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

[rtbates]

Could be your neighbors are putting a current in the water that you are picking up through your ground.

Also make sure ALL DOCK recpt are wired correctly... No swap of HOT /NEUTRAL..

[bruce smith]

The most learned and wisest cruisers do not have 'frigeration on a boat!

[CharlieJ]

This is truly nothing to screw around with...as Maine Sail said...and you concurred...hire a pro and do it ASAP.

One piece of info strikes me as odd:

There are just two main breakers one 40 amp one 30 amp, they both have to be on to get 220.

Do you have two 30A/120VAC shore power inlets or one 50A/250VAC shore power inlet?

Charlie

[DSDman]

Haha, well when I got the boat and it had four...yes four, AC units I figured fixing the refer was only keeping the true sprit of the boat intact.
I am not picking up stay current from other boats as it only happens when I am connected to shore power with the main breakers closed.

[DSDman]

just one 50 amp/220

[CharlieJ]

Having two CB to protect a 50/250 circuit is electrically incorrect, and not in accordance with the ABYC Standards. Doesn't really matter if "that's the way it has always been", it is not correct.

You should have a double pole 50A circuit breaker that breaks both L1 and L2 on overload. You could go a bit overboard and have a three pole circuit breaker that breaks L1, L2 and N on overload but that is not necessary.

I have not seen a panelboard wired this way and it leads me to believe that at one time this vessel was served by 2 x 30A/120VAC and was "converted" to 50A/250VAC without understanding all of the ramifications of said "conversion".

BTW, the quickest way to check for an improper neutral to safety ground bond on board is to unplug shore power and use your DMM to check for continuity at any 120VAC receptacle between N (the wide receptacle slot) and G. Anything < 25,000Ω is a failure and must be corrected.

Charlie

[DSDman]

Thanks Charlie,
I think you may be right. The boat was originally a 110 boat and it does seem to make sense that may have happened in the past. Time to call in the pro's I guess.

[Celestialsailor]

Originally Posted by DSDman

I am not picking up stay current from other boats as it only happens when I am connected to shore power with the main breakers closed.

Not necessarily...When you close your breaker not only do you power up but you tie into the rest of the electrical grid on the dock.

[DSDman]

After I said that I went back and reread some of the post and that makes sense, basically I would be completing the circuit back to the dock from some other boat. I get it now.

[twistedtree]

Another danger that your breaker arrangement poses is the possibility of both 120v legs being energized even though you only have one breaker closed. If there is a 240v appliance turned on, say a hot water heater, it will bridge power between the two 120v legs. It could create quite the surprise.

[CharlieJ]

Not necessarily...When you close your breaker not only do you power up but you tie into the rest of the electrical grid on the dock.

There is a fine, but important point that has to be made about this statement. It is true as far as it goes. However, the safety ground wire, if the shore and the ship's systems are wired correctly, are always connected whenever the vessel is plugged in, regardless of the position of the shore power breakers (on board and ashore). Thus, the ship's DC system and the bonding system (such as it is on the subject boat) is always electrically tied to the safety ground system ashore, again, regardless of the position of the shore power breakers.

Charlie

[Celestialsailor]

Personally, what I would do is (with the Harbor Masters permission) is unplug neighbor's dock cords around you to see if it effects the meter on your boat. Have someone on the meter in your boat reporting back to you. Don't just turn the breaker off, but unplug the cord completely.

[cal40john]

Originally Posted by CharlieJ

There is a fine, but important point that has to be made about this statement. It is true as far as it goes. However, the safety ground wire, if the shore and the ship's systems are wired correctly, are always connected whenever the vessel is plugged in, regardless of the position of the shore power breakers (on board and ashore). Thus, the ship's DC system and the bonding system (such as it is on the subject boat) is always electrically tied to the safety ground system ashore, again, regardless of the position of the shore power breakers.

Charlie

Not entirely true with a galvanic isolator as it isn't connected until a fault occurs, and never true if an isolation transformer is installed.

John

[DSDman]

So would an easy test for stray current be to put a muti meter in the ground on the shore power plug and stick the other end in the water?

[CharlieJ]

Not entirely true with a galvanic isolator as it isn't connected until a fault occurs, and never true if an isolation transformer is installed.

Of course!!

Charlie