Re: System Saver IIgs -- ID of burned part?-- line protection

[w_tom <w_tom1@usa.net>]

  In this previous case, the MOV did not vaporize - which is what would happen if
it was a spark gap.  Therefore everything on the protected side suffered no
damage.  At the time, I never thought of measuring MOV degradation.  In hindsight,
I wish I had.  But had the MOV become a spark gap, it would have been toasted
black or vaporized.

  In another case, I had MOVs totally vaporize.  The surge was completely from the
utility which are the higher energy surges.   I never determined how the surge was
created - how the backhoe cause the surge.  But in that case,  39 joules
demonstrated what grossly undersized means.  All that was left were four wire
leads where once stood two MOVs.  Rather spooky looking.

  Of course because those MOVs vaporized, then many items inside the house were
damaged including the TV and all power strip surge protectors.  The occupants
reported sparks flying out of the power strip surge protectors.  Great.  Purchase
surge protection and get a fire hazard?

  The point being that because the MOVs were too small, then they vaporized and
therefore provided no effective surge protection.

"Michael J. Mahon" wrote:

> Yes, and in this case the MOV was functionally equivalent to a spark gap!