Hilton Mills, HP&D grounding specialist, was presenting at a technical conference about best practices for testing substation grounding systems. During his presentation, he stated that after a ground grid is freshly installed, it will take some time for the voids in the soil to compress, providing a good connection between the ground grid conductors and the soil. Immediately after installation, these voids can cause higher than designed (calculated) impedance, touch, and step values, which should…
