How to Wire a Spotlight on a Boat

Updated February 21, 2017

Most spotlights for use on recreational boats are handheld, but whether they are handheld or if the spotlight is permanently affixed to the boat, wiring the light correctly is more complicated than plugging in a desk lamp. Because of the dangers posed by a fire at sea, not only must an inline fuse be added to the positive wire of the spotlight, but the electrical connections must be made with the right kind of connectors.

Crimp the spotlight's red power wire into one end of a butt connector, using a pliers-type crimper. Crimp one end of an inline fuse holder into the other end of the butt connector on the spotlight's red power wire. Solder the other end of the inline fuse holder to one of the terminals of a toggle switch, using a soldering iron and silver-bearing rosin-core solder.

Crimp a ring connector onto one end of a red-and-yellow wire. Solder the other end of the red-and-yellow wire to the unused terminal of the toggle switch.

Remove one of the screws from the common power bus, slip it through the red-and-yellow wire's ring connector and screw it back into the common power bus with a screwdriver.

Drill a 1/2-inch hole in the boat's dash. Remove the 1/2-inch trim nut from the toggle switch. Push the toggle switch up through the dashboard and thread the trim nut onto the switch to hold it in place.

Twist the inline fuse holder to open it and insert a fuse of the amperage recommended for the spotlight. Close the inline fuse holder. Connect the black ground wire from the spotlight to the boat's common ground.


You may drill additional holes in the dash or control console to accommodate the wire to the spotlight, if you choose to do so. To use a screwdriver correctly, insert the blade of the screwdriver into the slot machined across the top of the head of the screw. Put a slight downward pressure on the screwdriver to prevent the blade from riding up and out of the slot as you turn the screwdriver to the left, or counterclockwise, to loosen the screw, or as you turn the screwdriver to the right, or clockwise, to tighten the screw. Remember, "righty-tighty; lefty-loosey."


Disconnect the negative cable of your battery before performing any maintenance work on your outboard motor, to prevent electrical shock or accidental starting. Remove the nut from the negative post with a 5/16-inch box-end wrench. Lift the cable from your battery, move it outside of the battery box and close the lid of the battery box. After the work is complete, reconnect the negative battery cable.

Things You'll Need

  • Butt connectors
  • Pliers-type wire crimper
  • Inline fuse holder
  • Soldering iron
  • Silver-bearing rosin-core solder
  • Ring connector
  • Red-and-yellow wire
  • Toggle switch
  • Screwdriver
  • Drill
  • 1/2-inch bit
  • Fuse, sized according to the spotlight's Instructions
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About the Author

Will Charpentier is a writer who specializes in boating and maritime subjects. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. He is also a certified marine technician and the author of a popular text on writing local history.