115 Volt Wiring Colors

There are two sets of color codes for both the 12-volt DC system and the 115-volt AC system, those specified by the American Boat and Yacht Council, which has the ear of the rule-maker, the U.S. Coast Guard, and the usual red and black color one expects to see for power and ground wiring. On a boat though, the two systems -- both color and power -- are intertwined.

  1. Grounding and Neutral Conductors

    • Green wires, or green wires with a yellow stripe, are DC grounding wires. These wires are used to bring both the AC and DC systems to a common ground. Black wires are used to ground the AC circuit to the same terminal to prevent stray charges in the water next to the boat, or between boats in marinas. Black wires ground the AC circuits aboard and connected directly to the boat's common ground. Unlike circuits ashore, the neutral leads in AC systems afloat are yellow aboard a boat.

    Instruments and Accessories

    • The wiring for most of the switches is almost boring. One, however, lives a "double life." The purple wire runs from a single point in two directions, carrying power from the ignition switch to the ignition coil and from the ignition switch to the electronic or electrically supported instruments. The lead from from the alternator to the breaker panel is orange, as is the lead to the AC accessory switch. Dark blue wiring runs from the switch-plate to cabin lights and from the 12VDC switch on the instrument panel to the instrument lighting.

    Starting, Tilt and Trim

    • The wiring for "tilt up" and "trim out," and for all other circuits that control the trim and tilt system, except the electric motor that powers the hydraulic pump, is blue with a stripe, usually black. The 115 VAC hydraulic motor wiring is red for power and black for ground. The key switch starting system's 115 VAC wires are red, as are all positive power mains leading from the main distribution panel, or red with a stripe. Push-button starting switches are wired with a red positive wire, a black negative wire and a yellow neutral wire.

    All the Way to the Bilge

    • The bilge blowers, an AC system on larger vessels, are connected using brown wire with yellow stripes. The wires between the alternator and the voltage regulator are brown, as are the wires from the bilge pump switch to the bilge pump.