I keep tripping my marina's power pedestal when I turn on my main shore pwr breaker

[carl_dzinh]

Originally Posted by Lepke

Check the voltage at the power pedestal and at the socket you are using. Low voltage causes appliances to draw more amps, possibly over the rating. Marinas often have low voltage problems in the winter from all the boats running heaters. Also a breaker that has tripped many times will start tripping at lower amps and you need to replace it. The sockets can also go bad from too many hours at max rating. Like running a heater.

Noted! This is very helpful to know

[carl_dzinh]

Originally Posted by Lou-In-NJ

SailingHarmonie had the best answer so far as far as I'm concerned. Understanding what trips GFI protected breakers and outlets will help you troubleshoot the issue. GFIs need to detect the same amount of current on the return (neutral) leg as they are supplying on the hot leg; any imbalance means current is finding another path to neutral (which is tied to ground), and that path could be through somebody's body, which would not be good for their health. Why is it when you plug in your vacuum? I don't know, unless it's a 3 prong plug, which likely means some component in the vacuum is losing some of its current to the ground wire instead of completing the circuit through the neutral wire.

As far as dead outlets, it would be very strange someone would disconnect outlets, and if they did because they couldn't resolve a problem, they better have done it completely (all 3 wires) at the buss-bar, not just clip a wire or two somewhere. I would trouble shoot this with a no-contact voltage detector you can buy at any home center for just a couple of dollars.

You should also own a volt/ohm meter, (very cheap at Harbor Freight or online) and test the hot side of the outlet to neutral and ground; you should have between 110-125 from hot to both neutral and ground, and if you don't, wire(s) is/are disconnected/broken. Also, normally it doesn't make much difference, but make sure the hot side of the outlet is wire hot, and neutral and hot aren't reversed, which is a popular unintended hack made by hacks, that could trip a GFI.
SIDE NOTE: I've seen a few images online showing the black (hot) wire going to the taller receptacle slot; THIS IS WRONG, the shorter slot should be hot and the taller slot should be neutral.

EXTREMELY helpful post - thanks so much. I will buy that device you posted and try those troubleshooting procedures. I took a basic DC electrical class for boats but unfortunately missed out on the AC stuff the following semester. I’ve put off learning more about AC but now is my opportunity to dust off those Caulder books…

[MerMike]

Spend $20 and get a Hubbel hospital grade outlet. Way better built than the cheap HD crap. There will be a green dot on the face.

[carl_dzinh]

Ok quick update: I bought a new 50’ 30a cord from west marine tonight, and at first it seemed to solve my problem.

After I plugged in the new cord I turned on the main breaker on my panel, and it didn’t trip the pedestal! So I turned on the “outlet” breaker, and my “battery charger” breaker which is a ProNautic 1260 (I think).

I felt very pleased with myself when suddenly the pedestal tripped again after maybe 5 mins. I reset the pedestal, then I turned on only the main breaker and the “battery charger” breakers, and those stayed on for about 20 mins. As a test I decided to flip on the “outlet” breaker and then after about 5 mins it tripped the pedestal, so something is definitely wrong with that outlet circuit.

Here’s a shot of the pedestal and the adapter I’m using:



And here is a shot of the main breaker behaving itself for now:



So as of now just the main breaker has been on for an hour without tripping anything like it was before.. Tomorrow I’ll run to Home Depot to get a new outlet just to see what happens but I’ll definitely have to investigate deeper into the system.

[carl_dzinh]

Originally Posted by MerMike

Spend $20 and get a Hubbel hospital grade outlet. Way better built than the cheap HD crap. There will be a green dot on the face.

Ok I’ll give that a shot! It appears the HD one only lasted about 4 months in these conditions.

[wholybee]

Does the "line current" meter on your panel work? In any case, I seriously doubt you are tripping the 30 amp breaker at the pedestal when your circuit is only 15A.

Most likely it is an imbalance issue as described by Lou-in-NJ. The best fix for that is to install an isolation transformer on your boat. Not cheap, but will fix it. Short of that, you probably need a qualified marine electrician to find the leak, and in the end they might still determine the transformer is what you need.

[carl_dzinh]

Originally Posted by wholybee

Does the "line current" meter on your panel work? In any case, I seriously doubt you are tripping the 30 amp breaker at the pedestal when your circuit is only 15A.

Most likely it is an imbalance issue as described by Lou-in-NJ. The best fix for that is to install an isolation transformer on your boat. Not cheap, but will fix it. Short of that, you probably need a qualified marine electrician to find the leak, and in the end they might still determine the transformer is what you need.

No unfortunately the line current meter doesn’t seem to work, but I think all your points are valid considering the pedestal breaker is actually 50a and it now trips when no devices are plugged into the outlet, when I activate the “outlet” circuit.

I’ll look into the isolation transformer because I’ve seen that suggestion in similar threads elsewhere. Hoping I can get it fixed before temps drop to the 20s next week. Luckily the pedestal has a 20a outlet so I might run an heavy gauge extension cable and run the heat from there for the time being.

[Lou-In-NJ]

One other thought is that your neutral wire is connected to your hull's zinc bonding system, if that were the case it would explain the inconsistency of the timing of the breaker tripping. It also means that somebody else's boat wiring could be wrong, and their return current is finding a path to ground through your boat. I have heard of this happening especially in salt or brackish water.
I don't know enough about marine AC to tell you what, if any, part of the AC system should be connected to the zinc bonding, so you'll have to get that answer from someone else. This is an excellent and comprehensive video series about electricity in the marine environment:

https://www.youtube.com/watch?v=3b4R...LptN4&index=14

I would suggest watching the whole series eventually; from what I remember, he even goes into detail about the components used in marine wiring, and the differences from automotive and household components.

[Lou-In-NJ]

This was a very useful video related to this topic...if you are not well versed in the subject, you should pause the video and study the diagrams, as well as watch it several times. Now the only question I have is, why on a fiberglass boat, would you need any aspect of the AC circuits, to be "grounded" to the water? After all, you can only get shocked if your body provides a path to ground, so just like birds sitting on a powerline, you can touch an energized appliance and not get shocked unless you touch metal that goes to "ground"...and even most metal sinks on a boat are isolated because they are connected using plastic pipes and hoses.

https://www.youtube.com/watch?v=iUZwgI7e-vg

P.S. He does mention that American GFCI breakers are subject to nuisance tripping.

[stevensuf]

I doubt the vacuum is the problem.

[stevensuf]

Remove the vacuum from the equation and all other items, one by one and you will find your problem.

[Bowdrie]

Originally Posted by Lou-In-NJ

[B] Now the only question I have is, why on a fiberglass boat, would you need any aspect of the AC circuits, to be "grounded" to the water?

The ABYC requires that the Green/Ground wires on AC circuits to be gathered together at a bus bar and that there be a connection/jumper from that bus to the boats DC ground bus.
This presumes that the DC ground is common to the engine and thence to the water via the prop shaft.
This DOES work to help prevent shock hazard, (I know).
Once whilst in a contorted position to change a pipe fitting on a seacock my elbow touched the water heater, I felt a strong tingle.
Upon stopping work and getting-out the voltmeter I found that there was 42VAC between the casing of the water heater and the seacock.
Why 42VAC? I don't know, but should that have been full voltage from the shore power I would have received a real jolt.
That's why ABYC requires that connection, they want to see a low resistance path from AC ground to the water.
Bonding? Now that's another subject.

[smac999]

Originally Posted by carl_dzinh

No unfortunately the line current meter doesn’t seem to work, but I think all your points are valid considering the pedestal breaker is actually 50a and it now trips when no devices are plugged into the outlet, when I activate the “outlet” circuit.

I’ll look into the isolation transformer because I’ve seen that suggestion in similar threads elsewhere. Hoping I can get it fixed before temps drop to the 20s next week. Luckily the pedestal has a 20a outlet so I might run an heavy gauge extension cable and run the heat from there for the time being.

the iso transformer will mask the boats problem to the dock breaker. but it doesn't fix the problem... The boat will still have a wiring problem. find and fix the problem. you said multiple outlets are not working. so that fact the outlet breaker trips the dock doesn't surprize me... open all the outlet boxes and check everything and get all the outlets working.

[Lou-In-NJ]

Originally Posted by Bowdrie

The ABYC requires that the Green/Ground wires on AC circuits to be gathered together at a bus bar and that there be a connection/jumper from that bus to the boats DC ground bus.
This presumes that the DC ground is common to the engine and thence to the water via the prop shaft.
This DOES work to help prevent shock hazard, (I know).
Once whilst in a contorted position to change a pipe fitting on a seacock my elbow touched the water heater, I felt a strong tingle.
Upon stopping work and getting-out the voltmeter I found that there was 42VAC between the casing of the water heater and the seacock.
Why 42VAC? I don't know, but should that have been full voltage from the shore power I would have received a real jolt.
That's why ABYC requires that connection, they want to see a low resistance path from AC ground to the water.
Bonding? Now that's another subject.

Thanks Bowdrie, you illustrate my point exactly; since it doesn't sound like you discovered an issue with your water heater, it must be that your elbow provided a path for some other boat's faulty wiring or device that was putting its fault current into the water! And you got shocked because your water heater jacket provided the path to ground. What this tells me is that your seacock was not properly tied to the grounding system through its galvanic wire, since, had it been, your elbow wouldn't have been the best path to ground whether your heater was the offending device, or current was coming from another nearby boat.

If you watch the video at the part where they talk about people getting electrocuted if swimming around boats with faults, this is why, and there was clearly a disagreement about the methodology of grounding to the water between regulating authorities.

Why did you find 42 volts instead of the local available voltage supplied by the mains? It could be several reasons:
Water's resistance is mineral and soluble solids content dependent, and while 120VAC or 220 VAC may be present at the fault of a nearby boat, after that voltage travels through the water for a distance, its voltage will not be as high.
And just because 42 volts is present at your seacock, doesn't mean there aren't also other boats "properly grounded", not also providing a path to ground for the wayward current.
Also, if your seacock galvanic tie wire was corroded enough at a connection point, that 42 volts out of the whatever got to your seacock, found your water heater a better path than your galvanic wire.

[Bowdrie]

Originally Posted by Lou-In-NJ

Thanks Bowdrie, you illustrate my point exactly; since it doesn't sound like you discovered an issue with your water heater, it must be that your elbow provided a path for some other boat's faulty wiring or device

I should have been more clear? Yeah.
Perhaps I didn't use enough words and failed to relate "The rest of the story".
It had nothing to do with any other boats, it turned out to be a "leaking" heater element.
There were no bad/corroded wires/connections.
I didn't indicate it was my boat, (I work/worked on boats).