225.30 Number of Supplies. A building or other structure
that is served by a branch circuit or feeder on the load side of a
service disconnecting means shall be supplied by only one
feeder or branch circuit unless permitted in 225.30(A)
through (E). For the purpose of this section, a multiwire
branch circuit shall be considered a single circuit.
Where a branch circuit or feeder originates in these additional
buildings or other structures, only one feeder or branch
circuit shall be permitted to supply power back to the original
building or structure, unless permitted in 225.30(A)
through (E).
(A) Special Conditions. Additional feeders or branch circuits
shall be permitted to supply the following:
(1) Fire pumps
(2) Emergency systems
(3) Legally required standby systems
(4) Optional standby systems
(5) Parallel power production systems
(6) Systems designed for connection to multiple sources of
supply for the purpose of enhanced reliability
(7) Electric vehicle charging systems listed, labeled, and identified
for more than a single branch circuit or feeder
(B) Special Occupancies. By special permission, additional
feeders or branch circuits shall be permitted for either of the
following:
(1) Multiple-occupancy buildings where there is no space
available for supply equipment accessible to all occupants
(2) A single building or other structure sufficiently large to
make two or more supplies necessary
(C) Capacity Requirements. Additional feeders or branch
circuits shall be permitted where the capacity requirements are
in excess of 2000 amperes at a supply voltage of 1000 volts or
less.
(D) Different Characteristics. Additional feeders or branch
circuits shall be permitted for different voltages, frequencies,
or phases, or for different uses such as control of outside lighting
from multiple locations.
(E) Documented Switching Procedures. Additional feeders or
branch circuits shall be permitted to supply installations under
single management where documented safe switching procedures
are established and maintained for disconnection.
