Quick Hits

Article 120 of the 2026 NEC is where electrical systems get sized with real-world logic instead of guesswork. This article covers how to calculate the total electrical load for branch circuits, feeders, and services so that equipment like panels, conductors, and main breakers are properly rated for the job.

Instead of assuming every load runs at full capacity at the same time, Article 120 introduces structured methods using unit loads, demand factors, and noncoincident load rules. This allows electricians to design systems that are both safe and practical, reflecting how buildings actually use power.

From lighting and receptacles to HVAC and large appliances, Article 120 ties everything together into one complete load calculation system. The final result determines service size, feeder sizing, and overall system capacity.

In short: NEC 120 is the blueprint for turning electrical loads into properly sized, code-compliant systems that won’t fail under real operating conditions.