4/0 AWG Conduit Fill by Conduit Size
How many 4/0 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
4/0 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 | 1 | 4 | 7 | 10 | 14 | 18 |
| IMC | — | — | 1 | 1 | 2 | 4 | 6 | 9 | 13 | 16 |
| RMC | — | — | 1 | 1 | 1 | 4 | 6 | 9 | 12 | 15 |
| PVC Sch 40 | — | — | 1 | 1 | 1 | 4 | 5 | 8 | 12 | 15 |
| PVC Sch 80 | — | — | 1 | 1 | 1 | 3 | 5 | 7 | 10 | 13 |
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 4/0: the standard 200 A service raceway
4/0 aluminium is the most common 200 A residential service conductor, so the counts on this page correspond to one of the most frequently installed raceways in the trade. Three 4/0 conductors plus a grounding conductor generally requires 2 inch, and 2-1/2 inch is common where the run is long or has multiple bends.
Service masts and underground laterals at 4/0 are usually the longest single pull on a dwelling, which makes bend count and sweep radius as important as the fill number. Upsizing the raceway one trade size above the minimum is standard practice on service work for exactly 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 4/0 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 4/0 AWG wires fit in 3/4 inch EMT?
- 0 conductors, using a nominal THHN outside diameter of 0.642 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 4/0 AWG THHN?
- About 0.3237 square inches, from A = π × (OD / 2)² with a nominal insulated OD of 0.642 in.
More on 4/0 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.
Related charts & calculators
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