What Size Conduit for a 200-Amp Service?
For a 200A residential service with 2/0 copper or 4/0 aluminum per NEC 310.12, use 2-inch EMT or larger. Non-dwelling 200A feeds also typically use 2-inch.
For a 200-amp residential service entrance, the standard conduit size is 2-inch EMT, IMC, RMC, or PVC depending on the conductor material:
| Conductors | Conductors area total | Required min @ 40% | Standard conduit |
|---|---|---|---|
| 3 × 2/0 copper (310.12 dwelling) | 0.667 in² | 1.668 in² | 2-inch (3.356 in²) — 19.9% fill |
| 3 × 4/0 aluminum (310.12 dwelling) | 0.971 in² | 2.428 in² | 2-inch (3.356 in²) — 28.9% fill |
| 3 × 3/0 copper (310.16 standard) | 0.804 in² | 2.010 in² | 2-inch (3.356 in²) — 24.0% fill |
| 3 × 250 kcmil aluminum (310.16) | 1.191 in² | 2.978 in² | 2-1/2-inch (5.858 in²) — 20.3% fill |
Why 2-inch is the common pick
Three factors:
- Manufactured meter base hubs are most commonly 1-1/2" or 2" knockouts. 2" provides margin for the riser nipple.
- Inspection routine — most AHJs expect 2" for 200A service; smaller raceway gets flagged for re-verification.
- Pulling tension — 200A conductors are heavy; the extra room in 2" eases the pull.
Service entrance configuration
Typical 200A residential service in 2-inch EMT or IMC riser:
- 2 × 2/0 copper (or 4/0 aluminum) — hots
- 1 × 2/0 copper (or 4/0 aluminum) — neutral
- No EGC in service entrance (bonded at main disconnect)
Total: 3 conductors. Fill in 2" EMT: 19.9% (copper) or 28.9% (aluminum). Lots of headroom.
Underground service lateral
Below grade, PVC is the common choice:
- 2-inch PVC Schedule 80 above grade (riser, where exposed to physical damage)
- 2-inch PVC Schedule 40 below grade in the trench
PVC Sch 80 at 2" has 2.874 in² interior (vs Sch 40's 3.291 in²). With 4/0 aluminum × 3 = 0.971 in², Sch 80 fills to 33.8% — passes.
When 2-inch isn't enough
Some 200A configurations push to 2-1/2 inch:
- 3/0 copper standard (non-dwelling): 2-inch fits at 24.0% — still fine actually
- 250 kcmil aluminum (non-dwelling): 2-inch fills to 35.4% — fits but tight
- 350 kcmil for derating margin: 350 kcmil aluminum × 3 = 1.582 in² needs 2-1/2" (15.8% fill)
Quick reference
- Standard service raceway: 2-inch EMT, IMC, RMC, or PVC
- Dwelling exception conductors: 2/0 Cu or 4/0 Al
- Standard conductors: 3/0 Cu or 250 kcmil Al
- Meter base hub: 2" knockout typical
- PVC riser: Sch 80 above grade, Sch 40 below
For 400A or larger services, see the conduit fill calculator — typically 3-inch or 3-1/2-inch for 400A.