Let me show you something...Now that's a fire!

I have been having trouble starting the car in the cold weather and my battery died all together this weekend, so yesterday I replaced the ground wire (from the negative battery terminal to the cold start valve) with a new piece of 12 gauge wire. I noticed the "stock" wire (which was melted and frayed looking) was a little thicker (maybe 10 gauge...Anybody?). I also bought a new battery. It started fine all day and night, then this morning (blistering wind and cold) it wouldn't start and the NEW battery went dead after about 8 or 9 tries...I didn't have time to mess with it so I took my wife's Jetta to work. Tonight I go out there and pop the hood and the new wire I had replaced was melted (and I mean melted) from one end to the other...and suprise, the car wouldn't start :-) Can a cold start valve short out and cause this ?