Grounding Image


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

Mobile trailer grounding

I am building a Tiny house on top of a steel trailer. My tiny house on wheels will be mobile and off grid with batteries charged by PV array. Will have the occasional plugin to a Generator for extra charging if need be.

My question is how does the ground circuit work in this scenario.

- Does the earth wire from the inverter, MPPT, PV panels grounds, battery casing, AC power outlets, lights, trailer frame, etc all join to a copper steak that I can drive into the ground when I park the trailer?

- Should the battery negative also be joined to the earth buss bar?

I have attached a rough diagram of how I think the earth circuit would go (earths in green). Could someone please let me know if this looks right. I quickly drew this diagram mainly for to show the earth circuit so I do apologise about the rough nature and any symbols that aren't quite right.

Thank you!

Brandon asked
Kevin Windrem commented ·

1 Answer

RCD Tripping randomly

I have just about installed Multiplus 48/1200/13 and hooked it up to Li-ion 14s1p batteries.

It has been working perfectly in UPS mode and pass through. To test the capacity, I turned off the mains and the UPS kicked in, I let the system run - till the cut off voltage was reached.

When I turned on the grid/mains - the RCD (on the mains consumer unit) tripped. It did this a few times. I disconnected the load and the same happened (rocker switch in ON position). Then I switched it to charger and it did not trip.

I tried various combinations and unfortunately - the RCD tripping is very random and not reproducible.

AC in comes from the grid

AC out goes to feed a total of 250W (a few pumps)

Any input or help would be appreciated.

ispookie666 asked
Carlos Carvalho answered ·

7 Answers

"Ground Relay" setting, on or off?

Hello, I have a Multiplus 2000/12/80. The Ground Relay setting is on by default. Based on my reading it looks like I should turn it off. I don't have a ground relay wire hooked up and I didn't buy an autotransformer. All I have hooked up to my multiplus is the battery, chassis ground, shore power, AC, and battery temperature cable. Am I missing anything or should this be turned off? Would having it turned on have caused any issues?

Thanks for the help!

kaplan78 asked
johnny answered ·

8 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
bernard-forrer answered ·

4 Answers

Ground relay is it necessary on auto-transformer

So i just installed a Victron Auto Transformer 32 amp version. I currently have a Multiplus 12/3000/120, I am feeding it to the autotransformer. This install is in my vehicle, the multiplus is grounded to the chassis, should I ground the autotransformer to the same chassis ground as the multiplus.

Or is it necessary to uncheck the ground relay setting in the multiplus. The picture i posted depicts the ground relay connection from the multiplus going to the earth relay on the autotransformer. Is this necessary.??

If it is necessary, where can I get 10mm long ferrules to connect to the 2 pin connectors.?? My standard 8mm ferrules are not long enough.


saullyman asked

0 Answers

Conjoncteur de Neutre

Bonjour, je souhaiterais savoir si l'un d'entre vous a déjà utilisé un conjoncteur de NEUTRE pour connecter la terre au système ?

En fait j'ai fabriquer une box énergie mobile qui est équipé d'un Multiplus 5kva et de batterie pylontech. Le but est d'avoir la terre et cela même si je n'ai aucune solution comme l'absence de bornier de terre ou l'impossibilité de planter un piquet de terre. Merci pour vos réponses

mobilvolts asked
Thierry Cortassa (Victron Energy Staff) answered ·

1 Answer

dual installation 12V and 24V negative busbar

Hi all

If I have two lines, 12V and 24V, can I connect both to the same negative busbar?
if the answer is yes, can that be grounded, must be grounded or some other answer?

many thanks in advance

pepvan asked
dazey77 answered ·

1 Answer

My client can't make the neutral-ground connection on a 12V 1200VA Phoenix

On the 12V 1200VA inverter, there isn't the surrounded red bloc below :


Here photo of the client :



As response, Victron France said: "You have to make the connection as the manual says."

@jfeiman, ask the same question for 12V 500VA NEMA inverter 2 months ago, no answer too.
His message :

"My 12/500 Phoenix inverter also lacks the internal neutral-ground jumper. According to the manual, a GFCI outlet will not provide ground fault protection without a neutral-earth bond. When a single extension cord or other electrical device is plugged directly into the inverter, there is no load distribution center on the AC side for external neutral-earth bonding.

1) Am I correct in interpreting this to mean that an extension cord equipped with a GFCI device does not provide ground fault protection when plugged into this inverter?

2) Is there a plug-in solution for providing ground fault protection?

3) Is there a VE service document that details a procedure for bonding neutral to earth internally with this inverter?"

myshopsolaire asked
myshopsolaire commented ·

1 Answer

Ground Issues with Victron MultiPlus 24V DC - 3000W

Hi everyone, We have experienced issues with Victron inverters. Since the marina installed ground-fault relays (breakers) on the docks I have 4 customers that are tripping the GFI breakers on the dock and the marina office is requiring them to get it fixed. The Problem with all of them is the Victron inverter. I just installed a new one but as soon as I ground the chassi and inverter turns on it trips the dock GFI. Same problem on other boats. If the Grounds are removed from the inverter problem is solved and GFI does not trip. Just For reference The marina just got the GFI system installed and it is set to 0.2 Amps. Is there a way to fix that problem and what should I tell the owner who just paid for the new Victron inverter that got installed but it can`t be grounded. The only way to work is if there is no ground to the inverter neither for input or output or chassis.

nixyacht asked
Kevin Windrem answered ·

2 Answers

Changing the connection ground-minus


I am planning to install a MultiPlus 3 KW / 24 V AC inverter/charger in my expedition motor home (RV).

The inverter/charger is unfortunately 3.6 m away from the batteries and from the Central Negaive Busbar. Routing the 50 mm2 wires is a bit difficult due to the confined space.

The original Victron wiring diagram shows independent cables for the chassis ground and for the battery negative connection, but both lead to the same central negative busbar.

What is wrong with bringing together (connecting) the cables for ground-case and for battery-minus directly after Multiplus and thus saving a long cable to the central negative busbar, which would simplify the cable routing considerably in my case?


hilmar asked

0 Answers


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