NEC 2023 & 2026
PVC Conduit Fill Chart
How many wires fit in PVC conduit? Schedule 40 and Schedule 80 side by side, because the thicker Schedule 80 wall holds fewer. Every number is worked out from NEC 2023 & 2026 Chapter 9.
Updated
Values are the same in NEC 2023 and NEC 2026.
For reference only. Always verify with the NEC edition adopted by your AHJ.
Full charts by schedule
Schedule 80 has a thicker wall than Schedule 40, so the same trade size has a smaller inside area in Table 4. Open the full chart for the schedule you use, from 1/2" up.
#14 THHN in PVC: Schedule 40 against Schedule 80
| Trade size | Schedule 40 | Schedule 80 | Inside area (sq in), 40 / 80 |
|---|---|---|---|
| 1/2" | 11 | 9 | 0.285 / 0.217 |
| 3/4" | 21 | 17 | 0.508 / 0.409 |
| 1" | 34 | 28 | 0.832 / 0.688 |
| 1-1/4" | 60 | 51 | 1.453 / 1.237 |
| 1-1/2" | 82 | 70 | 1.986 / 1.711 |
| 2" | 135 | 118 | 3.291 / 2.874 |
| 2-1/2" | 193 | 170 | 4.695 / 4.119 |
| 3" | 299 | 265 | 7.268 / 6.442 |
| 3-1/2" | 401 | 358 | 9.737 / 8.688 |
| 4" | 517 | 464 | 12.554 / 11.258 |
| 5" | 815 | 736 | 19.761 / 17.855 |
| 6" | 1178 | 1055 | 28.567 / 25.598 |
#12 THHN in PVC: Schedule 40 against Schedule 80
| Trade size | Schedule 40 | Schedule 80 | Inside area (sq in), 40 / 80 |
|---|---|---|---|
| 1/2" | 8 | 6 | 0.285 / 0.217 |
| 3/4" | 15 | 12 | 0.508 / 0.409 |
| 1" | 25 | 20 | 0.832 / 0.688 |
| 1-1/4" | 43 | 37 | 1.453 / 1.237 |
| 1-1/2" | 59 | 51 | 1.986 / 1.711 |
| 2" | 99 | 86 | 3.291 / 2.874 |
| 2-1/2" | 141 | 124 | 4.695 / 4.119 |
| 3" | 218 | 193 | 7.268 / 6.442 |
| 3-1/2" | 293 | 261 | 9.737 / 8.688 |
| 4" | 377 | 338 | 12.554 / 11.258 |
| 5" | 594 | 537 | 19.761 / 17.855 |
| 6" | 859 | 770 | 28.567 / 25.598 |
#10 THHN in PVC: Schedule 40 against Schedule 80
| Trade size | Schedule 40 | Schedule 80 | Inside area (sq in), 40 / 80 |
|---|---|---|---|
| 1/2" | 5 | 4 | 0.285 / 0.217 |
| 3/4" | 9 | 7 | 0.508 / 0.409 |
| 1" | 15 | 13 | 0.832 / 0.688 |
| 1-1/4" | 27 | 23 | 1.453 / 1.237 |
| 1-1/2" | 37 | 32 | 1.986 / 1.711 |
| 2" | 62 | 54 | 3.291 / 2.874 |
| 2-1/2" | 89 | 78 | 4.695 / 4.119 |
| 3" | 137 | 122 | 7.268 / 6.442 |
| 3-1/2" | 184 | 164 | 9.737 / 8.688 |
| 4" | 238 | 213 | 12.554 / 11.258 |
| 5" | 374 | 338 | 19.761 / 17.855 |
| 6" | 541 | 485 | 28.567 / 25.598 |
#8 THHN in PVC: Schedule 40 against Schedule 80
| Trade size | Schedule 40 | Schedule 80 | Inside area (sq in), 40 / 80 |
|---|---|---|---|
| 1/2" | 3 | 1 | 0.285 / 0.217 |
| 3/4" | 5 | 4 | 0.508 / 0.409 |
| 1" | 9 | 7 | 0.832 / 0.688 |
| 1-1/4" | 16 | 13 | 1.453 / 1.237 |
| 1-1/2" | 21 | 18 | 1.986 / 1.711 |
| 2" | 36 | 31 | 3.291 / 2.874 |
| 2-1/2" | 51 | 45 | 4.695 / 4.119 |
| 3" | 79 | 70 | 7.268 / 6.442 |
| 3-1/2" | 106 | 95 | 9.737 / 8.688 |
| 4" | 137 | 123 | 12.554 / 11.258 |
| 5" | 216 | 195 | 19.761 / 17.855 |
| 6" | 312 | 279 | 28.567 / 25.598 |
#6 THHN in PVC: Schedule 40 against Schedule 80
| Trade size | Schedule 40 | Schedule 80 | Inside area (sq in), 40 / 80 |
|---|---|---|---|
| 1/2" | 1 | 1 | 0.285 / 0.217 |
| 3/4" | 4 | 3 | 0.508 / 0.409 |
| 1" | 6 | 5 | 0.832 / 0.688 |
| 1-1/4" | 11 | 9 | 1.453 / 1.237 |
| 1-1/2" | 15 | 13 | 1.986 / 1.711 |
| 2" | 26 | 22 | 3.291 / 2.874 |
| 2-1/2" | 37 | 32 | 4.695 / 4.119 |
| 3" | 57 | 51 | 7.268 / 6.442 |
| 3-1/2" | 77 | 68 | 9.737 / 8.688 |
| 4" | 99 | 89 | 12.554 / 11.258 |
| 5" | 156 | 141 | 19.761 / 17.855 |
| 6" | 225 | 202 | 28.567 / 25.598 |
PVC conduit fill questions
- How many #12 THHN wires fit in 1/2" PVC conduit?
- Up to 8 in 1/2" Schedule 40 PVC and 6 in 1/2" Schedule 80, at the 40% fill limit for three or more wires under NEC 2023 & 2026 Chapter 9.
- How many #12 THHN wires fit in 3/4" PVC conduit?
- Up to 15 in 3/4" Schedule 40 PVC and 12 in 3/4" Schedule 80, at the 40% fill limit for three or more wires under NEC 2023 & 2026 Chapter 9.
- How many #12 THHN wires fit in 1" PVC conduit?
- Up to 25 in 1" Schedule 40 PVC and 20 in 1" Schedule 80, at the 40% fill limit for three or more wires under NEC 2023 & 2026 Chapter 9.
- Why does Schedule 80 PVC hold fewer wires than Schedule 40?
- Schedule 80 has a thicker wall, so the same trade size has a smaller inside area in Chapter 9 Table 4. For example 1" Schedule 40 is 0.832 square inches against 0.688 for Schedule 80, and the fill percentage is taken from that area.
- What is the conduit fill limit for PVC?
- The same NEC 2023 & 2026 Chapter 9 Table 1 limits apply to PVC as to every raceway: 53% of the inside area for one wire, 31% for two and 40% for three or more.
You can read the NEC 2023 for free at NFPA free access. Need a different combination? Use the conduit fill calculator.