When using the direct method to test earth resistance, what is essential regarding the ground rod under test?

When employing the direct method to test earth resistance, it is crucial for the ground rod under test to be close to the water-pipe system. This is because the water pipes can provide a reliable conductive path that enhances the accuracy of the resistance measurement. Water, especially when it contains minerals, improves conductivity and aids in obtaining a more representative reading of the ground rod's effectiveness in dissipating electrical energy into the earth.

Having the ground rod located near the water-pipe system ensures that the test conditions are optimal and that the measurement reflects the true performance of the earthing system. This proximity allows for proper current distribution during the testing process, ensuring that the readings obtained are valid and consistent with actual operational conditions.