Isolation Tranformer Image

Isolation Tranformer

Are the Isolation Schematics on the Victron Website Wrong?

This question has been asked before (@Charmcityboater) but not really answered:

It seems like the Victron diagrams below show the Multiplus BEFORE the Isolation Transformer in the chain from shore power to loads? I thought that the isolation transformer would be the first and only thing directly connecting to shore power and the multiplus would connect to the Isolation Transformer?


msg43 asked

0 Answers

Isolation Transformer buzzing on electric heated blanket

Hello All, very confused. Victron I.T 3600w 115/230v on a boat connected to shorepower. Very happy and (almost) quitly doing its thing until i plug in the electrical heating blanket. The buzzing is too much and changes with the setting of the heating from low = annoying to high = unbearable. The blanket is an Inventum HN1312V with a draw of 60w. Very curious why this is and if there is a way to still be warm at night and being able to sleep.

goyow asked
Alexandra answered ·

1 Answer

Is it possible to put 230v via a switch directly between transformer output and multiplus input


I would like to use an isolation transformer to convert from 120v to 230v.

Is it possible to put 230v via a switch directly between transformer output and multiplus input like in the picture?

What if 120v is connected on the 230v output side because the switch position is wrong. Will the transformer and the Multiplus switch off or will there be damage?

Exactly the same question what happens if the input voltage is bridged differently than actually present?

This is unfortunately not described in the manual


service-1 asked
Mike Dorsett answered ·

1 Answer

3600W output Isolation step up voltage incorrect, possible failure?

Hello I currently have a Victron 3600W 115v/230v(not auto)isolation transformer. I have the jumper above the inputs set properly for 115v In(measured: L-120v/N-0v/PE-0v) and I have the output jumper set correctly(middle two spades) for 230v output but the output voltage is messured: L-77v/N-65v/PE-0v which makes no sense to me at all. If any one has a suggestion as to what may be causing this I would greatly appreciate it.


Image Caption


I do not have the J33 and J21 jumpered, will this make a difference?

miller76 asked
wkirby answered ·

1 Answer

Isolation Transformer fan operation

We have an ITR3600 auto transformer.

Recently, the temperature light has illuminated, the unit is still passing power, but the fan is not operational.

Does anyone with experience with this unit know if the fan always runs at variable speed, or is it sometimes off during operation?

Have hooked up a replacement fan, which is behaving the same way, though I have been unable to reproduce the temperature light.

Should it be running during operation, energ without the temperature light?

Attempting to troubleshoot and rule out a thermostat or other internal error vs fan failure.

kelzamedic asked
mike4nl answered ·

1 Answer

Isolation Transformer cooling fan broken?

How can I tell if my 3600W Isolation Transformer’s cooling fan is working? I have never seen it on, even when the unit is obviously hot and running near max load for some time. It’s a 5 year old unit and I’ve been using it for several months now.

I read that the transformer should shut down if it overheats, but fortunately that hasn’t happened either.

kdagley asked
jmarc answered ·

2 Answers

Isolation transformer high output voltage

I have an automatic isolation transformer that I am supplying with 120VAC input.

I’ve set the output voltage to 230VAC via the jumper settings provided in the manual but I am seeing 260VAC output.

What am I missing?

rspott asked
Rod answered ·

3 Answers

3600 transformer connector question - J34 to J34A

Hello. Please could anyone help with my 3600 transformer connector question - wire from J34 to J34A.

5 years ago I purchased a steel narrowboat and asked a electrician to fit a Victron Transformer 3600 when floating in water. After 5 years with the steel boat in water, the Victron 3600 case was removed and saw that the wire (green yellow) was connected from J34 to J34A.

When the boat is in water should this be?

Connect PE to J34A
Remove J34 to J34A

I have attached a link to the manual - Page 7

I am hoping the electrician has not made a mistake.
Could be my boat has not been protected for many years. Does it still protect the boat with the J34 to J34A connected when in water and is it just a safety feature when on land?

I appreciate any help on this.

mark-hawkins asked
mark-hawkins answered ·

2 Answers

Is the input of a Phoenix C 24/2000 isolated from the output?

I currently have 2 batteries connected by a non-isolated DC-DC converter. Battery A is feeding a Phoenix 24/2000 which is feeding a Multiplus via an isolation transformer, which is in turn charging battery B. Odd I know, but works fine.

My question is, if I remove the isolation transformer from the circuit, would I create a ground loop? Or are the input and output of the Phoenix inverter suitably isolated anyway?

andyrlm asked
andyrlm commented ·

0 Answers

Noisy isolation transformer

I have a Victron 3600VA 115/240V isolation transformer finally installed to our yacht about an year ago. At first it was fine but during the last sailing season it became more and more noisy - so intencive that no one was able to sleep in that cabin. It was a mild disappointment as I’ve been happily using Victron stuff in my yachts already from the 80’ies. But, I’m a handyman and able to tear it down and rebuild it. (I’m not interested in sending it from Finland to Netherlands for repair as it is so heavy and dont have the original cardboard box anymore. Silly me).

The sharp loud metallic resonating noise at 50Hz starts immediately and always when connected to shorepower at different questharbours. The transformer is in my homelab right now and before tearing it to pieces I kindly ask Your idea before my next moves with it!

thank You in advance,

IHe, M.Sc


finihen asked
finihen answered ·

5 Answers

Isolation Transformer Frequency Conversion 230V (50Hz) <=> 115V (60Hz)

I understand that the isolation transformer can convert the voltages, but does it also alter the frequency? For example 230V (50Hz) to 120V (60Hz)? This one is important because the frequency will affect my devices that require 60Hz if they are getting 50Hz.

If the isolation transformer does not change the frequency, what can I use to change the frequency?

ftlsailor asked
sebastianlehmann answered ·

3 Answers

Isolation Transformer 115<=>230 ?

normaly i was asked, but now i have to ask because i definitly don't know, and i never had one in my hand, and i also can't read out of the manual.

Is the Isolation Transformer only isolating between same Voltage or do the transformer can also do an Transformation between 115 => 230 and 230 =>115. In manual is just written about auto switching and output and input 115 "or" 230, but it doesn't explain if the "or" in Datasheet is depending or independing to supply Voltage.

Best regards


Peter Polz asked
ftlsailor answered ·

6 Answers

Isolation Transformer, internally fused against overload?

Hi, is the current line of isolation transformers internally fused/protected against overload?

About to install a 2000W isolation transformer. Is there an internal fuse/protection? From the datasheet: "Input circuit breaker: yes". Meanwhile no information is provided in the manual about an input circuit braker, only the soft start.

Should there be an RDC/automatic fuse before and/or after the isolation transformer rated to protect the isolation transformer itself agains overload?

What current rating RDC should be installed to be sure that isolation transformer itself will not be damaged if too much current is drawn? 6A 8A 10A? Will think that the characteristic of the fuse be important here? ( A, B, C etc, C=1,45*Current rating for up to one hour use)

Thank you for any help :)

boatelectronics asked
boatelectronics edited ·

0 Answers

two rcd's or a single rcd isolation transformer and multiplus


What are the guidelines with RCD's with a mobile (boat) setup that has shore power going thru an isolation transformer and then to a multiplus? Should there be two RCD's installed in this situation (one after the isolation transformer and a second after the multiplus or is a single RCD after the multiplus correct)?

It is also my understanding that a type "A" RCD is not good enough and a "B" type trip rating is needed.

The setup is 230V@50Hz shore and output.

Thanks for your help

lyric asked
Mike Dorsett answered ·

1 Answer

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
christern answered ·

3 Answers


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