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Isolation Tranformer

Isolation transformer wiring question

Simple question. I am installing an isolation transformer and a 12/3000 multiplus charger on a sailboat. I assume the isolation transformer gets installed first, right after the shore power cord and ELCI breaker then the multiplus correct? I ask because I had seen some diagrams that show the isolation transformer wired after the multiplus on the AC output side of the multiplus.

looking for confirmation.



charmcityboater asked
hjohnson answered ·

1 Answer

Isolation Transformer Marine Use Schematics?

Where can I find schematic examples of installing this unit on a boat? I plan to use the 3600 for galvanic isolation on my 40'ailboat on a 30A shorepower circuit, but cannot find any schematics showing one. I know it's relatively simple, but would like to see what the recommended marine installation looks like, including breakers etc.

shawn0900 asked
Mike Dorsett answered ·

1 Answer

Isolation Transformer trips when connecting shore power sometimes

Occasionally when I plug in shore power, the Isolation Transformer trips out. I then have to lift the boards up and reset it, and all is fine. Any ideas why?

I have a multiplus inverter and a steel hulled boat. All the wiring is fine. I believe that later versions of the Isolation transformer don't have a trip at all.

mikemarine asked
Paul B answered ·

1 Answer

Multiplus tripping Isolation Transformer if Lithium Batteries Turned Off

Hi everyone,

I'm looking for some help with our marine system.

We have a galvanic isolation transformer (not Victron) on our shore-power feed. This then goes into a MultiPlus 48V 5KVA unit, which charges a Torqueedo lithium battery bank (48V consisting of 4 x 24V batteries in series, and paralleled) via a 48V bus-bar, which also feeds an Orion 48-24V DC-DC converter which keeps our 24V house bank topped up.

If the Torqueedo 48V bank is "ON" via its BMS, then we have no issues at all. Should shore-power be temporarily interrupted, the MultiPlus nicely turns back on, and resumes what it was doing.

However, if we leave the boat for an extended time, the advice is to turn OFF our 48V Lithium bank via its BMS, keeping them completely isolated, and just allowing the output of the MultiPlus to feed the bus-bar, and therefore the DC-DC converter keeps charge in our 24V house bank.

In this state, should shore power be temporarily interrupted, the MultiPlus does not start up nicely again. Instead we see the blue light on the digital multi control flash for a short while, then instead of the relay clunk, our galvanic isolation transformer trips out.

The only reliable way we've found to correct this situation, is to turn ON the lithium batteries via the BMS, then go and re-set the galvanic isolation transformer. After this, the MultiPlus will turn on properly and resume operation, then we can turn the Torqueedo batteries back OFF again without a problem.

The danger here is if that if we're away from the boat when shore-power fails temporarily, there is no longer any 48V supply to the main bus-bar, and therefore no maintenance charge to our house bank from the DC-DC converter, and those batteries could easily be killed by running completely flat.

Any clues as to why this might be happening, and how it could be corrected?

benkay asked
Matthias Lange - DE answered ·

1 Answer

3 Phase Isolation Transformer possible with Victron Isolation Transformers

Hello Guys,

I have a question regarding a 3 phase isolation transformation schematic.

I would like to design a system where in the case of a missing neutral I still have neutral on the boat with the isolation transformers.

Main issue is that in America most shore power system with 3 phases are without neutral on the input and my device behind that needs a neutral.
Voltage and Frequency is clear that it will depend on the input, but that is not an issue in my case.

Question is would that work?




Phil asked
Phil edited ·

0 Answers

Shore Charge Current Dropping


I have this small campervan in which I have built some electrical equipment, but lately after some (I thought) improvement I am having some issues.

I have built a Phoenix Multiplus Compact 12A 1600VA together with a Victron Energy 220AH AGM Deep cycle battery into my van. I have connected both a VE.Bus Control panel and a BMV 602s to the system. It looks something like this in a schematic:


Where the ground === the chassis of the van and the leisure battery and the service battery (engine) of the van are separated by a separator/relay.

A few days ago I notices the leisure battery was not charged after a full day connected to shore, and the BMV showed only a voltage of 12V when disconnecting the system from shore... When connected to shore it shows a (expected?) voltage of around 14.5V, but only a charging current of 1A. It often starts out around 5A, but quickly drops to 1A, no wonder the battery is not charging.

After a few days of searching and trouble shooting I still havent figured out the problem, so my hope is on you! The gear is definitely not to newest anymore. But the battery was not heavily used since it was only used on the occasional trip.

Thanks a lot!

Bas Peter

bas-peter-dijkema asked
bas-peter-dijkema commented ·

1 Answer

Isolation transformer

I have a isolation transfer on a wooden boat, the installation manual states the enclosure should be connected to ”all metal parts of the boat” being a 1948 boat, and in line with wooden boat practice there is no ground loop connecting all the metal parts, rudders, through hulls, shafts etc. In this case what would be the installation procedure? There is mention in the manual of output neutral grounding by connecting J5 and J7 terminals, which if not connected result in the unit “floating” what does this mean in plain language.

thank you for any help.

ianbirdsall asked
hhau answered ·

2 Answers

Isolation transformer 120/240 US to 230v Euro

I’m trying to find out if the 7,000 watt 230v to 230v isolation transformer will take 120v/240v split phase (120v to ground, 240v leg to leg) and output 230v to ground. We have a European powered boat that is wired for 230v to ground and the breakers for the 230v panel are only single breakers, as the neutrals are to a common buss. We want to use incoming US power but not be concerned that we have not protected the wires on both legs. Our equipment does run fine on either 50hz or 60hz.

teetera asked
Matthias Lange - DE answered ·

2 Answers

3600W isolation transformer wiring for in water operation

I have a 3600W isolation transformer. ITR040362041 HQ1542RV7P1

I am trying to confirm that in the water I should connect a wire from the PE input side of the circuit to the J34A male spade connector. There has been a lot of back and forth on the forum and I am trying to get a simple answer on this question. I assume I have to make up this wire myself. I would also appreciate any input on wire gauge for this bit.


tcason asked
tcason commented ·

1 Answer

Victron 3600W Isolation Transformer stepping up voltage???

Hi I wondered if some one could help we are using the victron 3600 to prove our equipment cabinets can work using IT mode. our input voltage into the transformer is 240V and the output is 256V?!?! I was under the impression it was 1:1 ratio so input=output. It is causing our ATS (automatic transfer switch) to persistently switch between A and B feed due o over voltage protection. Can anyone explain why we are having this issue



jameskitching asked
Matthias Lange - DE commented ·

4 Answers

question about isolation transformer, multiplus and 16 amp circuitbreakers


I've been trying to find my answer but can anyone help me ?

I want my boat to have an isolated circuit and i am rewiring all the mess.

I have an isolation transformator and want to buy a multiplus.

Now i have this setup in mind:

Shore power-isolationtransformer-16amp / earthleak circuitbreaker-multiplus-....

Do i need another earthleak/circuitbreaker after the multiplus ?

best regards,


relaxteb asked

0 Answers

MultiPlus ‘No Grid Meter Alarm’

I’m installing a MultiPlus Compact 24/1200-25 in an automotive setting. I have configured it through VEConfigure 3 and am happy with all of the settings there however I am getting a ‘No Grid Meter’ alarm and cannot find where to disable this? Any guidance very appreciated!


maxh asked

0 Answers

Isolation transformer problem

I have a new isolation transformer that will not work. It is a 230v 3600 model. The input volt voltage is 245v the out put voltage is 0 with no leds lit on the panel or any other sign of life. Is there any tests that I can do with it before I return it. Thanks in advance

Jeremy asked
Kevin Windrem answered ·

1 Answer

Isolation Transformer and Diesel Generator

Dear all,

I have installed a 7000W isolation transformer ant it works great. I also avec an old 220V Generator when I trvel with the Boat.

Do you know if I can plug the Generator before the transformer but the quality of the current is quite bad.

Or do I need to put the Generator after the transformer, but in this case I will inject current inside the output of the transformer.

Thanks for all !

stephaneperrot asked

0 Answers

RCDs and neutral to ground link with Isolation Transformer -> Multiplus -> Autotransformer

Marine application has shore power coming in to an auto-switching 3600W isolation transformer then going to a Multiplus. The output of the inverter/charger is connected to a panel with some euro-spec single phase 230V outlets.

To accommodate 120V appliances in the US, one of the breakers on that panel now leads to an Autotransformer, with each leg leading to different groups of 120V outlets.

With the isolation transformer we are never directly using the earth to neutral link on shore. Given both the single phase outlets and 120V split phase outlets, where do we need to make these links?

banana asked
michaelhickey60 commented ·

0 Answers

Do I need a Isolation transformer with a Blue Power Ip22 charger


The sail drive on my boat suffers from electrolytic corrosion. I just have a Blue power IP 22 charger connected. Do I need a isolation transformer?

I was told the charger itself is a transformer and thus isolated as well so I don't need one. However the corrosion is there?

Many thanks for your opinion.


Martin van der Lee asked

0 Answers

Tripping of 3600 isolation transformer

My 2009 isolation transformer model 3600 has 2 red buttons on the front. The right hand button trips with sudden increase in loads that the Quattro doesn't handle. These loads seem to be the inductive ones which come from my induction hob or maybe from electric motors in freezer or washing machine. I have to keep the shore line amps down to 10 on the regulator. I want to eliminate these MCBs by bridging them out. The later transformers don't have them. Installation is in a steel Dutch barge.

banta asked
banta commented ·

0 Answers

I am new to the Victron product line and I'm finding it difficult to piece together a good kit for 24vdc van installation with the

Currently I have two 24vdc Battleborn batteries and at 240 watts (two 50 watt in parallel and one 100 watt panel in series with the two parallel panels).

I am considering the following:

1 each. Victron BlueSolar MPPT 75/10 for Solar to engine run battery maintenance.

1 each. Victron BlueSolar MPPT 75/15 for 24vdc system battery.

1 each. Victron Orion-Tr 12/24-5A DC-DC Converter for 12vdc to 24vdc ignition on charging for system battery while vehicle is running.

1 each C24/1600 inverter.

Question; would the the BMV-712 Battery Monitor work on a 24vdc system... recommendations?

the-archer asked
the-archer answered ·

2 Answers

Isolation Transformer ITR 3600 Auto - jumper connections

I'm struggling to understand the installation instructions supplied with this product,

The input side has the Auto voltage select feature and there are no terminals to attach Jumper cables to manually select the input voltage.

The output side however does have terminals to connect the supplied jumper wires in order select the desired output voltage, but the installation instructions make reference to only using these terminals for "other models" not the Auto

If this is the case why are the terminals available on the circuit board and why are the cables supplied? Should the jumper cables be fitted?

Also should the jumper cable be fitted on terminals J33 and J21 to link neutral and earth on the output?

There also seems to be differences of opinion on here relating to the internal earth connections (input PE to J34A) or (J34A to J34A1) if the boat is floating,

Can any one clearly indicate which method is correct regarding all or any of this.

Thanks in advance

aqnlr01 asked

0 Answers

Strange secundary voltage

Hallo eperts,

Situation: Aluminium hull in fresh. Shore power straight to isolation transformer, secundary going to a floating 220V system of only wall sockets. The 12V system is (as it should be!) not connected to the hull, so also "floating".

The iso trans is connected and wired the right way, input 230, output 230, in fresh no connection at PE.

If shorepower is connected, I measure 110V AC between hull PE and L output.

If I furthermore connect the charger, with no batteries connected, I measure about 6V DC between hull and charger's plus...

Since the hull is of aluminium, I'm very careful of leaking power, so can anyone explain this to me?


martin-dj asked
markus answered ·

1 Answer

Marine Euro 230v to US 120v - isolation + autotranformer or just isolation tranformer

I've read through the portal and have downloaded the PDFs... I can't find a straight answer to the question of if the isolation transformer will convert euro 230v power to us 120v.

On shore power, I'm looking to be able to hook up world-wide (assuming 50/60hz is a non-issue).... or do I want an isolation transformer that feeds an autotransformer?

I'm on a 120v boat with two 5-30s. I'm trying to avoid AC-DC-AC so that I don't have to limit AC usage when connected to shore power.

So, I'm thinking two isolation transformers, one per power inlet... and feed that into a pair of MultiPlus 12/3000/120...

...or do I need the Autotransformer to do the euro 230v to us 120v conversion.

csheldon asked
csheldon answered ·

1 Answer

Some variations to the Victron Van Install

Hi, I have roughly the same requirements as your van install except I don't require 115V. So in summary, it's a 12V system, I have solar which is 2 x 250W into a single Victron MPPT 100/50, a Victron B2B for charging from the alternator, and an electric hook-up. Ideally, I would like to continue to use the MPPT and the B2B, and solar panels. I currently have an inverter but I would like to change to the Victron Inverter/Charger 2000W as per van install. What I would like to know is, 1) is my MPPT compatible with your schematic? 2) Can I use my 18A B2B to charge from the alternator in place of the Buck Boost (including, is it OK to only charge the Lithium batteries at 18A max),?3) Will there be any connectivity issues (e.g. enough ports in the monitor)? 4) Is the grey block in the diagram on the top right the back side of the colour monitor and is the circular grey block in the bottom left by the battery the BMV 712? 5) Can you provide any help with the wiring of the B2B? 6) Do I need to use the GSM module or can I rely on the touch screen and my phone APP. The reason I ask this is because I will be mostly living in Europe and I am not sure whether I want to have another contract for data for the connectivity to the internet.

Thanks in advance for any advice.

beefburg asked

0 Answers

Isolation transformer (euro) 230 1 ph to (US) 220 split ph

US wired boat using 110v and 220v power. The boat is configured with (2) 2000 isolation transformers (1) for the 110v side with (2) 3000/12 Multiplus (1 as a slave) inverters. The other 220v for the (Air conditioners).

Looking for configuration when shore power (euro) is supplied as 230v 1ph

louisgombkoto asked
michelg answered ·

1 Answer

Isolation Transformer - Auto Switching Voltage - Can the output be fixed?


I understand that the Auto version of the ISO 3600 can detect the incoming voltage and switch the output. Pretty neat, but here's the thing - That doesn't make a lot of sense to me, generally you want the voltage at the output side to remain the same, not track the input voltage.

On my vessel, I want to be able to plug into either 110V OR 240V shore power, but always get 240V on the boat.

Can this be achieved on the ISO 3600 Auto?

It seems pretty pointless auto switching if the result is that you can plug into 240V and that gets 'automatically' passed through to your 110V wired boat. Did I read the manual wrong on this point?


duncan-ellison asked
jwfrary answered ·

1 Answer

Isolation Transformer Mounting

Any opinions on whether the Victron isolation transformers, specifically the 3600W, can be installed on their side? I have a customer asking for this orientation given the desired install location on the boat. The manual is ambiguous on this point. I am not super comfortable with this as it seems the design requires a vertical orientation for proper cooling. As a result the cooling fan would effectively be on the side instead of the bottom, heat rises, etc.

Does anyone have more information from Victron on this point? Has anybody installed these in this orientation?

Andy Blehm asked
Paul B answered ·

1 Answer

Auto switching 3600 Isolation Transformer question

Is it possible to set a Victron 3600 auto-switching isolation transformer to deliver 230v regardless of input (115v or 230v)? Or will it simply "autoswitch" the output between 115 and 230 depending on the proximate input voltage? My output is connected to a Centaur charger, a water heater and the AC panel selector switch- Shore/Off/Inverter.

wings45 asked
wings45 edited ·

1 Answer

Isolation transformer earth connection

Hi all,

Just confirming here that when my boat is floating on the water there should be a link from the input PE terminal to J34a.

So, the earth wire from the shore power supply flex is connected to the input PE terminal and I make a small wire up with a female spade connector from this input PE terminal and connect it to J34a?

This transformer is not the auto 115v - 230v switching model

Many thanks

metal-snapper asked
jwfrary commented ·

6 Answers

Isolation Transformer help

Hi! I bought the Isolation Transformer 3600W Auto 115/230V (SKU: ITR050362041) from a web shop in France in October 2019, brought it in Greece (Preveza) this summer, and installed it in my boat this week.

The connections are straightforward :

Input (L, N, PE) connected from the shore inlet with 6 mm2 wires (H07RNF 3G6) to handle future 110 V input;

Output (L, N, PE) to Differential Circuit Breaker (left open at the moment).

A 4 mm2 cable connects directly the transformer case to the ground common point of the boat.

The various shunts in the transformer are set in order to: 1) output 230 V; 2) connect N et PE outputs; 3) connect input and output PEs (the boat is on the dry).

Unfortunately, when I connect to shore power, only the green Led lights up, which would be normal if the input voltages was not in the proper ranges.

However, I checked that there is 227 V on the input side between L-PE and N-L, and 2 V between N-PE (same as on the shipyard post). 0V everywhere else at the output.

I addressed the problem to the retailer yesterday, but I don't know when I will get a response, and I am afraid that this response will be anyhow to send it back, which will not be very convenient for me (to say the least).

There is no Victron distributor in the Ionian area.

Is there anything I can do to identify the origin of the problem, and what can be done from this place (I won't stay here much longer than 2 weeks).

Much thanks for any help.

pcvk asked
pcvk answered ·

1 Answer

Isolation Transformer and Multi 12/3000/120

Hi, I've been using the 2000W Isolation Transformer and Multiplus for about a year and just recently there has been some issues.

Now if we use shore power via the Isolation Transformer it is disconnected from the Multi with any medium to high loads. It then reconnects and the Multi is in assisting mode. It used to just go straight to assisting, so not sure what's happened here. If I bypass the Isolation Transformer it works as it did before.



stocksy asked
Kevin Windrem answered ·

1 Answer

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