Maintaining the quality appearance and condition of your boat

Boat Wiring and Color Codes

American Boat & Yacht Council Standards for Boats

 

COLOR

ITEM

USE

Black

Ground

Negative / Neutral Main Return
Blue-Stripe Tilt up and or trim out Tilt and or trim circuits

Brown

Alternator Charge Light

Generator Terminal or Alternator Auxiliary Terminal to Regulator

 

Generator Armature

Generator Armature to Regulator

 

Pumps

Circuit Breaker or Switch to Pumps

Brown w/Yellow

Bilge Blowers

Circuit Breaker or Switch to Blower

Dark Blue

Cabin & Instrument

Circuit Breaker or Switch to Lights

Green or

Bonding System

Grounding Wires (if insulated)

Green w/Yellow Stripe

 

 

Green Stripe Tilt down and/or trim tab Tilt and or trim circuits

Grey

Navigation Lights

Circuit Breaker or Switch to Lights

 

Tachometer

Tachometer Sender to Gauge

Lt. Blue

Oil Pressure

Oil Pressure Sender to Gauge

Orange

Accessory Feed

Ammeter to Alternator or Generator

 

Common Feed

Distribution Panel to Accessory Switch

 

Feed

Accessory Circuit Breakers or Switches

Pink

Fuel Gauge

Fuel Gauge Sender to Gauge

Purple

Ignition

Ignition Switch to Coil & Electrical Instrument

Red

Power Feeds

Positive Main Power (particularly un-fused)

 

Instrument Feed

Distribution Panel Electrical Instruments

Tan Water temperature Water temperature sender to gauge

Yellow

Generator Field

Generator to Regulator Field Terminal

Yellow

Ground

Negative / Neutral Main Return

Yellow w/Red

Starting Circuit

Starting Switch to Solenoid

 Wire / Conductor Sizes

Length (feet): Determined by measuring the length of the wire from the positive (+) power source connection to the electrical device and back to the negative (-) power source connection.  Note that the power source connection may be the battery, panel-board or switchboard.

Current (amps): Determined by adding the total amps on a circuit.

Wire sizes not covered in Table C or Table D may be calculated by using the following formula:

After calculating the Circular Mil Area (CM), use Table B to determine the proper conductor size.  The National Fire Protection Agency and Coast Guard require that the next larger conductor be used when the calculated CM area falls between two conductor sizes.

CM=K x l x L / E

CM = Circular Mil area of Conductors

K = 10.75 (Constant representing the mil-foot resistance of copper)

I = Current - amps

L = Length - feet

E = Voltage drop at load (in volts)

For Example:

Q.  A bilge pump draws 10 amps.  The positive run is 11 feet from the power panel, including the float switch.  The negative run is only 10 feet.  What size wire?

A.  Use the following formula to reach the correct answer:

 CM = 10.75 x 10 (amps) x 21 (total length of run) / 0.36 (3% of 12v) = 6,271

The table below shows that 12 AWG wire has a CM area of 6,500 and is the correct choice. However, SAE wire has a CM area of only 5,833.  Under NFPA and USCG regulations, 10 SAE wire must be used.

CM = 10.75 x 10 (amps) x 21 (total length of run) / 0.96 (3% of 32v) = 2,352

Ampacity is the ultimate safe current carrying capacity of the wire before damage occurs to the insulation, without regard to voltage drop.  Because the insulation of most SAE wire types is not the same as ANCOR, this chart should not be used for other conductor types.

 

AWG

Sq.
mm

AWG
CM area

SAE
CM Area

Ampacity
Engine Space
Outside

Ampacity
Engine Space
Inside

18

0.8

1,600

1,537

20

17

16

1

2,600

2,336

25

21

14

2

4,100

3,702

35

30

12

3

6,500

5,833

45

38

10

5

10,500

9,343

60

51

8

8

16,800

14,810

80

68

6

13

26,600

24,538

120

102

4

19

42,000

37,360

160

130

2

32

66,500

62,450

210

178

1

40

83,690

77,790

245

208

1/0

50

105,600

98,980

285

242

2/0

62

133,100

125,100

330

280

3/0

81

167,800

158,600

385

327

4/0

103

211,600

205,500

445

378