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Galvanic isolators

3319 Views 11 Replies 8 Participants Last post by  eherlihy
Defender shows four thirty amp isolators made by Guest, Newmar, Pro Mariner and Yandina, costing from $90 to $300. Does anyone have experience with these models or can recommend any one of them. My only AC load is the battery charger, but I've been going through zincs at a rapid pace.
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I suggest that you read Nigel Calder's Boat Owner's Mechanical and Electrical Manual for a thorough explanation of what they are, and how they work. They will protect you from other boats when you are on shore power, but they will not protect you from dissimilar metals on you boat.

I have a Prosafe 30Amp unit on my boat, and it seems to work well.

I have also un-bonded all of my through hulls. I don't recommend that anyone else do this.
Very good to know, thanks!

My next question would be, where is the 'best' place to mount the isolator? I'm assuming that there would be room behind the boat's electrical power cb/control panel. I realize this will very much depend upon the layout of the boat, so in my case I'd be doing the install in a Catalina 30.

I did look at the DEI isolator, and the physical size and shape makes it look like finding a good spot for it should not be too difficult.
I put my GI in line with the main AC wire... Rather than rip out the original cable, I simply cut the jacket, in a convenient place to mount the GI, and spliced the GI into the ground line. Some day I will replace the cable, but for now...

Electrically, the GI is the last thing on the ground wire before the ground circuit leaves the boat (via a SmartPlug).
Removing the bonding wire takes the through hull out of the bonding circuit, thereby preventing galvanic corrosion from dissimilar metals that may be electrically connected. This includes your boat, and those near you. However, you are also increasing the damage that may be done to your boat if you are hit by lightning. If you have seawater in the bilge, and it touches these through hulls, then you have created a new circuit to promote galvanic corrosion, without the benefit of lightning protection..
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