Cabinets and Wire-Bending Space
(312), Underground Wiring (Table 300.7(A)), and the Article 300 General Rules
NFPA 70 National Electrical Code, 2023 edition · Reviewed 2026-09-21
Two named topics of the Wiring Methods and Materials blueprint — cabinets and panels, and underground wiring — plus the general rules of Article 300 that every other wiring-method question assumes. In the 2023 edition the Article 300 map is: 300.3 conductors, 300.4 protection against physical damage, 300.5 underground installations, 300.7 raceways exposed to different temperatures, 300.9 raceways in wet locations above grade, 300.11 securing and supporting, 300.13 conductor continuity, 300.14 free conductor length, 300.15 boxes, 300.17 raceway fill, 300.19 vertical supports; Article 312 runs 312.2 damp/wet, 312.3 position in wall, 312.4 repairing gaps, 312.5 cables entering, 312.6 wire-bending space, 312.8 splices in switch enclosures. Written from the 2023 text.
1. Underground wiring — 300.5 and Table 300.5(A)
Table 300.5(A) minimum cover, in inches (measured from the top of the conductor/raceway to the finished surface):
| Location | Col. 1 Direct burial cables/conductors | Col. 2 RMC / IMC | Col. 3 Nonmetallic raceways listed for direct burial (PVC, RTRC) | Col. 4 Residential 120 V, ≤ 20 A, GFCI-protected branch circuits | Col. 5 ≤ 30 V irrigation / landscape lighting (UF, listed cable) |
|---|---|---|---|---|---|
| All locations not specified below | 24 | 6 | 18 | 12 | 6 |
| In trench below ≥ 2-in. concrete | 18 | 6 | 12 | 6 | 6 |
| Under a building | 0 (in raceway, or MC/MI listed for direct burial) | 0 | 0 | 0 | 0 |
| Under ≥ 4-in. exterior concrete slab, no vehicles, slab extending ≥ 6 in. beyond | 18 | 4 | 4 | 6 direct / 4 in raceway | 6 direct / 4 in raceway |
| Under streets, highways, roads, alleys, driveways and parking lots | 24 | 24 | 24 | 24 | 24 |
| One- and two-family dwelling driveways and outdoor parking (dwelling use only) | 18 | 18 | 18 | 12 | 18 |
| Airport runways / adjacent taxiways | 18 | 18 | 18 | 18 | 18 |
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