y 750v..can anyone tell me where in the code book that i find the reason for 750v being low-voltage.and how did this number came about..

Section 36 deals with high voltage, which is voltages in excess of 750 volts. Check out rule 36-000 (1) (3).

Perhaps it was intended to keep the trolley bus in the low voltage definition.

what i am saying is,why wasn't it 790v as oppose to 750v.which means that this # did not just showed up,there must be some reasonning behind it.that is what i am trying to find out.code36(1)(3)talks about it briefly...but isn't saying how it came about.