Parametric Analysis of Safety Limit-Curves in Earthing Systems and Comparison of International Standard Recommendations

Recommendations and procedures for the design and safety of earthing systems from three national and international standards for earthing systems, namely IEEE 80, BS 7354 and EA-TS 41-24 have been considered in this investigation. In this paper, we present the results of a comparative parametric evaluation of the different recommendations taking into account the grid size, mesh density, earth resistivity and body resistance. Safety limit-curves were obtained, which classified the various designs according to the different standards. Through investigation of the so-generated safety limit-curves, it is possible not only to clarify for what grid characteristics safe conditions are obtained for the installation but also to develop an optimum design procedure that accounts for all conditions considered within the standards