I understand the need for a failsafe mode. However if there is no indicator light how would you ever know it failed unless you put a meter on it and tested it periodically?
On Wednesday, October 28, 2015, Josh Muckley via CnC-List < cnc-list@cnc-list.com> wrote: > 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 > <javascript:_e(%7B%7D,'cvml','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 >> <javascript:_e(%7B%7D,'cvml','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 >> <javascript:_e(%7B%7D,'cvml','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 >> <javascript:_e(%7B%7D,'cvml','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 >> >> >> -- Joel 301 541 8551
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