South Coast Sailboats

120v Shore Power Setup with three outlets

I had created a 120V shore power electrical system for use at the dock and when the boat is being serviced. Basically, there is receiving outlet mounted in the base of the transom. This is where we connect the boat to the dock, we then run a twenty-foot heavy extension cord to where we would normally plug into the dock. Before plugging into the dock, we install a four-foot extension that has three outlets and a GFI (ground fault interrupter) circuit built in. This is what we plug into the dock power. For convenience, this feeds two duplex outlets. One mounted in the cotpit, and one mounted inside near the keel winch. Additionally, there is one more feed that first goes to a standard wall switch, and then to a duplex box mounted up in the battery compartment in the bow. This is used to power a 120V battery charger that is in place and hooked up to one or the other series of batteries mounted in the bow


I have been fighting the corrosion thing for many years and when it comes to electrical systems, I have figured out a thing or two.

Some insights: When wiring in your shore power systems consider the following:

First for my wire, yes it is braided or mulitstrand wire (#14-2 with a separate insulated ground wire). This is wire meant for industrial grade extension cords. I like multistranded wire much more than solid wire (even in lighter wire) because it is more flexible, not prone to snap or break where kinked. It also when setup properly, will last for many years without degrading and corroding. All my AC wiring is made from this same type of wire. I used this for "the cattle prod" line, as well as for box to box wiring.

Second, the boxes I used were simply outdoor grade with rubber seals and snap over covers. In the two positions where I was not using special boxes, they are standard galvanized metal boxes with Stainless Steel cover plates.

Third, all connections with or without metal crimp on connectors should be coated, dipped or otherwise impregnated with something called No-Lox. No-Lox can be purchased at any electrical supplier as well as Home Depot. It is non-conductive, and is similar in appearance to automotive grease on color and consistence. It prevents the air and moisture from making it's way up into the mulitstranded wire. Cover the wire with No-Lox before adding a crimp connector, and also brush on more over screw down connections. By giving the wire ends a decent air/water seal, the corrosion is stopped before it can start. This is also a very good idea for the battery terminals.

Also, in place of metal boxes, you might consider the current crop of plastic boxes. They are of reasonable quality, won't rust, and should provide good long-term service.

To answer a specific question, why not wire directly to the boat? The simplest answer is for flexibility. I keep my boat in tidal waters (at QCYC tides rise and fall 7-10 feet, in can simply disconnect (it has give). I also like being able to coil up the line and store it way when it is not being used. The double plug line allows for very easy hookups with a minimum of fuss and bother.

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