Source : Free On-Line Dictionary of Computing

red wire
     
        (IBM) Patch wires installed by programmers who have no
        business mucking with the hardware.  It is said that the only
        thing more dangerous than a hardware guy with a code patch is
        a {softy} with a soldering iron.
     
        Compare {blue wire}, {yellow wire}, {purple wire}.
     
        [{Jargon File}]
     
        (1994-12-23)