Main breaker panel keeps tripping

[streetdoc432]

I keep having this issue...I have a 1988 270 Sundancer. The main switch on my breaker panel in the cabin keeps tripping & when that happens, my batteries don't charge. I haven't added any new circuits. My bilge heater is directly wired to my dock power. It never does it when I am there for the weekend. I thought it might trip when the marina loses power during a storm, but they swear they haven't lost power in months. Is the main switch a standard 30amp? Do they make a 30 amp slow blow? Thanks for the help, in advance.

 

[JVM225]

Is the dock power line that you have the boat plugged in to the same one you have the bilge heater plugged in to?

 

[Little Ducky]

Time for some trouble shooting.

Turn everything off, Turn AC breaker on, Then reactivate things one at a time.

I think there was actually a post earlier this year talking about similar symptoms ..... it turned out to be some electrical component that had failed and melted. If I come across it I'll post a link.

 

[streetdoc432]

Is the dock power line that you have the boat plugged in to the same one you have the bilge heater plugged in to?

Happens even when I have the heater unplugged during the summer. But yes, i am running a 50 amp/two 30 amp Y cord. One wye goes to the boat, One wye to the heater. Only plug that in when there is a freeze warning.

 

[streetdoc432]

Time for some trouble shooting.

Turn everything off, Turn AC breaker on, Then reactivate things one at a time.

I think there was actually a post earlier this year talking about similar symptoms ..... it turned out to be some electrical component that had failed and melted. If I come across it I'll post a link.

Thanks Ducky, I did a search & got everything but what I was looking for...
The thing is, I live two hours from the boat, spend maybe 4 days in a row on the boat. Doesn't happen while I'm there, even with everything on, including the air conditioner & running the microwave. Very frustrating!

 

[JVM225]

Thanks Ducky, I did a search & got everything but what I was looking for...
The thing is, I live two hours from the boat, spend maybe 4 days in a row on the boat. Doesn't happen while I'm there, even with everything on, including the air conditioner & running the microwave. Very frustrating!

You didn’t specifically mention the bilge heater not working when you return, so I’ll assume the issue is only with the main breaker on the boat and the bilge heater has no breaker on it so you wouldn’t know if it worked continuously while you’re away.
So you have a “y” coming off of a 50 amp receptacle on the dock and it supplies two 30 amp ends at the other end of your “y”. That should be plenty of power. Although I have two separate 30 amp receptacles at my home dock, when I travel to a transient slip that has a single 50 amp I use the same type of adapter as you do to supply both my AC units along with 2 fridges and all the other 110 stuff on my boat without any problems. That’s the case whether I’m at a place that has 50/125 or 50/250 on their docks.
If you have everything running when you’re there (including things that typically cycle on and off like the fridge and charger), including the bilge heater, and don’t have a problem, but the problem happens randomly when you’re not there and there is presumably less stuff running then there is when you are there then there is a good chance that the problem is an intermittent one with the power source on the dock that coincidentally hasn’t happened while you’re there.
Just to further eliminate the problem being with your boat:
Is your main breaker on the boat nice and tight and healthy?
Can you open the panel to make sure that the wires supplying power to the main breaker are clean with no evidence of burning (black copper)?
Are the male prongs on the dockside inlet on your boat nice and clean with no evidence of burns or arching?
The wires on the back of that inlet on most boats can be tough to get to to inspect. But if can you get to them, are they nice and clean?
If so:
Any signs of burning on the “Y” adapter or either end of your cord?
Can you borrow another “Y” adapter and power cord supplying your boat to use next time you’re leaving for a few days to eliminate yours as a problem?
Can you put a breaker somewhere in line on the side supplying the bilge heater to see if that trips too while you’re not there?
Is the point where the bilge heater itself connects to the 30 amp line susceptible to moisture from rain or any other source when you’re not there?
Are there any others on the same dock that are having similar problems?
Is it possible that although the Dock has a 50 amp receptacle that there is either a problem with it, there are too many boats drawing too much power in a spike type time from the line supplying the whole dock or maybe the wiring for the dock and receptacles has issues?

 

[streetdoc432]

Thanks for all the info....I am going up to the boat this weekend. I will pull the cabin breaker panel out & check all the wires. The shore cord is in good shape. I cleaned all the prongs on all the cords with contact cleaner. I only use the heater when freeze warnings are expected, I pulled it apart to make sure no bug nests or anything, it is all clean & working correctly. I am on a covered dock, so all my connections stay pretty dry. I will update after my trip.. Thanks again for all the help!

 

[Island Time Buffalo]

This doesn't sound like the same problem I encountered, but it may help you locate the issue:
http://www.clubsearay.com/index.php?threads/380-da-tripping-shore-breaker.84539/#post-952849

 

[bobeast]

Before you start ripping everything apart. be aware that breakers themselves can fail. Every time you throw a breaker, a small arc occurs at the internal contact points. Over time this actually damages the contacts, increasing their resistance, and that can cause the breaker to trip.

We throw our breakers much more often on boats than we do in our houses, so I'd start there.