Current-carrying wiring devices (NAICS 335931) are designed to conduct electrical current — examples include receptacles, plugs, connectors, switches, and lamp holders. Noncurrent-carrying devices (NAICS 335932) provide mechanical support or protection without conducting current, such as conduit fittings, junction boxes, and cable trays. The distinction affects both NAICS classification of the manufacturer and, in some cases, the applicable HTS subheading for imports.

Ground-fault circuit interrupter (GFCI) and arc-fault circuit interrupter (AFCI) outlets incorporate protective electronics but are generally classified within the same HTS subheadings as standard receptacles under Chapter 85, based on their function as current-carrying wiring devices. However, the added electronic components can sometimes raise classification questions, and a binding ruling from CBP may be warranted for high-volume imports of these specialty devices.