5" PVC-40 Conduit Fill Chart
How many wires fit in 5" PVC-40 (PVC Schedule 40). Maximum conductor counts per AWG at the NEC 2023 40% fill cap for three or more conductors.
MAXIMUM CONDUCTORS BY WIRE GAUGE
40% fill (3+ conductors per NEC 2023 Ch.9 Table 1). 5" PVC-40 interior area = 19.7610 in².
| AWG | THHN / THWN-2 | XHHW-2 | RHH / RHW-2 |
|---|---|---|---|
| #14 | 814 | 814 | 378 |
| #12 | 594 | 594 | 304 |
| #10 | 374 | 374 | 237 |
| #8 | 215 | 215 | 142 |
| #6 | 155 | 155 | 108 |
| #4 | 95 | 95 | 81 |
| #3 | 81 | 81 | 69 |
| #2 | 68 | 68 | 59 |
| #1 | 50 | 50 | 41 |
| #1/0 | 42 | 42 | 35 |
| #2/0 | 35 | 35 | 30 |
| #4/0 | 24 | 24 | 21 |
WORKED EXAMPLE & NEC REFERENCES
The NEC numbers behind 5" PVC-40
NEC 2023 Chapter 9, Table 4 lists the interior cross-sectional area of every standard trade size for each conduit family. For 5" PVC-40 (Article 352), the total 100% area is 19.7610 in². The allowable conductor fill is then derived from Table 1: 53% for a single conductor (10.4733 in²), 31% for two (6.1259 in²), and 40% for three or more (7.9044 in²) — covering nearly all real-world raceway pulls.
Worked example — four #12 THHN conductors
Each #12 THHN conductor occupies 0.0133 in² (NEC Ch.9 Table 5). Four conductors fill 4 × 0.0133 = 0.0532 in², which is 0.0532 ÷ 19.7610 = 0.3% of total area. Because that is well below the 40% NEC limit for 7.9044 in², the pull is compliant — and you can keep adding conductors up to 594× #12 THHN before exceeding the cap.
If you exceed the fill cap
Step up one trade size. Increase a 5" PVC-40 to 6" when the calculated fill crosses 40%. Reducing one trade size is rarely worth the labor: pull tension climbs fast, jam probability spikes (NEC Ch.9 Informational Note re: 2.8–3.2 conduit-ID to wire-OD ratio), and you lose room for de-rating or future moves.
Source citations
NFPA 70 (2023) — National Electrical Code. Chapter 9, Table 1: percent of cross section of conduit and tubing for conductors. Table 4: dimensions and percent area of conduit and tubing (Article 352). Table 5: dimensions of insulated conductors.