Short-circuit calculations must be submitted for systems with an aggregate generating capacity of 1500 kilowatts or more by utilizing one of the following methods:

1. (a) Exact calculations using actual impedance and reactance values of system components.
2. (b) Estimated calculations using IEC 61363-1:1998 for AC systems and IEC 61660-1:1997 for DC systems (both incorporated by reference; see § 110.10-1 of this subchapter).
3. (c) The estimated calculations using a commercially established analysis procedure for utility or industrial applications.