How Many 8 AWG Wires Fit in PVC Conduit?
Complete NEC-compliant fill chart for 8 AWG THHN wires in Schedule 40 PVC (PVC) conduit. Maximum wire counts for all standard conduit sizes.
Quick Answer
For 8 AWG THHN wires in PVC conduit at 40% fill (3+ wires):
- • 1/2" PVC: 3 wires
- • 3/4" PVC: 5 wires
- • 1" PVC: 9 wires
8 AWG in PVC Conduit Fill Chart
| Conduit Size | Max Wires (40% Fill) | Fill % | Max Wires (Nipple 60%) | Fill % |
|---|---|---|---|---|
| 1/2" | 3 | 39% | 4 | 51% |
| 3/4" | 5 | 36% | 8 | 58% |
| 1" | 9 | 40% | 13 | 57% |
| 1-1/4" | 15 | 38% | 23 | 59% |
| 1-1/2" | 21 | 39% | 32 | 59% |
| 2" | 35 | 39% | 53 | 59% |
| 2-1/2" | 59 | 40% | 89 | 60% |
| 3" | 94 | 40% | 142 | 60% |
| 3-1/2" | 124 | 40% | 186 | 60% |
| 4" | 156 | 40% | 234 | 60% |
Understanding the Fill Chart
According to NEC (National Electrical Code) Chapter 9, Table 1, the maximum conduit fill percentage depends on the number of conductors:
- 1 conductor: 53% fill maximum
- 2 conductors: 31% fill maximum
- 3 or more conductors: 40% fill maximum
- Nipples (24" or less): 60% fill maximum
This chart shows the maximum number of 8 AWG THHN conductors that can fit in each PVC conduit size while maintaining NEC compliance.
Calculation Example
Question: How many 8 AWG THHN wires can fit in 3/4" PVC conduit?
Wire area: 0.0366 sq in per conductor
Conduit internal area: 0.508 sq in
Allowable fill (40%): 0.2032 sq in
Maximum wires: 0.2032 ÷ 0.0366 = 5 wires
Answer: You can fit up to 5 wires of 8 AWG THHN in 3/4" PVC conduit.