2005 Mainship 430 Aft Cabin Trawler – Galvanic Isolator

[jimL]

Hi All,

We are moving forward in the purchase of this boat knowing there are a few gremlins we’ll have to deal with. What boat doesn’t have a few gremlins?

Our immediate concern is the Galvanic Isolator: It’s a Pro Mariner that appears to be original. With Shore power plugged in at the dock, the Galvanic Isolator self tested with an alarm for a Ground Fault. We swapped out the Twin 30A to Single 50A adaptor, and the isolator continued to show a fault. The surveyor indicated that it may be an issue with the marina’s power or could be a bad unit.

Several Questions: Where is the isolator located? Has this occurred to anyone? What should I be looking for? I see on a different thread there are directions on how to test the unit itself.

We will be transiting 190 miles of the Erie Canal and Hudson River within the next several weeks, and I plan on testing the unit at different shore power outlets along the way if I don’t get time to locate and test the unit. I do plan on resolving the situation as soon as I get to my home port.

Thanks for your advice and opinions

JimL

 

[jskinner30PII]

Jim,





I have the 30 pilot Rumrunner with same system. The unit onmy boat was just under the refrigerator unit. I had a similar issue and didfind a loose ground wire at the 30 amp power hook up. I also had an issue whileon the hard. I found out it was a three way plug I was using and not the system.Reverse polarity is a problem. Open ground maybe the electric your pluggedinto. Email Pro Mariner and they willsend you the trouble shooting pages foryour unit.

 

[bglad]

Purchase a three light tester from hardware store and check your system. Get one with a GFCI test button so you can prove those fixtures too: Dawson 3 Wire/GCFI Outlet Tester-DET300 - The Home Depot If tests indicate open ground then the isolator may have failed. If that is the case rewire your green ground direct or replace isolator with fail safe type. Safety trumps protection against galvanic corrosion. Note: Fail safe isolators do not require a monitor.

Hi All,

We are moving forward in the purchase of this boat knowing there are a few gremlins we’ll have to deal with. What boat doesn’t have a few gremlins?

Our immediate concern is the Galvanic Isolator: It’s a Pro Mariner that appears to be original. With Shore power plugged in at the dock, the Galvanic Isolator self tested with an alarm for a Ground Fault. We swapped out the Twin 30A to Single 50A adaptor, and the isolator continued to show a fault. The surveyor indicated that it may be an issue with the marina’s power or could be a bad unit.

Several Questions: Where is the isolator located? Has this occurred to anyone? What should I be looking for? I see on a different thread there are directions on how to test the unit itself.

We will be transiting 190 miles of the Erie Canal and Hudson River within the next several weeks, and I plan on testing the unit at different shore power outlets along the way if I don’t get time to locate and test the unit. I do plan on resolving the situation as soon as I get to my home port.

Thanks for your advice and opinions

JimL

 

[boatpoker]

The alarm is telling you either you have lost ground or the GI is failing.
Check your ground continuity before pulling the unit.
If you follow the ground wire from your panel it should lead directly to the GI.

 

[Marlinmike]

If you are staying in fresh water you really don't need it in my opinion.

 

[rwidman]

Whatever you do, unplug the boat from the pedestal before you start checking wires.


There are two connections on the GI (aside from any alarm indicators. One is coming from the boat's electrical panel. The other is going to the shorepower plug. It's fairly simple to check these with a VOM or even a continuity checker. Remove either wire from the GI. Now check for continuity between one of the wires and the ground prong on the end of the shorepower cord (remember, it's unplugged and lying on the dock). Check the other wire for continuity to the ground connection on any AC receptacle on the boat. If you have continuity on both wires, it's not a problem with the boat's ground circuit. Put the wire back where it came from.


Plug the shorepower cord into as many different power pedestals as it will reach. If slip neighbors are not having a problem but your fault light stays on no matter where you plug it in, it's pretty likely that your GI is defective.


If you don't understand any of this, my advice is to hire a pro to fix this. I wouldn't advise bypassing the GI regardless of where you are boating.

 

[porman]

We've had the ground fault come on twice on our 430. Both times it was a bad shore power pedestal. Changing to a different one fixed the problem.

 

[psneeld]

As posted...an easy check or bad unit. Check first, chuck second.

 

[jimL]

Looks like the closing is scheduled for next week. We'll take possession by the weekend and I'll conduct the tests mentioned above. Thanks everyone for the collective advice. I did download the trouble shooting directions from ProMariner.

I'll let you know how I make out.

JimL

 

[jimL]

We took possession of the new to us 2005 Mainship this weekend. As expected the anticipated gremlins were neutralized while new ones poked their head up. The galvanic isolator issue was solved by the yard who plugged us into another power pedestal, with no issues.

We plan to start the movement of approx 180 inland miles on the Erie Canal late next week.

Thanks for your assistance!

More to follow . . .

JimL

 

[jimL]

I'd like to report no further issues with this. All of the other shore power connections were fine. It must have been the specific pedestal. We are now located at a different marine, 190 miles away and all is fine.

JimL