10 AWG Wire — Ampacity, Conduit Fill & Dimensions
Everything the code tables say about 10 AWG conductors on one page: ampacity by temperature rating, breaker limits, conduit fill, physical size, resistance and voltage-drop distances.
10 AWG copper carries 30 A at 60°C, 35 A at 75°C and 40 A at 90°C. Overcurrent protection is capped at 30 A for copper and 25 A for aluminum by the small-conductor rule in 240.4(D), whatever the ampacity column says.
10 AWG ampacity
| Copper | Aluminum | |||||
|---|---|---|---|---|---|---|
| Installation | 60°C | 75°C | 90°C | 60°C | 75°C | 90°C |
| Raceway, cable or earth — Table 310.16 | 30 | 35 | 40 | 25 | 30 | 35 |
| Single conductor in free air — Table 310.17 | 40 | 50 | 55 | 35 | 40 | 45 |
Typical use: 30 A circuits: electric dryers, water heaters, air-conditioner condensers, and long 20 A runs upsized for voltage drop.
Use the column that matches the lowest temperature rating in the circuit — usually the 75°C terminations on breakers and lugs. The 90°C column is a starting point for derating, not a rating you can load the wire to. NM-B (Romex) cable is always limited to the 60°C column.
As a copper equipment grounding conductor, 10 AWG is the minimum for circuits protected at up to 60 A; in aluminum, up to 20 A. See the grounding conductor table.
10 AWG conduit fill
| Conduit | 1/2" | 3/4" | 1" | 1-1/4" | 1-1/2" | 2" | 2-1/2" | 3" | 4" |
|---|---|---|---|---|---|---|---|---|---|
| EMT | 5 | 10 | 16 | 28 | 38 | 63 | 111 | 167 | 279 |
| PVC Schedule 40 | 5 | 9 | 15 | 27 | 37 | 62 | 89 | 137 | 238 |
| PVC Schedule 80 | 4 | 7 | 13 | 23 | 32 | 54 | 78 | 122 | 213 |
| Rigid Metal Conduit | 6 | 10 | 17 | 29 | 39 | 64 | 92 | 142 | 244 |
| IMC | 6 | 11 | 18 | 31 | 42 | 69 | 97 | 150 | 258 |
| Flexible Metal Conduit | 6 | 10 | 15 | 24 | 35 | 62 | 93 | 134 | 238 |
| Liquidtight Flexible Metal Conduit | 6 | 10 | 16 | 29 | 37 | 61 | 92 | 141 | 240 |
| ENT | 5 | 9 | 15 | 27 | 37 | 62 | — | — | — |
Mixing sizes or using another insulation? Use the conduit fill calculator.
10 AWG dimensions
| Insulation | Diameter (in) | Diameter (mm) | Area (in²) | Area (mm²) |
|---|---|---|---|---|
| THHN, THWN, THWN-2 | 0.164 | 4.17 | 0.0211 | 13.6 |
| XHHW, XHHW-2, XHH | 0.176 | 4.47 | 0.0243 | 15.7 |
| TW, THW, THHW, THW-2 | 0.176 | 4.47 | 0.0243 | 15.7 |
| RHH, RHW, RHW-2 (with outer covering) | 0.236 | 5.99 | 0.0437 | 28.2 |
10 AWG voltage drop
| Load | 120 V 1-phase | 240 V 1-phase | 208 V 3-phase | 480 V 3-phase |
|---|---|---|---|---|
| 5 A | 290 ft | 580 ft | 581 ft | 1340 ft |
| 10 A | 145 ft | 290 ft | 290 ft | 670 ft |
| 15 A | 96 ft | 193 ft | 193 ft | 446 ft |
| 20 A | 72 ft | 145 ft | 145 ft | 335 ft |
| 30 A | 48 ft | 96 ft | 96 ft | 223 ft |
Based on 1.24 Ω per 1000 ft for stranded copper at 75°C (2.04 Ω for aluminum). For other loads and lengths use the voltage drop calculator.
All wire sizes
- 14 AWG
- 12 AWG
- 10 AWG
- 8 AWG
- 6 AWG
- 4 AWG
- 3 AWG
- 2 AWG
- 1 AWG
- 1/0 AWG
- 2/0 AWG
- 3/0 AWG
- 4/0 AWG
- 250 kcmil
- 300 kcmil
- 350 kcmil
- 400 kcmil
- 500 kcmil
- 600 kcmil
- 700 kcmil
- 750 kcmil
- 800 kcmil
- 900 kcmil
- 1000 kcmil
Frequently asked questions
How many amps can 10 AWG wire carry?
10 AWG copper is rated 30 A at 60°C, 35 A at 75°C and 40 A at 90°C when run in conduit or cable. Aluminum is rated 25, 30 and 35 A. Breaker size is limited to 30 A for copper.
What size conduit do I need for 10 AWG wire?
Three 10 AWG THHN conductors need at least 1/2-inch EMT. 1/2-inch EMT holds 5 and 3/4-inch holds 10.
What is the diameter of 10 AWG wire?
The bare conductor is 10,380 circular mils (5.26 mm²). With THHN insulation the overall diameter is about 0.164 in (4.17 mm) and the area is 0.0211 in², which is the figure used for conduit fill.
How far can I run 10 AWG wire?
For a 3% voltage drop on a 240 V single-phase circuit carrying 30 A, about 96 feet one way in copper. Halve that at 120 V. Lighter loads go proportionally farther.
NECTables.com is an independent reference and is not affiliated with, endorsed by, or a substitute for the National Fire Protection Association (NFPA). NEC® and National Electrical Code® are registered trademarks of the NFPA. Values shown are commonly published engineering data and independent calculations based on the methods of NFPA 70; they are not a reproduction of the Code. Always confirm against the edition adopted in your jurisdiction, including local amendments, and consult a licensed electrician or engineer before doing electrical work.