Ernie - 4/11/2007 15:01
The number of wires in a cable makes a big difference in current conductivity. Electrons flow along the out side of wire. More wires of smaller size will carry more current . Example ... 100 fine wires in a 00 cable will carry more current than say 6 wires in the same 00 size.
The idea that electrons flow along the outside of a wire is a little misguided. This is based on skin effect, but only happens at high frequencies. Direct current transmits electricity uniformily across the cross section of a wire. A cable with finer strands will be more flexible, but will have the same DC conductivity as a solid wire of the same cross section.The old 6 volt systems had larger sized cables than the 12 volt. The larger size was required to carry the same amp load at lower voltage. Required cabling size is based only on current flow, not voltage. The 6 volt systems required a larger diameter than 12 volt systems because the amp load had to double to transmit the same power. (P=IV, so to transmit 60 Watts at 12 Volts requires 5 Amps. To transmit the same 60 watts at 6 Volts requires 10 amps. ------------------------------------------------------------------- http://en.wikipedia.org/wiki/Alternating_current#Techniques_for_reducing_AC_resistance A direct, constant, current flows uniformly throughout the cross-section of the (uniform) wire that carries it. With alternating current of any frequency, the current is forced towards the outer surface of the wire, and away from the center. This is due to the fact that an electric charge which accelerates (as is the case of an alternating current) radiates electromagnetic waves, and materials of high conductivity (the metal which makes up the wire) do not allow propagation of electromagnetic waves. This phenomenon is called skin effect. At very high frequencies the current no longer flows in the wire, but effectively flows on the surface of the wire, within a thickness of a few skin depths. The skin depth is the thickness at which the current density is reduced by 63%. Even at relatively low frequencies used for high power transmission (50–60 Hz), non-uniform distribution of current still occurs in sufficiently thick conductors. For example, the skin depth of a copper conductor is approximately 8.57 mm at 60 Hz, so high current conductors are usually hollow to reduce their mass and cost. | 
8640 Deere has two 6V batteries
