So you are saying that if such a service or feeder exists it allows the ampacity reduction factor to apply to every feeder in the dwelling unit? If that had been intended, the wording would have been different.
Perhaps. I cannot speak to the intent with any certainty.
If the main is 100A, the likelihood of having a sub feeder is greatly reduced. Additionally, demand reduction for general loads doesn't even kick in until the load goes over 10kVA (42A at 240V). Where the general load is less than the main, the demand as a percentage of the before-reduction load would be greater.
The only place I see a potential problem is under (C)(5) where four or more space heater loads are permitted a 40%-of-nameplate demand.
The condition clearly (to me anyway) applies to the service or feeder wire whose ampacity you are calculating. Simple English grammar.
Exactly. Including any feeder that does not supply the total load. Simple English grammar does not exclude a sub feeder. The context of the first sentence of (A) establishes the dwelling unit must be supplied by conductors, service or feeder, of 100A or greater.
Dwelling unit is the subject of the first sentence. There is no conditional clause regarding the feeder mentioned in subsequent sentences. One could say the feeder mentioned in subsequent sentences must be the same feeder mentioned in the first sentence, which is your position. I do not see enough context in the subsequent sentences to support that interpretation.
Under your interpretation the factor would apply to every feeder in almost every dwelling and most of our accepted test answers would be wrong.
The scope of that statement is quite broad. Which feeders? What answers? You'll have to be more specific.
