/ Field knowledge · NEC 90.1 · Sparky Edition
Scope does not stop at the exterior wall.
NEC 90.1 / 90.2(A)(1): before you size a feeder, decide whether the installation is even in the Code. Scope does not stop at the exterior wall, the service equipment, or new construction.
Educational 2026 NEC 90.1 and 90.2(A)(1). Confirm the adopted edition. Pairs with 90.2(A)(2) not covered.
- 90.1 is the Code’s operating manual: how it is used, applied, arranged, and enforced — including mandatory “shall,” permissive “shall be permitted,” and informational text.
- 90.2(A)(1) covers installation and removal of electrical conductors, equipment, and raceways; signaling and communications systems; and optical-fiber cables.
- Covered installations include buildings, structures, mobile homes, RVs, and floating buildings; yards, parking areas, carnivals, and industrial substations; connections between premises wiring and the electricity supply; certain utility-used buildings outside generating plants, substations, and control centers; marina and boatyard shore-power systems, including leakage-current monitoring; and systems exporting vehicle power to premises wiring or allowing bidirectional current flow.
Trace each path from source to load. At every transition — utility to premises, existing to new, energized to de-energized, fixed to vehicle-exportable — identify ownership, protection, the disconnecting means, and where that is documented. “Existing to remain” is a claim, not a verified condition. “By utility” without a demarcation is not a scope determination.
Site lighting, demolition, V2B
Site work, demolition, marina shore power, and vehicle-to-building export affect grounding, overcurrent, disconnects, ratings, and available fault current. Put the scope on the drawings, not only in a spec. Specialty systems need their own one-line, not a generic note.
Source: Sparky 90.1 / 90.2(A)(1) · not covered: 90.2(A)(2) · service: service boundaries.
What to send
The one-line, what is “existing to remain,” and any site / marina / vehicle-export piece.
If the set never says what is in NEC scope
Send the one-line. Masterbuild will say whether 90.2(A)(1) even covers that path — or the team assumed the wall was the limit.
Send Project Background+1 (786) 398-6940 · osmany.portal@masterbuildconsulting.com
Masterbuild provides engineering services under a written scope. Nothing on this page is project-specific engineering advice, a code interpretation for your project, or a representation about permit approval. Confirm the adopted edition. Field observations do not establish electrical safety; only qualified personnel using required safe-work procedures should access electrical equipment.