Amid declining birth rates and a global labor shortage, automated electrical testing has become essential for industrial development. However, many factories face technological lock-in due to long-term reliance on a single vendor’s automation systems, resulting in high sunk costs and significant challenges when upgrading or switching platforms. In this paper, we propose a universal automated high-potential test system (UHPTS) designed to operate seamlessly across multiple instrument brands. The system unifies communication protocols by mapping instrument commands to standardized labels and retrieving the required instructions from a centralized database, in accordance with the selected test environment. This architecture enables cross-platform interoperability within a single testing framework. The UHPTS can also be integrated with the manufacturing execution system (MES), allowing automatic parameter loading via product barcodes and supporting fully automated, operator-independent testing. Experimental results verify that the proposed system reduces operational complexity, eliminates vendor lock-in, minimizes human error, and enhances testing efficiency and reliability. Overall, the UHPTS offers a scalable and practical solution for modernizing withstand-voltage testing in power supply manufacturing.