Ground-Fault Circuit Interrupters (GFCIs) – from a Standards Perspective

Ground-fault Circuit Interrupters (GFCIs), especially Class A GFCIs, have been instrumental in reducing electrocution. A tri-national North American standard governs the testing and certification requirements for Class A GFCIs in Canada, US, and Mexico. However, the standard governing the requirements for special-purpose GFCIs (SPGFCIs), which include GFCI Classes C, D and E, is only defined in the US. On the other hand, installation requirements for GFCIs in Canada and the US are defined in Part I of the Canadian Electrical Code (CE Code) and the National Electrical Code (NEC) respectively. Both the certification and installation requirements for GFCIs have evolved overtime. This paper covers the evolution of these requirements. The physiological effect of current, theory of operation and various types of GFCIs are explained. Finally, GFCIs application issues and the effect of frequency on the operation of GFCIs are discussed.