Electrical Issue (Please help)

[LandonL]

Alright, after the wire burnt up from the alternator to the battery (red one) I went to replace it. I replaced it with 10 gauge automotive wire, and spliced it into the red wire going from the voltage regulator to the cab's clip like it was from the factory. I've gotten everything hooked back up and now when I put the battery cables back on one of them sparks, and begins to melt the terminal. As far as I know I didn't ground out the red wire anywhere, WHAT could possibly be the problem.. This trucks been driving me down the path to insanity..

EDIT:
I didn't change the regulator it's original. What happened was the connection to the alternator(red wire) was loose and it started sparking and the wire heated up and melted the casing all the way to the battery and the truck shut off.