Sizing of main feeder

[m sleem]

Continous load X 1.25 + Non Continous load+ 25% of largest motor

Are we using the above rule to calculate (main feeder,main breaker,transformer,generator)?

 

[augie47]

That would be true for sizing the feeder (see 430.24).
The feeder short-circuit ground fault could be sized be 430.62.
Transformers and generators can get tricky especially if large motors are involved. Engineering and/or factory assistance plays a good role in those situations due to the different characteristics of motors such a LRA>

 

[Little Bill]

Continous load X 1.25 + Non Continous load+ 25% of largest motor

Are we using the above rule to calculate (main feeder,main breaker,transformer,generator)?

In a nutshell, most everything but the service size.