First and foremost, ensure that your TPA device is indeed functioning correctly.

Quick test: Insert the two probe tips directly into the socket between the two phases, avoiding the central earth hole. Rest assured, it will not burn out. If the device measures between 000.3 and 001.5, it indicates proper functionality. We have developed a device called the Grounding Tester/Simulator to address these issues.

If you don’t have this device, you can use the neutral as if it were an earth. The resistance of the neutral, depending on the conditions of the local utility transformer, typically ranges from 0.3 to 1.5 ohms. Any earth resistance meter should measure within these values.