catflap.org Online Dictionary Query

  power hit
       
          (Or "power glitch") A sudden increase (spike) or decrease
          (drop-out) in the mains electricity supply.  These can cause
          crashes and even permanent damage to computers.  Computers and
          other electronic equipment should really include some kind of
          over-voltage protection in its mains input to prevent such
          damamge.
       
          [{Jargon File]
       
       

  power hit n. A spike or drop-out in the electricity supplying your
     machine; a power glitch. These can cause crashes and even permanent
     damage to your machine(s).