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
Dark Gray	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
Orange	Common Feed	Distribution Panel to Accessory Switch
Purple	Ignition	Ignition Switch to Coil & Electrical Instruments
Purple	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

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