|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 Green w/Yellow Stripe||Bonding System||Grounding Wires (if insulated)|
|Green Stripe||Tilt down and/or trim in||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|
|Instrument Feed||Distribution Panel Electrical Instruments|
|Red||Instrument Feed||Distribution Panel to Electrical Instruments|
|Power Feeds||Positive Main Power (particularly un-fused)|
|Tan||Water temperature||Water temperature sender to gauge|
|Yellow||Generator Field||Generator to Regulator Field Terminal|
|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)
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. Use Table C & D to find proper wire size to insure adequate performance.
|AWG||Sq. mm||AWG CM area||SAE CM Area||Ampacity Engine Space|