Re: [Amel Yacht Owners] Re: Explanation of Bonding System


karkauai
 

The biggest difference between the Amel bonding system and a typically wired ABYC (American Boat and Yacht Council) boat, is that the DC system does not use the bonding system as the DC negative.  There should be no connections between the DC system and the bonding system on your Amel.  If there is a DC connection, and a fault occurs in the DC wiring or equipment that is not enough to trip the breaker, stray current can go out through the underwater metallic parts of the boat and cause severe electrolytic corrosion to those metals.

I have not been able to identify a connection between the DC negative and the bonding system on Kristy, despite 100+ hrs of looking and two days of a marine electrician specializing in this.  I have decided to keep looking when/if I see any evidence of a current leak.  I am watching my zincs closely and monitor hull potential regularly with a silver/silver chloride reference electrode and multimeter.

OK, all you engineers and electrical and Amel gurus...fire away!  I'm still eager to learn what I still don't understand.

Kent
SM243
Kristy




On Aug 16, 2016, at 11:45 AM, sailor63109@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Ian,


When you're back in Brunswick let me know, we're on dock 14 in BLM.

First, I'm not an expert in bonding systems.  But here is what I understand.

If you connect different metals together with a conductor, one will corrode (the anode and less noble metal), and the other will not (cathode and more noble metal).  

Seawater will conduct electricity.  

When seawater is in contact with different metals (say a stainless steel pump impeller and a bronze seacock) one of these is less noble and will corrode (the anode).  Zinc is more anodic than the other metals on your boat.  By connecting all the metals that are in contact with seawater, and then connecting that wire to the zinc anode on the rudder, the zinc will corrode and protect the other metals in contact with seawater.

This is a form of "cathodic protection", check wikipedia for a more detailed explanation of cathodic protection.  This is an electro-chemical reaction.

Duane
Wanderer, SM #477

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