Calculating Air conditioning Loads in optional Load calcs for single family dwelling

[Designer101]

220.82(c) Heating and Air condition load( optional)
When there is two or more Ac units, do we have to take Largest or have to consider both?I know if there is a Heating we used the largest between the AC and Heat but when there are two or more AC units what we select, we select both or largest of two?

 

[david luchini]

220.82(c) Heating and Air condition load( optional)
When there is two or more Ac units, do we have to take Largest or have to consider both?I know if there is a Heating we used the largest between the AC and Heat but when there are two or more AC units what we select, we select both or largest of two?

Both

 

[Designer101]

I saw a lot post on this but I am still confused, I saw the article says size wires based on minimum ampacity and size fuses based on maximum ampacity.
Now my concern here is I am trying to Derate the main panel and what amps I should use to calculate the power , maximum current or minimum ampacity from the name plate.

 

[follybeacher]

Populate your panel schedule based on each unit’s MCA. MOP is the breaker/fuse size. If there’s 2 mechanical units, you need to populate both loads in the panel schedule.

I’m not sure if this is what you’re asking, but it may be… if there’s non-cononcurrent loads in a single piece of equipment you may take the largest of the two loads. An example would be if there is strip heat and it will not run concurrently with the AC. You can take the largest loads, presumably the strip heat and then add the blower motor load. In this example, would be more VA than the compressor and blower motor and they would not run concurrently. In reality, I would imagine the unit’s namplate and MCA/MOP would already take that into consideration.

ETA - don’t assume anything and get yourself in trouble please