The Electrical Code

220.40 General. To begin part 3 of article 220 it refers to feeders and service calculation. Because you have gotten this far this action independently speak volumes about your curiosity of the subject of electricity.

“The calculated load of a feeder or service shall not be less than the sum of the loads on the branch circuits supplied, as determined by Part II of this article, after any applicable demand factors permitted by Part III or IV or required by Part V have been applied.

Informational Note: See Examples D1(a) through D10 in Informative Annex D. See 220.18(B) for the maximum load in amperes permitted for lighting units operating at less than 100 percent power factor.”