Calculation Example: Earth Electrode Resistance and Protective Coordination (TN, TT, IT)

This worked example demonstrates how to calculate the earth resistance of a single vertical ground rod ($R_A$) using Dwight's formula for a low-voltage electrical installation. It evaluates fault protection safety against indirect contact and analyzes protective device coordination across TN, TT, and IT earthing systems in accordance with EIT and IEC 60364 standards.