I don't believe the NEC (codes) apply to autos. The code were written for the insulation around the wire, not the amount of current a wire will handle without melting. For example, a #12 bare wire hung in free air will conduct much more than 20 amps without melting. Another example, and one I have never understood, is the "Spal" radiator fan I have installed in on of my rides. It draws about 15 amps. The wire pigtail supplied from the factory is about a #22 gauge. Another is the output wire from a high output alternator. It's very common to see a #10 or #8 wire. Some output around 90 amps. Go figure?
