Strange Battery Drain

[Arthur, Keith]

Hello,

My 1991 90 is acting up and I was dumb enough to leave the Bentley at
school.  The fat red wire that is bolted onto the top of the positive
terminal with a 10mm bolt is drawing 12V's with the ignition off.  I guess
this either goes to the starter or alternator.  Could someone confirm which
it goes too and what could cause this voltage drain?

Thanks,
Keith