OPEN-CIRCUIT NST LIFE

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Original poster: Ed Phillips <evp@xxxxxxxxxxx>

   For a couple of years I used half of a 9 kV 60 ma Franceformer 
NST connected to wire running around the yard on 6" high PVC pipe as 
"skunk and possum zapper".  100% effective.  Reason for the note is 
the recent series of comments about the short life of NST's run without load.
That's counter to experimence here.   For the record this particular 
transformer was open circuited in this application and ran outdoors 
in the weather, rain or shine, 12 hours/day for over 2 years.  Worked 
fine at the beginning and works fine now.
Because of the capacitance of the wire the terminal voltage was 
slightly higher than the terminal voltage.

    I don't know the design insulation levels which suppliers use 
but I've seen other NST's used to power precipitators and they sure 
ran open circuited for many years in those applications.

Ed