Inverter Neutral question

[TheRealPapaK]

Hello everyone. I tried to search this answer but I didn’t find anything specific to my question.

I have set up an inverter in my van that is hooked up to a DPDT relay so that when I plug into shore power, it automatically switches the receptacles from being powered by the inverter to being powered by the shore power.

Because it’s DPDT, the neutrals also switch between shore power and the inverter The grounds do not switch and are tied into the back of the box like you would in a regular house install

I fully understand the theory behind the neutral and the ground but in a vehicle I’m having a little more trouble wrapping my head around it. There seems to be a little copper lug on my inverter that might be for a ground wire but the instructions don’t really say anything about this (separate question, my converter also has a little lug like this but I don’t know what I should connect to it? The vehicle isn’t grounded itself and the negative is already on the chassis??).

Does the ground for my 110v receptical need to be tied back to the inverter and if so is it ok for it to also be tied to the shore ground? With the auto switching they will never both be running.

Thanks!

 

[DaveInDenver]

Are you really sure you fully understand neutral and ground and the operation of transfer switches?

The vehicle chassis is your safety ground in this scenario. Are your outlets plain or GFCI? Does the inverter bond its neutral leg to the enclosure or ground lug? Is the inverter UL-458 compliant?

You would not wire neutrals to ground in the RV, keep all 3 wires separate all the way back to the panel. On shore (Earth-referenced) power they will be connected upstream by the utility. On inverter or generator the neutral and ground bond would need to be handled locally.

The UL and NEC suggest a neutral-ground bonding relay so that you can deal with both separately derived (inverter) and non-separately derived (shore) sources to achieve your one (only one) ground-neutral bond.

In the end, do what the installation manuals for your inverter and transfer switch say to do.