2017 National Electrical Code- Article 215 Feeders
Ground Fault Protection of Equipment (Feeders)
Each feeder disconnected rating of 1000 amperes or more and installed on solidly grounded wye electrical systems of more than 150 volts to ground, but not exceeding 600 volts phase to phase, shall be provided with ground fault protection of equipment in accordance with the provisions of 230.95
Feeder grounded conductor
Feeder grounded conductor size of the feeder circuit grounded conductor shall not be smaller than the required by 250.122, except that 250.122(F) shall not apply where grounded conductors are run in parallel.
Feeder overcorrect protection
Feeders shall be protected against overcorrect in accordance with the provisions of part I of article 240. Where a feeder supplies continuous loads or any combination of continuous and non continuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125% of the continuous load.
Ground Fault Circuit Interrupter Protection for Personnel (Feeders)
Feeders supplying 15 and 20 ampere receptacle branch circuits shall be permitted to be protected by a ground fault circuit interrupter installed in a readily accessible location in lieu of the provisions for such interrupters as specified in 210.8 and 590.6(A)
Ampacity Relative to Service Conductors
The feeder conductor ampacity shall not be less than that of the service conductors where the feeder conductors carry the total load supplied by service conductors with an ampacity of 55 amperes or less.
Ungrounded Conductors Tapped From Grounded Systems
Two-wire DC circuits and AC circuits of two or more ungrounded conductors shall be permitted to be tapped from the ungrounded conductors of circuits hav ing a grounded neutral conductor. Switching devices in each tapped circuit shall have a pole in each ungrounded conductor.
Feeders with Common Neutral Conductor.
Up to three sets of 3 wire feeders or two sets of 4 wire or 5 wire feeders shall be permitted to utilize a common neutral.
Feeder Equipment Grounding Conductor
Where a feeder supplies branch circuits in which equipment grounding conductors are required, the feeder shall include or provide an equipment grounding conductor in accordance with the provisions of 250.134 to which the equipment grounding conductors of the branch circuits shall be connected. Where the feeder supplies a separate building or structure, the requirement 250.32(b) shall apply
Feeders with Common Neutral Conductor in a Metal Raceway or Enclosure
Where installed in a metal raceway or other metal enclosure, all conductors of all feeders using a common neutral conductor shall be enclosed within the same raceway or other enclosure as required in 300.20
Minimum Rating and Size, Feeders not more than 600 volts
(a)Where a feeder supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum feeder conductor size shall have an allowable ampacity not less than the noncontinuous load plus 125% of the continuous load. (b) the minimum feeder conductor size shall have an allowable ampacity not less than the maximum load to be served after the application of any adjustment or correction factors.