byronlj wrote:
So first - rewire the fronts. I could only get so far before pulling the cable through the belly and up into the electrical access meant I could pull no further, so there I tapped into the factory run 12ga for the final 3 feet through the wall itself.
Since you went to the original 12 ga wire anyway, you might have well run 12 ga all the way. If you put a fuse on those front jacks greater than 20a you will now turn that 12ga section of wire into a fuse that is inside your walls. Your circuit is just like a chain, it is only as strong as it's weakest link.
Dave
12AWG can carry 40 to 45 amps before melting the insulation (which would take some amount of time which may be longer than the duty cycle he runs the jacks). The voltage drop on the 4AWG+12AWG run will be much less than if you used 12AWG the whole way = more power for the motors.
12AWG has a resistance of 0.00159 ohms per foot. A round trip 20 foot run would thus have a resistance of 0.032 ohms and a voltage drop of about 1.25 volts at 40 amps. The motors would get somewhere around 11 volts at that current level.
