Q. What is the Code rule for ground fault protection of equipment?
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A. Service disconnects and feeder circuits rated 1,000A or more, supplied from a 4-wire, 3-phase, 277/480V wye-connected system must be protected against ground faults in accordance with Sec. 230.95 [215.10 and 230.95]. The requirement for ground fault protection of equipment doesn’t apply to [240.13]:
1) Continuous industrial processes where a non-orderly shutdown will introduce additional or increased hazards.
2) Installations where ground fault protection of equipment is already provided.
3) Fire pumps [695.6(H)].
Article 100 defines “Ground Fault Protection of Equipment” as a system intended to provide protection of equipment from ground faults by opening the overcurrent device at current levels less than those required to protect conductors from damage. This type of protective system isn’t intended to protect people, only connected equipment. See Sec. 215.10 and Sec. 230.95 for similar requirements for feeders and services.
Ground fault protection of equipment isn’t required for emergency power systems [700.27] or legally required standby power systems [701.26].