3 AWG Wire Specs
Ampacity, geometry, resistance, conduit fill and maximum run length for 3 AWG conductors in copper and aluminium.
Quick answer
3 AWG copper carries about 93 A at 75 °C (79 A at 60 °C, 105 A at 90 °C). The bare conductor is 0.2294 in (5.83 mm) and 52,635 circular mils, with 0.1970 Ω per 1000 ft. It pairs with a 90 A breaker at 75 °C terminations.
Copper 75 °C
93A
Aluminium 75 °C
73A
Diameter
0.2294in
Circular mils
52,635
Full specification
| Size designation | 3 AWG |
|---|---|
| AWG gauge number | 3 |
| Circular mils | 52,635 |
| kcmil | 52.63 |
| Bare diameter (in) | 0.2294 |
| Bare diameter (mm) | 5.827 |
| Cross-section (mm²) | 26.67 |
| THHN/THWN-2 OD (in) | 0.352 |
| Insulated area (sq in) | 0.0973 |
| Copper resistance (Ω/1000 ft) | 0.1970 |
| Aluminium resistance (Ω/1000 ft) | 0.3230 |
| Max standard breaker (Cu, 75 °C) | 90 A |
Published standard — source: Geometry computed from the ASTM B258 AWG formula; resistance from standard resistivityFormula estimate — source: Ampacity from the site model
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 | 105 A | 96 A | 86 A | 74 A |
| 6 | 84 A | 77 A | 69 A | 59 A |
| 9 | 74 A | 67 A | 60 A | 52 A |
| 15 | 53 A | 48 A | 43 A | 37 A |
| 25 | 47 A | 43 A | 39 A | 33 A |
Source & method: The governing value is also capped by the termination rating, commonly 75 °C, which for this size is 93 A. Run your own conditions.
Maximum run length at 3% voltage drop
One-way distance for 3 AWG copper before drop exceeds 3%.
| Load | 120 V 1Ø | 240 V 1Ø | 208 V 3Ø | 480 V 3Ø |
|---|---|---|---|---|
| 10 A | 734 ft | 1,468 ft | 1,470 ft | 3,392 ft |
| 15 A | 489 ft | 979 ft | 980 ft | 2,261 ft |
| 20 A | 367 ft | 734 ft | 735 ft | 1,696 ft |
| 30 A | 244 ft | 489 ft | 490 ft | 1,130 ft |
| 40 A | 183 ft | 367 ft | 367 ft | 848 ft |
| 50 A | 146 ft | 293 ft | 294 ft | 678 ft |
How many 3 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 | 3 | 6 | 8 | 13 | 24 | 36 | 47 | 60 |
| IMC | 1 | 1 | 3 | 6 | 9 | 14 | 21 | 32 | 43 | 56 |
| RMC | 1 | 1 | 3 | 6 | 8 | 14 | 19 | 30 | 41 | 52 |
| PVC Sch 40 | 1 | 1 | 3 | 5 | 8 | 13 | 19 | 29 | 40 | 51 |
| PVC Sch 80 | 1 | 1 | 2 | 5 | 7 | 11 | 16 | 26 | 35 | 46 |
Neighbouring sizes
Frequently asked
- How many amps can 3 AWG wire carry?
- 3 AWG copper is estimated at 79 A at 60 °C, 93 A at 75 °C and 105 A at 90 °C, at 30 °C ambient with no more than three current-carrying conductors. Aluminium of the same size is about 73 A at 75 °C.
- What breaker size goes with 3 AWG copper?
- The largest standard overcurrent device that 3 AWG copper supports at 75 °C is 90 A. For a continuous load, the load itself must not exceed 80% of that rating.
- What is the diameter of 3 AWG wire?
- The bare conductor is 0.2294 inches (5.827 mm) in diameter, which is 52,635 circular mils. With THHN/THWN-2 insulation the nominal outside diameter is about 0.352 inches.
- What is the resistance of 3 AWG wire?
- About 0.1970 ohms per 1000 feet for copper and 0.3230 ohms per 1000 feet for aluminium, at 75 °C.
- How far can I run 3 AWG wire?
- Distance depends on load and voltage. At 20 A on a 120 V single-phase circuit, 3 AWG copper stays under 3% voltage drop for about 367 feet one-way. Doubling the voltage roughly doubles the allowable distance.
Materials for this size
Materials for this size
Wire, cable and terminations for 3 AWG.
- THHN/THWN-2 3 AWG copper3 AWG copperBuilding wire in the size this page covers (3 AWG copper).Check price on Amazon →
- NM-B cable 3 AWG3 AWGRomex-type cable for dry indoor branch circuits at this size.Check price on Amazon →
- Wire connectors for 3 AWG3 AWGPush-in or twist-on connectors rated for this conductor size.Check price on Amazon →
- Terminal lugs & anti-oxidantCopper-rated mechanical lugs for panel and disconnect terminations.Check price on Amazon →
Links go to Amazon search results, not a single listing — confirm ratings, insulation type and listing details before buying, and make sure the part is approved for your application.
Related charts & calculators
- Voltage Drop CalculatorPercent drop, end voltage and minimum conductor for any run length.
- Conduit Fill CalculatorFill percentage and maximum conductor count for EMT, RMC, IMC and PVC.
- Breaker Size CalculatorOvercurrent device rating and minimum conductor from load current.
- Wire Ampacity CalculatorDerated ampacity for ambient temperature and bundled conductors.
- Box Fill CalculatorVolume allowances for conductors, clamps, devices and grounds per NEC 314.16.
- Ampacity ChartEstimated allowable ampacity by conductor size, material and insulation rating.