Hello everyone!
Admin, Thanks for the add!
So I am having problems with my shore power. I have a 1986 holiday mansion when I plug in the 2- 30 amp shore cords individually, both circuits operate fine. When I plug them both in, it pops the GFCIs on the dock pedestal immediately even with all breakers off on the boat, (even the 2 mains ). I have recently purchased the boat and have never tried to use both cords at the same time until now.. I have tried a different power source on the dock and there's no difference. All the hardware appears fine, no burn marks etc..



Q- on the boat side sockets (no cords connected), Is the ground to shore cord 1 and shore cord 2 suppose to have continuity? How about the whites?

Any troubleshooting tips would be appreciated..

THANK YOU!!

if its popping the GFI's even with the mains on the boat turned off i would concentrate on the receptacles on the boat where the cords plug into...something is not wired right. My guess is one of the receptacles has a hot/neutral swapped around. you wouldn't notice it just running one cord at a time from either side.

Thanks for the suggestion! I spent the day disconnecting the 3 wires to that go from the each main to the breakers at the panels. Then I plugged in the shore cords and they still popped, There was some ground wiring that was substandard so I removed it but it made no difference either.. Tomorrow Ill pull all the outlets apart and see what there is going on, I wonder why there is continuity between the blacks on 1 & 2... Time will tell.. Thanks again..

if the mains are off and the cords are not plugged in there should be no continuity between the 2 blacks inside the boat...they should be totally separate lines and should each go their own breaker. two lines...two breakers each its own circuit. The whites can be tied together (common) at the bus bar

Do you have a generator/shore power switch? My brother bought a boat and that switch was wired wrong. If you're having this problem, I would meter everything out. I used to work on motor homes and travel trailers and we would have to rip them all apart to pull out melted wires and find shorts, not fun.

Sounds like the Black and/or white are connected together, or . Dual cords are setup to run different things like HVAC for one and everything else for the other. All grounds are connected together after the galvanioc isolator

No Generator on board..

wiring is the same just without Gen

Neutral and ground swapped in one of the cords??

OK Guys. Years ago all boat manufactures were required to install a GFI grounding fault/ground monitoring system. The system most used was from Pro Mariner. The earlier units sent a pulse to test the neutral and ground. This was before docks began to use GFI protected outlets. THEY ARE NOT COMPATIBLE WITH GFI PEDESTALS. This is going to be a huge issue as more and more marinas upgrade to GFI systems. I spent days searching the issue on my 400SS with a expensive marine electrician. Pro Mariner knows there is a problem. There was never a problem and their system worked great until GFI's appeared on docks so its not really their fault. I found mine hooked up to a 20 amp gfi circuit hooked to my house. We should somehow post this on this site so boaters don't waste thousands of dollars searching when its a simple fix.