1/2" PVC Schedule 80 has 0.526" inside and 0.217 in² of area, so the 40 % fill limit is 0.087 in². It holds 9 × 14, 6 × 12, 4 × 10, 2 × 8 or 1 × 6 AWG THHN. A 60 A EV run (two 6 AWG and a 10 AWG ground) fills it 56 %: too full.
03 · Conduit fill · Chapter 9 Tables 1, 4 & 5
USE:
1/2" PVC 80 · 24.5% FILL · PASS
4 conductors take 0.0532 in² of the 0.217 in² inside 1/2" PVC 80: 24.5 % against the 40 % allowed.
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| Actions | |||||
|---|---|---|---|---|---|
| 17.9 % | 0.0480 in² | 3 | 2 | ||
| 24.5 % | 0.0336 in² | 2 | 1 | ||
| 38.9 % | 0.0024 in² | 0 | 0 | ||
| 60.3 % over | over by 0.0441 in² | — | — | ||
| 18.4 % | 0.0469 in² | 3 | 2 | ||
| 30.6 % | 0.0203 in² | 1 | 0 |
gnd: Table 250.122 ground. 1/2" PVC 80 allows 0.087 in² at 40 %.
05 / Field guide
1/2" PVC Schedule 80 has 0.526" inside and 0.217 in² of area, so the 40 % fill limit is 0.087 in². It holds 9 × 14, 6 × 12, 4 × 10, 2 × 8 or 1 × 6 AWG THHN. A 60 A EV run (two 6 AWG and a 10 AWG ground) fills it 56 %: too full.
1/2" PVC Schedule 80 (Article 352) has 0.217 in² inside. One conductor may fill 53 % (0.115 in²), two 31 % (0.067 in²), three or more 40 % (0.087 in²). A nipple 24" or shorter may take 60 % (0.13 in²): 9 × 12 AWG.
fill % = Σ Table 5 areas ÷ 0.217 in²
Schedule 80 is for runs exposed to physical damage (352.10(F)). The heavier wall leaves 0.217 in² inside against 0.285 in² for Schedule 40 of the same size.
Secure 1/2" PVC Schedule 80 within 3 ft of each box and support it at least every 3 ft (352.30). A 60 A EV run (56.5 %) does not fit; nor does a 60 A subpanel feeder (79.8 %).
For a mix, add the areas. Two 6 AWG and a 10 AWG ground (a 60 A EV run) take 0.1225 in², 56.5 %; three 3 AWG and an 8 AWG (a 100 A subpanel) take 0.3285 in², 151.4 %.
Questions
6 THHN conductors at the 40 % limit (0.087 in² ÷ 0.0133 in²); 6 current-carrying 12 AWG are derated to 80 % (310.15(C)(1)).
4 THHN, or 3 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, 79.8 % of 0.217 in²: over the 40 % limit; use 1" PVC 80.
0.526 inch nominal (NEC Chapter 9 Table 4), 0.840 inch outside. Use the inside area, 0.217 in², for fill.
10 AWG THHN: three fit within 40 %.
29 % smaller than 1/2" EMT (0.304 in²): the thick wall of Schedule 80 costs inside room.