1 1/4" EMT has 1.380" inside and 1.496 in² of area, so the 40 % fill limit is 0.598 in². It holds 61 × 14, 45 × 12, 28 × 10, 16 × 8 or 12 × 6 AWG THHN. A 60 A EV run (two 6 AWG and a 10 AWG ground) fills it 8 %: it fits.
03 · Conduit fill · Chapter 9 Tables 1, 4 & 5
USE:
1 1/4" EMT · 3.6% FILL · PASS
4 conductors take 0.0532 in² of the 1.496 in² inside 1 1/4" EMT: 3.6 % against the 40 % allowed.
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| Actions | |||||
|---|---|---|---|---|---|
| 2.6 % | 0.5596 in² | 42 | 26 | ||
| 3.6 % | 0.5452 in² | 40 | 25 | ||
| 5.6 % | 0.5140 in² | 38 | 24 | ||
| 8.8 % | 0.4675 in² | 35 | 22 | ||
| 11.6 % | 0.4252 in² | 31 | 20 | ||
| 19.0 % | 0.3146 in² | 23 | 14 | ||
| 22.0 % | 0.2699 in² | 20 | 12 | ||
| 26.6 % | 0.2003 in² | 15 | 9 | ||
| 34.7 % | 0.0791 in² | 5 | 3 | ||
| 40.6 % over | over by 0.0088 in² | — | — | ||
| 2.7 % | 0.5585 in² | 41 | 26 | ||
| 8.2 % | 0.4759 in² | 35 | 22 | ||
| 4.4 % | 0.5319 in² | 39 | 25 | ||
| 6.2 % | 0.5053 in² | 37 | 23 | ||
| 8.3 % | 0.4741 in² | 35 | 22 | ||
| 11.4 % | 0.4276 in² | 32 | 20 | ||
| 14.4 % | 0.3830 in² | 28 | 18 |
gnd: Table 250.122 ground. 1 1/4" EMT allows 0.598 in² at 40 %.
05 / Field guide
1 1/4" EMT has 1.380" inside and 1.496 in² of area, so the 40 % fill limit is 0.598 in². It holds 61 × 14, 45 × 12, 28 × 10, 16 × 8 or 12 × 6 AWG THHN. A 60 A EV run (two 6 AWG and a 10 AWG ground) fills it 8 %: it fits.
1 1/4" EMT (Article 358) has 1.496 in² inside. One conductor may fill 53 % (0.793 in²), two 31 % (0.464 in²), three or more 40 % (0.598 in²). A nipple 24" or shorter may take 60 % (0.897 in²): 67 × 12 AWG.
fill % = Σ Table 5 areas ÷ 1.496 in²
1 1/4" EMT is 1.510" outside and 1.380" inside, a 0.065" wall; the steel is an equipment grounding path (250.118).
Secure 1 1/4" EMT within 3 ft of each box and support it at least every 10 ft (358.30). At 101 lb per 100 ft, each 10 ft span hangs 10.1 lb of pipe. A 60 A EV run leaves room for 35 more 12 AWG THHN; a 60 A subpanel feeder leaves room for 31.
For a mix, add the areas. Two 6 AWG and a 10 AWG ground (a 60 A EV run) take 0.1225 in², 8.2 %; three 3 AWG and an 8 AWG (a 100 A subpanel) take 0.3285 in², 22.0 %.
Questions
45 THHN conductors at the 40 % limit (0.598 in² ÷ 0.0133 in², rounded up by Note 7); 45 current-carrying 12 AWG are derated to 35 % (310.15(C)(1)).
28 THHN, or 24 XHHW (thicker insulation, 0.0243 in² against 0.0211 in²).
Within 3 ft of every box or fitting and at least every 10 ft along the run (NEC 358.30): a 50 ft straight run takes 6 straps, a 100 ft run 11. Keep the bends between pull points to 360° or less (358.26).
Three 6 AWG THHN and a 10 AWG ground take 0.1732 in², 11.6 % of 1.496 in²: that fits the 40 % limit.
1.380 inch nominal (NEC Chapter 9 Table 4), 1.510 inch outside. Use the inside area, 1.496 in², for fill.
1/0 AWG THHN: three fit within 40 %.
EMT is the reference: 1 1/4" EMT has 1.496 in² inside.