Six THHN conductors in 3/4-inch EMT pass with plenty of room to spare — enough room that a smaller, cheaper conduit would technically work too.
| Conduit type | EMT (Electrical Metallic Tubing), 3/4" trade size |
| Conductors | 6 x #12 AWG THHN |
| Fill rule | 3+ conductors → 40% maximum fill (NEC Table 1) |
NEC Chapter 9 Table 5 gives the area of #12 AWG THHN as 0.0133 in².
| Check | Requirement | Actual | Status |
|---|---|---|---|
| Fill percentage | ≤ 40% | 15.0% | ✓ PASS |
Key insight: Passing the fill-percentage check doesn't automatically mean the smallest theoretically-compliant conduit is the right practical choice — pulling tension, future spare capacity, and simply being able to physically pull six conductors through a tight radius all matter too. Fill percentage is a maximum, not a target to design toward.
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Open Conduit Fill calculator →NEC Chapter 9 Table 1 allows 53% for a single conductor, 31% for exactly two and 40% for three or more — so the limit is not simply lower as the count rises. Two conductors get the lowest figure because two round cables lying side by side are the most likely to wedge across the conduit diameter in a bend; with three or more they nest together more easily. The limits reflect the free space needed to pull conductors in without excessive friction or jamming.
No — this fill-percentage check is purely an area-based rule from NEC Chapter 9. A separate jam-ratio check (comparing conduit ID to conductor OD, most relevant for exactly three same-size conductors) covers physical jamming risk during the pull, which the Cable Pulling Tension calculator on this site addresses directly.