Re: [Amel Yacht Owners] Re: Prop Shaft Electrolysis


I have one Mike, and it has been reading -950mv all along...with or without shore power, generator, AC and/or DC appliances.

But my zincs are disappearing too fast and I have a connection somewhere from AC ground to the bonding system.

Obviously the reference electrode isn't a panacea.


On Dec 1, 2015, at 8:34 AM, Mike Johnson mike.k.johnson@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Kent,

Have you considered getting a Silver-Silver Chloride probe and working your way around all the components.  This may have been discussed previously.

Very best wishes

Mike & Peta
SM2K #461

On 1 Dec 2015, at 13:06, Kent Robertson karkauai@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Bill,
Thanks for your thoughts.

I'll look at the plug again, but I'm sure it's wired correctly.  I'll also check the pedestal...I think I should find 120VAC between the red and white posts, and between the black and white posts, and 240VAC between the red and black posts.  Should I find voltage between the red or black and ground?

The voltage is still there with the water heater disconnected, so I doubt it has anything to do with that.  It could be that it's significant that the breakers for the water heater and the forward A/C on the 220 panel are adjacent to each other???

6 months ago I added a galvanic isolator between the switch that chooses generator 220 over shore power 220.  That only affects the ground wire, so I don't  think that is going to be the problem.

I have a 110VAC->220VAC transformer that isn't in play when connec ted to 200V 50A shore power.

SM 243

On Dec 1, 2015, at 3:28 AM, 'Bill & Judy Rouse' yahoogroups@... [amelyachtowners] <amelyachtowners@...> wrote:



I think that you have two issues. Heating element and wrong wiring.I agree with Eric that there is leakage between the green yellow A/C wire and one of the hot wires. And it also sounds like exactly what has happened to several others when the power cord head is wired wrong in the US. Carefully look at this: 
and this: 

A few things that have not been discussed so far in this thread:
< ol>
  • When the heating element needs replacing, it will not continually throw a ground fault. In the beginning of a failure, tiny holes develop in the heating element that allow water inside only when it becomes very hot and the water around it is very hot. You probably need a heating element replacement if it has been 3 or more years since you replaced it.
  • Do you have any devices ON (connected) while all of the breakers are off such as an isolation transformer? If so, look at it for incorrect wiring.
  • I am thinking that the wiring from shore power plug through to the 220VAC panel is faulty, or maybe the pedestal is wired wrong.
  • Bill
    BeBe 387

    On Tue, Dec 1, 2015 at 5:32 AM, Kent Robertson karkauai@... [amelyachtowners] <amelyachtowners@yahoogroup> wrote:

    I am on a U.S. 220v 50 amp pedestal.  The plug is wired as you suggested, leaving the white lug unused.
    I know that U.S. 220AC is comprised of two 110AC legs.  I'm wondering, since the voltage between the brown wire and the bonding system is almost exactly half of the 244 v AC, is it possible that one leg of the shore power is touching the bonding system somewhere?  That wouldn't explain the 72vAC I see when running the generator disconnected from shore power.

    I also looked for AC current using the reference electrode in the water and the bonding system and got 0 VAC connected to shore power and with all A/C and the water heater breakers turned on.  I don't know if that is even a legitimate test.


    On Nov 30, 2015, at 8:17 PM, kimberlite@... [amelyachtowners] <amelyachtowners@...> wrote:


    Hi Kent,

    If you are plugged into a 50 amp US outlet at the dock i assume you did not hook up the white lug in the plug to anything.

    I believe the brown wire should go to the red lug and the blue to the black lug. the yellow green to the green lug.

    If I am not mistaken you will still have about 10 volts between the ground and the power lugs in the plug--as the ground and the white neutral are essentially the same.

    I think somewhere on your boat there is leakage between the green yellow A/C wire and one of the hot wires.

    I am doing this from memory as I am not near the boat.


    sm 376 kimberlite.

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