1" PVC Schedule 40 has 1.029" inside and 0.832 in² of area, so the 40 % fill limit is 0.333 in². It holds 34 × 14, 25 × 12, 15 × 10, 9 × 8 or 6 × 6 AWG THHN. A 60 A EV run (two 6 AWG and a 10 AWG ground) fills it 15 %: it fits.
03 · Conduit fill · Chapter 9 Tables 1, 4 & 5
USE:
1" PVC 40 · 6.4% FILL · PASS
4 conductors take 0.0532 in² of the 0.832 in² inside 1" PVC 40: 6.4 % against the 40 % allowed.
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| Actions | |||||
|---|---|---|---|---|---|
| 4.7 % | 0.2940 in² | 22 | 13 | ||
| 6.4 % | 0.2796 in² | 21 | 13 | ||
| 10.1 % | 0.2484 in² | 18 | 11 | ||
| 15.7 % | 0.2019 in² | 15 | 9 | ||
| 20.8 % | 0.1596 in² | 12 | 7 | ||
| 34.1 % | 0.0490 in² | 3 | 2 | ||
| 39.5 % | 0.0043 in² | 0 | 0 | ||
| 47.8 % over | over by 0.0653 in² | — | — | ||
| 4.8 % | 0.2929 in² | 22 | 13 | ||
| 14.7 % | 0.2103 in² | 15 | 9 | ||
| 8.0 % | 0.2663 in² | 20 | 12 | ||
| 11.2 % | 0.2397 in² | 18 | 11 | ||
| 14.9 % | 0.2085 in² | 15 | 9 | ||
| 20.5 % | 0.1620 in² | 12 | 7 | ||
| 25.9 % | 0.1174 in² | 8 | 5 |
gnd: Table 250.122 ground. 1" PVC 40 allows 0.333 in² at 40 %.
05 / Field guide
1" PVC Schedule 40 has 1.029" inside and 0.832 in² of area, so the 40 % fill limit is 0.333 in². It holds 34 × 14, 25 × 12, 15 × 10, 9 × 8 or 6 × 6 AWG THHN. A 60 A EV run (two 6 AWG and a 10 AWG ground) fills it 15 %: it fits.
1" PVC Schedule 40 (Article 352) has 0.832 in² inside. One conductor may fill 53 % (0.441 in²), two 31 % (0.258 in²), three or more 40 % (0.333 in²). A nipple 24" or shorter may take 60 % (0.499 in²): 37 × 12 AWG.
fill % = Σ Table 5 areas ÷ 0.832 in²
1" Schedule 40 is 1.315" outside and 1.029" inside (0.143" wall). PVC is not a grounding path: pull an insulated ground.
Secure 1" PVC Schedule 40 within 3 ft of each box and support it at least every 3 ft (352.30). At 34 lb per 100 ft, each 3 ft span hangs 1.0 lb of pipe. A 60 A EV run leaves room for 15 more 12 AWG THHN; a 60 A subpanel feeder leaves room for 12.
For a mix, add the areas. Two 6 AWG and a 10 AWG ground (a 60 A EV run) take 0.1225 in², 14.7 %; three 3 AWG and an 8 AWG (a 100 A subpanel) take 0.3285 in², 39.5 %.
Questions
25 THHN conductors at the 40 % limit (0.333 in² ÷ 0.0133 in²); 25 current-carrying 12 AWG are derated to 45 % (310.15(C)(1)).
15 THHN, or 13 XHHW (thicker insulation, 0.0243 in² against 0.0211 in²).
Within 3 ft of every box or fitting and at least every 3 ft along the run (NEC 352.30, Table 352.30): a 50 ft straight run takes 16 straps, a 100 ft run 33. Keep the bends between pull points to 360° or less (352.26).
Three 6 AWG THHN and a 10 AWG ground take 0.1732 in², 20.8 % of 0.832 in²: that fits the 40 % limit.
1.029 inch nominal (NEC Chapter 9 Table 4), 1.315 inch outside. Use the inside area, 0.832 in², for fill.
2 AWG THHN: three fit within 40 %.
4 % smaller than 1" EMT (0.864 in²).