Service Calculations for Bus Duct

[tom2298]

In an industrial project I have 3 runs of 1000 A 480V/3 Bus Duct. I also have 3 runs of 600 A 208V/3 Bus Duct and 3 runs of 200A 240v/3 Bus duct. Do I have to include the entire load in the service calculations? There is no way there will be that much load connected.

 

[charlie b]

Service load calculations are not based on the choices you make for wire sizes. Using various sizes of bus duct is essentially a choice of wire sizes. You need to start with the connected load, then apply any allowable demand factors. The final value of calculated service load is what you tell to the utility. They will then give you a transformer that is perhaps 40% of that size.

If all you know about the loads at this point in the design phase is that you will have that set of bus ducts, then I think you have started in the middle, and need to return to the beginning.

Welcome to the forum.