This standard specifies the method for measuring the breakdown strength of power frequency by insulating adhesive tape under continuous uniform boost. During the test process, by applying a gradually increasing power frequency voltage until the sample breaks down, record the voltage value at the time of breakdown, and calculate the ratio of the breakdown voltage to the thickness of the sample as the breakdown strength. The standard requires that the sample should be 300mm in length, not less than 12mm in width, and kept clean, drying and free of obvious defects. The test instrument includes concentric electrode device and high voltage breakdown device. It is necessary to ensure that the electrode is smooth and free of defects. The accuracy of the voltmeter is not less than 1.5 levels to ensure the accuracy and Reliability of the test process.