Specifies requirements for the design and construction of busbar trunking systems (busways) for use on alternating current systems with rated voltages exceeding 32 V and up to 1000 volt and on direct current systems with rated voltages exceeding 115 V and up to 1500 V. Covers busbar trunking systems enclosed by metal or insulating material or a combination of both and applies to complete factory manufactured units, prefabricated and site assembled units and to units fabricated and assembled on site. Specifies requirements and tests for dielectric properties, temperature-rise limits, short-circuitry capacity and mechanical strength.