Since we're on topic. It seems that there is a bit of differing opinions on bonding the under water metals.
What are the shaft and prop zincs protecting? If a shaft coupling isolator were installed and no bonding wire attached then the chance of stray galvanic currents is eliminated. Right? What is the risk of this situation? I don't have bonding plates, bronze through hulls, keel coolers or anything else except the keel that is metal and in contact with the water. I've considered possible corrosion effects on internal engine components and A/C components. Seems plausible but no one ever talks about it. Thoughts? I've also considered the anode in the water heater. Seems like the most likely to experience stray galvanic currents and the least likely to be replaced or checked on any regular periodicity despite its ease of access within the boat. I have 2 30 amp connections but use a y-adapter so only 1 shore power cord is required. I also built my own galvanic isolator for ~$30 with parts from mouser.com, I've just never had the urgent need to install it. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Oct 28, 2015 12:32 PM, "Frederick G Street via CnC-List" < cnc-list@cnc-list.com> wrote: > Also, the ProMariner FS Series is a “fail-safe” type isolator; no remote > panel needed. Under $300 for a 30-amp unit. > > http://promariner.com/products/galvanic-isolation/prosafefs-series/ > > Fred Street -- Minneapolis > S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI :^( > > On Oct 28, 2015, at 11:29 AM, Frederick G Street via CnC-List < > cnc-list@cnc-list.com> wrote: > > Steve — the “fail-safe” versions of galvanic isolators are also > ABYC-approved, and don’t require the remote panel. There’s a company up in > our neck of the woods that started out making electrical equipment for > dairy farms; they realized that their ground isolation products would also > work well on boats, so they expanded into the marine market. All their > units are the “fail-safe” types, and their prices are reasonable. > > http://www.dairyland.com/products/galvanic-isolator > http://www.deimarine.com > > > Fred Street -- Minneapolis > S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI :^( > > On Oct 28, 2015, at 11:24 AM, S Thomas via CnC-List <cnc-list@cnc-list.com> > wrote: > > Ed, > What you say is true from the perspective of having effective > galvanic isolation, but there are a couple of design issues that come to > mind. In order for galvanic isolation to work, all wiring grounds to the > boat must be interrupted by a galvanic isolator. This means that if there > are two shore power receptacles then both of them would have to have their > wiring grounds taken to the isolator and then out again to the distribution > panel(s). From an engineering perspective, a wiring ground only needs to > have enough capacity to reliably trip a circuit breaker without catching on > fire, but most electrical codes require that they have the same capacity as > the main conductors. In other words, if you care about regulations and some > people on this list have indicated that they do, then the galvanic isolator > would most likely have to have at least the current capacity of the sum of > both shore power receptacles. > According to the instructions that came with a galvanic isolator that > a friend of mine bought last year, a galvanic isolator requires an > (optional and at an additional cost for that particular product) indicator > light to be ABYC compliant. I was shocked at the price tag on the > commercial units. The prices are grossly out of line with what they > actually contain. > If you don't care about the light and just want something that works, > then a big enough bridge rectifier, 30 amps for example, with the DC > terminals connected together will work fine and cost a lot less than > something that says "marine" on it. The voltage rating of the rectifier > does not matter, just the current rating. It will provide about 1.2 volts > of isolation from the mains ground. > > Steve Thomas > Port Stanley, ON > > > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the > bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > >
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