The base ampacity for 2 AWG copper wire is 115 amps (at the 75°C termination rating) and for 2 AWG aluminum wire is 90 amps (at 75°C). If you are using the 90°C column strictly for derating calculations before terminating, 2 AWG copper handles up to 130 amps and aluminum handles up to 100 amps. These values assume an ambient temperature of 30°C (86°F) and no more than three current-carrying conductors in a raceway, per the NFPA 70 National Electrical Code (NEC) Table 310.16.

How to Read the NEC 310.16 Ampacity Table

Before pulling wire or sizing a breaker, you must understand how the NEC structures ampacity tables. The table is divided into three primary temperature columns: 60°C, 75°C, and 90°C. The column you use depends on the lowest temperature rating of any connected component, terminal, or device in the circuit.

The 75°C Rule for Terminations: Under NEC 110.14(C), equipment terminations for circuits rated 100A or less are generally evaluated using the 60°C column, while circuits over 100A use the 75°C column. However, modern breakers and lugs are almost universally rated for 75°C. Therefore, the 75°C column is the standard baseline for determining the maximum overcurrent protection (breaker size) for 2 AWG wire in residential and commercial panels.

The 90°C column is rarely used to size the breaker. Instead, it provides a higher baseline number used exclusively as the starting point for derating calculations (adjusting for heat and bundling). Once you apply your derating factors to the 90°C number, the final calculated ampacity must still be equal to or greater than the load, and you must cap your breaker size at the 75°C column limit.

Complete 2 AWG Ampacity Reference Table

The following data is extracted directly from NEC Table 310.16 for single-insulated conductors rated 0 through 2000 volts. Bookmark this section for quick jobsite reference.

Table 1: 2 AWG Wire Ampacity (Source: NEC Table 310.16, 30°C Ambient)
Conductor Material Insulation Types (Examples) 60°C Column (Amps) 75°C Column (Amps) 90°C Column (Amps)
Copper TW, UF (60°C)
THHW, THW, XHHW (75°C)
THHN, THWN-2, XHHW-2 (90°C)		 95A 115A 130A
Aluminum / CCA TW, UF (60°C)
THHW, THW, XHHW (75°C)
THHN, THWN-2, XHHW-2 (90°C)		 75A 90A 100A

Note: CCA (Copper-Clad Aluminum) must always be sized using the Aluminum column. Never use the Copper column for CCA, as the core is aluminum and will overheat at copper ampacity levels.

Derating Factors and Installation Limits

The numbers in the table above represent ideal laboratory conditions. On a real jobsite, two main factors will reduce (derate) the actual ampacity of your 2 AWG wire: ambient temperature and conductor bundling.

How Derating Modifies the Base Value

Derating always starts with the 90°C column value, even if your termination is limited to 75°C.

Worked Example: You are pulling four current-carrying 2 AWG THHN copper conductors through an attic where the ambient temperature reaches 110°F (43°C).

  1. Base 90°C Ampacity: 130A
  2. Temperature Correction (110°F): Multiply by 0.87 (per NEC Table 310.15(B)(1)) = 113.1A
  3. Bundling Adjustment (4 conductors): Multiply by 0.80 (per NEC Table 310.15(C)(1)) = 90.48A

Your final derated ampacity is 90.48 amps. Because this is below the 75°C termination limit of 115A, your overcurrent protection (breaker) cannot exceed 90A. You would need to step up to 1 AWG or 1/0 AWG to maintain a 100A+ circuit in this hot, bundled environment.

What the Table Cannot Tell You: NEC Table 310.16 only addresses thermal limits (preventing the insulation from melting). It does not account for voltage drop. According to the Southwire Voltage Drop Calculator, pushing 115A through 2 AWG copper on a 240V circuit will result in a 3% voltage drop at roughly 150 feet. If your subpanel is 200 feet away, you must upsize to 1/0 AWG or 2/0 AWG to prevent equipment damage and dimming lights, regardless of the thermal ampacity table.

2 AWG Wire Ampacity FAQ

Can I use 2 AWG aluminum wire for a 100-amp subpanel feeder?

No. The 75°C ampacity for 2 AWG aluminum is 90 amps. While it is physically close to 100A, the NEC requires the conductor ampacity to be equal to or greater than the non-continuous load plus 125% of the continuous load, and the breaker must protect the wire. A 100A breaker will not adequately protect a 90A wire under all fault conditions. For a full 100-amp feeder, you must step up to 1 AWG aluminum (rated 100A at 75°C) or use 3 AWG copper (rated 100A at 75°C).

Does 2 AWG wire ampacity change if I use THHN vs. XHHW-2?

For standard ampacity and derating, no. Both THHN/THWN-2 and XHHW-2 are rated for 90°C in dry or damp locations, giving you the same 130A starting point for copper derating. However, XHHW-2 has a thinner insulation profile than THHN. If you are pulling 2 AWG wire through tight conduit bends, XHHW-2 yields a smaller overall diameter, which can help you stay under the NEC 40% conduit fill capacity limits and make the physical pull significantly easier.

How does the ground wire size relate to 2 AWG current-carrying conductors?

Ampacity tables dictate the size of your hot and neutral conductors, but your equipment grounding conductor (EGC) is sized separately via NEC Table 250.122 based on the rating of the overcurrent device (breaker). If you are using 2 AWG copper on a 100A breaker, Table 250.122 requires a minimum 8 AWG copper or 6 AWG aluminum ground wire. If you upsize your current-carrying conductors to 1/0 AWG to compensate for voltage drop, NEC 250.122(B) requires you to proportionally upsize your ground wire as well.