Alternator Belts and Cables


Below are the suggested standards for proper direct current wiring color selection. Note that YELLOW is being suggested for the ground wire of returns and negative mains. This attempts to prevent the catastrophic mix-up of XXvdc and XXXvac (e.g. 12vdc & 120vac) by an inadvertent connection of the DC ground to the AC positive. In the past, both used black wire.

Marine Wiring Color Code
Direct Current Systems Under 50 Volts
Color Item Use
Green Bonding System Bonding Wires (if insulated)
Yellow or Black Ground Return, Negative Mains
Red Main Power Feeds Positive Mains (particularly unfused)
Yellow w/ Red Starting Circuit Starting Switch to Solenoid
Yellow Generator Field Generator to Regulator Field Terminal
Brown w/ Yellow Bilge Blowers Fuse or Switch to Blower
Dark Gray Navigation Lights Fuse or Switch to Lights
Tachometer Tachometer Sender to Gauge
Brown Generator Armature Generator Armature to Regulator
Alternator Charge Light Generator Terminal or Alternator
Auxiliary Terminal to Regulator
Pumps Fuse or Switch to Pumps
Orange Accessory Feed Ammeter to Alternator or
Generator Output and Accessory
Fuses or Switches
Common Feed Distribution Panel to Accessory Switch
Purple Ignition Ignition Switch to Coil & Electrical
Instrument Feed Distribution Panel Electrical Instruments
Dark Blue Cabin & Instrument Fuse or Switch to Lights
Light Blue Oil Pressure Oil Pressure Sender to Gauge
Tan Water Temperature Water Temperature Sender to Gauge
Pink Fuel Gauge Fuel Gauge Sender to Gauge

↑ Recommend ZRD