Shore Power trips GFCI breaker at dock pedestal

[McNally260DA]

Our marina just installed new electric pedestals on the docks. My brothers boat had no issues prior to this. Now when he hooks up to shore power he trips the GFCI breaker at the dock. This happens when we switch the main on with all other switches and 110 systems off. We have tryed other shore power cords and dock pedestals but that did not help. We have isolated the problem to his boat but have not attempted any trouble shooting yet. To our knowledge this boat is the only boat having issues. It is a 2006 260 sundancer. Any help with this would be appreciated and I will post the cause when we get this resolved. Thanks

 

[Jay Bird]

I had a similar problem on my boat, turns out it was a ground fault/short in the hot water heater. Disconnected the water heater and it solved the problem.

 

[jason78]

Read through this thread. In this case the Hot Water Heater Element corroded and allowed Neutral and Ground to connect causing the same issue. The fix was a new water heater element.

http://clubsearay.com/showthread.php/59777-2007-260DA-Trips-GFCI-Breaker-on-Shore-Power

 

[McNally260DA]

Thanks for the quick response. So you're saying even with the hot water heater switched off this could still be the issue ? It's funny because the marina had GFCI pedestals before and there was no problems.

 

[jason78]

Thanks for the quick response. So you're saying even with the hot water heater switched off this could still be the issue ? It's funny because the marina had GFCI pedestals before and there was no problems.

Yes. The Breaker to switch off the hot water heater only disconnects the hot. So regardless of the breaker state of the HWH you could still have it causing problems. I think I explained it all pretty well toward the end of that thread. If I have time I will look at it more later on. Easiest way to figure it out is to disconnect all power, open the breaker panel and find the cable going to the HWH. Turn off the HWH breaker and disconnect the neutral for only that cable form the neutral bar and tape it off. Close up panel and restore power. See if problem goes away or remains.

 

[Boat Guy]

The new breakers are possibly more sensitive than the old ones.

So:

The main breaker is off above the shore power connection.

The Shore breaker is off on the main panel.

If you turn the main breaker on with the shore breaker off, it trips? Or is it after you turn the shore breaker on that it trips?

I don't think there should be any reason that any equipment on breakers should cause the trip if they are off, unless the breaker is faulty.

 

[PatSea]

The description of your problem sounds almost identical to what I experienced last year. After an exhaustive search I found two causes:

1. The water heater. I had abandoned the water heater a few years back because it had a leak and I decided not to replace it. However, I left the 120V wiring connected to the heater, just turned it off at the breaker. Rust/corrosion had developed around the connection point which allowed enough dampness to allow enough leakage current to trip the dock pedastal breaker. I simply disconnected the cable to the heater and insulated the ends. Simply turning off the breaker was not sufficient.

2. I found that one of the GFI outlets in the cabin was defective allowing enough leakage current to trip the dock pedastal breaker. Installed new GFI's throughout the cabin.
Problem solved, no tripping since.

I would urge you to track down the root cause(s) and fix them. This type situation can cause ESD (electrical shock drowning).

 

[HUMPH]

Old GFIs do not necessarily work. You could have had this issue for years but if the GFI is not tested regularly, you will never know if it functions properly or not. GFIs should be tested at least a couple of times a year to verify the are functioning correctly! An easy way (I don't trust the buttons) is to take your meter and test voltage from hot to ground. if the GFI is functioning, it will trip. If it doesn't trip, replace it. This goes for breakers and receptacles.

 

[McNally260DA]

Trying to get a marine mechanic down to the dock today. Thanks for suggestions will let you know what we find. Checking your suggestions as well. The breaker above the shore power outlet is on. The breaker on the dock trips when you turn the main power on in cabin. Thats the switch right next to the volt meter. I won't be able to check this thread until tonight but any further posts would be appreciated.