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].