Rigid PVC conduit, Schedule 80 fill chart
The most THHN wires of one size each PVC Sch 80 size may hold, with three or more wires at 40 % fill. Pick a size for XHHW-2 and THW as well.
| Trade size | Inside area | 40 % | #14 | #12 | #10 | #8 | #6 | #4 | #2 | #1/0 | #4/0 | 250 kcmil | 500 kcmil |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2" | 0.217 | 0.087 | 9 | 6 | 4 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 |
| 3/4" | 0.409 | 0.164 | 17 | 12 | 7 | 4 | 3 | 1 | 1 | 1 | 0 | 0 | 0 |
| 1" | 0.688 | 0.275 | 28 | 20 | 13 | 7 | 5 | 3 | 1 | 1 | 1 | 0 | 0 |
| 1-1/4" | 1.237 | 0.495 | 51 | 37 | 23 | 13 | 9 | 6 | 4 | 2 | 1 | 1 | 0 |
| 1-1/2" | 1.711 | 0.684 | 70 | 51 | 32 | 18 | 13 | 8 | 6 | 3 | 1 | 1 | 1 |
| 2" | 2.874 | 1.150 | 118 | 86 | 54 | 31 | 22 | 14 | 10 | 6 | 3 | 3 | 1 |
| 2-1/2" | 4.119 | 1.648 | 170 | 124 | 78 | 45 | 32 | 20 | 14 | 9 | 5 | 4 | 1 |
| 3" | 6.442 | 2.577 | 265 | 193 | 122 | 70 | 51 | 31 | 22 | 14 | 8 | 6 | 3 |
| 3-1/2" | 8.688 | 3.475 | 358 | 261 | 164 | 95 | 68 | 42 | 30 | 18 | 10 | 8 | 5 |
| 4" | 11.258 | 4.503 | 464 | 338 | 213 | 123 | 89 | 54 | 39 | 24 | 14 | 11 | 6 |
| 5" | 17.855 | 7.142 | 736 | 537 | 338 | 195 | 141 | 86 | 61 | 38 | 22 | 18 | 10 |
| 6" | 25.598 | 10.239 | 1055 | 770 | 485 | 279 | 202 | 124 | 88 | 55 | 31 | 25 | 14 |
Areas in square inches, from Chapter 9, Table 4 (2023 NEC). THHN/THWN-2 areas from Table 5.
About PVC Sch 80
Schedule 80 has a thicker wall for where it can be hit, so it holds fewer wires than Schedule 40 of the same trade size. Support is the same as Schedule 40 (Table 352.30). See strap spacing and the fill rules.