A comment on the test methods for the breakdown voltage of dielectric liquids

The electrical breakdown at 50 or 60 Hz of an insulating liquid is of importance as a measure of the liquid's ability to withstand electrical stress. In national and international Standards (ASTM and IEC) different methods are reported for evaluating this fundamental property of an insulating liquid. Nevertheless, these test methods differ, depending upon the procedure, shape and dimension of the test specimen holders and types of electrodes. In the present communication an improvement of a test cell is described, which may be useful in a possible revision of Standards for improving the scatter of the test results in the measurement of the 50 or 60 Hz dielectric strength of different insulating liquids.