Cable Wiring Methods: NM, AC, MC, SE and UF — Where Permitted, Support, Protection and Ampacity
Type NM cable is the residential wiring method, so the Residential Wireman exam leans on Article 334 hard; Journeyman and Master items mix NM with AC, MC, SE and UF. The cable articles share the raceway template (.10 uses permitted, .12 not permitted, .15 exposed work, .17 through framing, .23 attics, .24 bending radius, .30 securing/supporting, .80 ampacity), so this lesson is organized by *rule* with the numbers per cable. Written from the 2026 text.
NFPA 70 National Electrical Code, 2026 edition · Reviewed 2026-09-19
Type NM cable is the residential wiring method, so the Residential Wireman exam leans on Article 334 hard; Journeyman and Master items mix NM with AC, MC, SE and UF. The cable articles share the raceway template (.10 uses permitted, .12 not permitted, .15 exposed work, .17 through framing, .23 attics, .24 bending radius, .30 securing/supporting, .80 ampacity), so this lesson is organized by rule with the numbers per cable. Written from the 2026 text.
1. Nonmetallic-sheathed cable — Article 334
Where permitted (334.10): one- and two-family dwellings and their attached or detached garages/storage buildings; multifamily dwellings and detached garages permitted to be Type III, IV or V construction; other structures permitted to be Type III–V where the cable is concealed in walls/floors/ceilings giving a 15-minute finish rating (small Type V grade-level storage garages < 1500 ft² excepted); cable trays in Type III–V where identified; Type I and II construction only inside raceways permitted there.
- Type NM: exposed and concealed in normally dry locations; fished in air voids of masonry block/tile walls not exposed to excessive moisture.
- Type NMC: dry, wet, damp or corrosive locations; shallow masonry chases protected by a 1/16-in. steel plate and plastered over.
Not permitted (334.12): any structure not on the 334.10 list; exposed within a dropped or suspended ceiling cavity in other than one-, two- and multifamily dwellings; as service-entrance cable; commercial garages with classified areas; theaters (except 518.6(C)); motion picture studios; storage battery rooms; hoistways/elevators; embedded in poured cement, concrete or aggregate; hazardous locations except where permitted; direct burial; subject to physical damage. Type NM specifically: not where exposed to corrosive fumes, not embedded in masonry/concrete/adobe/plaster, not in wet or damp locations.
Exposed work (334.15): follow the surface or running boards; where subject to damage, protect with RMC, IMC, EMT, Schedule 80 PVC, RTRC-XW or other approved means; **through a floor — enclose in conduit or tubing
This is where the public part ends.
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