This standard is a national method standard for determining the insulating properties of vulcanized rubber under power frequency voltage. It provides test methods for two key indicators: breakdown voltage strength and withstand voltage value. Specifically, it includes measuring breakdown strength by applying uniform or stepwise increasing voltage until the sample breaks down, as well as rapidly raising the voltage to a specified value and maintaining it for a certain duration to test the withstand voltage performance. The core instrument for conducting this test is the voltage breakdown tester (also known as the power frequency breakdown voltage strength tester). This type of instrument typically consists of a high-voltage generator, a voltage regulation system, test electrodes, and overcurrent protection devices. It is capable of precisely controlling the voltage ramp rate and automatically recording the voltage value at the moment of breakdown, providing standardized testing basis for evaluating the electrical insulation safety and durability of rubber materials.