This Standards Publication covers products for distribution of electric power at 600 volts or less, consisting of enclosed sectionalized prefabricated busbars rated at 100 amperes or more, and associated structures and fittings, classified as follows:

a. Feeder busways (indoor or outdoor)

b. Plug-in busways (indoor only)

c. Accessories required to complete the busway system

It does not pertain to metal-enclosed busways as described in the ANSI/IEEE C37.23 Standard.