The sample shall with stand an A.C. voltage of 2000 volts having a frequency of 50 Hz for a period of 15 minutes after conditioning in a water Bath at 27 5 Deg C for a period of 24 Hours without break down.The sample shall with stand a D.C. Voltage of 500 Volts in water bath kept At a temp. of 60 2 Deg C for a period of 2 hours minimum insulation resistance shall be 100 M ohm.