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 milfoot resistance of copper) I = Current  amps / L = Length  feet E = Voltage drop at load (in volts)
