Where it moved
In the 2026 NEC, branch-circuit, feeder and service load calculations moved from Article 220 to Article 120, in Chapter 1. Expect older notes, spreadsheets and plan-review comments to cite 220 for the same rules for a while.
What Article 120 covers
Branch-circuit, feeder and service calculations.
Dwelling and multifamily loads.
Lighting and receptacle demand.
Motors and air-conditioning equipment.
Electric space heating, appliances and cooking equipment.
EVSE.
Neutral loads.
Existing-building capacity.
Optional calculation methods and special occupancies.
Why it matters
A building can have 500 kVA of connected equipment without needing a 500 kVA service. Aggressive demand assumptions can also undersize the infrastructure. The engineering question is what load the system must be designed to carry under the NEC, and the answer depends on connected load, maximum demand, demand factors, noncoincident loads, controlled loads and optional methods. Those decisions size branch circuits, feeders, services, transformers, panelboards and generators, and decide whether an existing service can take electrification.
MEP coordination
Article 120 runs on other disciplines’ data: HVAC MCA and nameplate data, electric heat, motors and pumps, water heaters, kitchen equipment, EV charging and the equipment operating sequences. When the mechanical or equipment schedule changes, the electrical calculation can change with it.
The 125 percent point
Article 120 does not require continuous loads to be calculated at 125 percent. That does not retire the 125 percent concept: the conductor and overcurrent-device sizing rules for branch circuits, feeders and services still apply it. Load calculation and equipment sizing are related, but they are not the same calculation.
How the series will run
How the calculation logic works.
Where demand factors can and cannot be used.
How MEP equipment drives electrical infrastructure.
Existing-building capacity.
Common plan-review mistakes.
Where optional methods materially change a project.
Code basis
NEC 2026 Article 120 education from the owner-provided Daily Code Talk. The 2026 NEC is the model edition; Florida’s building code references an earlier NEC edition, where these rules sit in Article 220. Confirm the adopted edition before applying a 2026 change to a project.