The importance of an SPD life tester lies in its ability to identify previously damaged surge protective device (SPD) modules. Faulty or damaged modules can be inspected on-site, and if found unserviceable, they can be replaced in a timely manner to prevent faults. As faults in these modules are usually not visible to the naked eye, visual inspection cannot determine their life expectancy. The SPD life tester is designed to detect and assess electrical and thermal stress that can cause damage to the SPD module. By utilizing the tester, it is possible to evaluate the module's life expectancy and replace it when necessary to maintain optimal performance.