MH's Electrical NEC Exam Prep Book...question

[frankgi]

This may be a long shot, because I do not know how many people have the book, but I am trying to find out about a factor in a commercial calculation in the MH Exam Prep book. On page #469-Unit#11- Commercial Calculations-Part C- Examples-11.20 Bank (120/240 single phase), in the summary, bottom of the page, where are they getting the rule to apply the "largest motor 25%" from? The 1610 VA shown is 25% of the Sprinkler Pump load ..6440VA. (6440 x.25) I just cant seem to find where this rule applies, and why is it shown as a neutral calc (in the summary) when it is a 230v load. AND the largest motor in the calc is the AC at 11,500VA.
Am I missing something?
Thanks in advance!

 

[bphgravity]

Article 220.18(A) of the NEC....

 

[frankgi]

Thanks BPHGRAVITY. That accounts for the 25% motor load (1.25 would of made it 1 step) of the sprinkler motor, but still dont see why it would be added to the neutral line AND not applied to the AC load which is larger than the sprinkler motor.

 

[frankgi]

Upon further reading, "motor-operated utilization equipment that is fastened in place" is what separates the AC load from the sprinkler,(??) which is why the 125% of the sprinkler load is part of the calc. Still cant see why the 25% is applied to the neutral line though.