NEC 2023, Articles 300 (wiring) and 310 (conductors) — translation

Clause-by-clause translation of NEC Articles 300 and 310: NM cables and EMT, cable protection, burial depths, ampacity per Table 310.16, AWG to mm².

Document

Document	NEC 2023, Articles 300 (wiring) and 310 (conductors)
Edition	2023
Status	Current (latest NEC edition)
Issued by	NFPA
Applies to	Wiring methods (300) and conductors/ampacity (310)

Document structure

№	Chapter / section
300.1–300.25	General wiring methods
310.3–310.10	Conductors: types, insulation
310.12	Dwelling service simplified sizing
Table 310.16	Ampacity table (60/75/90 °C)

Wiring (300.1–300.25)

300.4 Cable protection plates at wall/beam penetrations.

300.5 Burial depths: UF cables 0.45 m (18 in), conduits 0.15 m (6 in) with protection, under driveways 0.6 m (24 in); above-ground exits protected.

300.15 Splices only in accessible boxes.

Conductors (310.3–310.10)

310.3 Conductor types per environment: THHN, THWN-2, XHHW-2 (90 °C class).

310.12 Simplified dwelling sizing 120/240 V: up to 100 A — 4 AWG copper (2 AWG aluminium).

Ampacity Table 310.16

Copper at 75 °C, ≤ 3 conductors in conduit: 14 AWG — 20 A; 12 AWG — 25 A; 10 AWG — 35 A; 8 AWG — 50 A; 6 AWG — 65 A; 4 AWG — 85 A; 2 AWG — 115 A; 1/0 — 150 A. Correction factors: ambient, 4–6 conductors 0.8, 7–9 — 0.7.

Practical takeaways

12 AWG (3.31 mm²) — 25 A, close to 2.5 mm² per PUE (27 A). The difference: AWG sizes and 60/75/90 °C columns; dwellings use 75 °C.

Data is for reference. Final design decisions must follow current regulations and a qualified engineer.
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