Thermal Sizing and Electric Shock Calculations for Equipment Grounding Conductors

This paper presents the thermal sizing procedure of equipment grounding (protective) conductors and the electric shock calculations as per the standard 60364 of the International Electrotechnical Committee (IEC) that is used worldwide. The application of IEC standards in the design of low-voltage systems (i.e., not exceeding 1 kV) governed by the National Electrical Code (NEC) and the American National Standards Institute (ANSI), which are adopted in the U.S., is discussed and proposed in this paper. The authors propose an interpretation of the NEC installations in light of the earthing definitions included in the IEC realm. On this premises, IEC sizing criteria are applied to typical North American installations to prove their general applicability and their legitimacy to NEC/ANSI-based electrical systems. Examples are also presented for both thermal sizing and electric shock calculation of equipment grounding conductors.