The most THHN / THWN-2 conductors of one size allowed in each EMT trade size, worked out from NEC Chapter 9: conduit areas from Table 4, conductor areas from Table 5, and the fill limits from Table 1 (53% for one conductor, 31% for two, 40% for three or more). Note 7 rounds a count up when its decimal is 0.8 or more. Informative Annex C, Table C.1 lists EMT counts made the same way.
Values are from the 2017 NEC (NFPA 70); check the edition your AHJ enforces. Count the equipment grounding conductor too (Chapter 9 Note 3). This is a reference for same-size stranded conductors only: compact conductors, mixed sizes and nipples are not covered, and the ampacity adjustment for more than three current-carrying conductors (310.15) and local rules still apply.
THHN in EMT, 14 to 6 AWG
Example: 12 AWG THHN in 1/2" EMT. 40% of 0.304 in² is 0.1216 in²; one wire is 0.0133 in², and 0.1216 ÷ 0.0133 = 9.14, so 9.
Most THHN / THWN-2 conductors in EMT, 14 to 6 AWG| EMT size | 14 AWG | 12 AWG | 10 AWG | 8 AWG | 6 AWG |
|---|
| 1/2" | 12 | 9 | 5 | 3 | 2 |
|---|
| 3/4" | 22 | 16 | 10 | 6 | 4 |
|---|
| 1" | 35 | 26 | 16 | 9 | 7 |
|---|
| 1¼" | 61 | 45 | 28 | 16 | 12 |
|---|
| 1½" | 84 | 61 | 38 | 22 | 16 |
|---|
| 2" | 138 | 101 | 63 | 36 | 26 |
|---|
| 2½" | 241 | 176 | 111 | 64 | 46 |
|---|
| 3" | 364 | 266 | 167 | 96 | 69 |
|---|
| 3½" | 476 | 347 | 219 | 126 | 91 |
|---|
| 4" | 608 | 443 | 279 | 161 | 116 |
|---|
THHN in EMT, 4 AWG to 1/0
Large conductors in small conduit fall back to the 31% limit for two conductors and 53% for one: one 1/0 THHN fits in 1/2" EMT (0.53 × 0.304 ÷ 0.1855 = 0.87, rounded up by Note 7), two do not.
Most THHN / THWN-2 conductors in EMT, 4 AWG to 1/0| EMT size | 4 AWG | 3 AWG | 2 AWG | 1 AWG | 1/0 AWG |
|---|
| 1/2" | 1 | 1 | 1 | 1 | 1 |
|---|
| 3/4" | 2 | 1 | 1 | 1 | 1 |
|---|
| 1" | 4 | 3 | 3 | 1 | 1 |
|---|
| 1¼" | 7 | 6 | 5 | 4 | 3 |
|---|
| 1½" | 10 | 8 | 7 | 5 | 4 |
|---|
| 2" | 16 | 13 | 11 | 8 | 7 |
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| 2½" | 28 | 24 | 20 | 15 | 12 |
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| 3" | 43 | 36 | 30 | 22 | 19 |
|---|
| 3½" | 56 | 47 | 40 | 29 | 25 |
|---|
| 4" | 71 | 60 | 51 | 37 | 32 |
|---|
Counts are whole conductors after the Note 7 round-up, which is why a few of them fill a little over the limit (22 × 14 AWG in 3/4" EMT is 40.04%).
Estimates only. Check measurements, product labels and local building codes before you buy or build.