Requirements for GFPE

摘要

During a recent National Electrical Code (NEC) training program, inquiries about ground-fault protection of equipment (GFPE) were raised. Two questions were: Why is ground-fault protection required for large equipment rated at 1,000 volts (V) or less, and what are the requirements for GFPE when the equipment is installed in healthcare distribution systems? The third question related to required performance testing for installed GFPE. This article addresses each of these questions. First, let's look at the reason GFPE is required. It protects large equipment from devastating arcing events and destructive burn-downs. If a phase-to-ground voltage is 120V, GFPE is generally not an NEC requirement. In a circuit of 277V to ground, electric arcs generate significant amounts of heat and an arcing fault is readily sustained.