1/0 AWG Conduit Fill by Conduit Size
How many 1/0 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
1/0 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 | 3 | 4 | 7 | 12 | 19 | 24 | 31 |
| IMC | — | 1 | 1 | 3 | 4 | 7 | 11 | 17 | 22 | 29 |
| RMC | — | 1 | 1 | 3 | 4 | 7 | 10 | 16 | 21 | 27 |
| PVC Sch 40 | — | 1 | 1 | 3 | 4 | 7 | 10 | 15 | 20 | 27 |
| PVC Sch 80 | — | 1 | 1 | 2 | 3 | 6 | 8 | 13 | 18 | 24 |
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 1/0: the point where 2 inch appears
1/0 is where a full feeder set with a neutral and a grounding conductor commonly reaches 1-1/2 inch or 2 inch raceway. The count in a 1 inch tube is down to one or two conductors, which is useful only for a single-conductor tap or a separately routed neutral.
Pulling equipment becomes assumed at this size. Even a legal fill count requires lubricant, a rope and usually a puller, and sidewall pressure on tight bends becomes a genuine risk to the insulation. Practical raceway sizing at 1/0 leaves margin above the minimum count for that reason.
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 1/0 AWG wires fit in 1/2 inch EMT?
- None — this size does not fit 1/2 inch EMT; step up a trade size.
- How many 1/0 AWG wires fit in 3/4 inch EMT?
- 1 conductors, using a nominal THHN outside diameter of 0.486 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 1/0 AWG THHN?
- About 0.1855 square inches, from A = π × (OD / 2)² with a nominal insulated OD of 0.486 in.
More on 1/0 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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