110.1 Scope
Article 110 establishes general requirements for examination and approval, installation and use, access and space around equipment, personnel-entry enclosures, and tunnel installations.
110.2 Approval
Conductors and equipment required or permitted by the NEC must be approved. Approved = acceptable to the Authority Having Jurisdiction. A listing or label does not eliminate the AHJ’s role.
110.3(A) Examination
Equipment evaluation considers suitability for intended use, mechanical strength, wire-bending and connection space, insulation, heating and arcing effects, type, size, voltage, current capacity, and use. The question is not only “is it listed?” It is also “is it suitable here?”
110.3(B)–(C)
Listed, labeled, or identified equipment must be installed and used according to the instructions associated with that evaluation. Listing is performed by recognized qualified electrical testing laboratories.
Field tip
When equipment seems questionable, go beyond the nameplate. Check the listing, instructions, intended use, and actual installation condition. Next: 110.4–110.8.
Code basis
NEC 2026 Article 110 education from the owner-provided Daily Code Talk. Confirm adopted edition. Not an equipment selection.