alternative charging options?
- Thread starter Justin_NSA
- Start date
I hate to 
this subject but I am still trying to figure out my shore GFCI tripping problem. It's probably not the charger.
The boat has been on the trailer since we hauled out in September and the yard GFCI hasn't tripped once with the same basic AC/DC breakers left on. So it's either an 'intolerance' with the shore power although I've plugged into different dock pedestals, or I might have a 'leak' to the water. Humidity perhaps?
My question is, could there be a ground leak thru the prop causing this? I have a ground strap that rides on the prop that is grounded to the engine, but even with the strap removed isn't the propshaft still mechanically grounded thru the engine?
Does the water complete a bad path to ground maybe? Could I test this by running a wire from the prop to the AC ground?
I don't have any good schematics that would show how the AC system relates to the engine. Should the engine ground be connected to the AC ground? I have a AC leak meter but there's nothing to measure now.
this subject but I am still trying to figure out my shore GFCI tripping problem. It's probably not the charger.The boat has been on the trailer since we hauled out in September and the yard GFCI hasn't tripped once with the same basic AC/DC breakers left on. So it's either an 'intolerance' with the shore power although I've plugged into different dock pedestals, or I might have a 'leak' to the water. Humidity perhaps?
My question is, could there be a ground leak thru the prop causing this? I have a ground strap that rides on the prop that is grounded to the engine, but even with the strap removed isn't the propshaft still mechanically grounded thru the engine?
Does the water complete a bad path to ground maybe? Could I test this by running a wire from the prop to the AC ground?
I don't have any good schematics that would show how the AC system relates to the engine. Should the engine ground be connected to the AC ground? I have a AC leak meter but there's nothing to measure now.
Generally, yes. The AC ground (green wire) should be connected to the engine at the same point as the DC negative is connected. I don't recall if you have an Galvanic Isolator or not, if not, then adding one would be a good idea.
The issue may be a cumulative ground fault, i.e., there is not one device that is tripping the GFCI, however, several might be leaking a little bit. If your boat is leaking 3 ma and the pedestal is leaking 3 ma the GFCI should trip because the total is above the 5ma threshold.
In an article I just read, the author claims that electric hot water heaters are a prime source for ground faults, followed by air conditioners and refrigerators. Not sure if any that applies to you.
But why doesn't the GFCI in the boatyard trip? I would still have the same cumulative leakage. Under the same conditions i.e. only the DC and AC main breakers are on, it only trips at the dock, and on different pedestals.
It is possible that the dockside GFCI is wearing out. Those breakers can go bad, just like breakers in a house. If they trip too much, they can start tripping too easily.
- Will (Dragonfly)
- Will (Dragonfly)
Justin,
I just went back and reread the thread. What I didn't read was a systematic look at the AC loads. When the boat is back in the water try this:
Turn all AC loads off including the main breaker.
Turn the main breaker on with all loads off. Does it trip?
Turn 1 breaker on, does it trip? Turn that breaker off.
Turn the next breaker on. Does it trip? Turn that breaker off.
Repeat as necessary.
If a particular breaker trips, that is where the problem lies. If they all work, then it is a combination of breakers that is causing the problem. Systematically repeat the above process for each combination. (hopefully you only have a few circuits.)
Since the problem seems to be intermittent, what AC loads do you have that are intermittent?
The first one to look at would be the hot water tank, if you have one. The heating element creates an intermittent load and is an electrode in a can of water, good place for a ground fault and it is probably empty now that the boat is on the hard.
Next choice would be refrigeration or AC. Refrigeration is probably DC, however, when it comes on while the boat is on the hard, battery voltage will drop and the charger should come on. If it trips, then the charger would be the source of the ground fault.
Good luck.
I just went back and reread the thread. What I didn't read was a systematic look at the AC loads. When the boat is back in the water try this:
Turn all AC loads off including the main breaker.
Turn the main breaker on with all loads off. Does it trip?
Turn 1 breaker on, does it trip? Turn that breaker off.
Turn the next breaker on. Does it trip? Turn that breaker off.
Repeat as necessary.
If a particular breaker trips, that is where the problem lies. If they all work, then it is a combination of breakers that is causing the problem. Systematically repeat the above process for each combination. (hopefully you only have a few circuits.)
Since the problem seems to be intermittent, what AC loads do you have that are intermittent?
The first one to look at would be the hot water tank, if you have one. The heating element creates an intermittent load and is an electrode in a can of water, good place for a ground fault and it is probably empty now that the boat is on the hard.
Next choice would be refrigeration or AC. Refrigeration is probably DC, however, when it comes on while the boat is on the hard, battery voltage will drop and the charger should come on. If it trips, then the charger would be the source of the ground fault.
Good luck.
Sorry Dave, most of this was covered in a different thread. This problem has plagued me since we brought the boat to our dock. The previous 'home' didn't have a GFCI at the pedestal. It will trip with just the main AC breaker on. No other loads except the charger. Everything else off which is why I thought it might be the charger. I have taken the charger completely out of the picture and it still pops. It's random so there's no way to see for sure what causes it.
Definitely. Even fresh water is surprisingly conductive per volume.
Why not run a wire from the prop to the green earth wire coming form the AC source.. Try the AC clamp meter you bought on the incoming AC power. You will need a special modified AC extension segment so you can measure individual wires or sets of wires with the clamp but even if you dont find anything now, you will still need that cord with access to individual wires (black, white, green) when the boat goes back in the water. If your clamp current meter has resolution down in the ma range, I am curious what you measure..
By cumulative leakage I suspect he means multiple boats, in your marina, are on the load side of the GFCI you plug into. This is not all that uncommon and allows a marina to comply with NEC/NFPA laws, for outdoor receptacles, without the expense of a GFCI for each pedestal. Is it the right way to do this in a marina?? No, due to cumulative leakage, but it's a legal compromise that saves a marina money. Heck it is also not correct to use a 120V outlet for shore power, but folks insist on doing it and many low budget grandfathered marinas still offer 120V receptacles as an only choice. Ridiculous? You bet....
Let's assume you have three other pedestal mounted recepticals fed of the load side of your GFCI:
Boat #1 leaks 1.1mA
Boat #2 leaks 3.8mA
Boat #3 leaks 2.1mA
Cumulative Leakage = 7mA
Trip Point for GFCI = 5mA
None of those boats has enough leakage to trip a 5mA GFCI on their own, but when all three are plugged in, or just boats #2 & #3 the GFCI can trip.
You need to measure what's flowing on your green wire/safety ground, then hunt it down and fix it....
That all makes sense, but I am the only boat on the load side of the GFCI. Each pedestal has 2 separate GFCIs on 4 separate circuit breakers. Every boat plugs into a separate GFCI outlet. No matter which GFCI I plug into, I still get random tripping. So that kind of cumulative leakage doesn't seem to be the problem.