Home›Knowledge›NEC Article 310 — Conductors for General Wiring
📋 Codecodeselectrical

NEC Article 310 — Conductors for General Wiring

Updated Mar 26, 2026
Conductor types, ampacity tables, temperature ratings, derating for fill and ambient temperature.

NEC Article 310: Table 310.16 is THE ampacity table. Copper at 60C/75C/90C column (use connector rating, not conductor). 14 AWG: 15/15/15A. 12 AWG: 20/20/25A. 10 AWG: 30/30/35A. 8 AWG: 40/50/55A. 6 AWG: 55/65/75A. 4 AWG: 70/85/95A. 3 AWG: 85/100/115A. 2 AWG: 95/115/130A. 1 AWG: 110/130/145A. 1/0: 125/150/170A. 2/0: 145/175/195A. 310.15(B)(3)(a) adjustment for >3 current-carrying conductors: 4-6 = 80%, 7-9 = 70%, 10-20 = 50%. 310.15(B)(2) ambient temperature correction per Table 310.15(B)(2)(a). Conductor types: THHN/THWN-2 (most common, 90C dry/wet), XHHW-2, USE-2 (underground).

TAGS
NECconductorampacitywire-sizingTHHNtemperature-rating
DETAILS
code year
2023
code system
NEC
code section
Article 310
RELATED KNOWLEDGE
📋 Code
IBC 903.2.1 — Group A Occupancies (Sprinkler Requirements)
Automatic sprinkler system required throughout buildings with Group A occupancy where fire area exceeds 5,000 square feet, or overall building area exceeds 12,000 square feet, or occupant load of the fire area exceeds 300.
📋 Code
IBC 903.2.7 — Group M Occupancies (Retail Sprinkler Requirements)
Automatic sprinkler system required in Group M (mercantile) occupancies where fire area exceeds 12,000 square feet or building is more than three stories above grade.
📋 Code
IBC 903.2.11.3 — Buildings 55 Feet or More in Height
Automatic sprinkler system required throughout buildings with a floor level having an occupant load of 30 or more that is located 55 feet or more above the lowest level of fire department vehicle access.
📋 Code
IBC 1015.1 — Exit and Exit Access Doorways Required
Two exits or exit access doorways required from any space where occupant load exceeds the table values. Spaces with occupant load exceeding 500 require a minimum of 3 exits. Spaces exceeding 1,000 require 4 exits.
📋 Code
IBC 1017.2 — Exit Access Travel Distance
Maximum travel distance from any point in a building to an exit shall not exceed 200 feet unsprinklered or 250 feet sprinklered for most occupancies. Specific occupancies have modified limits.
📋 Code
IBC Table 601 — Fire-Resistance Rating Requirements
Specifies minimum fire-resistance ratings for structural elements based on construction type (Type I through V). Type IA requires 3-hour rated structural frame, 2-hour floors, and 1.5-hour roof.
← Back to Knowledge Garden