Mast wiring - common ground? - SailNet Community . Mast wiring - common ground? I plan to add an anchor light, a light to illuminate the windvane and potentially a foredeck light. Is there anything wrong with using a common ground wire for all 4 lights, thus requiring only 5 wires total? How to Install the Wiring in a Sailboat Mast Gone Outdoors . Sailboat mast wiring is best run inside a hollow aluminum mast. Many masts have a pre-installed conduit inside. If not, use a PVC pipe or other protection to prevent the wires from slapping against the mast walls or chafing against the halyards that may also run inside the mast.