Re: Why 42.4Vac/60Vdc - or 250V

[fdominguez]

Vic,
I believe that the rationale for the 42.4Vac/60Vdc numbers are in IEC 479 - 
Effects of current on human beings and livestock.  Another relevant 
standard would be IEC 990 - Methods of measurement of touch-current and 
protective conductor current.  I would bet you a virtual beer or maybe a 
bottle of virtual vino that the IEC 950 committee consulted these standards 
to determine the SELV, Limited Current Circuit and Energy Hazard limits.
Ciao,
Frank Dominguez
TUV Product Service