The EPM program should include the essential ingredients of Chapter 12 of NFPA 70B, "GroundFault Protection." This includes ground fault circuit interrupters (GFCls) and ground-fault protection for equipment (GFPE).

Ground-fault protective devices are intended to protect personnel and equipment. There are two distinct types, GFCI and GFPE, and it is of extreme importance to understand the difference between them.

A GFCI is defined in Article 100 of the NEC as a device intended for the protection of personnel in their job assignments. (See NEC Sections 210-7(d), 210-8, 215-9, 305-6, 427-26 and Section 2.7¹.)

A GFPE is defined in Article 100 of the NEC as a system intended to provide protection of equipment from line-to-ground fault currents. GFPE systems (equipped with or without a test panel) shall be inspected and tested at installation and at specified intervals as recommended by the manufacturer. (See NEC Sections 215-10, 230-95, and 240-13 and Section 4.14.)

Figure 3-1 shows a zero sequence type of ground fault protection. See NEC Section 230-95 and 240-13 and NEMA PB2.2, "Application Guide for Ground Fault Protection Devices for Equipment."

¹ See Appendix D, Reference Matrix

Figure 3-1. Ground-fault protection shall be provided with 277/480-V, three-phase, four-wire services with overcurrent protection devices of 1,000 A or more. A ground fault sensor (window) can be used to encircle all service conductors, including the grounded conductor (neutral).