When the step length is much less than the rod length, i.e., when
the step voltage can be approximated
The step potential can be expressed as a fraction of the ground rod potential as follows:
The fractional step voltages for ground rods of various length are given in Table 2-7. For this Table, rod
diameter is assumed to be one inch (2.54 cm) and the pace length is assumed to be three feet (0.91 m).
Step Voltages for a Buried Vertical Ground Rod
Ratio of Step Voltage
To Electrode Potential