Inverter "ground terminal"

[peterc10]

The new Renogy inverter I have just bought has a "ground terminal", which my previous inverter didn't. It is shown on the diagram but no advice in the instructions as to what, why or how as to its use. Should I connect it and what is it for? If I do use I assume that I should attach it to a separate metal part of the chassis rather than the common negative pole on my shunt?

Many thanks

 

[tkk]

Cannot answer definitely, but somewhere on this forums “inverter threads“ is a post by someone who took off the casing and found that it connected to nothing but the case so I suppose it is the same as the grounding point on metal light fittings in A/c domestic setting just to protect you from live leak to the case.
Somewhere else on the Forum (cant pinpoint it) is a thread discussing how it isn’t easy to electrocute yourself with inverter output. I am unclear myself on the theory but someone will be along to clarify I hope. From the photos Ive seen on the Forum use of the earth point is rare.

 

[Boringfrog]

My Sterling inverter has a ground, I connected to a bolt near the handbrake.

 

[ctc]

Most motorhomes have rubber tyres, there is no "ground".

 

[peterc10]

Most motorhomes have rubber tyres, there is no "ground".

Two problems with that. It is "grounded" or "earthed" if plugged into the EHU I would guess.

And secondly I have metal hydraulic levelling jacks fitted to the chassis, so more than just tyres.

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[tkk]

Just to stir it, on one of the forum threads I mentioned raised the issue of earthing A/C output to the common earth of the D/C system. The situation discussed gets very complicated when you introduce earthed “shore “supply to the equation, modifications to circuit connections required , if I recollect correctly. If I find the thread Ill post. Also a lot of people use “metal steadies” even if they don’t have levelling jacks so its a common potential problem.

 

[tkk]

Thread started by kwhkwh@hotmail Aprril 2020 or search “inverter earthing” should bring it up

 

[peterc10]

Just to stir it, on one of the forum threads I mentioned raised the issue of earthing A/C output to the common earth of the D/C system. The situation discussed gets very complicated when you introduce earthed “shore “supply to the equation, modifications to circuit connections required , if I recollect correctly. If I find the thread Ill post. Also a lot of people use “metal steadies” even if they don’t have levelling jacks so its a common potential problem.

Thread started by kwhkwh@hotmail Aprril 2020 or search “inverter earthing” should bring it up

Thanks. Yes I also remember something on a thread, but it was more recent than that. Come to think of it, I think Raul contributed to it, so he may remember or be able to help

 

[Raul]

I can’t remember where I posted but tkk is right. Grounding PE to the chassis it’s ok if sistem functions in stand alone off grid mode. When shore supplied PE is connected, you end up with two bondings from neutral to earth. This is why multiplus has a relay for grounding the PE when stand alone, and opens the relay when detects ehu or shore power.

 

[peterc10]

I can’t remember where I posted but tkk is right. Grounding PE to the chassis it’s ok if sistem functions in stand alone off grid mode. When shore supplied PE is connected, you end up with two bondings from neutral to earth. This is why multiplus has a relay for grounding the PE when stand alone, and opens the relay when detects ehu or shore power.

Thanks. When we are away we rarely have EHU. But sometimes we do when away and always plugged in at home. So maybe I could use a manual switch. But what are the dangers if I just don't ground at all? Also what size should the ground wire be with a 2000W inverter

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[daveclare]

Watching this one and ready to buy a thicker wire than you! Just bought the 3000W Renogy inverter.

 

[Raul]

The danger of not grounding is electric shock if you happen to touch a life wire, or neutral.
There are sistems that work without ground, double isolated. If you touch one wire nothing happens as you don’t complete the circuit. Only if you touch both. But in this system you have no rcd.
The size of the ground should be close to equal to the life wire. On 1.5 life wire you can have 1mm PE.

I recommend you google for “victron wiring unlimited “, very nice explanation in there with schematics, better than me explaining.