What Article 220 Actually Does
NEC Article 220 is the code section governing how to calculate branch circuit, feeder, and service loads — the procedure that turns "what's connected to this building" into "how big does the electrical service need to be." It exists because a building's total connected load (every outlet, fixture, and piece of equipment added up at face value) is almost always far larger than what actually gets used simultaneously — sizing a service to the full connected load would be enormously wasteful. Article 220's demand factors are the code-sanctioned way of accounting for that: statistically reasonable assumptions about how much of the connected load actually operates at once, applied so the calculated service size reflects realistic demand rather than a worst-case sum of everything installed.