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) used worldwide. The application of IEC standards in the design of low-voltage systems (i.e. not exceeding 1kV) governed by the National Electrical Code (NEC) and the American National Standard (ANSI), adopted in the US, 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, as well as their legitimacy, also to NEC/ANSI based electrical systems. Examples are also presented for both thermal sizing and electric shock calculation of equipment grounding conductors.