Motor subpanel

[jefftino]

Hi,
I am trying to properly size a subpanel for motors and pumps and a lighting circuit.

Here's what I have:
15 HP 3 phase
7.5 HP 3 phase
7.5 HP 3 phase
2 120 volt dispensing pumps 20 amps each
1 20 amp lighting circuit (maybe 208 volts)
1 120 volt control circuit

I go to 220.50 Motors
Then 430.24 motors and other loads

This is the 125% of largest motor plus sum of FLA ratings of other motors plus
100% non continuous loads plus
125% continuous loads

I get 191.15 amps
This would be for the minimum ampacity for the conductors.
So I am looking at a 3 phase 200 amp sub panel. Is this correct?

Thanks for your help.

Jeff


Sent from my iPhone using Tapatalk

 

[augie47]

I came up with a smaller number (did you take into account the 120v loads could be divided between he phases ?)
Your 200 amp panel looks o.k., IMO

 

[Smart $]

Didn't do the math, but I mostly agree. However, there might be an issue if it is a main breaker panel. If there is an occasion where all the loads are energized at the same instance, such as upon power restoration after an outage, the main breaker could trip. Shouldn't be a problem if MLO. See 430.63 to start with.