Ground-Fault Protection of Equipment

Ground-fault protection of equipment shall be provided for solidly grounded wye electrical systems of more than 150 volts-to-ground, but not exceeding 600V phase-to-phase for each individual device used as a building or structure main disconnecting means rated _____ or more, unless specifically exempted.

a) 1,000A
b) 1,500A
c) 2,000A
d) 2,500A

See answer and applicable Code reference

The correct answer is: a) 1,000A

The rules for overcurrent protection can be found in Art. 240 of the 2011 NEC. The requirements for ground-fault protection of equipment are outlined in Sec. 240.13. The first sentence in this section of the Code states, "Ground-fault protection of equipment shall be provided in accordance with the provisions of 230.95 for solidly grounded wye electrical systems of more than 150V to ground but not exceeding 600V phase-to-phase for each individual device used as a building or structure main disconnecting means rated 1,000A or more."