That 50 A fuse goes to the ignition switch and then feeds 9 fuses, and some of those fuses feed more than one circuit....
You will get a big spark when you go to reconnect the bat cable, because you are completing circuits through "awakened" modules......there will be an initial high current flow, but over the course of 10 minutes, current should drop to about 30-25 ma or 0.030-0.025 Amps......