Music City Mystery

[Sanford Gentry]

A few days ago at the Nashville City Dock, I plug in my 30 amp cord, to a splitter then to the A and B boat connections, just like always. Flipped the A and B switches on the Paneltronics panel and the breaker on the dock outlet pops.
Trouble shoot and learn I can plug into the B side but not the A. Undo the wires going to the boat breakers, the fancy main that forces you to decide shore or generator power and all measures correctly.
I work around by moving my battery charger, AC and water heater to the B bus side.
Yesterday, at a different marina, wife Val suggest I give it a try and everything works as it should. So I fix my wiring back to original. All good.
The Paneltronics was done by a pro and looks great on the back side. There is wiring I do not understand between the A bus and B bus with the generator. Including what look like diodes between the breaker posts.
Does anyone have a suggestion?

 

[Comodave]

Did the dock in Nashville have GFIs on it? It can be that your boat has some wiring issues that will cause the GFIs to trip. The boat will work ok, except you may be leaking current, on a non GFI dock but fail with a GFI dock. Usually related to the neutrals in the boat.

 

[Sanford Gentry]

Is there such a thing as a 30 amp GFI breaker? It didn't look like a standard house breaker.

 

[Comodave]

Yes, I have 2 of them on the dock at my house.

 

[Sanford Gentry]

Thank you, I will look up the process for finding a leak. Any advice appreciated.
We are heading downstream on the Cumberland for next two days. We dock the boat at Kuttawa for now. Plan on heading south first of November.

 

[tiltrider1]

If you were on a GFI dock the mere use of a splitter would cause the trip. A better explanation of your set up would be helpful. Were you plugged into a 30a socket or a 50a 125/250v socket? Do you have two sockets on the boat one feeding A and the other B or is there only one socket feeding both.

On the surface it sounds like you have a misplaced neutral, in other words one of A’s neutrals is attached to the B bus. However, it’s also possible you have a chaffed wire that is actually leaking.

You boat in fresh water, therefore any electrical leakage is deadly for anyone swimming near your boat. I am not saying you have leakage but you have just been handed a red flag. In this day and age I would not boat in fresh water without having an ELIC installed on my boat.

 

[SteveK]

Another cause for tripping (I read) dock GFI breaker was inverter too slow switching to pass through. Solution was to turn off inverter, plug in and turn on again.

 

[rslifkin]

Another cause for tripping (I read) dock GFI breaker was inverter too slow switching to pass through. Solution was to turn off inverter, plug in and turn on again.

If it's wired properly that shouldn't be an issue. The key is that the inverter input and output neutrals need to be kept separate. If they're allowed to mix, then the inverter neutral/ground bond when inverting will cause a GFI trip if it doesn't switch over fast enough.

 

[Comodave]

Back when his boat was built is was common for the builder to put all the neutrals on one bus bar even if there were 2 shore power inlets. This would work fine, not necessarily safely, until the new NEC code changed and required GFIs on docks. We had a 1987 President trawler that had this issue. I have had GFI breakers on my home dock since we moved here. When we got the President home it immediately blew the breakers. But we had traveled 45 days and stopped at 40+ marinas and had no problems. But none of those marinas had GFIs. I had to rewire the boat and separate the neutrals and add a second neutral bus bar. Now as more and more marinas are coming up to the new cose there are more marinas with GFIs so it is becoming more important to have the boat wired properly.

 

[rslifkin]

Back when his boat was built is was common for the builder to put all the neutrals on one bus bar even if there were 2 shore power inlets. This would work fine, not necessarily safely, until the new NEC code changed and required GFIs on docks. We had a 1987 President trawler that had this issue. I have had GFI breakers on my home dock since we moved here. When we got the President home it immediately blew the breakers. But we had traveled 45 days and stopped at 40+ marinas and had no problems. But none of those marinas had GFIs. I had to rewire the boat and separate the neutrals and add a second neutral bus bar. Now as more and more marinas are coming up to the new cose there are more marinas with GFIs so it is becoming more important to have the boat wired properly.

Agreed. The 1980s is when boat builders were just starting to get better about AC electrical in a lot of cases. Some got things right like separating neutrals for multiple inlets (mine had this done properly in 1986 for example), but plenty of boats have issues with it. And of course there's always the potential for improperly done changes to the system by previous owners.

 

[tiltrider1]

We recently converted one of the Yacht Club’s docks to GFI. This is one of our most popular docks so we knew trouble was coming. Turned out 10% of the boats had issues. Now 9 out of 10 boats had a simple misplaced neutral. One boat had issues with an inverter/charger. This was easy to solve with a bypass switch and a backup charger, this route was chosen because all the components already existed on the boat and this was the only GFI dock the boat ever saw.

One boat had a mysterious issue that was random. Owner took it to the yard and they couldn’t track down the problem. This peaked the interest of me and my buddy, we like challenges. Being that we knew the owner we offered to give it a shot. After many hours we were able to replicate the failure. If we plugged in a two prong plug in to a specific circuit there was no issue. If you plugged in a 3 prong plug then you got a trip. I am simplifying this somewhat but that is basically what we found. In the end we could never actually find the true cause but we solved the problem by completely re running two unrelated circuits. It’s my belief that a nail or a screw pierced the circuit at some point.

 

[SteveK]

Tilt, did you rule out a reversed hot and neutral?

 

[tiltrider1]

Tilt, did you rule out a reversed hot and neutral?

That was ruled out. Along the way we found some unusual leakage like a salt trail from positive to neutral on the back of a socket and some leakage related to the water heater element due to corrosion. These were very minor leakages and ultimately not the primary issue. We also found an LED gauge that was wired from positive to ground. This had a leakage but again not enough to trip.

 

[Sanford Gentry]

Thank you everyone for the input. I talked to my all-around boat mechanic at my dock and we are going to try to chase it down when I get back to home port in Kuttawa KY.
We intend to head south first of November and trying to sort things out before leaving.

 

[Comodave]

Not to nock your mechanic but this will take someone with a good knowledge of electrical work. You want an experienced electrical person hopefully with ABYC certification. I worked on a friend’s boat with this problem and found 4 different things that were causing the dock breakers to trip. We had to keep working through problem after problem until we got them all. Several of the problems in his boat were very obscure and tough to find.

 

[Helmsman]

Thank you everyone for the input. I talked to my all-around boat mechanic at my dock and we are going to try to chase it down when I get back to home port in Kuttawa KY.
We intend to head south first of November and trying to sort things out before leaving.

Sanford,

Here is a link to tests that you can run.

AC Safety Tests for Boats – Cruising Aboard Monk36 Trawler Sanctuary

Posts about AC Safety Tests for Boats written by gilwellbear

gilwellbear.wordpress.com

It sounds to me like the marina you stayed at have updated their power pedestals. The GFCI’s are mandated today, but there is flexibility when a marina installs them. There are also explanations on this website that explain them in more detail. As tiltrider stayed you may have an electrical leak. Common areas for that are the water heater, the refrigerator power unit, or perhaps another short somewhere. If it isn’t a short, it could be neutrals from one leg connected to the other. These can be tedious to figure out, but can be.

 

[tiltrider1]

I'm not trying to spook people. Most GFCI tripping is caused by a miss placed Neutral. When this isn't the issue things get challenging. Fortunately, true leakage can be tracked down with a Leak detection meter. Its usually easy to find the effected circuit. Every now and then you get a head scratcher like the time a refrigerator was wired backwards from the factory. We identified the circuit easy enough. It took us a while to understand why the refrigerator was the cause. Once we figured it out we just had to reverse two wires and all was well.

 

[Helmsman]

My problem was a NovaKool power box short. I used Jim Healey’s website I attached above to learn about what causes tripping. The “best electrician on the river” put a ground to neutral connection in the panel “to fix it”, which caused my home port pedestal to trip.

I took that off and began the search. The source of power should be the only ground to neutral connection, which in the case of shore power is back on shore.

 

[tiltrider1]

The way I like to start testing is turn off all circuit breakers including the pedestal and the boat’s main breaker. Then slowly turn on one breaker at a time. First the pedestal breaker then the boats main breakers, one line at a time if multiple lines. Then the individual breakers until I trip the pedestal breaker.

This method will track down 90% of the problems.

If you don’t have access to a GFIC dock pedestal to test then install an ELIC breaker in the boat.

There are leak detection meters available that will tell you exactly how much leakage you have.

 

[Sanford Gentry]

Thank you everyone for the input. I talked to my all-around boat mechanic at my dock and we are going to try to chase it down when I get back to home port in Kuttawa KY.
We intend to head south first of November and trying to sort things out before leaving.

Tracked down to an issue with the invertor neutrals being mixed with the shore neutrals. Splitting them has mostly correct issue. I can still get it to pop when I have shore and inverter power on at same time then switch off invertor. POP.
At least I know how to manage.
This is probably as bad as the oil debates: do you tie the 12v ground to 120v ground? I get mixed answers online.