significant amount of energy, so I want to get this right.

My system will NEVER be connected to shore power, and probably never even a land based charger, so it will never see a true ground.

A. Do I ground the inverter?
B. To what?
C. How does a GFCI work in this situation?

 

[speedhighway46]

1) Ground the inverter to the frame (which is also tied to the negative battery terminal because it is grounded to the frame also) using the "green" wire.

2) The black wire 120 vac output of the inverter should go to the hot, or switched, side of the bus of the service panel used for your various 120 vac circuits controlled by the circuit breakers.

3) The white (neutral, unswitched) wire of the 120 vac output of the inverter is tied to all the white wires of your various distribution circuits. This is important: you cannot use the neutral bus inside your distribution panel as would be normal in a typical household installation as it is GROUNDED like the green wires are grounded. You want to "float" the neutrals; that is, the neutrals DO NOT go to ground. This is a safety feature as your vehicle is not truly grounded, it sits on four rubber insulators (tires). If it were connected to ground it could present a dangerous shock hazard; potentially fatal.

For additional information about this; Google "floating neutrals" and the National Electric Code as it pertains to motorhomes and vehicles.

 

[Lafnbug]

I am plugging necessary appliances/tools straight into the inverter when necessary, I am not using an additional service panel.

I don't need 120vac for much, so I am building the most basic system that will support my needs.

I understand the floating neutrals, but wasn't sure is grounding 120vac to my vehicle chassis would cause issues with the vehicle electrical system if something went wrong.

As of now, I have a completely separate house system.

Thanks for the response!

 

[speedhighway46]

Understood. If you are using the "socket" built into the inverter, still connect the green wire to the chassis ground, and make sure the white wire going to the internal socket isn't grounded also.

 

[highdesertranger]

the invertor has a separate grounding lug, this goes to chassis ground. it should be in your instructions. the battery ground should go to your battery or shunt(if you are running one). highdesertranger

 

[Lafnbug]

Thank you, Gentlemen!

 

[ccbreder]

Yes. Use the grounding lug on the inverter case to chassis ground. You don't have to mess with the 120 volt side. You can ground the 12 volt negative to the vehicle chassis, but it is not necessary.