Tripping Exrernal Ground Fault

[SeaJay]

I've a 32+2 which has recently gone back into the water. She is not at her dock yet, sitting in a tempory slip for the time being and until she gets summerized. I'm having to use a cheater cord for power, my first time needing that with this boat. All breakers are off and I trip the ground fault breaker on the shore outlet as soon as I flip the AC breaker on board. Tried different outlets to confirm that the outlet itself isnt at fault. I'll be going up this week to troubleshoot the problem, any ideas as to what I should look for, suggestions on how to proceed?

[DougSea]

Since you said "cheater cord" I'm assuming you're plugged in to a standard Edison outlet and are using an Edison-to-twist lock (Hubbell) adapter. Since all outlets are tripping, are you sure the adapter is ok? Is it home built or a pre made? If it's home built the neutral (white) and hot (black) may be reversed. I'd start with that.

[SeaJay]

Since you said "cheater cord" I'm assuming you're plugged in to a standard Edison outlet and are using an Edison-to-twist lock (Hubbell) adapter. Since all outlets are tripping, are you sure the adapter is ok? Is it home built or a pre made? If it's home built the neutral (white) and hot (black) may be reversed. I'd start with that.

Thanks for the response, but no, the cheater cord is pre-made, I've used it in the past just not with this boat. My assumption was also that 'if' the cheater cord itself was faulty, I'd trip the ground fault without having to flip my AC breaker(?), butbhave tried a cheater cord from the Marinia as well.
And, yes I'm plugged into a standard, house hold outlet, with an adapter to convert that for connection to the twist lock Hubbell. It is only the external, shore outlet that I'm plugging into that trips, all breakers in the boat itself are manually set to the off position.

[SeaJay]

My brother, an Electrian, says the ground fault (GFI) breaker is extremely sensitive and any small, minor short (milli-amps) will trigger it. Something as simple as a little moisture could be the problem. I'll try a hair dryer on the panel and see if that makes a difference.
QUESTION - are the regular 30 amp Hubbell power outlets typically protected with GFI breakers? I can't recall and if not, this issue might have existed previously but never significant enough to present a problem (i.e. Trip a regular breaker).

[DougSea]

QUESTION - are the regular 30 amp Hubbell power outlets typically protected with GFI breakers? I can't recall and if not, this issue might have existed previously but never significant enough to present a problem (i.e. Trip a regular breaker).

No, 30A shorepower is not normally protected by any type of GFI, just a "typical" overcurrent protecting breaker. So yes, it's possible that this problem's been around for a while. You can "leak" a lot of current before the shorepower breaker will trip.

While looking in to this I came across the following on another forum:

Quote:
Originally Posted by Greggegner
a second question...GFIs pop for my boat also. The 120 and 12 volt grounds are the same. I have one of those power panels that indicate if the polarity is correct on the 120. Will this polarity monitoring cause the GFI to pop? I have no other signs of power issues, zincs do not wear.

Quite possibly.

It’s important to note that the Reverse Polarity Indicator Circuit must have a minimum resistance of 25,000 Ohms.

By applying Ohm's Law, we find that, if the polarity is reversed on a 120-volt circuit, activating the device, the current flow will be 120/25,000 = 4.8 milliamps, which is just below the tripping threshold of U.S. Ground Fault Circuit Interrupters (GFCIs); which trip at 5 milliamps. This way the alarm will alert the operator without tripping the circuit. With such a high resistance in the circuit provided by the 25K-ohm resistor, there is no need to worry about leaks to ground, galvanic corrosion, etc.

➥ AC Reverse Polarity - Resources - Blue Sea Systems
http://bluesea.com/viewresource/84

➥ Reverse Polarity Indicators - Resources - Blue Sea System
http://bluesea.com/viewresource/90

[jleonard]

"the current flow will be 120/25,000 = 4.8 milliamps, which is just below the tripping threshold of U.S. Ground Fault Circuit Interrupters (GFCIs); which trip at 5 milliamps."

Which means it is tripping as it is intended considering manufacturing tolerances.

[SeaJay]

Thanks Guys, my suspicions confirmed with solid explanation. Appreciate the time you took to respond

[Dexter]

Just came across this thread. A tripping GFI is never within normal specs. I had a similar problem on my 31TE. I tripped as soon as I plugged the boat in. When I plugged my 38 Blackfin on the same GFI no problem detected. After much investigation I found that the insulation around the power indicator lights on the DC breaker panel was grounding out. I put new insulating shrink wrap around each one and problem was gone. A small power leak can destroy all of your hardware on the minor side, on the major side it can kill someone. I was searching on line to find a fix for this problem and came across a video of this (forgot where) about a man whose son was swimming at a marina and died because one of the boats were leaking and he got electrocuted. This man almost lost his wife also because when she jumped in to try and save her son she also got electrocuted and almost drowned. GFI breakers are there for a reason. If it is tripping you should hunt it down and fix the leak. This man who lost his son investigated the problem and found that a boat in the marina had a short between 12 v and 120 v system and the boat electrified the water and no one new it until this boy went swimming. Most faults can be found by isolating circuits at the breaker panel. If it trips when the main is off then the short is before the panel. If it trips with the main on then turn off all breakers and put one on at a time. Eventually you will trip the GFI and find the offending circuit. Then just follow the circuit or just rewire it. Hope this helps.