Ancor
   Technical Data - Table B - Conductor Sizes (AWG) for 3% Voltage Drop at 12 Volts
     

IMPORTANT!
Length (feet): Determined by measuring the length of the conductor 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 either the battery, panelboard or switchboard. Current (amps): Determined by adding the total amps on a circuit. Conductor sizes not covered in Table B or Table C may be calculated by using the following formula: CM = K x I x LE

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

Length
5
10
15
20
25
30
40
50
60
70
80
90
100
18 14 12 12 10 10 8 8 6 6 6 4 4
16 12 10 10 8 8 6 6 4 4 4 2 2
14 12 10 10 8 8 6 6 4 4 4 2 2
14 10 8 8 6 6 4 4 2 2 2 1 1
12 10 8 6 6 4 4 2 2 2 1 1/0 1/0
12 8 6 6 4 4 2 2 1 1/0 1/0 2/0 2/0
10 8 6 4 4 2 2 1 1/0 1/0 2/0 3/0 3/0
10 6 6 4 2 2 1 1/0 2/0 2/0 3/0 3/0 4/0
10 6 4 2 2 2 1/0 2/0 2/0 3/0 3/0 4/0 4/0
8 6 4 2 2 1 1/0 2/0 3/0 3/0 4/0    
8 4 4 2 1 1/0 2/0 3/0 3/0 4/0      
8 4 2 2 1 1/0 2/0 3/0 4/0 4/0      
8 4 2 2 1 1/0 2/0 3/0 4/0        
6 4 2 1 1/0 2/0 3/0 4/0 4/0        
6 4 2 1 1/0 2/0 3/0 4/0        
6 2 2 1/0 2/0 2/0 3/0 4/0          
6 2 1 1/0 2/0 3/0 4/0            
6 2 1 1/0 2/0 3/0 4/0            
6 2 1 2/0 3/0 3/0 4/0            
Use 3% voltage drop for any “critical application” affecting the safety of the vessel or its
passengers: bilge pumps, navigation lights, electronics, etc....