2 AWG Wire — Amp Rating, Ampacity & Diameter
Ampacity, geometry, resistance, conduit fill and maximum run length for 2 AWG conductors in copper and aluminium.
Quick answer
Copper 75 °C
108A
Aluminium 75 °C
84A
Diameter
0.2576in
Circular mils
66,371
Full specification
| Size designation | 2 AWG |
|---|---|
| AWG gauge number | 2 |
| Circular mils | 66,371 |
| kcmil | 66.37 |
| Bare diameter (in) | 0.2576 |
| Bare diameter (mm) | 6.543 |
| Cross-section (mm²) | 33.62 |
| THHN/THWN-2 OD (in) | 0.384 |
| Insulated area (sq in) | 0.1158 |
| Copper resistance (Ω/1000 ft) | 0.1563 |
| Aluminium resistance (Ω/1000 ft) | 0.2561 |
| Max standard breaker (Cu, 75 °C) | 100 A |
Ampacity with derating
Estimated ampacity from the 90 °C column at various ambient temperatures and conductor counts.
| Conductors in raceway | 30 °C ambient | 40 °C ambient | 50 °C ambient | 60 °C ambient |
|---|---|---|---|---|
| 3 | 122 A | 111 A | 100 A | 86 A |
| 6 | 98 A | 89 A | 80 A | 69 A |
| 9 | 85 A | 78 A | 70 A | 60 A |
| 15 | 61 A | 56 A | 50 A | 43 A |
| 25 | 55 A | 50 A | 45 A | 39 A |
Source & method: The governing value is also capped by the termination rating, commonly 75 °C, which for this size is 108 A. Run your own conditions.
Maximum run length at 3% voltage drop
One-way distance for 2 AWG copper before drop exceeds 3%.
| Load | 120 V 1Ø | 240 V 1Ø | 208 V 3Ø | 480 V 3Ø |
|---|---|---|---|---|
| 10 A | 926 ft | 1,852 ft | 1,853 ft | 4,277 ft |
| 15 A | 617 ft | 1,234 ft | 1,235 ft | 2,851 ft |
| 20 A | 463 ft | 926 ft | 926 ft | 2,138 ft |
| 30 A | 308 ft | 617 ft | 617 ft | 1,425 ft |
| 40 A | 231 ft | 463 ft | 463 ft | 1,069 ft |
| 50 A | 185 ft | 370 ft | 370 ft | 855 ft |
How many 2 AWG conductors fit in conduit
Maximum count of this size alone, at the fill percentage matching the resulting count.
| Conduit | 1/2" | 3/4" | 1" | 1-1/4" | 1-1/2" | 2" | 2-1/2" | 3" | 3-1/2" | 4" |
|---|---|---|---|---|---|---|---|---|---|---|
| EMT | 1 | 1 | 2 | 5 | 7 | 11 | 20 | 30 | 39 | 50 |
| IMC | 1 | 1 | 3 | 5 | 7 | 12 | 17 | 27 | 36 | 47 |
| RMC | 1 | 1 | 3 | 5 | 7 | 11 | 16 | 25 | 34 | 44 |
| PVC Sch 40 | 1 | 1 | 2 | 5 | 6 | 11 | 16 | 25 | 33 | 43 |
| PVC Sch 80 | — | 1 | 1 | 4 | 5 | 9 | 14 | 22 | 30 | 38 |
2 AWG copper ampacity vs aluminium ampacity
Ampacity by conductor material and insulation temperature rating, at 30 °C ambient with no more than three current-carrying conductors.
| Material | 60 °C (TW, NM-B) | 75 °C (THW, THWN, XHHW) | 90 °C (THHN, THWN-2, XHHW-2) |
|---|---|---|---|
| Copper | 92 A | 108 A | 122 A |
| Aluminium | 72 A | 84 A | 95 A |
The 2 AWG copper ampacity figure you use on a real circuit is the 75 °C column, 108 A, because breakers and lugs on most equipment are listed for 75 °C even when the conductor insulation is rated 90 °C. The 90 °C value, 122 A, is the starting point for ambient and conductor-count derating only — you derate from 90 °C, then cap the answer at the termination rating.
Aluminium of the same size carries roughly 78% of the copper value (84 A at 75 °C), so an aluminium feeder is normally stepped up one to two sizes to match a copper circuit. NM-B cable is always read from the 60 °C column regardless of the temperature stamped on the conductor insulation.
Source & method: Values are model estimates from conductor geometry and resistivity — see methodology and verify against the NEC edition enforced locally.
Neighbouring sizes
Compare 2 AWG with the sizes immediately above and below it before sizing a circuit.
Circuits that use 2 AWG
Breaker ratings whose smallest copper conductor at 75 °C terminations is 2 AWG.
2 AWG amp rating, diameter and metric equivalent
The amp rating for 2 AWG wire depends on the insulation temperature rating, not on the conductor alone. Copper ampacity is about 92 A on a 60 °C conductor, 108 A at 75 °C and 122 A at 90 °C, all at 30 °C ambient with no more than three current-carrying conductors in the raceway. The carrying capacity drops from there in hot spaces or crowded conduit, and terminations rated 75 °C cap what you can actually use.
Geometrically, 2 AWG is 0.2576 in (6.54 mm) in bare diameter, which is 66,371 circular mils. The cross sectional area works out to 33.63 mm², so the nearest IEC 60228 metric conductor is the next standard size at or above that figure — AWG sizes and mm² sizes never line up exactly, so round up rather than to the closest value.
American Wire Gauge (AWG) is a standard specification for the sizes of solid round wires used as electrical conductors, and the AWG number counts the drawing operations used to reach the diameter. That is why larger gauges are thinner wire and why standardized wire steps follow a fixed ratio: one AWG step changes diameter by about 12.2% and area by about 26%. Above 1 AWG the American standard continues 1/0 to 4/0, then switches to kcmil for anything larger.
Where 2 AWG actually gets used
2 AWG is a workhorse feeder size: aluminium 2 AWG is the classic 100 A dwelling service conductor and the standard 100 A subpanel feeder, while copper 2 AWG covers 115 to 130 A feeders and larger commercial branch equipment. It is one of the most common conductors in overhead and underground service laterals.
This is where the aluminium-versus-copper decision usually gets made on cost rather than preference. Aluminium at 2 AWG is dramatically cheaper per foot at the same job amperage, at the price of needing AL9CU-rated connectors, correct antioxidant treatment where the connector listing requires it, and verified torque. Thermal cycling at a poorly torqued 2 AWG aluminium lug is a leading cause of panel failures.
Mechanically, 2 AWG is stiff enough that bending radius inside a load centre matters. Full-size gutters, offset lugs and careful conductor training are normal at this size, and a 90 degree pull into a shallow panel is where insulation gets damaged during rough-in.
Frequently asked
- How many amps can 2 AWG wire carry?
- 2 AWG copper is estimated at 92 A at 60 °C, 108 A at 75 °C and 122 A at 90 °C, at 30 °C ambient with no more than three current-carrying conductors. Aluminium of the same size is about 84 A at 75 °C.
- What is the amp rating for 2 gauge wire?
- Use 108 A for 2 AWG copper on equipment with 75 °C terminations, which covers most breakers and panel lugs. Read 92 A instead when the conductor is inside NM-B cable, and treat 122 A as the derating base only. Aluminium of the same size is about 84 A at 75 °C.
- What breaker size goes with 2 AWG copper?
- The largest standard overcurrent device that 2 AWG copper supports at 75 °C is 100 A. For a continuous load, the load itself must not exceed 80% of that rating.
- What is the diameter of 2 AWG wire?
- The bare conductor is 0.2576 inches (6.543 mm) in diameter, which is 66,371 circular mils. With THHN/THWN-2 insulation the nominal outside diameter is about 0.384 inches.
- What is the resistance of 2 AWG wire?
- About 0.1563 ohms per 1000 feet for copper and 0.2561 ohms per 1000 feet for aluminium, at 75 °C.
- How far can I run 2 AWG wire?
- Distance depends on load and voltage. At 20 A on a 120 V single-phase circuit, 2 AWG copper stays under 3% voltage drop for about 463 feet one-way. Doubling the voltage roughly doubles the allowable distance.
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