225.30; 225.37 [lang]

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fmtjfw

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Section/Paragraph: 225.30, 225.37

Revised Text

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 supply-service 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 an outside supply originates in these additional buildings or other structures, only one feeder or branch circuit outside supply 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 supply-services 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

(B) Special Occupancies.

By special permission, additional feeders or branch circuits supply-services shall be permitted for either of the following:
(1) Multiple-occupancy buildings where there is no space available for supply-service equipment accessible to all occupants
(2) A single building or other structure sufficiently large to make two or more supplies supply-services necessary

(C) Capacity Requirements.
Additional feeders or branch circuits supply-services 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 supply-services 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 supply-services shall be permitted to supply installations under single management where documented safe switching procedures are established and maintained for disconnection.

225.37 Identification.
Where a building or structure has any combination of feeders, branch circuits, or services passing through it or supplying it, a permanent plaque or directory shall be installed at each feeder and branch-circuit disconnect location denoting all other services, feeders, or branch circuits supplying that building or structure or passing through that building or structure and the area served by each.
Where a building or structure has a combination of more than one of the following:
(1) supply-service supplying it, or
(2) outside-supplies passing through it
a permanent plaque or directory shall be installed at each supply-service disconnect location denoting all other supply-services and the area served by each.


Exception No. 1: A plaque or directory shall not be required for outside-supplies for large-capacity multibuilding industrial installations under single management, where it is ensured that disconnection can be accomplished by establishing and maintaining safe switching procedures.

Exception No. 2: This identification shall not be required for branch circuits installed from a dwelling unit to a second building or structure.

Substantiation

This proposal provides the same words for the same concepts in Articles 225 and 230, in conjunction with my "230.2 [lang]" proposal. It uses the defined terms proposed in my "100 Supply, Outside. and Supply-Service[new]" proposal.

The NEC_StyleManual 3.3.5 states: Parallel construction means stating similar requirements in similar ways for greater consistency. This helps makes the NEC clear for users. Lack of consistency often creates confusion, causing users to ask: Does this difference in wording represent a different requirement? Or is it simply two different ways of trying to say the same thing? ....

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