The baseline ampacity for 2 AWG copper wire is 115 amps in the 75°C column and 130 amps in the 90°C column. For 2 AWG aluminum wire, the ampacity is 90 amps (75°C) and 100 amps (90°C). Because most residential breakers and lugs are rated for 75°C terminations, you must default to the 75°C column for standard installations, yielding a safe, code-compliant maximum of 115A for copper and 90A for aluminum.
The Official 2 AWG Ampacity Reference Chart
The following data is extracted directly from NEC Table 310.16 (NFPA 70), which dictates the allowable ampacities of insulated conductors rated up to 2000 volts. This table assumes an ambient air temperature of 30°C (86°F) and no more than three current-carrying conductors in a raceway or cable.
How to read this table: Locate your wire material (Copper or Aluminum) on the left. Read across to the temperature column that matches your termination equipment rating (usually 75°C for modern breakers). The intersection is your maximum continuous current capacity before the wire insulation begins to degrade from heat.
| AWG / kcmil Size | Copper (60°C) | Copper (75°C) | Copper (90°C) | Aluminum (60°C) | Aluminum (75°C) | Aluminum (90°C) |
|---|---|---|---|---|---|---|
| 4 AWG | 70A | 85A | 95A | 55A | 65A | 75A |
| 3 AWG | 85A | 100A | 115A | 65A | 75A | 85A |
| 2 AWG (Target) | 95A | 115A | 130A | 75A | 90A | 100A |
| 1 AWG | 110A | 130A | 145A | 85A | 100A | 115A |
| 1/0 AWG | 125A | 150A | 170A | 100A | 120A | 135A |
Source: NFPA 70 National Electrical Code (NEC), Table 310.16.
Which Temperature Column Applies to Your Installation?
A common mistake on the jobsite is looking at the 90°C column (130A for copper) and assuming you can push 130 amps through a 2 AWG wire on a 125A breaker. In almost all residential and light commercial scenarios, you cannot.
NEC Article 110.14(C) governs terminal temperature provisions. It states that the ampacity of a conductor must be selected based on the lowest temperature rating of any connected termination, conductor, or device. Because standard breakers, panelboard lugs, and disconnect switches rated 100A and above are generally tested and listed for 75°C terminations, your wire's effective ampacity is bottlenecked by that 75°C rating.
How Derating Modifies Base Ampacity (And What the Table Misses)
Table 310.16 assumes ideal conditions: 30°C (86°F) ambient air and a maximum of three current-carrying conductors (CCCs) in a conduit. Real-world installations rarely match this perfectly. When conditions change, you must apply adjustment factors to the 90°C column value.
1. Bundling (More than 3 CCCs)
If you pull four or more current-carrying conductors through a single conduit, they heat each other up. NEC Table 310.15(C)(1) requires you to multiply the base ampacity by a derating percentage.
Worked Example: You have four 2 AWG copper THHN wires in a conduit.
Base 90°C ampacity = 130A.
Derating factor for 4-6 CCCs = 80%.
130A × 0.80 = 104A.
Because 104A is less than the 75°C termination limit of 115A, your final allowable ampacity for this run is 104A.
2. High Ambient Temperatures
If your conduit runs through an attic in a hot climate where temperatures reach 50°C (122°F), you must apply a temperature correction factor. For THHN (90°C rated) at 50°C ambient, the correction factor is 0.82.
130A × 0.82 = 106.6A.
What the Table Cannot Tell You: Voltage Drop
Ampacity charts only tell you the maximum current a wire can carry before the insulation melts. They do not account for voltage drop over distance. If you are feeding a 100-amp subpanel in a detached garage 150 feet away using 2 AWG copper, the wire will safely handle the heat, but the voltage at the far end will drop below the NEC-recommended 3% threshold for feeders.
For long runs, you must calculate voltage drop (using the formula VD = (2 × K × I × D) / cm) and likely upsize to 1/0 AWG or 2/0 AWG to maintain power quality, even though 2 AWG meets the thermal ampacity requirement.
2 AWG Ampacity Frequently Asked Questions
Can I use 2 AWG aluminum wire for a 100-amp subpanel?
No. This is a frequent and dangerous misconception. While 2 AWG aluminum has a 90°C ampacity of 100A, your panel lugs and breakers are limited to the 75°C column per NEC 110.14(C). In the 75°C column, 2 AWG aluminum is only rated for 90 amps. To safely and legally feed a 100-amp subpanel with aluminum, you must use 1/0 AWG aluminum (rated 120A at 75°C). If you want to use 2 AWG wire for a 100A panel, it must be copper (rated 115A at 75°C).
What is the maximum standard breaker size for 2 AWG copper wire?
Under the 75°C column, 2 AWG copper is rated for 115 amps. NEC 240.4(B) allows you to use the "next standard size up" rule if the exact ampacity doesn't match a standard breaker size and the overcurrent device is rated 800A or less. The standard breaker sizes (per NEC 240.6) above 115A are 125A. Therefore, you can technically protect a 115A load on 2 AWG copper with a 125-amp breaker. However, in practice, 2 AWG copper is most commonly paired with 100-amp or 110-amp breakers for subpanel feeders and heavy EV charging circuits.
Does 2 AWG wire ampacity change if it is buried underground?
Yes, the installation method changes the applicable table. If you are using direct burial cable (like UF-B), you must reference NEC Table 310.101(A)(1) instead of Table 310.16. Furthermore, earth ambient temperatures and soil thermal resistivity can require additional derating. If you are pulling individual THWN-2 conductors inside a buried PVC conduit, Table 310.16 still applies, but you must ensure the conduit is not filled with water, which can alter the thermal dissipation profile. Always check local AHJ requirements for underground feeder depths and derating.
How much does 2 AWG wire cost compared to 1/0 AWG?
As of current market pricing, 2 AWG THHN copper wire costs approximately $1.60 to $2.10 per foot, while 1/0 AWG copper runs about $2.50 to $3.20 per foot. For aluminum, 2 AWG SER (Service Entrance Round) cable is roughly $3.50 per foot, whereas 1/0-1/0-1/0-2 AL SER cable is closer to $5.50 per foot. While upsizing to 1/0 to solve a voltage drop issue or meet a 100A aluminum requirement adds roughly 40-50% to your wire material cost, it prevents overheating, breaker nuisance trips, and failed inspections.
