2 AWG copper wire is rated for 115 amps in both the 75°C and 90°C columns, and 95 amps in the 60°C column. 2 AWG aluminum wire is rated for 90 amps (75°C) and 75 amps (60°C). These base values assume an ambient temperature of 30°C (86°F) and no more than three current-carrying conductors bundled in a raceway. Sourced directly from the National Electrical Code (NEC), these numbers dictate your breaker sizing and termination limits.
The 2 AWG Wire Ampacity Chart (NEC Table 310.16)
To use this chart effectively, you need to understand how the NEC structures ampacity. The rows represent the American Wire Gauge (AWG) size, while the columns represent the maximum temperature rating of the wire's insulation. The values below are extracted from NFPA 70 (NEC) Table 310.16, which is the definitive standard for conductor ampacities in the United States.
| Wire Size (AWG) | Material | 60°C (140°F) | 75°C (167°F) | 90°C (194°F) | Common Insulation Types |
|---|---|---|---|---|---|
| 4 AWG | Copper | 70 A | 85 A | 95 A | THWN, THHN, XHHW |
| 3 AWG | Copper | 85 A | 100 A | 105 A | THWN, THHN, XHHW |
| 2 AWG | Copper | 95 A | 115 A | 115 A | THWN-2, THHN, XHHW-2 |
| 1 AWG | Copper | 110 A | 130 A | 130 A | THWN-2, THHN, XHHW-2 |
| 1/0 AWG | Copper | 125 A | 150 A | 150 A | THWN-2, THHN, XHHW-2 |
| 4 AWG | Aluminum | 55 A | 65 A | 75 A | THWN, THHN, XHHW |
| 3 AWG | Aluminum | 65 A | 75 A | 85 A | THWN, THHN, XHHW |
| 2 AWG | Aluminum | 75 A | 90 A | 100 A | THWN-2, THHN, XHHW-2 |
| 1 AWG | Aluminum | 85 A | 100 A | 115 A | THWN-2, THHN, XHHW-2 |
| 1/0 AWG | Aluminum | 100 A | 120 A | 135 A | THWN-2, THHN, XHHW-2 |
Which Temperature Column Applies to Your Installation?
A common mistake on the jobsite is looking at the 90°C column because most modern THHN wire is rated for it. However, NEC 110.14(C) enforces the weakest link rule. Your allowable ampacity is limited by the lowest temperature rating of any connected component, including the breaker lugs, bus bars, and terminal strips.
- The 75°C Column (The Standard): Almost all modern breakers, panelboards, and disconnect switches manufactured after the 1990s are rated for 75°C terminations. If you are pulling 2 AWG copper THHN into a standard Square D or Eaton panel, your legal termination limit is 115 amps. Notice that for 2 AWG copper, the 75°C and 90°C columns share the exact same value (115A)—an anomaly in the NEC table that makes this specific wire size forgiving.
- The 60°C Column (The Legacy Limit): You must use the 60°C column (95A for copper, 75A for aluminum) if you are terminating into older equipment lacking a 75°C stamp, or if you are using NM-B (Romex) cable. While 2 AWG NM-B is exceptionally rare in modern branch circuits, if you encounter it, the NEC mandates the 60°C ampacity regardless of the wire's actual insulation rating.
- The 90°C Column (For Derating Only): You can only use the 90°C column as a starting point for calculating derating factors (explained below). The final calculated ampacity after derating can never exceed the 75°C termination limit of your breaker.
How Derating Factors Modify the Base Ampacity
The 115A and 90A figures in the chart above are laboratory ideals. In the real world, heat dissipation is compromised by high ambient temperatures and bundling wires tightly together in conduit. When these conditions occur, you must apply correction and adjustment factors outlined in OSHA and NEC Article 310.15.
1. Ambient Temperature Correction:
If you are routing 2 AWG THHN (90°C rated) through a South Texas attic that hits 110°F (43°C), you cannot use the base 115A. According to Table 310.15(B)(1), the correction factor for 90°C wire at 41-45°C is 0.87.
Calculation: 115A × 0.87 = 100.05A. Your wire is now legally limited to 100 amps before it even hits the breaker.
2. Conduit Bundling Adjustment:
If you pull more than three current-carrying conductors in a single raceway, they heat each other up. For 4 to 6 conductors, Table 310.15(C)(1) requires you to multiply the 90°C ampacity by 80%.
Calculation: 115A × 0.80 = 92A.
Frequently Asked Questions About 2 AWG Wire Amps
Can I use 2 AWG wire for a 100-amp subpanel?
If you are using 2 AWG copper, yes. Its 75°C ampacity is 115 amps, which safely exceeds the 100-amp breaker protecting the feeder. However, if you are using 2 AWG aluminum (like SER cable), the answer is no. 2 AWG aluminum is only rated for 90 amps at 75°C. For a 100-amp aluminum feeder, you must step up to 1 AWG or 1/0 AWG aluminum, depending on your local AHJ's interpretation of continuous loads and voltage drop.
How many watts can 2 AWG copper wire handle at 240 volts?
Using the formula Power = Voltage × Current (P = V × I), a 240-volt circuit on a 2 AWG copper wire rated at 115 amps can handle a maximum of 27,600 watts (27.6 kW). However, if the load is continuous (running for 3 hours or more, like an EV charger or HVAC unit), NEC 210.20 requires you to derate the breaker to 80% of its capacity. In that scenario, your continuous wattage limit drops to 22,080 watts (92 amps × 240 volts).
What size breaker do I use with 2 AWG copper wire?
The most common and practical breaker size for 2 AWG copper is 100 amps. While the wire's ampacity is 115 amps, standard commercial breaker sizes jump from 100A to 110A and then 125A. NEC 240.4(B) allows you to round up to the next standard breaker size if the wire's ampacity doesn't match a standard breaker exactly, meaning a 110A or 125A breaker is technically permissible under specific non-continuous load conditions. However, pairing it with a 100A breaker is the industry standard for subpanel feeders, ensuring the termination limits of standard 100A lugs are never exceeded.
