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Help ! Carver shore power

Discussion in 'Carver Yacht' started by Old Navy, Aug 2, 2012.

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  1. Old Navy, Aug 2, 2012
    #1
    Old Navy

    Old Navy New Member

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    I have had my 1990 3607 at several marinas and had no problem with shore power but I recently moved the boat to another state and the marinas shore power breakers were all ground fault breakers. My boat requires 2 shore power cable, 1 for the a/c's and one for the house circuits (outlets, reefer, etc). All work fine at other marinas and on genset but when I plug in to shore power at marina with ground fault the cable for the house circuits trips instantly, the other shore power cable is fine and yes, I have tried swapping cables and different shore power outlets. HELP, I'm pulling my hair out !!!
  2. Capt Ralph, Aug 2, 2012
    #2
    Capt Ralph

    Capt Ralph Senior Member

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    Do you have an isolation transformer? Galvanic isolator?
    Try turning off ALL breakers except for the main service breaker. If the GFI still trips you have a problem in your service entry. If GFI stays good. Bring on-line the sub breakers one at a time. This may isolate it down to just a certain circuit or even an appliance.
    On another page, GFIs can trip on excessive DC current on the green wire also. Galvanic currents from/to your boat could be an issue also.
    I heard of a battery charger driving an issue like this.
    Good, luck, let us know your progress.
  3. Old Navy, Aug 3, 2012
    #3
    Old Navy

    Old Navy New Member

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    No isolation transformer. With all breakers off and main breaker off shore power does not trip. With all breakers off it trips as soon as I turn on main breaker.
  4. Capt Ralph, Aug 3, 2012
    #4
    Capt Ralph

    Capt Ralph Senior Member

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    Is your main breaker 2, 3 pole. does it open Green ground, White neutral, Black bottom 115vac? I'm assuming it's all 30amp 115vac system. Do you have a polarity reverse alarm?
    Turn everything off, Take an ohm meter to your service entrance. Any readings between any of the pins?

    Trying to think what would be on just the main breaker with all other breakers off. Volt meter? Amp meter? Idiot light? If there tied from to black to green instead of blk to white it could cause fault current.
  5. captainwjm, Aug 3, 2012
    #5
    captainwjm

    captainwjm Senior member

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    If everything was ok at other marinas, then the problem is probably at the dock pedestial. Not unheard of for a dock to be wired wrong.
  6. Capt Ralph, Aug 3, 2012
    #6
    Capt Ralph

    Capt Ralph Senior Member

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    High amp GFI is rare down this way but I can see the benefits (some). Galvanic currents may trip the cheaper ones. Your other marinas may not of had this GFI stuff also.
    And Yes, the problem could be at this marina but your going to have a hard time proving it.
    Still think you may have a white and green tied somewhere. Could even be at your gen-set if your transfer switch does not isolate green and white wires from the ship when turned off.
    Ahh, just remembered something I read long ago. Old inverters tied white and green. The fix was some kind of green wire isolation relay.

    Good luck and let us know if you find it.
  7. Old Navy, Aug 13, 2012
    #7
    Old Navy

    Old Navy New Member

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    Shore power problem found. There was a small (22 gauge) wire jumper from neutral to ground. Removed it and problem with GFCI breaker solved.
  8. Capt Ralph, Aug 13, 2012
    #8
    Capt Ralph

    Capt Ralph Senior Member

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    Yep, that will do it. A little return current induced on the green wire. Did it look like factory work or some mod from a previous owner?
    I found a factory strap like that on a Hunter sail boat a couple of years ago. Never understood the logic.
  9. Old Navy, Aug 14, 2012
    #9
    Old Navy

    Old Navy New Member

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    It looked like it was factory all the way