Ground fault on shore power trips

[Panacea2183]

I have a 2002 novatec sundeck trawler.
Have never had a problem with plugging into shore power.
Just had my home dock rebuilt and new wiring code requires a ground fault breaker (in house at breaker box)
Now when I plug in, ground fault blows immediately.
This is with the power selector (in the boat between gen and shore power) turned to off and all breakers in the boat turned off.

Temporarily replaced the new ground fault breaker with a regular one and back to normal.

Thoughts and help appreciated!
Thanks

[Frankly]

I think the first thing I would check is if the neutral and ground on the yacht are isolated. Unplug the shore power cable from its feed and check between the ground contact and the neutral contact on the shore power cable end. Look up the contact identification on google. Typically L5-30 for a 30 amp 120 volt connection.

[smac999]

if it is blowing with the shore power breaker off, assuming you have a double pole breaker. then you have something weird going on, but it should be easy to find as it'll be between the plug and switch / breaker. or it's in the dock wiring.

you should find and fix the problem not just leave the breaker. that means you are leaking power into the water.

if it happened only with the main on then you'd have a lot more to look through on the boat.

I'm thinking it could be a netraul to ground cables swaped somewhere in the dock. and the n from the house is being connected to the ground of the boat.

[smac999]

Originally Posted by Frankly

I think the first thing I would check is if the neutral and ground on the yacht are isolated. Unplug the shore power cable from its feed and check between the ground contact and the neutral contact on the shore power cable end. Look up the contact identification on google. Typically L5-30 for a 30 amp 120 volt connection.

if he had a N-G bond on the boat it would most likly be after the main breaker, and not show up or cause issues with a double pole switch / breaker off.

[Scott Berg]

This may help tracking it down

https://gilwellbear.wordpress.com/20...sts-for-boats/

[GordMay]

GFCIs will trip when the load side neutral and equipment grounding conductors are joined, even if there is no ground fault.

[Steve_C]

Originally Posted by GordMay

GFCIs will trip when the load side neutral and equipment grounding conductors are joined, even if there is no ground fault.

As usual GordMay is correct.

If I understand correctly, the new GFCI is located before the main panel on your vessel?

The Neutral and ground are probably tied to a common buss on your boats panel where the main and load breakers are located. These would need to be separated and the Neutral buss cannot be grounded.

[ralter]

My guess beyond those that have been mentioned already is that there is probably a "ground fault buzzer" (or maybe just a light) onboard the boat. What either of those is is a load in the normally unusual place between the grounding (green) and grounded (white) leads on the boat. All that load does is ring a buzzer (or light the light) when there is voltage between those two legs, which there normally should not be. That load however will likely appear to the shoreside GFI breaker as just the kind of leakage that breaker is designed to complain about, and it did. If you have such a buzzer or light, just open-circuit it temporarily to prove that is the problem. If a light, remove the bulb; if a buzzer, lift one leg of it. Then plug in the boat and all should be well.

The only permanent solution I can think of that will maintain compatibility with other places you might want to plug the boat into would be to place a switch in series with that light or buzzer. Then label that switch "Ground fault test". Whenever you plug in, just close that switch temporarily. If the buzzer or light activate, you have a fault. If not, you're fine. If the shore breaker pops, open the switch, reset the shoreside breaker, and trust it for the protection you're looking for.

That's my $.02. Good Luck!

[Panacea2183]

Thanks for all the info
Have not had a chance to trouble shoot yet
But to clear up a few things.
The GFI is in the house at the main panel, it was just installed by the same company that wired the house, very well known co in this area.
I do have a reverse polarity light, and galvanic isolater
New magnasine inverter with neutral switching installed by a pro.

Yes it trips with gen/shore power selector turned to off and main double pole breaker turned off on boat panel, (trips as soon as it is plugged in). That's the weird part as you would think with it off no current would flow?

I suspect my problem lies with the selector switch as it does not appear to change the neutral wire (very hard to see where it is located)
Will dive into it more when I have time.

For now just replaced the breaker in the house with a non GFI unit. (It's been this way for 14 yrs with no problems)
Have a pro scheduled to come out in a week or 2

[rwidman]

Originally Posted by Panacea2183

Thanks for all the info
Have not had a chance to trouble shoot yet
But to clear up a few things.
The GFI is in the house at the main panel, it was just installed by the same company that wired the house, very well known co in this area.
I do have a reverse polarity light, and galvanic isolater
New magnasine inverter with neutral switching installed by a pro.

Yes it trips with gen/shore power selector turned to off and main double pole breaker turned off on boat panel, (trips as soon as it is plugged in). That's the weird part as you would think with it off no current would flow?

I suspect my problem lies with the selector switch as it does not appear to change the neutral wire (very hard to see where it is located)
Will dive into it more when I have time.

For now just replaced the breaker in the house with a non GFI unit. (It's been this way for 14 yrs with no problems)
Have a pro scheduled to come out in a week or 2

As I suggested on the other forum, the problem could be with the reverse polarity indicating circuit. Remove the bulbs if possible, otherwise, disconnect them. See if that solves your problem.

Most of these indicating circuits are a ground fault by design. A lamp connected between the hot wire and ground to indicate proper polarity.

[Panacea2183]

Originally Posted by rwidman

As I suggested on the other forum, the problem could be with the reverse polarity indicating circuit. Remove the bulbs if possible, otherwise, disconnect them. See if that solves your problem.

Most of these indicating circuits are a ground fault by design. A lamp connected between the hot wire and ground to indicate proper polarity.

Question is if the selector switch is turned to OFF how can any power flow into the boat to trip the GFI?

[a64pilot]

Originally Posted by Panacea2183

Question is if the selector switch is turned to OFF how can any power flow into the boat to trip the GFI?

I think it's because the breaker removes power, yet leaves ground and neutral connected


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[DotDun]

Originally Posted by Panacea2183

Question is if the selector switch is turned to OFF how can any power flow into the boat to trip the GFI?

Usually the reverse/no-reverse lights are wired ahead of the selector switch. This is done so you can decide yes or no before final connection using the selector switch in case of a reversal.

[Panacea2183]

Originally Posted by DotDun

Usually the reverse/no-reverse lights are wired ahead of the selector switch. This is done so you can decide yes or no before final connection using the selector switch in case of a reversal.

Good thought I'll check that as well. Although I believe it's wired at the panel.

[smac999]

Originally Posted by a64pilot

I think it's because the breaker removes power, yet leaves ground and neutral connected


Sent from my iPad Pro using Cruisers Sailing Forum

both his main breaker and Gen / shore switch will cut off both the hot and nuetreal. if wired right. which will also eleminate seeing a N-G issue on the boat... you can't see an N-G bond on that boat if the N is open.

so the issue should be between the house breaker and the boat main breaker or selector switch, and not past that in the boat

the rev light is before the main breaker (though probabbly after his selector switch which is off. also they are supposed to be atleast 10,000 ohms and shouldn't interfere with a GFI.