1 AWG Conduit Fill by Conduit Size
How many 1 AWG THHN conductors fit in EMT, IMC, RMC and PVC conduit, 1/2 inch through 4 inch, with the 40% fill rule applied.
Quick answer
1 AWG conductors per conduit trade size
Same-size conductors only, at 53% for one, 31% for two and 40% for three or more.
| Conduit | 1/2" | 3/4" | 1" | 1-1/4" | 1-1/2" | 2" | 2-1/2" | 3" | 3-1/2" | 4" |
|---|---|---|---|---|---|---|---|---|---|---|
| EMT | 1 | 1 | 1 | 3 | 5 | 8 | 14 | 22 | 29 | 37 |
| IMC | 1 | 1 | 1 | 4 | 5 | 9 | 13 | 20 | 27 | 34 |
| RMC | 1 | 1 | 1 | 3 | 5 | 8 | 12 | 19 | 25 | 32 |
| PVC Sch 40 | — | 1 | 1 | 3 | 5 | 8 | 12 | 18 | 24 | 32 |
| PVC Sch 80 | — | 1 | 1 | 3 | 4 | 7 | 10 | 16 | 22 | 28 |
Source & method: Counts are the largest whole number where n × conductor area stays inside the raceway area times the applicable fill percentage. Mix conductor sizes in the calculator.
Fill behaviour at 1 AWG: reusing existing raceway
1 AWG earns most of its use in raceway-constrained retrofits: an existing conduit that cannot accept 1/0 will sometimes accept 1 AWG at the same fill percentage, which can save an entire trenching or wall-opening job on a service upgrade.
For new installations the counts here mainly serve as a check against 1-1/4 inch and 1-1/2 inch raceway. Three conductors plus a ground at this size is a full 1-1/4 inch tube, and adding a fourth conductor generally moves the design up a trade size.
Source & method: Counts referenced above come from the computed table on this page — how these numbers are derived.
What each raceway type means
- EMT — EMT (electrical metallic tubing)
- IMC — IMC (intermediate metal conduit)
- RMC — RMC (rigid metal conduit)
- PVC Sch 40 — PVC Schedule 40
- PVC Sch 80 — PVC Schedule 80
Full fill charts by raceway
Per-type counts for every trade size, plus the cross-type comparison and reverse lookup.
- EMT conduit fill chart — 1/2" to 4"Electrical metallic tubing, thinnest wall, highest count per trade size.
- Conduit fill chart — all raceway types comparedEMT, IMC, RMC, PVC 40 and PVC 80 side by side with reverse lookup.
- PVC conduit fill chart — Schedule 40 and 80Thicker walls, roughly 15 to 25% fewer conductors than tubing.
- Rigid conduit fill chart — RMC and IMCThreaded metal raceway counts and usable areas.
Frequently asked
- How many 1 AWG wires fit in 1/2 inch EMT?
- 1 1 AWG THHN conductors fit in 1/2 inch EMT at the applicable fill percentage.
- How many 1 AWG wires fit in 3/4 inch EMT?
- 1 conductors, using a nominal THHN outside diameter of 0.446 in and the 40% fill rule for three or more conductors.
- Do neutrals and grounds count toward fill?
- Yes, every conductor in the raceway counts for fill. Grounds are excluded only from the count of current-carrying conductors used for ampacity adjustment.
- What is the cross-sectional area of 1 AWG THHN?
- About 0.1562 square inches, from A = π × (OD / 2)² with a nominal insulated OD of 0.446 in.
More on 1 AWG
Conduit fill for nearby sizes
Same 40% fill rule applied to the sizes either side of this one, wrapping around the range so every size is reachable.
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- Conduit Fill CalculatorFill percentage and maximum conductor count for EMT, RMC, IMC and PVC.