What Gauge Wire for a 200-Amp Service?

For a 200-amp residential service entrance, per NEC 310.12:

• 2/0 AWG copper (175A at 75°C from Table 310.16, allowed for 200A under §310.12 dwelling exception)
• 4/0 AWG aluminum (180A at 75°C, allowed for 200A under §310.12)

For a non-dwelling 200A feeder or downstream sub-panel, use NEC 310.16 directly:

• 3/0 AWG copper (200A at 75°C)
• 250 kcmil aluminum (205A at 75°C)

NEC 310.12 dwelling reduction at 200A

The 83% rule applied to 200A = 166A minimum conductor capacity. 2/0 copper at 175A and 4/0 aluminum at 180A both clear that threshold.

Service entrance configuration

A typical 200A residential service includes:

• 2 × 2/0 copper (or 4/0 aluminum) — line 1 and line 2 (hots)
• 1 × 2/0 copper (or 4/0 aluminum) — neutral
• Grounding electrode conductor (GEC) sized separately per NEC 250.66 (4 AWG copper for 200A service)

Conduit fill

200A service entrance conductors in conduit:

2-inch EMT fits both options easily. 1-1/2" EMT (2.036 in² interior) fits 2/0 copper at 32.8% but is too small for 4/0 aluminum at 47.7%.

Ampacity derating

If service entrance is run with more than 3 current-carrying conductors (rare for 200A residential service), apply NEC 310.15(C)(1):

• 4 CCCs: × 0.80 — 2/0 Cu drops to 140A (insufficient for 200A)
• For shared raceways carrying 200A circuits with other CCCs, upsize one step

Quick reference

• Standard wire: 2/0 copper or 4/0 aluminum (per NEC 310.12 dwelling)
• Standard wire (non-dwelling): 3/0 copper or 250 kcmil aluminum
• Breaker: 200A 2-pole main
• Neutral: Same size as ungrounded conductors (or reduced per NEC 220.61 in some cases)
• GEC: 4 AWG copper to ground rod / Ufer
• Conduit: 2-inch EMT typical for service entrance riser

For larger commercial 200A feeders, see the conduit fill calculator.