The arc resistance of electrical insulating materials is an important subject in the insulation design of electrical equipment. At present, ASTM D495-71 test has been designated as the standard arc resistance test method to simulate the service conditions. However, it is considered that a complete elucidation of their properties at the failure of electrical insulation against various types of electrical arc is impossible by only one test method. Consequently, the incorporation of other test methods such as a modified ASTM arc resistance test with the standard method is desirable to the proper appraisal of arc resistance of plastics.
In this paper, various test methods such as the rotary disc arc resistance test, the middle current arc resistance test, the high frequency arc resistance test, the electrical furnace arc resistance test and the arc resistance test by the chemical flame were used for the measurement of arc resistance. As the test samples, various plastic materials were used. The mutual comparison of experimental results showed that the combination of various measured values is useful to the appraisal of arc resistance. Among the test plastics, the resins such as silicone glass and melamine glass show large arc resistance and the resins such as phenol resin, epoxy paper-filled, tetron epoxy laminate insulation and epoxy glass cloth show comparatively small arc resistance.