There are many companies that sell a bus duct. Examples of companies that sell a bus duct include South Land Electrical, Sailing Electrical, and BD Electrical.

busbar sizing & calculation

The output from a utility generator is low-voltage and very high current (later stepped up to a high voltage for transmission). The high current requires very large conductors, and busbars enclosed in a bus-duct are the most practical way to accomplish this. Some generating systems also circulate coolant through the bus-duct to keep the bus bars from overheating.

Bus bars are actually simple conductor strips of copper using for connection between one system to another.for example transformer to panel. bus ducts are enclouser of that bus bar

A bus duct by itself should have a SC time in the milliseconds. What is connected directly upstream and downstream of the bus duct, breakers, meters? Is this for an Arc Flash Hazard Study?