This is one of the reasons why you run a fused dist. block right here folks..its cheap, and easy to do, and can save your vehicle, and components. you sure its rated for 4ga wire??I didnt think it would be,i could be wrong though.Ive never understood the reason for oversized power wire either??Use whats rated..What was used @ the battery??Fuse?You are very lucky your vehicle wasnt up in flames...how do you explain that to an insurance co??Well,looks like it may be a good idea to yank all that power cable back out for sure,and replace it,im sure its crystalized somewhere in line