Ricerc@Sapienza

This paper introduces a characterization of grounding systems (GSs) and defines their condition of “conventionally safe” and “intrinsically safe.” A single GS and a set of GSs are intrinsically safe if they guarantee touch/step voltages permanently permissible for an assigned ground fault value. A new definition of global grounding systems (GGSs) is proposed, revising that offered by the Standards IEC 61936-1/EN 50522. A safety criterion, useful for urban and industrial areas with reduced accessibility, allows identifying the safety zone of influence, and the intrinsically safe condition of a single GS and of a GGS, constituted by a set of interconnected single GSs.