Things You'll Need
16-gauge black wire
16-gauge red wire
12-volt test light
Many electrical items are designed to plug into a 12-vold cigarette lighter socket or power receptacle. Adding a 12-volt receptacle to your boat will allow you to charge cell phones, plug in high-power spotlights or can be used to power any number of electronic devices.
Determine where on the boat the power receptacle will be mounted. The dashboard (if there is one) is a logical place, but a power plug-in at the stern (especially if your boat is tiller steer) or at the bow, if you fish from the front deck, might make more sense.
Check to ensure you can get access to the rear of the power socket where you are mounting it. The wire connections and attaching ring nut are on backside of the receptacle.
Read any installation instructions which come with the receptacle. Chances are it will list the size of the hole required to mount the unit. If not, measure the outside diameter of the receptacle, choose the appropriate-sized drill bit and drill the hole.
Insert the receptacle into the hole and tighten the ring nut on the back side of the unit to secure it to the surface of the mounting location.
Route the wires directly from the battery (or the power panel on the boat, if one is present) to the rear of the receptacle. Do not simply splice into existing wires leading to lights, radio or other electronics. The black wire is the negative wire and should attach to the ground on the power panel or the negative post on the boat's battery, the red wire is the hot wire and should attach to a vacant positive post on the power panel or directly to the positive terminal on the battery.
Bundle wires with wire ties or electrical tape and secure in out-of-the-way areas.
Use the appropriate size and style of solderless connector to make all connections.
Use a solderless butt connector to splice an in-line fuse holder onto the end of the red wire. The wire attachment contacts on the rear of most receptacles are the spade type, but some receptacles may have threaded posts requiring ring tongue connector. Attach whichever style connector is appropriate to the end of both the black wire and the red wire coming from the in-line fuse holder.
Insert a 5-ampere fuse in the fuse holder. Test the wire connections by attaching the clip on the ground wire of a 12-volt test light to the connector on the black wire, then touch the red wire's connector with the light's probe. If the light glows, all is right. Disconnect the tester and attach the wires to the receptacle.