Services — Service Entrance Requirements

The electrical service is where utility power enters a building. Article 230 governs every component of that entry point, organized into eight parts. Part I covers general requirements, including the rule that a building should normally have only one service (with exceptions for large buildings, fire pumps, and similar situations). Part II covers service drops — the overhead wires from the utility pole to the building — including clearance heights above ground, driveways, and rooftops. Part IV covers underground service laterals, including burial depth requirements that tie back to Table 300.5. Part V covers service-entrance conductors, which run from the service point to the service disconnect. Part VI is where the critical disconnect rules live. Section 230.70 requires the service disconnect to be installed at a readily accessible location either outside or inside nearest the point of entry. The old six-disconnect rule (230.71) was significantly revised in the 2020 NEC: you can still use up to six disconnecting means as the service disconnect, but each must now be in its own separate enclosure — you can no longer have six breakers in a single panelboard serve as the service disconnect. Perhaps the most impactful 2020 change was the addition of Section 230.85, which requires an emergency disconnect on the exterior of every one- and two-family dwelling. This outdoor disconnect must be clearly marked with the words 'EMERGENCY DISCONNECT' in letters at least one-half inch high, and it must be readily accessible to first responders. It can be the main breaker itself, a meter disconnect, or a dedicated switch.