6.6.3 Measures for protection against step voltages

Step voltage is part of the earth potential that can be bridged by a person taking a step of 1 m. The current path runs through the human body from foot to foot (Figure 6.6.3.1). The magnitude of the step voltage depends largely on the shape of the potential gradient area. As the distance from the building increases, the step voltage generally decreases. Nevertheless, under certain conditions, proximity to the down conductors of a lightning protection system can be life-threatening – even if the lightning protection system (LPS) has been designed and installed in accordance with standards.
In order to reduce the risk posed by step voltages to an acceptable level, IEC 62305-3 and application notes published in Germany to supplement IEC 62305-3 describe various conditions for reducing the risk and any necessary protective measures. As with touch voltages, the risk posed by step voltages is reduced if at least one of the following conditions is met: