abyc wire color codes
Color-coded cables. The ABYC recommends some standard primary wire and cable color codes for boat wiring installation. The insulation color of the cable shows the purpose of that wire used in the boat wiring. See the table below for a list of the cable color codes for DC voltage systems:
| Color | Items used for | Usage |
| Red | DC +Ve connector "L+" | Positive mains "-" |
| Black or yellow | DC -Ve connector "L-" | Negative mains "-" |
| Yellow with red stripe | Staring circuit | Starting switch to solenoid" |
| Brown | Generator armature, pumps, alternator charge light | Generator armature to regulator, fuse or switch to pumps or lights, generator - terminal - alternator or light to regulator |
| Brown with yellow stripe | Bilge blower | Fuse of switch to blower |
| Dark blue | Cabin and instrument lights | Fuse or switch to lights |
| Light blue | Oil pressure | Oil pressure sender to gauge |
| Tan | Water temperature | Water temp sender to gauge |
| Orange | Common feed and accessory feed | Distribution panel to accessory switch, ammeter to alternator, or generator output & accessory fuses or switches |
| Purple | Ignition and instrument feed | Ignition switch to coil & electrical instruments, distribution panel to electrical instruments |
| Pink | Fuel gauge | Fuel gauge sender to gauge |
| Grey | Tachometer and navigation lights | Tachometer sender to gauge, fuse or switches to lights or bonding wires (if insulated) |
| Green/Green with yellow stripe | Protective ground "PG", DC grounding conductor | Bonding system, bonding wires if insulated |
On color-coding wires. Trying to make sense of wiring on a new-to-you vessel when nothing is labelled or easily identifiable is painful experience. Color-coding wires will make it easy to identify a wire in any part of the boat.
Surveyors won't lose their heads if the colors are wrong (although sticking to black and red for pos and neg is crucial), but it is at least good to label the wires at various points. We like to label wires on a narrow piece of paper and to enclose it in gorilla tape around the wire, so it follows the wire and doesn't stick out. Enclosing the wire in tape will ensure the name doesn't get rubbed out, and that the paper doesn't fall prey to rot (using a see-through heat shrink is another possible option).
A wire that doesn't have the right color won't cause any electrical problems, the only downside is if the vessel is sold, a lack of color-coding may cause confusion that might lead to problems, say, using a red wire for a grounding wire instead of green.