Shorepowerless

[Freeebird]

Had to move the 41 this morning to a temporary transient slip on the fuel dock at my marina and now have an odd electrical issue. Nothing on the boat is switched on, but the instant I switch the 50A breaker on the pedestal with my two 30’s into a 50 adapter, it trips the breaker at the main marina breaker box. If I turn on the pedestal breaker without my cord attached, it’s fine.

I tried both 50A receptacles on the pedestal and even switched from starboard to port connections on the boat with the same result. Short of moving my boat to another slip, I’m not sure how to see if this is their problem or mine. Seems it would be on their end, given the breaker at the pedestal isn’t the one that’s tripping, but I’m not a Sparktrician. Marina personnel are in the middle of expanding the dock (resulting in my move) and it’s New Year’s Eve, so I figured we could address it later.

Thoughts?

[MadHatter53]

Have you tried without the cord plugged in to the boat?

[Freeebird]

Nope, but unless there’s a short in the cord, I can’t see that doing anything. Cords are in great shape. I just find it odd that the main panel breaker is tripping and not the pedestal breaker. A bad panel breaker seems to make the most sense.

[Oldlaxer1]

When I first moved to my slip I had a similar thing happen. With my shore power cord connected to the pedestal and to the forward 50 amp input on the stb side the dock breaker would blow, not the pedestal. (marina managers boat is right next to mine and I melted his Nutty Buddy's in his freezer because I thought the problem was on my boat, not the dock...welcome to the neighborhood )
Once we got power back to the pedestal I was able to connect to the aft input on the stb side and it worked fine. I just recently replaced the forward input with a Smart Plug and replaced both ends of the spare shore power cord and will be trying it again. Electrician didn't see any issues with the onboard plug other than the fact there is no ground connection coming from the pedestal on my vintage Hatteras. (verified by Hatteras btw)
In both our cases it is odd that the main breaker blows but not the pedestal. In my case the pedestal was virtually brand new. I may try the smart plug tomorrow and will report back. Different situations but maybe it will help you pinpoint the issue.

[Freeebird]

Thanks, John, nothing like a Nutty Buddy meltdown to get a marina manager’s attention.

These docks are only a couple of years old, so that just deepens the mystery.

[SeaEric]

New docks with current marina code GFI's don't like our old boats shore power systems. Go back to an older dock and power supply or install an isolation transformer on the boat. That's on my long term list to do.

[Freeebird]

Been at that marina going on three years now (I think) and have never had an issue. Everything was put in at the same time, even though that marina dates back to the 60’s, and maybe earlier.

Kept my first, twin engine cruiser there in ‘84, but the marina eventually... disappeared. New owners finished it off, then replaced it will all new docks. It’ll be interesting to see what we find out.

[rustybucket]

I'd try just the adapter plugged in first, it may be bad and causing a short.

After that I'd probably try ohming the shorepower cable to rule it out as a culprit. I wouldn't think you should get continuity between any leads except ground and neutral.

It could be the actual plug on the pedestal but sounds like you tried both and same result for both. Next I'd probably test the plugs on the pedestal to make sure something isn't reversed or that they don't have a hot where a neutral should be...etc.

[Freeebird]

Good idea just trying the adapter. Didn’t think to try that. Still bugs me the non-pedestal breaker is the tripper. Now that I think about it, I have to wonder why that one breaker trips when either 50A outlet is used. It has to be a higher rated breaker to feed two 50A circuits, right?

If it were a short between the pedestal and my boat, seems the pedestal breaker would trip first.

[SEVEN]

That happened to me and it took a new breaker on the panel to correct the issue.