Issuing body: UL
UL 857
Busways
UL 857 covers service-entrance, feeder and branch-circuit busways and their associated fittings, rated 600 V or less and up to 6000 A. A busway under this standard is a grounded metal enclosure containing factory-mounted copper or aluminium bars, rods or tubes. It excludes metal-enclosed bus used to connect switchgear assemblies in prefabricated distribution systems. For a busway manufacturer this is the standard that constrains housing construction, joint design and the current ratings that can be declared.
Technical background
Standards
Which busbar standard applies to your job
A decision tree from product type, voltage class and destination market to the governing standard set, with each standard placed at its actual scope boundary.
Busduct and busway
Joggle, flare and fish plate: how a busduct joint is made
How busduct conductors are joggled, flared and fish-plated into a single-bolt joint, and why hole pitch accuracy compounds along a run.
Busduct and busway
What data-centre demand changes on a busway shop floor
What rising rack density changes on a busway shop floor: joint-plane tolerance, joint count, plating specification, throughput and batch records.
Standards and compliance
Processes