HVAC Calculation

[gmayeux]

I am trying to back check a commercial feeder calculation, and there is a disagreement on HVAC calculations. Please let me know if this is correct, determine which is the larger load, AC or heat (excluding any heat pump scenarios), the larger load is used, the other load is dropped. if the AC is the larger load what is the approved method, largest motor at 125% plus the sum of other motor loads? or do you follow you 440.22 (B)2

 

[augie47]

I very well may be incorrect in my view, but IMO, Art 440 does not address feeders.
440.22, etc. discuss branch circuit calculations. I am of the opinion you must follow 440.3 and use Part V of Art 430.

 

[Smart $]

You have to go by this, and wherever it leads to...

220.50 Motors. Motor loads shall be calculated in accordance
with 430.24, 430.25, and 430.26 and with 440.6 for
hermetic refrigerant motor compressors.

FWIW, the extra 25% for the largest motor can come from either cooling or heating, regardless of which HVAC portion is the largest overall.