Standard calculations are for all types, commercial, SFD, and multi family dwellings.
Optional is for SFD and MFD of at least 100 amps per dwelling.
IV. Optional Feeder and Service Load Calculations
220.80 General. Optional feeder and service load calculations
shall be permitted in accordance with Part IV.
220.82 Dwelling Unit.
(A) Feeder and Service Load. This section applies to a
dwelling unit having the total connected load served by a
single 120/240-volt or 208Y/120-volt set of 3-wire service
or feeder conductors with an ampacity of 100 or greater.
220.84 Multifamily Dwelling.
(A) Feeder or Service Load. It shall be permissible to
calculate the load of a feeder or service that supplies three
or more dwelling units of a multifamily dwelling in accordance
with Table 220.84 instead of Part III of this article if
all the following conditions are met:
(1) No dwelling unit is supplied by more than one feeder.
(2) Each dwelling unit is equipped with electric cooking
equipment.
Exception: When the calculated load for multifamily dwellings
without electric cooking in Part III of this article exceeds
that calculated under Part IV for the identical load
plus electric cooking (based on 8 kW per unit), the lesser of
the two loads shall be permitted to be used.
(3) Each dwelling unit is equipped with either electric space
heating or air conditioning, or both. Feeders and service
conductors whose calculated load is determined by this
optional calculation shall be permitted to have the neutral
load determined by 220.61
