Simpler yet, how about an AC source selector switch - 2P3T, two poles, three throw (two positions plus center OFF) for 120 VAC sources, or 3P3T, three poles, three throw (two positions plus center OFF) for a 120/240 VAC sources. You switch both the hot and neutral wires (black and white in a 120 VAC system, black, red and white in a 120/240 VAC system). The boat's AC system is connected to the movable contact, the shore power inlet to position 1 of the fixed contacts, nothing is connected to position 2 of the fixed contacts, and the inverter output (or on-board generator output) is connected to position 3 of the fixed contacts.
With this setup, the inverter output is never connected to the shore power cord. Blue Seas Systems sells switches and switch panels for just this purpose. The switch panels come with reverse polarity indicators, too. They offer them in 20-amp and 65-amp current ratings, and in 2, 3, and 4 poles. See <http://bluesea.com/category/4/productline/221> for the Blue Seas selection of AC source selector switches and switch panels. Jim Maynard S/V Mistress of Portland, Oregon Saint Helens, Oregon, USA On 2011-03-05 05:33 PM, [email protected] wrote: > I forgot to answer your question. > > How about a relay operated by the output of the inverter that would unpower > the shore power cord. But that would use coil power whenever your inverter > was on. > > How about a relay that only connects the shore power cable to the boat (and > disconnects the inverter) when shore power is available. > > Maybe connect the relay (a DPDT type) coil to the shore power cable and the > NO contacts, the boat to the moving contacts and the inverter to the NC > contacts. > > > Norm > S/V Bandersnatch > > . This, however, means that the male plug >> that goes to shore is _live_ when my AC system is being driven by the >> on-board inverter. >> >> Now, yes, I *should* be aware enough to cut off the inverter before >> hooking into external power or even handling the plug (which is normally >> kept in a recessed tube designed for the purpose) - and I usually am >> - but for things like this, I strongly prefer some kind of an automatic >> system that prevents getting shocked (or frying the inverter.) _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://liveaboardonline.com/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
