1" PVC Schedule 80 has 0.936" inside and 0.688 in² of area, so the 40 % fill limit is 0.275 in². It holds 28 × 14, 20 × 12, 13 × 10, 7 × 8 or 5 × 6 AWG THHN. A 60 A EV run (two 6 AWG and a 10 AWG ground) fills it 18 %: it fits.
03 · Conduit fill · Chapter 9 Tables 1, 4 & 5
USE:
1" PVC 80 · 7.7% FILL · PASS
4 conductors take 0.0532 in² of the 0.688 in² inside 1" PVC 80: 7.7 % against the 40 % allowed.
Sort any column, print a shop sheet, download CSV. Click a row to load it in the calculator.
| Actions | |||||
|---|---|---|---|---|---|
| 5.6 % | 0.2364 in² | 17 | 11 | ||
| 7.7 % | 0.2220 in² | 16 | 10 | ||
| 12.3 % | 0.1908 in² | 14 | 9 | ||
| 19.0 % | 0.1443 in² | 10 | 6 | ||
| 25.2 % | 0.1020 in² | 7 | 4 | ||
| 41.3 % over | over by 0.0086 in² | — | — | ||
| 5.8 % | 0.2353 in² | 17 | 11 | ||
| 17.8 % | 0.1527 in² | 11 | 7 | ||
| 9.7 % | 0.2087 in² | 15 | 9 | ||
| 13.5 % | 0.1821 in² | 13 | 8 | ||
| 18.1 % | 0.1509 in² | 11 | 7 | ||
| 24.8 % | 0.1044 in² | 7 | 4 | ||
| 31.3 % | 0.0598 in² | 4 | 2 |
gnd: Table 250.122 ground. 1" PVC 80 allows 0.275 in² at 40 %.
05 / Field guide
1" PVC Schedule 80 has 0.936" inside and 0.688 in² of area, so the 40 % fill limit is 0.275 in². It holds 28 × 14, 20 × 12, 13 × 10, 7 × 8 or 5 × 6 AWG THHN. A 60 A EV run (two 6 AWG and a 10 AWG ground) fills it 18 %: it fits.
1" PVC Schedule 80 (Article 352) has 0.688 in² inside. One conductor may fill 53 % (0.365 in²), two 31 % (0.213 in²), three or more 40 % (0.275 in²). A nipple 24" or shorter may take 60 % (0.413 in²): 31 × 12 AWG.
fill % = Σ Table 5 areas ÷ 0.688 in²
Schedule 80 is for runs exposed to physical damage (352.10(F)). The heavier wall leaves 0.688 in² inside against 0.832 in² for Schedule 40 of the same size.
Secure 1" PVC Schedule 80 within 3 ft of each box and support it at least every 3 ft (352.30). A 60 A EV run leaves room for 11 more 12 AWG THHN; a 60 A subpanel feeder leaves room for 7.
For a mix, add the areas. Two 6 AWG and a 10 AWG ground (a 60 A EV run) take 0.1225 in², 17.8 %; three 3 AWG and an 8 AWG (a 100 A subpanel) take 0.3285 in², 47.7 %.
Questions
20 THHN conductors at the 40 % limit (0.275 in² ÷ 0.0133 in²); 20 current-carrying 12 AWG are derated to 50 % (310.15(C)(1)).
13 THHN, or 11 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, 25.2 % of 0.688 in²: that fits the 40 % limit.
0.936 inch nominal (NEC Chapter 9 Table 4), 1.315 inch outside. Use the inside area, 0.688 in², for fill.
3 AWG THHN: three fit within 40 %.
20 % smaller than 1" EMT (0.864 in²): the thick wall of Schedule 80 costs inside room.