Here is a chart, but I still don't know what the load will be on the fuse block. The wires running the injectors and most everything else are small, like 16-18 gauge. I have 7 - 15 amp circuits and 1 - 20 amp. That's 125 amps. So according to the chart, I only need a 10 awg supply since it is 18" long. Anybody...
http://www.offroaders.com/tech/12-vo...gauge-amps.htm
Amps @ 12 Volts LENGTH OF WIRE
American Wire Gauge (AWG)
3' 5' 7' 10' 15' 20' 25'
0 to1 18 18 18 18 18 18 18
1.5 18 18 18 18 18 18 18
2 18 18 18 18 18 18 18
3 18 18 18 18 18 18 18
4 18 18 18 18 18 18 18
5 18 18 18 18 18 18 18
6 18 18 18 18 18 18 16
7 18 18 18 18 18 18 16
8 18 18 18 18 18 16 16
10 18 18 18 18 16 16 14
11 18 18 18 18 16 16 14
12 18 18 18 18 16 16 14
15 18 18 18 18 14 14 12
18 18 18 16 16 14 14 12
20 18 18 16 16 14 12 10
22 18 18 16 14 12 12 10
24 18 18 16 14 12 12 10
30 18 16 14 12 10 10 10
36 16 14 14 12 10 10 10
40 16 14 12 12 10 10 8
50 16 14 12 10 10 10 8
100 12 12 10 10 6 6 4
150 10 10 8 8 4 4 2
200 10 8 8 6 4 4 2