New AC System for Small Sailboat

[Mike Hancock]

I am considering adding shore power to my San Juan for no other reason than to run a small air conditioner and perhaps a coffee pot and a charger to keep the battery up. I will also be adding a limited DC system for running and cabin lights.The boat has no electrical system at all. All of the references that I have read discuss grounding issues and the possibility of leakage from the AC to the DC system. Is this a concern when the only contact between DC and AC is a charger? The references that I have read suggest grounding to the auxillary to deal with the leakage problem. Of course, I do not have a good point for such grounding in a small boat. I have done quite complex residential wiring with no problems, but I am a bit confused about proper grounding in this case.

 

[Trevor - SailboatOwners.c]

AC to DC Ground

Hi Mike -Boat wiring is different from residential wiring because grounding wiring and neutral are not connected together. To provide shock protection and proper bonding a single connection between AC ground and DC ground is required. Refer to Nigel Calder’s Boatowners Mechanical and Electrical Manual for a good guide. Typically the ship's ground is engine, due to its contact with the water via the shaft and propeller; you will need to provide an alternative with either a grounding plate or connecting to your bonding system and keel.Hope this helps!Trevor

 

[Benny]

I've done it.

I connected a a three prong male inlet by drilling a hole thru the side deck lined up forward of the interior stringers. Obtained this pluf at West marine and I believe it is intended to allow for the plug in of an extension to connect inboard battery chargers on fishing skiffs. It comes with a rubber flap to cover the plug when not in use. My next step was to install an electrical box and a GFIC two outlet connector. This were obtained at Home Depot and joined the two with a piece of three wire 10 gauge. This will give you two 15 AMP outlets. I connected to dock thru a modified extension cord with an adapter end. make sure you have correct polarity and the grounding will be taken care of at the ground prong.It has worked great but in essence it provides the same service as running an extension cord into the boat. san juan's are wet boats so I would seriously include the FGIC outlet.As far as 12V that is simpler. Just run your negative connections to a buzz board and your positive to the switch board.Hope this has been of help.Agachao, 1976 MKII