Neutral Ground Fault

[captvan]

I recently bought a 91 Sundancer 350 from a gentleman on Kent Island, MD. The wife & I ran the boat down to Little Creek Norfolk, VA and into her new home at Morningstar Marina. Morningstar has the newest shore power posts equipped with the latest GFCI breakers which are Very sensitive. Right away I had a problem. As with many mid-sized cabin boats mine has 2 30 amp 120v shore power receptacles which feed into separate breakers in the electrical panel. I knew a commercial electrician who has solved other tricky electrical issues on tugs I have run and called him. He charges $150/hr and has a 4 hr minimum. I told him I would be very happy to pay him $600 if he were to figure out the problem in 15 minutes. After the 1st 15 minutes we had the " AHA!" moment. The reverse polarity indicator lights on the electrical panel were wired across the neutral and ground. He removed these lights and the shore post breakers held - until we switched on ANY breaker in the panel. After six more hours of searching and testing and failing to find the source of the problem we examined another set of main breakers located below the main panel. On my boat there are shore power inlet recepticles on the stern as well as the port side of the boat. This other set of main breakers were there to choose from which location you can power the boat. These breakers ALSO had reverse polarity indicator lights as part of the breakers themselves. These indicator lights were also wired across both the neutral and ground. After disabling these lights the shore power GFCI bfreakers held just fine with everything turned on. During the process of finding my issue many of my new neighbors stopped by to commiserate with me and regailed me with their story of the long arduous process of finding the mysterious grounding issue on their boat. It cost me $1000 but I put that issue to rest.

 

[ttmott]

I recently bought a 91 Sundancer 350 from a gentleman on Kent Island, MD. The wife & I ran the boat down to Little Creek Norfolk, VA and into her new home at Morningstar Marina. Morningstar has the newest shore power posts equipped with the latest GFCI breakers which are Very sensitive. Right away I had a problem. As with many mid-sized cabin boats mine has 2 30 amp 120v shore power receptacles which feed into separate breakers in the electrical panel. I knew a commercial electrician who has solved other tricky electrical issues on tugs I have run and called him. He charges $150/hr and has a 4 hr minimum. I told him I would be very happy to pay him $600 if he were to figure out the problem in 15 minutes. After the 1st 15 minutes we had the " AHA!" moment. The reverse polarity indicator lights on the electrical panel were wired across the neutral and ground. He removed these lights and the shore post breakers held - until we switched on ANY breaker in the panel. After six more hours of searching and testing and failing to find the source of the problem we examined another set of main breakers located below the main panel. On my boat there are shore power inlet recepticles on the stern as well as the port side of the boat. This other set of main breakers were there to choose from which location you can power the boat. These breakers ALSO had reverse polarity indicator lights as part of the breakers themselves. These indicator lights were also wired across both the neutral and ground. After disabling these lights the shore power GFCI bfreakers held just fine with everything turned on. During the process of finding my issue many of my new neighbors stopped by to commiserate with me and regailed me with their story of the long arduous process of finding the mysterious grounding issue on their boat. It cost me $1000 but I put that issue to rest.

You can change those lamps to LED and won't have the problem. But to think that two little 26 gauge wires and tiny lamp caused all this. Goes back to a recent discussion had on this board about using the 5ma vs 30ma GFI circuit breakers on the dock side.
Anymore you gotta have multi-meta ohms between neutral and ground conductors.

 

[captvan]

I did find replacement LED lights from Custom Marine Services. They weren't cheap - $100 for 2

 

[quality time]

Ironically, we found out that our new to us boat had the same issue on vacation this summer on our way to Morningstar Little Creek. We tripped the GFCI at our first stop in Kilmarnock and had to be moved to another dock. We contemplated cancelling Little Creek because I knew they had the new pedestals but decided to go anyway and the dock breakers held without issue for two days. Still quietly trying to figure out the issue but haven't been to a marina with GFCI's since.

 

[Richard Carlisle]

Many older boats had bonded neutral and ground. Plugging that into a GFCI will trip it every time. Newer boats have isolation transformers. When our marina installed GFCI breakers, lots of boats got rewired and/or isolation transformers installed.