Loads Calcs with multiple AC units

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monkey

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On a residence with multiple air conditioning/ heating systems must I take the total of all the systems at 100%? The residence in question has two 5 ton units and a 2 ton. The total Air Cond load comes to 23,040 VA if I add them all together, including the air handler motors. The 25% of the largest motor adds another 2,130VA.

This residence also has a mechanics lift, at 1,656 VA, which I am assuming must be included in the calcs.
 
unless the air conditioning units are coincident loads and will not operate at the same time, you will have to take 100% or the nameplate of the larger of the air conditioning or heating, but not both, 220.82(C).

The air handling unit should be calculated as a motor load per 220.14(C).

The lift probably falls under 220.14(A). I do not know if that would qualify as one of the "four or more" appliances. Does the inspector consider the lift an appliance per the definition in Artical 100?:D
 
Wirenut, you are confusing me :D . 220.82C says I must take "100% of the nameplate rating(s) of the air conditioning and cooling". It doesn't say just one of them at 100 %.

Yes they could all (3) run at the same time, the residence is 4,000 square feet and in Arizona. In fact, they WILL all be running at the same time.
 
I should not have even mentioned heat. The heat is gas, the AC is definately the largest load, and there are three of them which will all run at once. So I it looks like 100% of the total of the three units to me.
 
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monkey said:
I should not have even mentioned heat. The heat is gas, the AC is definately the largest load, and there are three of them which will all run at once. So I it looks like 100% of the total of the three units to me.
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That is the way I interpret it.
 
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