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Multiplus 12/3000/120-50 Ideal Grounding on Travel Trailer

I've spent quite a bit of time researching this question, in the Wiring Unlimited document, along with the Multiplus manual and a multitude of forum postings. I realize some elements of the question are largely redundant so I will try and be as specific as possible. This installation is for a personal RV, and although I'm not a licensed electrician I have done quite a bit of high voltage electrical work, and as a computer scientist have had some exposure to electrical engineering principles and issues when working with microcontrollers, etc, though most of my work does not involve machinery or process automation. I'm by no means an expert, however.

I'm working to complete an installation of 2xMultiplus 12/3000/120-50 inverters connected to a 6x100AH Battleborn battery bank in parallel configuration. I also have a SmartSolar 150/85 MPPT controller connected to 7x195Watt PV panels mounted on the roof. The Multiplus units are in a split phase parallel configuration. Proper size wiring and current protection devices (breakers and fuses) on both the A/C and DC side are installed and various points(E.G. pre inverter A/C breaker, post PV combiner to MPPT controller, post MPPT controller to battery bank, post battery bank pre inverter, pre trailer existing wiring connection, post inverter A/C to trailer, etc). Properly sized wiring is used based on the current protection devices in place and maximum intended sustained amperage taking into account insulation rating, conduit fill rules (where applicable), etc.

At this juncture I have completed the majority of the installation on the system but have come to a question on proper ground application. Currently all equipment functions without grounding the equipment separately to the chassis(although I have full intention of doing so), and I have tested the system in excess of 250amps continuous DC flow to the inverters for extended periods of time(E.G. by turning on the A/C, electric hot water heater, etc). After working through a number of configuration "tuning" issues, I'm happy with the results, although an added element of safety is left dangling out there.

With that in mind, I believe the following is accurate:

1) Each Multiplus should be separately grounded to the chassis using a conductor of equal size to the conductors used in DC +- in the inverter. In my case 4/0 wire with 105c insulation.

2) The Solar MPPT controller should be grounded to the chassis, again with the same principle outlined in 1 regarding wire sizing.

In both 1 and 2, it would be alternatively acceptable to utilize a wire size equal to the acceptable size requirements for the current protection(e.g. for the battery bank a 300AMP fuse is used) device.

This brings me to my question(s):

Currently the negative and positive leads running to/from the inverters are connected to BusBars rated for 600A each. The positive side, prior to reaching the bus bars from the battery bank is fused, and then runs to a disconnect, then to the bus bar. The negative side, through a shunt and then straight to the BusBar.

One of the terminals on each BusBar runs off and connects to the main trailer wiring via the terminals where the previous manufacturer supplied batteries resided and then into the main trailer DC supply disconnect. This minimized the amount of rewiring needed to tie into the existing DC wiring. The positive side leading to the trailer manufacturer dc wiring is fused prior to reaching the existing trailer wiring system.

The existing trailer appears to have ran a frame chassis DC connection from the negative side of the DC wiring. Should I disconnect this and replace it with a larger 4/0 wire from the battery bank bus bar? Is it acceptable to leave it, and run an additional negative wire from the BusBar directly to the chassis(near the existing ground bar on the trailer)? Would/Could this create a ground loop/other situation with multiple DC paths to the chassis ?

Additionally, since the Multiplus requires a ground, should I route that to the negative BusBar, instead of a separate ground out to the chassis, and then use the larger ground noted above? The same applying to the MPPT controller. Similar to this:

In the aforementioned diagram, it would appear all negative and ground connections are terminated on the same negative busbar, and then a single chassis ground is ran to the frame. If that is the more suitable way to approach it, would it be necessary to disconnect the existing DC negative to chassis run the manufacturer installed(I would think so)? How would energizing the inverter chassis with high voltage A/C impact the DC negative connected equipment in the case of a short to the inverter housing using a common busbar scenario(or for that matter into the chassis) ?

I'm trying to determine the most ideal path forward to ensure safety and minimize complexity. The wiring space is extremely constrained as well. Any recommendations are much appreciated.

Thanks in advance for any thoughts.


chrisk asked
mt_mag edited ·

1 Answer

AERL Earth Guard detecting Negative to Ground fault on MultiPlus II 3000/48


Installing a ground fault detection device (the AERL EarthGuard) which references PV +, PV- and Ground.

System is 250/100 MPPT, 3 Multi Plus II 3000/48 / 35-32s, Kilowatt Labs 3.55kWh modules x2.

It all works fine, but when I installed the Earth Guard, which was the last thing I did. It detected a fault between ground and negative. Which I've isolated to be coming from the MultiPlus II.

Is there functional negative grounding in the MPIIs? Is there an option to turn this off?

The AERL manufacturer said it could be a faulty unit.

Isaac Shannos asked
Guy Stewart (Victron Community Manager) answered ·

1 Answer

Earth bonding inverter output in a camper installation

I have installed a Phoenix 12|500 inverter into a panel van camper conversion, with the DC input side connected to the 12v leisure battery & earth connection bonded to the metal chassis of the vehicle.

On the output side I am running a fused (3a) 3-pin plug into a two-gang RCD-protected plug socket, providing short circuit protection in the instance of a live fault raising the potential of the chassis to 230v and some poor soul stood on wet earth outside knocking on my door.

However I am left wondering what overcurrent protection there is on the output side. From what I understand in the product manual there is no continuity of earth (chassis) bond from the input to the output side. Ought I make an additional connection to the vehicle chassis on the output side to facilitate overcurrent operation of the 3a fuse in the case of an appliance fault?

Happy to answer queries and share pictures if beneficial. Thanks for helping with my head-scratcher..

ostrichwrangler asked
Kevin Windrem answered ·

1 Answer

Multiplus External Ground Relay control Does not Work

Hi Victron,

I have a SplitPhase Setup with an 48/5K 230v Multi + Autotransformer. The setup Manuals tells you to Disable the Multi+ Internal Ground relay by removing the check mark in VE Configure.


and that will enable the External Ground relay control at the Multi+ to use the Ground relay at the AT.


Multi+ gnd relay connection

I realized this AT external ground relay does not close at all. So I tested the relay applying 5volts and the relay close (Relay has a label attached that said 28VDC). Then I tried to read anything coming from the Multi+ Gnd relay green contact and nothing is coming out (no voltage, no Contact close)

I tested having the Multi in Inverter mode and connected to the Grid and the same results.

Multi+ Firmware: 473

Additionally, I tested changing the dip switches has the Manual advise and still no control over the AT gnd relay.



Thanks for your help

Yus asked
Yus answered ·

2 Answers

Earth Ground Breaker in Van?

The manual is saying that the AC side of my Multiplus 2000 should have an earth ground breaker. However, is this neccessary, or useful in a van installation? That breaker is pricy for sure but if it improves safety in the van I’m all about it.

This is the breaker that Victron seem to refer to -

Confused since there is no true “Earth” ground in a van. Greatful for any guidance. Thanks!

Kaplan78 asked
Dzl edited ·

4 Answers

Multiplus Ground Relay Voltage

I am troubleshooting the ground relay function. I have two multi plus II’s and an autotransformer. The autotransformer is not bonding neutral to ground when inverting, even though I have the ground relay wiring in the place and the ground relay option unchecked in the multi plus configuration. If I put a multimeter in the ground relay on the multi plus what should I read? Also what voltage range / amps can I supply the auto transformer to force the neutral to PE bond.... trying to isolate the problem....

Fagan1 asked
Yus edited ·

2 Answers

Neutral-ground bonding relay on an Autotransformer

Recently I bought an Autotransformer to convert a 240vAc to 120/240VAc(split phase). This Autotransformer contains a relay to control the Ground on the neutral.

Someone know how this relay works? Needs a signal to activate?

Halida35 asked
Yus answered ·

1 Answer

Will the internal relay H suffice the operation of electrical shock Protective devices when used on a boat without an earth plate?

I have a moving vessel with 2x 12/2000/80 Multiplus compacts in parallel with out an earth plate, will relay H allow electrical shock protective devices (Rcds) to work correctly without fault or will a earthplate need to be installed?

zac freeth asked

0 Answers

Grounding Phoenix 12/250 inverter in a camper van


Currently, my Phoenix Inverter is grounded to the same point on my van's chassis as my leisure battery. This set up works and I've had no problems, though after doing some reading I'm wondering whether it is the safest or best way to do it.

If the leisure battery is grounded, does the inverter need to be grounded at all? Should the inverter always have its own ground? Any advice would be much appreciated.



Jake Chapman asked

0 Answers

Easysolar 24/3000/70 grounding to chassis in Camper van

I have an Easysolar 24/3000/70 installed in my camper van. About 1500Wp of solar on the roof and a 24v 120Ah lithium battery pack.

The DC system of the van is 12v, with negative connected to chassis.

Should I connect the Easysolar ground to the chassis of the vehicle?
Should I connect the negative from the 24v DC system to the chassis of the vehicle?

Somehow I can't find a simple yes or no on these questions and there is no manual for the Easysolar (not so easy after all without a manual).

If yes to questions above, how should I connect it? Where in the Easysolar to connect the wire. What mm2 should I use?

Danalog asked
Danalog answered ·

4 Answers

Fault Loop Impedance.

Quatro 48/5000 has a fault loop Impedance of 4.9 ohms but should be < 1 ohm. Can this be adjusted / tested

IanK asked
Matthias Lange answered ·

1 Answer

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
Bassman answered ·

3 Answers

Do I need GFPD in my system?

For my passenger van I have a simple setup: 98W panel, disconnect, MPPT 75/15, 100Ah LiFePO4 with BMV-700 to run a cooler. Will I need a GFPD? What needs to be grounded in this situation?

Tim asked
Dzl commented ·

1 Answer

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. asked
suttridge commented ·

0 Answers

Ground Wire Size for Multiplus 12/3000 watt inverter/charger

I'm using two positive 2/0 gauge wires and two negative 2/0 gauge wires per connection to battery. What size ground wire do I need for the inverter ground? If I'm reading correctly, it says I use the same wire for the ground which would be two 2/0 gauge wires for ground. Is that correct?

ghaz asked
Stavarda commented ·

1 Answer

Wiring diagram for Orion 24/12 25amp?


I have looked all around victron site but could not find a wiring diagram for the Orion 24/12 25 non isolated converter.

I am using it on a 24v system for 12v accessories. Running 2 in parallel for 50amps (or May just use one and leave the other as a backup)

Instructions state the negative terminals are bonded inside. If that is the case, can I ground my fuse panel to my 24v system buss bar and only supply a negative 10guage conductor to one of the negative terminals? Why are there 2?

Leftishut asked

0 Answers

Grounding MPPT 100/30

Does the unit need to be grounded via the chassis ground screw on the side in an RV application?

eacheach asked
monse53 commented ·

3 Answers

Multiplus 24/800/16-16 Chassis Grounding

I want to wire my Multiplus to a 3 prong (L, N , E) plug and plug that into a home wall socket to use as a UPS. The manual states:

"- In a fixed (for example terrestrial) installation an uninterrupted chassis ground may be provided by the AC input ground wire."

What is not clear to me is if I need to split the earth wire coming from wall power to go into AC in and also the chassis ground. Are they combined internally or not?

KarlZA asked
KarlZA commented ·

1 Answer

Ground relay test disable

I have read quite a bit on Ground relay test failures and the bottom line seems to be: Earth Neutral properly before the inverter and keep neutral and earth separate after the Multis.

Why is that necessary?

I have an example of a property with 40 meter from the grid connection to the inverters. Ground resistance increases from 0.14 Ohm at the PoC to 0.34 at the inverter inputs. After the Multis, the cable runs 120 meter to the house and another 100 meter to some outside pumps.

I am concerned that the earth resistance gets too high if I do not add earth pegs at the house and pumps on the property. The property is on a hill with high lightning exposure.

If the requirement originates from the electronics in the inverter, then just say so and I have to accept it. asked answered ·

2 Answers

How do I safely ground a cabin install with detachable generator?

I'm currently setting up my multiplus with a breaker box on AC1. The grounding instructions don't address a detachable generator if not in a vehicle with a chassis to ground to. Any suggestions for grounding the system with a detachable generator in a no vehicle environment?

Fozzydabear asked
JohnC commented ·

2 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
Markus commented ·

5 Answers

Can I Connect load and battery ground at MPPT 75/15

Can I connect the battery ground and the load ground of the MPPT 75/15 to the same ground rail? Or do I have any disadvantages there?


Froop asked
JohnC answered ·

1 Answer

Easysolar grounding in vehicle

Hi, i experience some difficults to understand the grounding relay system in a Motorhome. In Many Diagram i've seen the ground (the ground point inside the easysolar panel where Ac in and Out ground should be connected) connected to vehicle chassis, for that OK.

Now, questions :

-Because of the built-in RDC inside the easysolar, should i connect the ground relay? And how?

-In my case i use a BYD Pro 10kw battery. Should i connect the ground of the box to negativ pole and to chassis? Or this already done inside the easysolar?

I don't have à DC distribution bus bar like in the byd/victron diagram (

In my opinion, it's difficult to find this Kind of informations for easysolar. The diagram always shown Multi and/or mppt etc... Maybe victron can made some specific diagram for easysolar, and the use in a vehicle? (or maybe it already exist but i didn't find it...)

Lambish asked
Daniël Boekel (Victron Energy Staff) commented ·

2 Answers

Phoenix 12/250 inverter neutral grounding and other ABYC requirements

I've just made the acquisition of a Pheonix VE.Direct 12/250 inverter for my sailboat. I understand that it has been engineered and manufactured according to european standards, but I would like to clarify some points to see if and how it should also comply with ABYC rules.

  • Neutral grounding

    According to ABYC E- and A-

"The inverter output neutral shall be grounded at the inverter."

Considering now the warning in the manual first page, I understand that the inverter comes by default with a floating (a.k.a. a non-grounded) neutral:

"The AC output is isolated from the DC input and the chassis. Local regulations may require a true neutral. In this case one of the AC output wires must be connected to the chassis, and the chassis must be connected to a reliable ground. Please note that a true neutral is needed to ensure correct operation of an earth leakage circuit breaker."

Am I understand properly the meaning of that paragraph and am I right to think that the neutral will have to be connected to chassis ground to comply with ABYC ? Is there gonna be any other issue that I need to be aware of in doing so (and why it shouldn't have been done by default ?)

  • Circuit protection

    According to ABYC A-

" Integral inverter receptacle(s) shall be protected by an integral Ground Fault Circuit Interrupter (GFCI) device in accordance with [ABYC E-11]."

Is there a GFCI on the inverter receptacle (NEMA 5-15 R), as the manual is silent about it ?

Also, is there any recommandation for selecting DC input wire protection device ? I've seen that many inverters recommend to use a Class-T fuse, but I'm planning to protect the DC input wire with a 60 amps circuit breakers ( Is there any problem with that ?

  • Certification

    According to ABYC A-

"All marine power inverters shall meet the applicable requirements of UL 458"

I've seen that some older model have that certification, but I haven't found it in the documentation that came with the 12/250. So is the unit certified to the mentioned standard and/or can the stated standard by the manual (IEC-60335-1) acceptable for marine use ?

Thanks a lot everybody

Julien asked
Daniël Boekel (Victron Energy Staff) commented ·

1 Answer

Orion Tr Negative ouput on ground chassis

Hi, i use 2 Orion Tr in my motorhome and i want to know if i can connect the negative output on the vehicule chassis, because in some case, equipement was energized by orion or vehicule (with a relay to change the power supply of equipement. I don't want to have to many cables.


Lambish asked
Lambish commented ·

1 Answer

How to best ground my Phoenix 12/800 - 120V Inverter

I have been running sensitive sonar equipment off a battery on our vessel, this battery is also connected to the Phoenix 12/800 Inverter. When both the sonar and inverter are running there is "noise" present in the sonar echogram, apparently this can happen if the ground is to the chasis and not the negative battery terminal. Is it OK to connect the ground to the negative battery terminal?

Thanks for the help

GLidin asked
JohnC commented ·

1 Answer

Grounding easysolar, BYD battery box and generator

Can my easysolar unit, BYD battery box and generator share one grounding stake?

Jakecloss asked
Daniël Boekel (Victron Energy Staff) answered ·

1 Answer

How to wire neutral and ground when "splitting" the panel for Multiplus 2000?

Trying to install a Multi Plus Compact 2000w in my RV. The shore power connection has four wires: two 50A hot legs (red and black), neutral, and ground. Since the Multi Plus inverter will only power one hot leg, my plan is to "split" my existing breaker panel so that one leg (about half the panel) is powered direct from shore power and the other leg runs through the Multi Plus.

Let's say I leave AC line 1 as the non-inverter side, going straight from shore power into the breaker panel. Then AC line 2 would go from shore power, to the Multi Plus AC-in, then from the Multi Plus AC-out to the second leg of the breaker panel.

But how do I wire the neutral and ground?

Normally AC line 1 and 2 share a neutral and ground (since 1 and 2 are out of phase, their currents cancel each other out on the neutral). But now line 2 gets sent to the Multi Plus while line 1 goes straight to the breaker panel. Is it fine for the neutral and ground wires to simply follow line 2 through the Multi Plus before arriving at the breaker panel? Or does line 1 now need its own neutral/ground? Do I need to split the neutral so that one neutral wire follows AC line 1 into the breaker panel and another neutral wire follows AC line 2 through the Multi Plus? If so, do I need to isolate the two neutrals by cutting the existing neutral bar in the breaker box?

I've read that a better solution is installing a sub-panel, but I'm trying to go for the simplest solution, which I believe would be keeping everything in the existing breaker panel.

Advice would be much appreciated.

joe6789 asked
Daniël Boekel (Victron Energy Staff) answered ·

1 Answer

100/30 MPPT Ground Screw Clarification

I am ready to finish the installation of the SmartSolar 100/30 MPPT charge controller and am confused as to whether or not I need to use the grounding screw on the controller.

On our trailer, the negative battery lead connects to the chassis. Nothing else connects to the negative battery terminal.

I will wire the controller b+ and b- directly to the battery.

Do I need to use the grounding screw on the controller body to ground it to the chassis?

Joboo asked
Justin Cook - Bay Marine Supply USA answered ·

1 Answer


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