How to Install Copper Ground Plates in a Sailboat

Copper ground plates help prevent damage to your or your vessel from lightning. Lightning, like any other electrical discharge, always seeks the shortest route to a ground. Like a lightning rod, the mast--since it's above the surface of the water--becomes the shortest route to a ground (the water) for a lightning strike. Copper grounding plates, when connected to a "lightning rod" system on your mast, can help assure that you're not part of the circuit.

Things You'll Need

  • Nuts
  • Bolts
  • Marine silicone caulk
  • 20 AWG copper wire
  • 8 AWG copper wire
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Instructions

    • 1

      Mount the grounding plate on the outside of the hull so that it will always be in contact with the water. On a sailboat (which leans--it's called "heeling") this may mean that it needs to be mounted near the lowest part of the boat's bottom, with nuts and bolts long enough to penetrate the hull; one of the bolts will be connected to the ground connector. Caulk the holes both inside and outside the hull with marine silicone caulk.

    • 2

      Attach the ground connector, which should be copper 20 AWG wire, to the grounding plate and run the wire, by the most direct route to the top of the mast. The NFPA Lightning Protection Code says the grounding connector "should be essentially straight, securely fastened to the mast, extended at least 6 inches above the mast and terminate in a sharp receiving point."

    • 3

      Connect every metal component of the boat that lies within 6 feet of the ground connector to the ground connector with 8 AWG copper wire, and ground the engine, if the vessel is an auxiliary sailing vessel, to the ground plate directly, rather than through the vessel's common ground. According to the National Fire Protection Association, "all masts, shrouds, stays, preventors, sail tracks and continuous metallic tracks on the mast or boom" that carries the ground connector should be connected to each other and grounded to the ground connector.