MCC bus sizing Help

[samtorres66]

I have a total of 654hp motor list, largest motor 150hp. The 150hp (on a starter contactor) runs a meat grinder which will only operate continuosly for no more than 10min at a time. My estimate gives me an 800amp bus. Will this size do the trick? how do you properly calculate the proper bus size for such load?
Thanks
Sam

 

[jraef]

If you are in the US and subject to the NEC, 125% of the largest FLC plus total of all other FLC of motors that will potentially be running at the same time. This is actually how you would size the main conductors if it were field wiring, but there is no other rule pertaining strictly to the bus bars that allows for anything less.

430.24 Several Motors or a Motor(s) and Other Load(s).
Conductors supplying several motors, or a motor(s) and other
load(s), shall have an ampacity not less than the sum of each
of the following:
(1) 125 percent of the full-load current rating of the highest
rated motor, as determined by 430.6(A)
(2) Sum of the full-load current ratings of all the other
motors in the group, as determined by 430.6(A)
(3) 100 percent of the noncontinuous non-motor load
(4) 125 percent of the continuous non-motor load

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[waross]

If you are in Canada and subject to the CEC you are probably safe with 800 Amp bus.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[healyx]

What voltage are you running at?