I'm Trying to determine proper wire size to the avionics buss. A single wire will carry power to the buss from the batt contactor through the avionics switch. However, the ground return will consist of numerous wires from the various devices. I'm using a single point ground so the ground wire distance from the devices may vary from as little as 2' (comm radio) to as much as 15' (A/P servos). Since the total wire length of a given circuit is used to determine wire size, how do I come up with a total when the lengths of ground wires vary so much? Should I consider the average length, longest, or...? I'm guessing it will be in the neighborhood of 16awg or 18awg but would still like to know how it is determined.