I disagree with this. I have had a galvanic isolator since about 1995 or so. Mercury Marine sold them to keep their outdrives from dissolving back then and I grabbed one. I can go on for a while about how they work, but the short version is every boat at the marina is wired together by the ground wires and is essentially one giant boat. If your neighbors don’t have zincs, no problem, your zinc will cover for them! It may not last long doing triple duty though ☹ The galvanic isolator prevents this from happening. As far as not grounding the AC system to ships ground, this would be a large and dangerous violation of ABYC regs and they exist for a reason. In a perfect world boats would have isolated 2 wire AC systems with no grounding at all. This is not the case presently and as long as various AC devices not built specifically for boats exist we have to deal with potential ground issues. Do not forget that the shoreside AC power *is not isolated* and you are floating in a more or less direct connection to the ground rod at the transformer and/or panel on shore. If some defective appliance puts AC voltage on any part accessible by a human you now have a hot wire in one hand and any part of the boats DC ground system is the other half of the circuit. This can be a deadly hazard on a boat depending on how good the green wire system on the boat and marina is and even if it is good you still can get a considerable charge through you. The interconnected grounds prevent this from happening. The ONLY way I could see trying to make an isolated AC system besides for an isolation transformer, which is actually a great idea but big and heavy, is if the BOAT had an ELCI installed. You cannot count on every marina having one at their end. Joe Coquina C&C 35 MK I
From: CnC-List [mailto:[email protected]] On Behalf Of Dreuge via CnC-List Sent: Sunday, June 02, 2019 4:07 PM To: [email protected] Cc: Dreuge <[email protected]> Subject: [EXTERNAL] Re: Stus-List Galvanic Isolators I would not spend much money on a galvanic isolator (GI). The main cause of the galvanic corrosion is a result of connecting the AC and DC grounds. Check if you have these grounds connected. Most older and smaller vessels don’t have the grounds connected and don’t have galvanic corrosion problem. Also, the industry is moving away from this requirement. One is better off investing in a whole vessel GFCI breaker(also called an ELCI Main Circuit Breaker). These cost much less than a typical fail-safe GI and provide galvanic isolation from stray AC currents by disconnecting the power, and more importantly they provide much better ground fault protection than connecting AC & DC grounds. If one still prefers bonding the AC & DC grounds then I would recommend the Yandina GI or better, a DYI GI, and connect the GI between the AC to DC connection to provide a fail-safe connection. I have a write up on my blog about this and also how to make a DYI GI, but in short, don’t waste money on an expensive GI, invest your money in an ELCI breaker, individual GFCI circuit protectors, and a decent marine charger (not a cheap HF/Walmart/Amazon brand ) http://svjohannarose.blogspot.com/search/label/GalvanicIsolator<https://protect2.fireeye.com/url?k=8c302211-d0a614f2-8c300b66-0cc47adc5fec-d02e08d2e81cb3ec&q=1&u=http%3A%2F%2Fsvjohannarose.blogspot.com%2Fsearch%2Flabel%2FGalvanicIsolator> - Paul E. 1981 C&C Landfall 38 S/V Johanna Rose Fort Walton Beach, FL http://svjohannarose.blogspot.com/<https://protect2.fireeye.com/url?k=39525ee8-65c4680b-3952779f-0cc47adc5fec-20fd4afe42647e7d&q=1&u=http%3A%2F%2Fsvjohannarose.blogspot.com%2F>
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