<VV> Engine Fire Found the culprit

[Smitty]

Smitty says;  An unused wire that used to feed the AC fan running through the middle of a coax of wires all taped together.  It burned off from the relay that supplied it and as I cut away and separated the other wires I could see it was less and less hot the farther I went.  Still don’t know what shorted it but the wire bundle was most severely burned where the wire went into it.  Beyond that I will not be performing any more autopsy.  Got to concentrate on the reconstruction.
Question;  where can I get some better lamp cord wire.  All that I have is fat insulation with small wire in it.  Next question;  is there any such thing as all copper or steel wire nuts.  The ones I used, the plastic all melted off of them.  Seems to me all metal ones would stand the heat better.