2 AWG Ampacity Chart: Copper vs. Aluminum Wire Ratings & NEC Rules

The ampacity of 2 AWG wire depends entirely on the conductor material (copper vs. aluminum) and the insulation temperature rating. For standard residential and commercial installations, 2 AWG copper wire has an ampacity of 115 amps (at 75°C) or 95 amps (at 60°C). 2 AWG aluminum wire is rated for 90 amps (at 75°C) or 75 amps (at 60°C). If you are using 90°C rated insulation like THHN in a raceway where terminals are also rated for 90°C—which is rare in standard panels—copper jumps to 130A and aluminum to 100A.

Below is the complete reference data, the rules for selecting the correct temperature column, and the real-world derating math that dictates what this wire can actually handle on your jobsite.

The Master 2 AWG Ampacity Reference Table

How to read this table: The rows represent the conductor material. The columns represent the temperature rating of the wire insulation and the connected terminals. The values are in Amperes (A). This data is sourced directly from NFPA 70 (NEC) Table 310.16, based on an ambient temperature of 30°C (86°F) and not more than three current-carrying conductors in a raceway.

Which Temperature Column Applies to Your Installation?

A common mistake on the bench and in the panel is looking at the 90°C stamp on a spool of THHN wire and assuming you can use the 90°C ampacity column. Under NEC 110.14(C), the allowable ampacity of a circuit is limited by the lowest temperature rating of any connected component, including breaker terminals, busbars, and lugs.

• The 60°C Column: Use this for older installations, NM-B (Romex) cable assemblies, or when connecting to equipment explicitly marked for 60°C. Note that while NM-B wire contains 90°C rated conductors, NEC 334.80 mandates that its ampacity be determined using the 60°C column.
• The 75°C Column: This is your default for almost all modern THW, THHW, and XHHW wire, and for terminating THHN wire into standard commercial and residential breakers (which are typically rated 75°C). For 2 AWG copper, this locks your base ampacity at 115A.
• The 90°C Column: Use this only as the starting baseline for derating calculations (ambient temperature and bundling). You can only use the 90°C final ampacity if every single termination point in the circuit is explicitly rated and marked for 90°C, which is exceptionally rare in standard building wiring.

Derating Factors: What the Base Table Cannot Tell You

The table above assumes a perfect environment: an ambient temperature of 30°C (86°F) and a maximum of three current-carrying conductors in a single raceway. When real-world conditions deviate, NEC 310.15 requires you to apply correction factors that can drastically reduce the 2 AWG ampacity.

Ambient Temperature Corrections

If your conduit runs through a hot attic or near a boiler, the wire's ability to shed heat drops. For example, if your 2 AWG THHN copper wire runs through an attic that reaches 40°C (104°F), you must apply a 0.91 correction factor to the 90°C base ampacity (130A × 0.91 = 118.3A). Since 118.3A is still above the 75°C terminal limit (115A), your final ampacity remains 115A.

Bundling (More Than 3 Current-Carrying Conductors)

When you pull multiple circuits through the same conduit, the wires heat each other up. If you pull four 2 AWG THHN copper conductors (e.g., two multi-wire branch circuits or a 3-phase feeder with a neutral that carries unbalanced current), you must apply an 80% adjustment factor.

Real-World Derating Example:
Imagine four 2 AWG THHN copper conductors in a conduit running through a 40°C (104°F) attic.

1. Start with 90°C base ampacity: 130A
2. Apply 40°C temperature correction (0.91): 130A × 0.91 = 118.3A
3. Apply bundling adjustment for 4 conductors (0.80): 118.3A × 0.80 = 94.64A

Because the derated ampacity (94.64A) is now lower than the 75°C terminal rating (115A), the 94.64A value governs. You must drop down to a standard 90A breaker. The base table cannot tell you this; you must run the math for your specific installation.