Help! Why am I reading current on my water strainer.

[DSDman]

Oh learned and wise cruisers please shed some light on my situation. While working on installing the new refrigeration system I was touching the water strainer, which was wet, and contacted a random screw in the boat and got a bit of a shock/tingle. Upon further investigation it only occurs when the boat is attached to shore power and the circuit breakers closed. If I run the generator and power all the components with the genny the is no stray current. Also while attached to the shore power and I run the AC units it pops the main breaker. While running the genny I can run all the units and no problem. So is it that I have lost the ground on the shore power? If so whats the easiest way to fix, just run a new ground from the shore plug to engine block? The idea of trying to find a short among the 100 bundles of wire running through the boat is almost an impossibilty. AS an aside there is a bonding system installed but it looks like it gave up the ghost about 15 years ago. All green and corroded and half of the wires are no longer attached to the thru hulls. Last fact, both shore power and genny make 220

[belizesailor]

Stray current can be a challenge to track down. Just be sure and disconnect all shore power/gen/inverter power before doing any work until you do isolate it.

What kind of shape is the marina power in? Could be they have a short to ground somewhere or could come from a nearby boat.

Also carefully inspect your shore power feeds between shore and you panel for chaffed insulation etc...

[DSDman]

Shore power looks in good shape and well maintained. never had a problem before and have been here since april.

[belizesailor]

Originally Posted by DSDman

Shore power looks in good shape and well maintained. never had a problem before and have been here since april.

Start opening breakers and when/if it goes away. If all breakers are open and you still have it then it is likely between the panel and the shore power connection.

[DSDman]

With all breakers open there is no current. When I close the two main breakers the current returns even though all the other AC components are not powered. which is odd that I don't get the same stray current when using the generator. It's a head scratcher that I hope someone else has experienced.

[sailorchic34]

HUM.. so you have a 220V boat. I assume the AC is 220 also. Sort of sounds like you have one leg of the 220 swapped with ground somewhere. Most likely at a connection on the ground system.... not neutral. That it happens with the AC on give you a starting point. Do you have any 120V loads??

On shore power you have a hot ground which is unpleasant and not good. The generator may not be connected to shore ground, just both hot legs and neutral, so all works right.

[sailorchic34]

Also is this a 220V or a 50A Twin 30amp plugs. Not quite the same thing. With two breakers sounds like you might have a 120V system with two main's, one for each 30amp shore plug.

If you have a rotary selector for 1-both- gen on the AC power side, the fault is upstream of that selector switch.

[boatpoker]

Sounds like you have a neutral/ground bond somewhere.... ok at home maybe but not on a boat.
Turn off your main breakers
leave shore cords connected on boat
pull shore ends of cords
check for continuity (ohms on your multimeter) between the ground and neutral prong on the cord. if you have continuity you have a potentially lethal problem and should hire a qualified marine electrician immediately, preferably an ABYC certified electrician.

[DeepFrz]

And don't go for a swim around your boat until the problem is corrected.

[Celestialsailor]

...the way I understand it...it could even be your neighbor with an older 2 prong (no ground) plugged in backwards. Saw this in Santa Cruz, Ca. once with an older junky runabout on the docks. The Harbor isolated him and the problem went away but not until it had damaged under the water fittings.

[DSDman]

Yes 220 coming into the boat. some components are 110, like battery chargers, water heaters, the AC units are 220. There are just two main breakers one 40 amp one 30 amp, they both have to be on to get 220. I can just turn on the 30 amp one and get 110 stuff to work. When I do that I register the current as well.

[Maine Sail]

Originally Posted by DSDman

Yes 220 coming into the boat. some components are 110, like battery chargers, water heaters, the AC units are 220. There are just two main breakers one 40 amp one 30 amp, they both have to be on to get 220. I can just turn on the 30 amp one and get 110 stuff to work. When I do that I register the current as well.

Hire a professional, please. This is nothing to joke around with and will be a relatively simple troubleshoot for someone who knows what they are doing.

To get a better handle on what you are dealing with. I would highly recommend Charlie Wings book, Boatowners Illustrated Electrical Handbook (Second edition).

Nigel Calders book is also excellent but may go a little over your head. Charlie's book is easier to understand and my customers tell me they "absorbed" more from Charlie's book than from Nigel's.

Both are excellent but Nigel's book is like a level 300 course and Charlie's book is like a level 100 course...

The bonding/Earth circuit on your boat is supposed to be 0 volts....

[twistedtree]

Originally Posted by DSDman

AS an aside there is a bonding system installed but it looks like it gave up the ghost about 15 years ago. All green and corroded and half of the wires are no longer attached to the thru hulls.

i'm surprised nobody has commented on this. I'd fix this first so you have a solid base to work from. In doing so, you might just fix/find your other problem.

Also, if you can get a multimeter between the two points where you got a tingle and see what the voltage is, it might help lead you to the source.

And do be careful. Fried cruisers are no fun :-)

[DSDman]

I'm am looking for a pro. Hard to find someone willing to come out and take a look. Most want to come in do the entire job and roll out with pockets full of cash. I need to figure out what needs to be done and then take it in stages. Anyone know a good electrician near Georgetown MD? When I get back out to the boat I will take a pic of the circuit board just so you guys can see what I'm dealing with. I just want to be able to put shore power back on so I can charge the batteries...safely.

[Bash]

Originally Posted by twistedtree

i'm surprised nobody has commented on this. I'd fix this first so you have a solid base to work from. In doing so, you might just fix/find your other problem.
b:-)

no! The electrolysis in the bonding system was a symptom, not a cause. You have a serious ground/neutral problem.

hire a professional. Once the problem is found and corrected, then you can replace the bonding yourself.