How Many #6 THHN Fit in 1-1/4" EMT?
Maximum #6 THHN conductor count for 1-1/4" EMT at the NEC 2023 40% fill cap (3 or more conductors).
In a 1-1/4" EMT, the NEC 2023 ceiling is 11 #6 THHN conductors. The code permits 40% of the conduit's 1.4960 in² interior to be filled when three or more conductors share the raceway (NEC Chapter 9, Table 1), which leaves 0.5984 in² of usable area; each #6 THHN takes 0.0507 in², so 0.5984 ÷ 0.0507 rounds down to 11. This is a fill limit, not an ampacity rating: every current-carrying conductor counts toward the total — including a neutral that carries current — and once more than three current-carrying conductors share the conduit you must also apply the ampacity adjustment factors in NEC 310.15(C)(1). THHN, THWN-2 and XHHW-2 share the same Table 5 cross-section, so the count is identical; RHH and RHW-2 are larger and fit fewer. On long or multi-bend pulls, plan pulling tension and lubricant even when the fill math says the conductors fit.
THE MATH IN ONE PASS
STEP UP OR STEP DOWN A SIZE
| Trade size | Area (in²) | 40% allowed (in²) | Max #6 THHN |
|---|---|---|---|
| 1" EMT (smaller) | 0.8640 | 0.3456 | 6 |
| 1-1/4" EMT ← | 1.4960 | 0.5984 | 11 |
| 1-1/2" EMT (larger) | 2.0360 | 0.8144 | 16 |
All values per NEC 2023 · Chapter 9 · Tables 1, 4 and 5. THHN/THWN-2/XHHW share identical conductor area.