I was at a small factory about 10,000 sf the other day and noticed something that did not look right to me.

There were 2 services because the bilding was devided in the past. Both 400 amp 3 phase. They each went into a 400 amp Disco and then straight to a bussway maybe 70' long. Off the 2 bussways fed the entire building. Maybe 6-8 panels in different locations 200 and 100 amp were run off the bussway. From those panels it must have fed the lighting, front office, HVAC, and general outlets. They also had the factory machines and a step up transformer off the same duct.

I looked in the NEC and could not find any violations with this. What's your opinion on this. Acceptibale or unaccepticable?

Tom

Regarding the bus duct, I can't think of anything wrong here. This is a very flexible means of distributing power, kind of expensive, but if the power requirements change on a regular basis, might end up being the least expensive way of doing things.

This is a common way of feeding high rise office buildings. Come out of the service gear with 4000A bus duct and run it vertical through the electric rooms. Each room has a place to set a couple of disconnects on the bus to feed the floor. From what you describe I see nothing wrong.

so, how much DOES a bus weigh?

A lot when you are on the other end of the rope hauling them up the elevator shaft.