scram switch

scram switch n.  [from the nuclear power industry] An
   emergency-power-off switch (see {Big Red Switch}), esp. one
   positioned to be easily hit by evacuating personnel.  In general,
   this is *not* something you {frob} lightly; these often
   initiate expensive events (such as Halon dumps) and are installed
   in a {dinosaur pen} for use in case of electrical fire or in
   case some luckless {field servoid} should put 120 volts across
   himself while {Easter egging}.  (See also {molly-guard},
   {TMRC}.)