Ground-Fault Circuit Interrupters: A Standards Perspective

Ground-fault circuit interrupters (GFCIs), ESPEcially class A GFCIs, have been instrumental in reducing electrocution. A trinational North American standard governs the testing and certification requirements for class A GFCIs in Canada, the United States, and Mexico. However, the standard governing the requirements for special-purpose GFCIs (SPGFCIs), which include GFCI classes C, D, and E, is defined only in the United States. On the other hand, installation requirements for GFCIs in Canada and the United States are defined in Part I of the Canadian Electrical Code (CEC) and National Electrical Code (NEC), respectively. The certification and installation requirements for GFCIs have evolved through time. This article covers their development. The physiological effect of current, the theory of operation, and various types of GFCIs are explained. Finally, GFCI application issues and the effect of frequency on the operation of GFCIs are discussed.