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Color Coding for Marine Wiring

technical article from Marinco website www.marinco.com


Marine Color Code

“Can I use ‘regular wire’ for my boat?” The answer to this common question is a qualified “yes,” if the wire is SAE (Society of Automotive Engineering) J378, J1127 or J1128. These wires are designed for “surface vehicles,” not for the special requirements of the marine industry, but meet the minimum standards for boats in limited circumstances. Even if tinned copper, they should not be run in bilge spaces or other areas subject to moisture from spray or dripping. They should not be run in engines spaces, unless marked “oil resistant” and “75°C”. They should not be used in applications where subjected to vibration or frequent flexing and must never be used for 110 volt applications. For safety, use only wire which is marked with size and type.

Most importantly, SAE wire is up to 12% smaller than AWG Boat Cable which means that, in many
applications, larger gauge wire must be used to stay within the voltage drop limits recommended by experts (see Tables C & D). The wire charts found in “Chapman’s Piloting” and other publications are all for “AWG” wire like ANCOR, not “SAE” type wire.

Using the wrong type of wire can cost you more in the long run. Insist on Marine Grade™ Boat Cable by ANCOR. It is UL approved for the corrosive marine environment and charter boat service. Marine Grade™ Boat Cable is specially designed to exceed all test standards for cold bend, moisture and oil resistance, heat shock and flammability. This ensures the safest, easiest to install, longest lasting and ultimately the least expensive electrical system you can buy. Only ANCOR offers a complete line of Marine Grade™ Boat Cable for every need.

Table A: Marine Color Code

Color Item Use


DC Positive Conductor Positive Mains

Black or Yellow

DC Negative Conductor Return, Negative Mains


or Green w/ Yellow Stripe

DC Grounding Conductor Bonding System

Bonding Wires (if insulated)


Generator Armature Generator Armature to Regulator
Alternator Charge Light Generator Terminal/Alternator Auxiliary Terminal to Light to Regulator
Pumps Fuse or Switch to Lights


Navigation Lights Bonding Wires (if insulated)
Tachometer Tachometer Sender to Gauge


Accessory Feed Ammeter to Alternator or Generator Output and Accessory Fuses or Switches
Common Feed Distribution Panel to Accessory Switch


Fuel Gauge Fuel Gauge Sender to Gauge


Ignition Ignition Switch to Coil & Electrical Instruments
Instrument Feed Distribution Panel Electrical Instruments

Brown w/ Yellow Stripe

Bilge Blowers Positive Mains (particularly unfused)

Yellow w/ Red Stripe

Starting Circuit Starting Switch to Solenoid


Water Temperature Water Temperature Sender to Gauge

Green/Stripe (G/x)

(except G/Y)

Tilt Down and/or Trim In Tilt and/or Trim Circuits

Blue/Stripe (Bl/x)

Tilt Up and/or Trim Out Tilt and/or Trim Circuits

Original article from Marinco website

Electrical Guides from Marinco Group Brands

Ancor Guide- Features and Benefits (pdf)

Marinco- A Boaters Guide to AC Electrical Systems (pdf)

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