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Ground wiring question about specific system with Autotransformer

Link to my hand drawn wiring diagram:


This is not a perfect or complete diagram, I am still figuring some things out like breaker placement, the auto start relay, and the temperature sensor. However it should be enough information to be able to answer my question. The busbars are those small unlabeled rectangles, the circles are where I have been debating if breakers should go. And I have crossed out some things.

I am using two Multiplus 2 units 48/5000, I am connecting a DC battery bank (1 battery at first that will be expanded to 4). I will be using the Multipluses in split phase. I will have generator hooked up to an automatic transfer switch, and a 30 amp shore power cord will run through a 32 amp autotransformer to be converted to split phase and the output of the autotransformer will also run into the automatic transfer switch. The output of the automatic transfer switch will go to the 2 Multiplus units (I have not at this time added a bypass switch but plan to, here). The multiplus units go to a 100amp autotranformer that will be used for balancing. The output of that autotransformer will go to my distribution panel.

Wiring Diagram of Distribution Box from manual:


Ground Diagrams From Wiring Unlimited:



My question is: Where do I connect the main ground of the 32 amp autotransformer to? Is it okay to connect it to the negative DC busbar with everything else?

Does my main ground on my distribution box go directly to the RV chasis? Or does it need to go to the negative DC busbar with everything else?

Also, it looks like the 30 amp shore power needs a wire splitting off from the ground that goes to that same negative DC busbar, do I do that before the 30amp auto transformer or after it before the automatic transfer switch.

I have included all the diagrams I have been using as a wiring references.

I have included links to all the components of this system.

So all of the diagrams say that the inverter/chargers should be grounded to the central negative DC busbar. And it says that the autotransformer should be grounded there too – however in the diagrams where it says this the autotransformer is always after the inverter/chargers. The one I don’t know where to send the ground to is before the inverter/chargers. I do plan to charge the battery bank from the 30 amp shore power and to supplement loads from the battery bank when pulling from 30 amp shore. Don’t know if that makes a difference.

Also, the diagrams in Wiring Unlimited, show connecting a ground wire to the negative battery terminal and connecting that wire to a ground bus bar where all the grounds I was going to put directly on the negative busbar go to. And that bus bar actually goes to the main grounding point. Is this acceptable in my system? Can I do this instead? It just seems like a cleaner wiring design. I though that electrically speaking its the exact same setup as grounding at the negative bus bar, but don’t want to misunderstand something. This looks so much cleaner and I want to know if its okay to wire my system this way. See attached photos or Wiring Unlimited.

Stacked Inverter Balancing with Generator - Autotransformer

120 to 120/240 split phase


Multiplus 2



Go Power Auto Transfer Switch

EG4 Battery

Distribution Box

Stormy R. asked

0 Answers

Grounding off grid setup

I have a caravan, that is completely off grid.

I am trying to understand how to safely earth my inverter, which has a ground terminal that the manual says needs to be grounded.

After the inverter I have a consumer unit, which has an earth bar.

I've seen other posts such as the following, that state the ground should be connected to the caravan chassis:

But my understanding is that the caravan chassis is insulated due to the tyres, doesn't this mean the caravan chassis is not a suitable grounding point?

Would I therefore need to buy an earth rod and connect the grounds to the earth rod instead?

matt-b-1 asked
matt-b-1 answered ·

2 Answers

Multiplus II and VE.bus error 11

Dear all, I recently install a Multiplus II on a 48V dc system with a Venius ESS enable node. I receive many VE.bus error 11 a day and after checking my installation and Victron website i don't seen something wrong except the type of grid network. I am in France with a TT network and Victron website explain that this error could append with a no TN network.

What exactly do the relay test sequence, is there a work around for using Multiplus II on TT residential network?


amrane asked
jonny-b answered ·

7 Answers

MultiPlus Ground Relay Question

I have a multiplus 12/3000/120. The manual states on page 9

"The MultiPlus is provided with a ground relay (relay H, see appendix B) that automatically connects the Neutral output to the chassis if no external AC supply is available."

If you examine the appendix B of that same manual it shows a relay action on "PE" of AC Out, L of AC Out 2, and the input L,N. It does not represent what is stated on page 9 where the AC Out N is connected to the chassis. Can you please clarify?

mtnscott asked
Kevin Windrem answered ·

3 Answers

Finding Ground relay problems

I have had a few sites where the ground relay test failed and finding the problem on a large installation is frankly a pain. I have made a video on why the test fails and posted that on YouTube with keywords "Victron Neutral Ground Relay Test". There are many reasons that would simply proof that you are an idiot so I ignored those reasons. The Neutral to Earth connection is mostly the difficult one to find in an existing electrical installation where one added a Victron system.

The problem is each time you isolate a circuit (read live and neutral) you have to switch the system off and start it again to see if the test fails. This takes an inordinate amount of time if you have many circuits.

If Victron can explain exactly how the test works, which impedance they test for, etc.. one can build a tester that would immediately find the error. I have seen in some cases (e.g.: light dimmers in one case) that simply testing between neutral and ground shows an open circuit. It's only when the live is powered that the Neutral to Ground leakage current exist.

Can Victron please help here?

I can see the sad result is that installers will simply not select the grid code to prevent the test from being done and have non-compliant installations, rather than spending days on site finding the problem.

energy asked
nesswill commented ·

1 Answer

Liaison Terre sur Multi 48/8000


Sur les Multi 48/8000 et 10000 il y a une barre de terre plus 3 x 2 connecteurs AC au lieu des 3 x 3 connecteurs habituels sur les 3000 et 5000.

Je pensais relier un câble depuis cette barre vers mon tableau mais je vois qu'il y a plusieurs boulons. Cela veut-il dire qu'il faille faire partir plusieurs câbles?

Merci pour votre avis.


maa asked
maa commented ·

14 Answers

Grounding options for Phoenix 12/1200 VE.Direct Inverter with GFCI Outlet

The Phoenix 12/1200 VE.Direct has two options for grounding the earth wire; neutral floating and neutral connected to earth. Which one needs to be used, in order for the model with the GFCI outlet, to function correctly?



cosecha asked
hjohnson commented ·

2 Answers

Grounding the Neutral of the Battery

We have a 3-phase ESS 5KVA multiplus-ll inverter installed it's using a Freedom Won 53V Battery.

The connection is battery to Bus-Bars. Bus-Bar to circuit breakers to inverters

My question is, must the neutral of the battery be grounded also?

Lindsay asked
semlohnhoj answered ·

4 Answers

Why connect the Negative DC battery terminal or busbar to Ground?


What is the reason why negative busbar and grounding busbar are common? How can we protect the system against impacts from the soil in this case?


cagataysahinoglu asked
T F answered ·

2 Answers

Boat grounding and mass

Hello there !

Forgive my "french" english but I'm hoping to find an answer here.

I am working on a 1908 Steel boat, doing everything. I plan on using a Multiplus II 24v, a Smart Solar 150/60, Orion Tr Smart to charge the service battery via the alternator, galvanic isolator, with all the fuses and protection needed, and a Cerbo GX.

My questions are : Do I need to use the hull of the boat as a mass for all of my DC current? To share an equipotential point or is it better to isolate the service (lights pumps etc) and having the motor side connected to the hull (connected to the - of the starter motor so the hull).

I know that in the US it is mandatory to connect the hull with the negatives of the batteries but it isn't in France and I wonder why...

About the AC current, with the shore power, my earth/ground is provided by the shore, I get it. But when sailing, where is driven the current if a fault occurs? I know that the multiplus has a Ground wire, is that it? And so, this Ground wire has to be connected to the hull or to my negative Busbar? I read about the ground relay that switch to the neutral, might be a stupid question but should I connect a neutral wire to the hull/negative busbar?

I tried to find a solution on the internet but I read something and then the reverse 3 min later... I plan to live on this boat with my wife and my son and I want it to be as safe as possible.

Thanks for your time, I am really worried about this.


bato-and-co asked
bato-and-co commented ·

8 Answers

quattro 240V with autotransformer neutral grounding question

In the Victron Schematic AT-1 split phase 240V to 120V-240V with Quattro 240V, How is the neutral of the autotransformer grounded when the Quattro has accepted the shore power or generator AC input, closed its input relays, and opened the grounding relay in the autotransformer via the GND relay control wiring?

It seems to me that it should be grounded or the fault current caused by a short circuit from one of the 120VAC lines to ground would not have a path to neutral to trip a circuit breaker.

ewbcvec asked
mvas edited ·

1 Answer

More details on the ground relay

Greetings Victron Community

Can someone provide more details on the internal ground relay itself. Are there any specifications and/or standards the relay is adhering to and what other safety features are included to ensure the ground relay is always in a working condition and that the neutral earth bridge is properly established.

Thank you in advance

faure asked
faure commented ·

1 Answer

Relying on earth rod in off grid?


Some thoughts about building a three phase system with multiplus 2 with off grid capability. Is there some way of confirming the connection to earth when in off grid (the multi disconnects L and N on AC in, correct?)

Seeing as I don’t want to risk sending a current back to the grid from the multi when using battery power, I cannot connect the AC out to the grids neutral or PEN. When in off grid mode the idea is to use a grounding rod as the neutral point and earth (effectively creating a TN-C from the multis when in off grid)?

How do I eliminate the risk of losing my neutral point (connection to earthrod is lost somehow, or the resistance to earth is to high) and thereby risking damaging electronics connected if the loads are uneven over the three phases (0-400V on regular outlets)?

Has anyone experienced problems with this? Is there some kind of module that could be installed that measures the ground resistance continuously and breaks the AC out if ground is lost?

calle asked
daza answered ·

4 Answers

GFPD Wiring

How do you wire in a GFPD between the PV array and the MPPT in a system with the negative terminal of the battery bank connected to the central grounding bus bar?

I am intending to install a MidNite Solar MNDC-GFP63 Ground Fault Circuit Breaker 63A


Apparently, with this particular GFCB, the battery negative cannot be connected to the central grounding point. Currently, my system is wired as the Victron diagram below.


glenn-matthiesen asked
Triton commented ·

2 Answers

Grounding question

I have a lynx power in connected to a lynx distributor, all the positive and negitive bus bars are filled on the distributor and it is grounded to the chassis, I have used one of the pos/neg bus bar slots on the power in. Do I need to ground both the lynx dist. and the lynix power in to the chassis?

mateaco asked
kevgermany answered ·

1 Answer

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