Your most pressing National Electrical Code (NEC) questions answered
Q. When is ground fault protection of equipment required for feeder circuits?
A. Each feeder disconnecting means rated 1,000A or more supplied by a 4-wire, 3-phase, 277/480V wye-connected system must be provided with ground-fault protection of equipment in accordance with 230.95 and 240.13 [215.10]. See the definition of "Ground-Fault Protection of Equipment"in Art.100.
Exception 2. Equipment ground-fault protection isn't required if ground-fault protection of equipment is provided on the supply side of the feeder and on the load side of the transformer supplying the feeder.
Ground-fault protection of equipment isn't permitted for fire pumps [695.6(H)], and it's not required for emergency systems [700.26] or legally required standby systems [701.17].