Need help with ground fault

Discussion in 'General Maintenance/Repair Questions' started by TitanTn, Jan 28, 2018.

  1. TitanTn

    TitanTn Member

    248
    Jul 12, 2015
    Chattanooga, TN
    1986 Saltare, 1987 300 Weekender, 1998 400 Express
    454 direct drive; twin 350s, twin 3116TA
    My marina has a very sensitive ground fault detection system. Ever since I got my 400EC last fall I've been fighting ground fault trips (it shuts down the whole dock).

    At first it was the fridge, and after rebuilding the main circuit board it seems fixed. But I'm getting trips without any regularity or pattern. I thought my salon aircon was tripping it, but then it tripped just by flipping the 120V A/C breakers. Basically I've figured out that anything which draws a large power consumption will trip the ground fault (example is a space heater).

    Everything I've read says to test systems and see what's causing the ground fault, but in this case it seems that anything on the 120v circuit will trip it. So how do I find this ground fault?
     
  2. Little Ducky

    Little Ducky Active Member

    515
    Jun 5, 2017
    Chattanooga TN/Dickson TN
    1998 SeaRay 290 Sundancer
    Twin 5.0L w/Alpha 1 drives
    So with nothing on, the boat will power up just fine. Then when you turn on the HVAC or plug in a heater it will trip?

    Do you have a generator? Does it power up the boat just fine?

    If you have a neighbor have them plug into your dock outlet and see if it trips when they power up their AC system. This will rule out the dock's wiring is at fault.

    Might want to pull your main breaker panel and see if there are any loose connections or burnt breakers ..... of course do this with the power off, boat unplugged and the batteries in the off position.

    If you haven't tried a new dock power cable...... might want to try one because it could have a broken ground somewhere.
     
    Last edited: Jan 28, 2018
  3. TitanTn

    TitanTn Member

    248
    Jul 12, 2015
    Chattanooga, TN
    1986 Saltare, 1987 300 Weekender, 1998 400 Express
    454 direct drive; twin 350s, twin 3116TA
    I appreciate the thoughts and those are good questions. I do have a generator and it powers everything fine. I've used a neighbor's pedestal for additional testing and nothing changes. I've also borrowed a neighbor's cords and no changes. I've opened up the panel and there is nothing obvious. Nothing loose, burnt, etc.

    It just feels like it's something on the 120V side in general and I'm just not sure where or what to look for at this point.
     
  4. Little Ducky

    Little Ducky Active Member

    515
    Jun 5, 2017
    Chattanooga TN/Dickson TN
    1998 SeaRay 290 Sundancer
    Twin 5.0L w/Alpha 1 drives
    hummmm.

    How about the plug socket on the boat that the dockside power plugs into?

    I'd pull it out and see if all connections are tight .... if that checks out I'd call a electrician.
     
  5. War Eagle

    War Eagle Member

    100
    Aug 22, 2015
    Guntersville Alabama
    1987 SR 270 Amberjack ... "Seabiscuit"
    Twin Merc I/O's 4 cyl 150 hp (PIA's) Alphas
    Re power in process!
    Ground faults occur when the current flowing in a circuit pair becomes unbalanced. ie The current flowing in via the black wire does not match the current flowing out via the white wire. The current difference is returning to ground indirectly - thru an unintended path. To fix this you are going to have to find where the "leak" is occurring. Because 120/240 is a lethal level of voltage, I strongly suggest you talk with a professional electrician with marine experience. With the right equipment and experience he can isolate the problem and fix it fairly quickly. This situation can be indicative of a potential shock hazard. Really needs to be investigated by a pro.
     
  6. TitanTn

    TitanTn Member

    248
    Jul 12, 2015
    Chattanooga, TN
    1986 Saltare, 1987 300 Weekender, 1998 400 Express
    454 direct drive; twin 350s, twin 3116TA

    Yes, I've replaced the inlets on the boat and thus have confirmed that they (and the connections to them) are not the problem.

    I'm a pretty handy guy, but electric certain isn't my favorite thing to work with. Especially A.C. The issue is that I'm not in a marine "hotpspot" for service and I don't know of anyone who fits the bill of a good electrician with marine experience. My last several rounds of hiring a professional has left me wishing I had just done it myself. That's where I'm at. I am hoping to get some advice pointing me in the right direction.
     
  7. TitanTn

    TitanTn Member

    248
    Jul 12, 2015
    Chattanooga, TN
    1986 Saltare, 1987 300 Weekender, 1998 400 Express
    454 direct drive; twin 350s, twin 3116TA
    I just wanted to close the loop on this thread in case it helps someone. I could not narrow down a system - at some point in time everything tripped the ground fault, and then other times nothing did. Didn't matter what was running or not - there was no pattern.

    Long story short. My fridge was replaced by someone about 10 years ago. I'm guessing that they installed an outlet for the fridge instead of direct wiring it. When I pulled the outlet apart I found that they wired the neutral and the ground backwards. Stupid stuff.

    So I switched the wiring and everything seems to be just great now.
     

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