ABSTRACT
The design of grounding systems is essential for a safe installation, and must be based on the type of the system ground, the ground-fault current return paths, and on the magnitude and duration of the fault currents. Electrical safety-by-design is achieved if contact with energized objects imposes the flow of a body current of magnitude and duration within safe limits. The hazard to persons is that a current circulating through the cardiac region might be sufficient to cause ventricular fibrillation. Body current safe limits at 50/60 Hz are translated into permissible touch voltage limits as a function of their duration.
