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Galvanic Isolator trips Dockside Breaker

Mar 30, 2013
63
Hunter 356 Georgian Bay
Does anyone have an idea what's happening here. When I plug into shore power the breaker on shore trips immediately this is with the main A/C breaker on the boat in the off position. After checking all wires back to the panel for faults I found that when I disconnect the Promariner Prosafe A/C Ground Galvanic Isolator's main AC supply from the hot side of the main breaker the breakers on shore and onboard do not trip and everything functions as they should. But the Galvanic Isolator monitor is off.

It was my impression that if there was a fault you would get power to the panel but the GI would issue a warning. But the dock side breaker trips immediately with the boat's main AC breaker off. I checked the shore supply and it doesn't appear to be reversed polarity there are many boats plugged in and they tell me their ok. I'm visiting a marina sporting new dock electrical supply stations. What gives and am I still protected form stray current.
 
Dec 7, 2013
24
Hunter 376 Lancaster Va
There should not be any "Hot" side feed into your GI. It should only be connected between your Green ground coming in and your panel.
 

Johnb

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Jan 22, 2008
1,182
Hunter 37-cutter Richmond CA
Please confirm whether the shore breaker is a GFCI type. If it is then you most likely have a "leak to ground" somewhere in the wiring. This may have existed for a long time and only manifested as a problem when you connected to a GFCI protected supply.

By disconnecting the galvanic isolator you may be removing grounding from the boat :yikes: thereby allowing the leakage to "liven up" whatever it is leaking to :yikes: without tripping the shore side GFCI.

If you are vague about what is happening and it cannot be fixed by doing some obvious clean/repair then get some help.
 
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Likes: kloudie1
Dec 2, 2003
535
Hunter 260 winnipeg, Manitoba
In having a quick look at the install manual for the GI, and from what you describe, I would suspect you have a problem in the control module - likely a dead short of some type. GI is likely still functional - can you remove the control module and have it tested?
 
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Likes: kloudie1
Mar 30, 2013
63
Hunter 356 Georgian Bay
This model GI does connect to the main hot line as seen on the attached photo. However the photo shows it should be connected after the breaker not on the hot line-in side as it was in my case.
image.jpeg
The shore power may be GFCI how can you tell? see photo,
image.jpeg
so your point is well taken re. Making the ground live. At this point the only wire I have disconnected is the 100v supply to the GI module, the ground wire is still connected from shore power through the isolator and to the panel board ground bus bar.
image.png
I have tested with the system live and get 124V readings between ground and the hot wire and between the hot and neutral but less than one volt between ground and neutral.
With shore power disconnected the resistance between neutral and hot is high (or no reading no short), between neutral and ground is no reading, between hot and ground is no reading. (Given that a zero reading would be a short circuit)
The only time I see a reading is between the supply wire to the GI that I disconnected and the ground but it's low at 012.50m ohms.
So yes it does seem to be pointing to a faulty controls module.


Sent from mobile
 
Jun 11, 2011
1,215
Hunter 41 Lewes
That diagram clearly shows it connected to the line side of the main breaker so that it works regardless of the breaker position. The breaker on the pedestal looks like an EGFI, equipment ground fault breaker. They call them EGFPD also, equipment ground fault protection devices. They usually have a low end trip of 30ma of leakage and can be ordered as high as 70 that I have seen. A GFCI to protect human life opens the circuit at about 5ma. It seems from your wiring diagram that it can only be the control module, providing nothing else is connected to the line side of your main breaker like the battery charger/inverter.
 
Mar 30, 2013
63
Hunter 356 Georgian Bay
Thanks all for your feed back and information, it's been most helpful. I will be removing the control module and have it tested as soon as I get back to home port as it is the only thing along with the shore power feed connected to the live side of the main breaker. As "johnb" rightly noted my home port does not have a EGFI supply so this was properly going on for some time, will post the out come.
 
Mar 30, 2013
63
Hunter 356 Georgian Bay
WOW! Just came across these older posts that might change things..
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I'm no expert, but I had the same problem with a GFI at the lift I rent. It was the Galvanic Isolator for my problem. Part of what it does is send a "short" to test the ground, and that will trip the GFI every time. I had to disconnect the isolators in order to use the electric with GFI.
Hope this helps,
Terry
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It's not the galvanic isolator itself that causes the tripping. What it is, is the monitoring system for the galvanic isolator. To maintain the ABYC requirements, the system must be monitored and tested, and requires the status be presented to the user. It's this testing when the system is turned on and every 6 hours afterwards that will create the ground fault. Only disabling the monitoring can one overcome the fault, as its designed to do what it's doing to test to make sure the system is operating normally.
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Chris in Texas is exactly right. In fact, I contacted the manufacturer of my galvanic isolation system (Pro Mariner) and they recommended I disconnect the monitor because they are familiar with this issue. I disconnected the monitor system and everything works fine with the GFCI and Galvanic isolator in place.