Chapter 1: Key NEC Article Relationships

Diagram showing NEC Article 220 branch circuit, feeder, and service calculations at the center, connected to Articles 210, 215, 230, 231, 240, 250, 422, 424, 440, and 550

Site plan showing overhead electric line from a utility pole to a house

Service entrance wiring diagram from a generator through high-voltage lines, a pole-mounted transformer, service drop lines, and a service head, into a multi-story building

Floor plan of a single-story home showing interconnected smoke alarms in each of three bedrooms, in the connecting hallway, in the living room area, and near the kitchen

Utility pole diagram showing high-voltage lines terminating at an insulator, a pole-mounted transformer, low-voltage lines branching in two directions, and a service drop connection point

Grid-tied photovoltaic system diagram showing solar panels connected through an inverter to a main panel, which connects to a dwelling/residential load and to the utility grid through a utility meter

Cross-section diagram showing circuit breakers in a panel, conduit running up an exterior wall to a fused switch, and an outdoor air conditioner condensing unit

Diagram showing service equipment feeding a panelboard and branch circuit receptacles, and a separate generator feeding an independent panelboard and its own branch circuit receptacles