Victron Isolation Transformer and Ground Fault Issue

[mdsilvers]

I am trying to figure out if I am chasing real issues or one based on the setup of my installation.

I have installed the Victron 3600 isolation transformer. The output of the transformer goes to a 30m Amp .1s breaker (photo attached).

Every time I turn on the unit and flip on my control panel's power, the GFCI trips.

If I remove the jumper (picture), it does not trip and works fine.

I don't want to 'fix' a problem incorrectly. I have tried to track down a ground fault but can't seem to find one. I noticed from a photo that another boat owner - Jedi - has a similar setup. He is using 120v in and 120v out - but the jumpers were not on J33 & J21.

The manual states to have this jump 'on' for GFCIs to function correctly.

I've hit a wall on this. Any advice from others would be appreciated.

Thanks.

[smac999]

I have installed a few without issue. You defiantly want the ground - neutral bond jumper on the output.

Is the gfci breaker before or after the transformer? Is this also new or was this already there? And not previously tripping on a 120v dock?

Is this a 120v 60hz boat being plugged into 230v 50hz? (Your jumpers are 230 in, 120 out)

Maybe the 60hz breaker does not like the 50hz

Oddly the ground - n bond has nothing to do with the ability of the gfci (Rcd) breaker tripping. My guess is you have another g-n bond on the boat. Having one on both sides of the breaker would cause this to trip with the jumper. But then it would have tripped back home without the transformer as well.

The input line goes direct to the shore plug with nothing else? Metal hull?

[mdsilvers]

Thanks, Smac999. Here are some answers:

* The GFCI is on the output of the transformer. The shore GFCI is part of the shore power plug in the marine. This is a new install, so the GFCI is new.

* This is a 120v 60hz boat, with input 240/50hz. You probably nailed the issue with the 60hz vs. 50hz GFCI. I'll try to source one locally and swap it out. It's hard to find 120v GFCIs here, but I'll track one down.

I used my meter to check for another g-n bond, and I could not find one.

I feel like I'm chasing a ghost. Thanks for your idea on the 60/50 GFCI. I"ll give that a try.

Mark

[smac999]

I don’t think you’d find a 120v 50hz rcd as no country uses that power. I’m kinda thinking that is not your issue. I have done the reverse here feeding 120v 60hz power into a 230v boat. And it’s 50hz rcd was not an issue on 60hz.

If the breaker is Also new I’m guessing it’s shownIng an existing issue That now needs to be found . And not an New issue with the transformer.

[mdsilvers]

It sounds like there may be an existing issue.

A couple of folks mentioned that I need to make sure to have a G-N tie on my current boat. If I check for continuity between my AC G-N on my main bus, with all breakers closed, and power 'off', I do not have continuity. When power is on, I have continuity.

As I understand, I need to have a tied to G on both AC N and DC N.

I'm not an electrician, so I'm careful about what changes I make.

[smac999]

You can not use the ohm meter with power on the wires. So that measurement is meaningless.

When you connect the jumper at the transformer it will create the n-g bond for the whole boat at that single point. If you have a 2nd one past the breaker then you’ll have 2 paths back for the neutreal current which will trip the rcd breaker. With the iso transformer you can not leak ac into the water. So you should not have a ground leak. So I think a n-g bond is the only thing. In North America you do not need a gfi / rcd breaker if you have an auto transformer.

With the boat unplugged. And Turn all breakers on. And with the jumper off at transformer. I would Measure ohms ground -netreal at both the transformer output and at the main ac panel. Both should be infinite. And both will go to 0 with the jumper back on.

The inverter will also cause issues if not wired with a separate neutral bus As they have a g-n bond relay. That will open and close. Some are closed whenever the inverter does not have power. Some only close when inverting. Incorrect inverter wiring will trip a gfi breaker.

[mdsilvers]

Thanks, smac999. I'll give your suggestion a try. I know that the mastervolt MassCombi N is tied to the main bus, as all N on the boat are in the same place. I'll do some testing on this later today (I'm in Malaysia) and see what I can diagnose.

It sounds like this has been an issue that never raised its ugly head until now.

[Jammer]

Well, you have a ground fault, otherwise the gfci wouldn't trip. You've checked continuity neutral to ground and there isn't any, so probably you have a hot-to-ground ground fault.


Typically these occur three ways:


1) Somewhere, there is something that is wired to use ground instead of neutral for a return.



2) You have a bad MOV somewhere. These are connected between hot and ground as surge suppressors. Sometimes they fail in a way that creates excessive leakage between hot and ground at normal line voltage.


3) You have a combination of minor leakage problems around the boat that, together, exceed the trip current for the GFCI.


The way you find this stuff is you disconnect things until the GFCI doesn't trip. You can, for example, disconnect the output wires from the GFCI, and then observe that it doesn't trip. Then try disconnecting all the branch circuits and connecting the wires. If it trips then try disconnecting all the branch neutrals too. If it still trips disconnect your panel, maybe there's leakage in the busbar insulators or something. Ultimately you'll get to the point where you can connect one branch at a time until you find the problem.


Good luck

[mdsilvers]

Thanks, Jammer. I've got my work cut out for me tonight. I'll report back the solution once I find it...

[sailcrazy]

Following. We too have had an issue with the Victron Isolation transformer. Our Asia-built boat is wired for 230v, 3-wire AC, and here in the Caribb all we've run into(so far) is US 110v power. Although it seemed to work perfectly, after installation and removal of the galvanic isolator, we suddenly noticed a significant stray current corrosion(?) issue.....with new bottom paint installed we "blew" the paint off several bronze thruhulls-but not all- in a matter of a few months in the water. A surrounding 6"-15" irregular oval was clean down to the gelcoat! Our f/g boat hull is fully bonded. I could not find any issue, but once I replaced the shore power cords, the shore power receptacle, the leads from the shore power receptacle to the transformer, rewired the transformer, and replaced the leads from the transformer to the electrical power distribution panel. We also reinstalled a (new) galvanic isolator....just in case?? and so far-the issue seems to have gone away! I should note we have owned this boat for over 20 years, and never had an issue before. And no, I do not understand all I know about this stuff!

[mitiempo]

Originally Posted by sailcrazy

Following. We too have had an issue with the Victron Isolation transformer. Our Asia-built boat is wired for 230v, 3-wire AC, and here in the Caribb all we've run into(so far) is US 110v power. Although it seemed to work perfectly, after installation and removal of the galvanic isolator, we suddenly noticed a significant stray current corrosion(?) issue.....with new bottom paint installed we "blew" the paint off several bronze thruhulls-but not all- in a matter of a few months in the water. A surrounding 6"-15" irregular oval was clean down to the gelcoat! Our f/g boat hull is fully bonded. I could not find any issue, but once I replaced the shore power cords, the shore power receptacle, the leads from the shore power receptacle to the transformer, rewired the transformer, and replaced the leads from the transformer to the electrical power distribution panel. We also reinstalled a (new) galvanic isolator....just in case?? and so far-the issue seems to have gone away! I should note we have owned this boat for over 20 years, and never had an issue before. And no, I do not understand all I know about this stuff!

If you have an isolation transformer there is zero reason to have a galvanic isolator.

[sailcrazy]

FWIW, Yes, Thanks...I know that. I should not have needed the galvanic isolotor, and that's why I removed it initially. But when nothing else seems to make a difference, and you had one before and did NOT have the problem, you try anything. And guess what.....since it was installed, we are not blowing paint off the thruhulls! That's why I mentioned it. It does not make sense to me, either...but it's tough to argue with success.