Grounding Image


Motorhome earthing

I am installing a Victron Inverter VE Direct 12/800.

Should the inverter chasis earth be connected to the vehicle chasis?

iainr asked
marcve answered ·

1 Answer

Earth ground


I have looked at other schematics and the chassis ground from mppt and inverter go back to the negative busbar. Is this all or does the negative busbar then have to be attached to an earth rod outside? Mine is an off-grid setup in a workshop?

roblad asked
Mike Dorsett answered ·

1 Answer

Ground Relay help for (2)-Multi's set at 180deg/split in RV

Need some help with the appropriate ground relay settings for (2)-Multiplus 12/3000/120 set 180deg-split phase.

Setup and programmed the system at a friend’s shop and followed the set-up Youtube video with the Master having “Ground Relay” ON and the Slave having it OFF. All worked great on both shore (2)-leg 50amp and on (2)-leg generator- with both units acting as one when it came to charging.

Currently plugged into an RV parks 50amp pedestal and the units will not recognize the incoming AC. A call to my friend revealed that his shop has the ground and neutral bonded.

It was suggested I turn the”UPS” to off, did so, but no change.

Any suggestions would be much appreciated.


sv-k asked
sv-k answered ·

3 Answers

No ground connection in SmartSolar MPPT 75/15 ?


I see that the bigger SmartSolar MPPT models have a ground connection on the side of the mounting plate.


What about the SmartSolar MPPT 75/15? It does not look like it has a ground connection?


Is the grounding only made on the battery side?

amidships asked
Paul B answered ·

1 Answer

Ground Relay Error 8 with Fronius IG Plus when switching back to grid

Hy All,

we deliverd a new Installation (Number 8) to an "existing" Farm House with a 3 - Phase ESS 15 kVA - Multiplus II System.

There is a Fronius IG-Plus 120-3 running for more than 12 years. So good for now.

Everything is working fine except we start the system in "Island" Mode with an Active IG-Plus. When AC Mains is connected, the System performs its Relais Test and after about 5 Minutes it is going to switch back to grid. Immediately, when switching back we get an Ground Relais Test Error 8.

When starting in Island Mode with a disconnected IG Plus everything is working fine.. after switching back to grid and connecting the IG Plus everything is working like a charm.

When coming from Grid with a GridLost, we also encounter the same problem when switching back to grid.
To make a conclusion.. When the Fronius IG-Plus is "Connected" (we switched off the system, because it starts working after 30 seconds.. so we could not test, if its a problem when standing by connected and producing), we get an Ground Relais Test Error when switching back to grid. (Always)

Whats wrong...

There is no mixed Ground and Netral (We have controlled that several times)

The Multis are showing those ERRORS:

Phase L1, device 1 (0) #44 0x820002
Phase L2, device 1 (0) #15 0x800024
Phase L3, device 1 (0) #19 0x800024

From the wiring...

AcMainSwitch - SwitchOverToGenerator - 100 mA 3 Phase FI - MulitplusII - FI-s to different Loads

the IG Plus is connected:
IG-Plus - LS 16A - FI- 003 A -To The MulitplusII Ac Out

As talking to Fronius Service Personal the have no Idea what s going on, because they say they do not connect Neutral to Ground ... so do we have issues with the 100 mA 3 Phase FI, or the FI 003A connected to the IG Plus?

The System is running the latest Firmware 487.

Unfortunately there is no Support from our Dealer, because they do not have the knowledge.

Have a nice day, always Sun and I hope to get some good feedback...

thank s in advance


Bernhard Matschinger asked
Bernhard Matschinger edited ·

0 Answers

Multiplus II – Ground relay test failed #8 - Error 11 0x24

Hello everyone,

This device worked perfectly over the past two weeks and today it started dropping the AC loads.

This notification is displayed – “MultiPlus-II 48/5000/70-50 - #8 Ground relay test failed”

The VE.Bus Error report shows – “Last VE.Bus Error 11 report 0x24/Error occurred/GND Relay Error”

When I restart the Multi it produces the error right away. The bulk and absorption LEDs are also on.

Current firmware version is v471 (Multiplus II software version: 2623471)

I have done the following:

-Verified that AC-in GND is properly connected to grid earth.

-Tested for voltage between AC-in GND and AC-in Neutral. Ok - no voltage measured

-Verified that earth and neutral is not connected somewhere. All ok.

-Physically disconnected all cables from AC- out1 and AC-out2 to verify that there is no problems with any of the loads.

-Switched loads directly to grid via change over switches - all loads functions properly.

-Tested RCDs all ok.

Thank you,


jeanmc asked
kyle answered ·

5 Answers

Phoenix 12/1200: How to connect the output neutral to ground

I need to ground the output from my Phoenix 12/1200. I see the diagram in the manual appendix but it's a bit too abstract for me. Has anyone seen better documentation or a video that explains this better? Thanks!

erictstahl asked

0 Answers

SmartSolar MPPT chassis grounding confusion for camping trailer

I'm building a small camping trailer with built in kitchen and roof tent. I'm starting with just PV to begin with, I may add mains hook-up and an inverter later. I don't intend to add split charging. The plan is to use a Victron 140W PV panel to charge a 110Ah leisure battery through a SmartSolar MPPT 100/20 controller ( I may add another panel later). I've added a picture of the first stage. My question is about grounding on the output of the controller. I get the PV side, no issue. On the load side of controller, does the negative also go to chassis ground?




farmer-giles asked
farmer-giles answered ·

1 Answer

Connecting Ground Screw on 100/30

I'm building a teardrop trailer and just installed a Victron 100/30 solar controller. I'm asking where the ground screw should be connected to? I'm using a Blue Seas bus bar where the battery + and - go to, the solar panels + and - go to and the battery charger go to. I'm wondering if the ground screw on the solar controller can go to the neg bus bar, as well? Thank you. Please ask for any additional info. Appreciate the help.

teardropper asked
Kevin Windrem answered ·

1 Answer

Grounding Off-Grid System - Some questions

Hello everybody,

in the past few months I've been designing the off-grid system for my farm, with the help of an electrician. I already bought (almost) all the components and I'm installing it right now.

Now, I find myself stuck with the grounding of the system, because I'm not quite sure how I should wire the whole system so that it's as safe as it should be.

As a side note, consider the following:

  • I know that it is advised to ask this kind of questions to a qualified electrician who knows the local regulations, but believe me, where I live (rural Panama) it's actually pretty hard to find one, let alone someone with experience with Victron products. In fact, I had to buy 80% of my components from the US because nobody sells them here. (for example it was literally impossible to find flexible wires, I had to buy them on Amazon. Same for 4/0 copper wire lugs and the tool to install them)
  • regarding local regulations, forget about it, there are no specific regulations and nobody checks whether what I'm doing is good or not. The person in charge in this town does not know anything about off-grid systems, and is in fact waiting for me to complete my system so that he can see how it works

I had some help from en electrician online, and of course I studied all what I could find online, but there are some things that I'm not sure about, so maybe you can help me out.

Please find attached the diagram of the system (It's a work in progress).

Electrical Drawing with 1x BYD LVL.pdf

I believe that the grounding wiring needs to be fixed, because:

  • 6 AWG for grounding the inverter is too small of a wire, because from reading Wiring Unlimited I think the wire should be tick enough to be able the carry the full current, which in my case is 250 amps, so the wire should be 4/0 AWG
  • it's not clear what happens between chassis grounding and AC grounding. Is it a floating system? Do I need one RDC before the AC distribution? Does the PV part of the system have a dedicated ground rod for lightning protection?

This is where I'm stuck.

From my understanding, I think the grounding should be fixed as follows:

  • the metal frames of the PV panels should be grounded with a ground rod
  • the ground output of the PV combiner box should be connected to the same ground rod
  • all the chassis of the components (the two inverters and the charge controller) should be connected in parallel with tick wire, and then connected to the central ground terminal of the Lynx Distributor
  • from there, I should run a 4/0 AWG wire to a ground busbar (not shown in the diagram), where I should also connect the grounding wire for the AC distribution panel
  • this ground busbar is connected to another dedicated ground rod
  • there should be a RDC breaker between the inverters and the AC distribution panel.

Well, there's that, not sure what I'm missing, but I'm sure that something is missing in my understanding of the whole grounding deal.

I appreciate any help!

Edit: I added a screenshot of the diagram.


niccolaiddis asked
shaneyake commented ·

4 Answers

DC Leakage via Protective Earth Conductor

I'm have this weird problem that during a no-load condition with an Smartsolar MPPT charging, I'm seeing a phantom load of around 22 W that doesn't seem to exist. The MPPT is mounted in a cabinet along with a Multiplus, and the whole cabinet and both devices are tied to a protective earth bus bar, which is bonded to battery negative, aka before the SmartShunt in the system. The Multiplus and the MPPT are then grounded on the load side of the SmartShunt. I also measured the current in the earth conductor, and it's around 1.4 A, which correspond quite well to the 22W phantom load on the system (12V system). There's also an equal discrepancy between the battery + and - conductors of the MPPT. So, is there an issue with my MPPT charger, or should I bond the protective earth bus bar on the load side of the SmartShunt?

sebastian-storholm asked
Alexandra commented ·

1 Answer

Isolated Orion-Tr negative wire thickness with both batteries grounded to chassis


The starter battery negative terminal is connected to my van's chassis (as per usual) and my leisure battery negative terminal is connected to the chassis via a 20mm2 wire. I have just ordered an Orion-Tr Smart 12/12-18 Isolated DC/DC Charger; I didn't need the isolated version as my batteries are already bonded via the chassis but it was cheaper than the 30A non-isolated version. I will connect the starter and leisure batterie's positive terminals to the Orion-Tr via 20mm2 wire.

My question is, given that the two batteries negative terminals are already connected via 20mm2 wire and the vehicle chassis, can I connect the negative input and output of the Orion-Tr to the chassis/battery negative with thinner wire (say 6mm2 or even 2.5mm2)?

From my limited understanding of electrics, I would think that the Orion-Tr just needs the negative wire to be able to power itself and sense the voltage of the two batteries and the current path will be through the vehicle chassis as that will be lower resistance.

I have attached a Wiring Diagram.jpg for clarity.


OutdoorAcorn asked
OutdoorAcorn commented ·

1 Answer

Phoenix Smart inverter grounded to my RV chassis, should the negative of the (dedicated) battery feeding the inverter also be connected to the chassis?

As per the title above. I searched through the excellent Victron Wiring Unlimited guide and here in this forum, but couldn't find an answer.

Just to make it clearer, I say it's a ''dedicated" battery because it's completely separated from the vehicle's pre-existing battery system, and it's connected only to the Victron inverter (with separate 70mm2 cables) and to my PV charge controller.

Thanks in advance for your help.

durval asked
wkirby commented ·

1 Answer

Multiplus: Jumpering Chassis Ground to Negative Input

Rather than run an additional large gauge cable from the Multiplus chassis terminal back to the system negative bus, or to a grounding bus that is also connected to the negative bus (which is connected to the vehicle chassis), why not just run a large gauge "jumper" from the Multiiplus chassis terminal to the second negative terminal connection point found on the Multiplus 3000?

Why isn't this done? Or if its done (and fine to do), why don't people talk about it?

nate-costello asked
nate-costello edited ·

1 Answer

BMV-712 shunt chassis ground

Where does the chassis ground go on the shunt?....line side (battery DC-) or load side (all DC- loads)?

Can't believe this isn't in any of the Victron installation documentation.

System is;

solar panel/AC shore power/vehicle battery can all charge the house battery via MPPT and B2B controllers; only want to monitor house battery not vehicle starting battery.

jongor asked
wesser answered ·

1 Answer

Ground relay test failed. Min resistance between neutral and earth?


i sometimes have problems with ground relay tests failing, when my system connects to the grid.
I think the problem is, that my electrical installation is quite large and old and the isolation resistence between neutral and earth is just above 1 mOhm. If i disconnect the elctrical installation from the Multis, the ground realy test does not fail.

What does the Multiplus measure during the ground relay test ? Resistance between neutral and earth? What is the lowes value that it will accept?

Nico Bayer asked
checkit commented ·

1 Answer

Smart Shunt Chassis Earth

I've purchased a Smart Shunt, and looking to install shortly.

However my AUX battery is in the engine bay, and the bulk of the loads will be in the rear of the vehicle. I therefore have two questions.

One, given I need to ground the AUX battery to the chassis for a common grounding between Start, DC charger and AUX. Do I earth this after the shunt? I believe I need to run the DC charger ground to the shunt to ensure it is captured, so AUX and DC would be sharing a grounding on the load side of the shunt?

Two, given I'm going to be measuring the voltage of the start battery also using the AUX plug, I understand the Neg terminal of the start battery also needs to connect to the shunt. Given the common grounding between both batteries and charger is this already achieved without wiring direct? Therefore related to common ground, if it is common could I then ground my DC loads in the rear of the vehicle to the chassis, or would I need to explicitly run a negative to the load?

Unusure how the shunt would determine if the load was for the AUX battery if it was a common ground?

I've attached what I believe are the two alternatives of my questions. Advice appreciated



dhearne asked
dhearne commented ·

1 Answer

Reusing ground chassis attachment


I am installing and integrating an EasyPlus and a new DC distribution board in a campervan with an existing grounded electric system.

My idea was to attach the ground connection of the EasyPlus to the negative busbar of the distribution board.

Then I would attach this negative busbar to the same location on the chassis where the rest of the equipment is grounded.

Is it a doable solution or should I connect the busbar to its own connection on the chassis?


amidships asked
amidships commented ·

1 Answer

Earth Rod attached to motorhome...any unforseen detrimental effects?

In a rubber tyre insulated motorhome, is there any downside to attaching an earth rod to the chassis when parked up, when using 240v ac inverter power only(no grid tie or grid earthing) ?
Is it safer with the earth rod connection or not?

maximoney1 asked
Kevin Windrem commented ·

2 Answers

Positive grounding for "Sunpower cell" based panel with Smartsolar 100/20 possible?

Hello Victron community,

I have bought Smartsolar 100/20 and 3pcs of "Sunpower series" Solarfam panels, each rated at 140w on my motorhome, mounted horizontally, and feeding 120AH AGM Battery.

I am however struggling to reach anywhere near the 420 Wp of the system. Yesterday at about 14pm CET at full sun and clear sky the output was 215w/(Batt Voltage 12.89 16.4A, under load attached to the battery of +-350w).

When I tried connect only one panel, the output was a bit over 70w, so it cleary has nothing to do with hitting the possible limit of 20A of the charger...

The panels are apparently some Chinese panels made from Sunpower cells sold under Solarfam ( brand. I have a suspicion on "potential induced degradation" - have read that Sunpower cells earlier required positive grounding, and with the negative grounding they tend to loose 30+% pretty quickly, when potential builds on their surface. Have emailed the manufacturer about the grounding, but they have not responded yet.

My question is, would that be anyhow possible to try to test this positive grounding with SmartSolar 100/20, to see, whether it could be the cause of the power degradation?

I might isolate the frame of the panel from the vehicle frame, but I cannot find any documentation on how to go about this positive grounding.

Thanks very much for any ideas.

ulab asked
michelg answered ·

1 Answer

Lynx Distributor ground and Smart Shunt Ground

Im doing a solar install where i have the Lynx Distributor and the BMV-712. My MPPT is a the 100/50 (ground wire connected to distributor). Do i need to make a ground connection to my chasis (travel trailer) from just the shunt, or both the shunt and the distributor?


ryancrist asked
raphael answered ·

1 Answer

Mettre neutre à la terre de l'onduleur solaire RS Smart

Bonjour à tous.

Je viens de recevoir l'onduleur RS Smart 48/6000. Étant totalement isolé du réseau et disposant d'un coffret de répartition avec 2 rangées qui débutent par des interrupteurs différentiels de 30mA, je dois réaliser une liaison du neutre à la terre.

Le manuel dit ceci : L'onduleur RS est équipé d'un relais de mise à la terre qui raccorde automatiquement la sortie du neutre au châssis. Cela permet le fonctionnement correct du commutateur de fuite à la terre et d'un disjoncteur différentiel interne connecté à la sortie.

Comment faire avec mes interrupteurs différentiels externes ? De plus, un petit câble de terre pré-dénudé se trouve dans la boîte. J'en fais quoi ?

bosti asked
Thierry Cortassa (Victron Energy Staff) answered ·

3 Answers

Bridging IS0 Tx Neutral and Auto TX Neutral in a Marine Application

I have a boat with a 50 Amp shore power feed going into an ISO TX. The Neutral and GND are connected on the output of the ISO TX. From there the ISO TX output goes to a Quattro 8K 230v Inverter (Hot 1 and Hot 2) and the Shore Power selection breaker (Hot 1, Hot 2 and ISO TX Neutral).

The Inverter feeds an Auto TX which is then connected to the Inverter selection breaker (Hot 1, Hot 2 and Auto TX Neutral).

The ISO Breaker and Inverter Breaker have a lock out only allowing one to be selected.

My question is: When AC power is going into the Inverter (not inverting) and being passed to the Auto TX and the Inverter breaker is selected should the ISO TX and Auto TX neutrals be connected?

When the Inverter turns on the ISO TX and Auto TX neutral disconnect and the Auto TX would create the Neutral/GND connection.

Please see the attached wiring diagram.




blueskytrawler asked

0 Answers

Vehicle chassis grounding of multiplus 24/3000/70-16 inverter charger

In the simple diagram below showing grounding arrangements within a motorhome, do i need to run a extra grounding cable from the consumer unit earthing bar to the grounding busbar. I don't understand how the RCD in the consumer unit will trip (when there is a fault) when there is no true earth connection, only chassis grounding? Thanks for any help offered.


maximoney1 asked
maximoney1 commented ·

1 Answer

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
Alexandra commented ·

2 Answers

Install Common Ground in my boat or not? Smart Orion DCDC Isolated.

Hi Community,

I just like to start mention that I have read through the “Wiring Unlimited”, many related questions and the wiring diagrams for the Smart Orion DC, and I’m still not sure what to do.

My set-up is a glass-fibre boat, 2 outboards with 2 alternators going to 2 AGM Dual Service starter batteries.

We are now expanding the House system to Lithium, and are therefore installing 2 Smart Orion Isolated DCDC chargers for charging the Lithium’s from the AGM’s.

We made this (attached) design but realised that the house battery bank and all the connected loads were completely isolated from the ground-plate, and the shore power ground cable.

Only connection is through the two DC-DC chargers. (PS!! The design does not show all switches and fuses on the lithium side)

Will this cause a problem?

- Personnel safety?

- Galvanic issues?

- VHF Radio ground requirements?

- Lightning? (all the electronics in the samson post is running through the dc-dc, so no connection to the ground-plate)

Should I add the green cable in the diagram, or is it OK without it? Pros and Cons for Isolated?


The 3 x Wiring diagrams on the “Smart Orion Isolated” shows that both negative cables are connected to the negative bus-bar, although indirectly.

On the live stream ( they are fully isolated, however a very simplistic diagram.

Thanks for any advice and help. Been waiting for the boat for 10 months, and hope to put it on water this week.

thomas-hamre asked

0 Answers

Can I mount multiplus in bare aluminum box

Can I mount a Multiplus in a bare aluminum box? I am mounting in a van and am wondering if there is a possibility to get shocked as it seems that the Multiplus ground terminal is bare on the back and is making contact with the aluminum backing. It will be grounded to the busbar and the busbar will be grounded to chassis. Should I put something non conductive in between the multi and the bare aluminum?

mrcc11 asked
Murray van Graan answered ·

1 Answer

Connect "ground" of load output to vehicle body? MPPT 75/15

Hi everyone!

Is there any reason I should or should not connect the ground/- pin of the load output to the body of the vehicle?

I'm having issues with my fridge (Dometic CB40 compressor, 60W) shutting down due to low voltage, so I connected the fridge as the only load to the load output of the MPPT 75/15. I used 6mm² cables, roundabout 1.5-2m length. In this first setup, ground of load output was connected directly to the ground pin of the fridge.
With that setup I was able to measure the current (up to 7A) that the fridge used. Unfortunately I still had a misterious voltage drop of 0.5V-1.0V along this connection, so the fridge would shut down due to low voltage (<10.5V).

Now I have connected the ground of the fridge to the vehicle body and the voltage seems to drop significantly less, at least the fridge doesn't swithc of any more....

But it seems that I can't measure the load current anymore?

brokenfeet asked
xmd answered ·

2 Answers

Off grid wiring digram

Hi there,
This is how I am planning in wiring my off grid tiny house on wheels (essentially a caravan) and just wanted to see if anyone can see any issues with it? Is the earth circuit correct? Photo attached.

I haven't drawn any of the AC side of of the installation for the purposes of this diagram but I'd like to add that in addition to the connections in this diagram, I will also have:

-All the earth's from my AC loads will connect back to my negative buss bar
-A large cable (same size as battery cable) joining my negative buss bar to the trailer chassis.

Another note - The reason I have run the MPPT positive cable through the other pole on my DC isolator is because when I switch that off I want everything to stop, including the charging of my batteries. I realise I can just turn the PV isolator switches off and achieve the same result, but I want it all to turn off with the flick of one switch.

Sorry for the long winded question and thank you in advance!


Brandon asked

0 Answers

Use same vehicle ground for negative of battery, PV, and load. Negative of PV connected to metal roof of van

Any reason I shouldn't do like that?

Can somebody explain why the manual says: "Never ground both the minus of solar array and the minus of battery."?

Ground would be identical to my minus lead to the controller.

joeoffgrid asked
offroadflow answered ·

5 Answers


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