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Old 11-09-2017, 07:54 AM   #11
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City: Jupiter, Florida
Country: United States
Vessel Name: Black Eyed Susan
Vessel Model: Grand Banks 42' Classic
Join Date: Nov 2016
Posts: 1,401
Originally Posted by djmarchand View Post
Well, if you are in a marina and keep your shore power cord plugged in all of the time, you could try leaving it unplugged. Sometimes an adjacent boat has a minor DC fault to ground which travels back to your boat through the shore power ground and causes zinc problems on your boat.

But that is one of many causes one of which is a DC fault to ground of your own. The most common is a bilge pump being wired wrong. But calling in a marine electrician is a good idea. He can test with a half cell and see what is going on.

Thanks David. I keep it plugged in to shore due to refrigeration/freezer and of course battery charging. I could work around that if needed to see. I believe there are tests that can be done in the water to see if there are stray currents? I'm reading up on the subject and going to call someone out to check things. Just want to learn some basics so when he/she comes out I have some idea of what is going on and can maybe learn something.
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