3/4-inch PVC Schedule 40 Conduit Fill
Wire capacity of trade size 3/4 (metric designator 21) Rigid PVC Conduit, Schedule 40, for THHN, XHHW, THW and RHW conductors from 14 AWG to 1000 kcmil.
3/4-inch PVC Schedule 40 holds 21 × #14, 15 × #12, 9 × #10 or 5 × #8 THHN conductors at 40% fill. Internal area: 0.508 in²; usable at 40%: 0.203 in².
| Wire size | THHN | XHHW | THW | RHW | THHN in a nipple (60%) | THHN area (in²) |
|---|---|---|---|---|---|---|
| 14 AWG | 21 | 14 | 14 | 7 | 31 | 0.0097 |
| 12 AWG | 15 | 11 | 11 | 5 | 23 | 0.0133 |
| 10 AWG | 9 | 8 | 8 | 4 | 14 | 0.0211 |
| 8 AWG | 5 | 4 | 4 | 1 | 8 | 0.0366 |
| 6 AWG | 4 | 3 | 2 | 1 | 6 | 0.0507 |
| 4 AWG | 1 | 1 | 1 | 1 | 3 | 0.0824 |
| 3 AWG | 1 | 1 | 1 | 1 | 3 | 0.0973 |
| 2 AWG | 1 | 1 | 1 | 1 | 2 | 0.1158 |
| 1 AWG | 1 | 1 | 1 | 1 | 2 | 0.1562 |
| 1/0 AWG | 1 | 1 | 1 | — | 1 | 0.1855 |
| 2/0 AWG | 1 | 1 | 1 | — | 1 | 0.2223 |
| 3/0 AWG | 1 | 1 | — | — | 1 | 0.2679 |
| 4/0 AWG | — | — | — | — | 1 | 0.3237 |
| 250 kcmil | — | — | — | — | — | 0.3970 |
| 300 kcmil | — | — | — | — | — | 0.4608 |
| 350 kcmil | — | — | — | — | — | 0.5242 |
| 400 kcmil | — | — | — | — | — | 0.5863 |
| 500 kcmil | — | — | — | — | — | 0.7073 |
| 600 kcmil | — | — | — | — | — | 0.8676 |
| 700 kcmil | — | — | — | — | — | 0.9887 |
| 750 kcmil | — | — | — | — | — | 1.0496 |
| 800 kcmil | — | — | — | — | — | 1.1085 |
| 900 kcmil | — | — | — | — | — | 1.2311 |
| 1000 kcmil | — | — | — | — | — | 1.3478 |
Mixed wire sizes? Calculate it
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3/4-inch conduit: PVC Schedule 40 vs other types
Trade size is nominal. The real inside diameter, and so the wire count, changes with the wall thickness of each raceway type.
| Conduit type | ID (in) | Area (in²) | 40% (in²) | #12 THHN | #10 THHN | #6 THHN |
|---|---|---|---|---|---|---|
| EMT | 0.824 | 0.533 | 0.213 | 16 | 10 | 4 |
| PVC Schedule 40 | 0.804 | 0.508 | 0.203 | 15 | 9 | 4 |
| PVC Schedule 80 | 0.722 | 0.409 | 0.164 | 12 | 7 | 3 |
| Rigid Metal Conduit | 0.836 | 0.549 | 0.220 | 16 | 10 | 4 |
| IMC | 0.864 | 0.586 | 0.234 | 17 | 11 | 4 |
| Flexible Metal Conduit | 0.824 | 0.533 | 0.213 | 16 | 10 | 4 |
| Liquidtight Flexible Metal Conduit | 0.830 | 0.541 | 0.216 | 16 | 10 | 4 |
| ENT | 0.804 | 0.508 | 0.203 | 15 | 9 | 4 |
Other PVC Schedule 40 sizes
Frequently asked questions
How many #12 wires fit in 3/4-inch PVC Schedule 40?
15 conductors of 12 AWG THHN/THWN-2 at the 40% fill limit. With thicker THW or XHHW insulation the count is 11.
What is the inside diameter and area of 3/4-inch PVC Schedule 40?
The internal diameter is 0.804 in. (20.4 mm) and the total cross-sectional area is 0.508 in². The usable area is 0.203 in² at 40% fill, 0.157 in² for two wires and 0.269 in² for one.
What is the largest wire I can pull three of in 3/4-inch PVC Schedule 40?
6 AWG THHN: 4 conductors fit at 40% fill. That is three current-carrying conductors with no ground; add the ground’s area and check again with the calculator if you need one.
Can I really load it with that many conductors?
For space, yes. But 15 current-carrying conductors in one raceway means heavy ampacity derating — 10 to 20 conductors are adjusted to 50% of their table ampacity. Fill tells you what fits; derating tells you what it can carry.
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