What Size Wire for a 200 Amp Service?

Short answer: for a 200 amp residential service (single-phase 120/240 V), use 2/0 AWG copper or 4/0 AWG aluminum service-entrance conductors (NEC Table 310.12). The grounding electrode conductor is 4 AWG copper (or 2 AWG aluminum), but only 6 AWG copper is needed to ground rods. For a 200 A feeder that doesn't carry the whole dwelling load, or for a commercial service, use 3/0 copper or 250 kcmil aluminum.

200 A conductor sizes

4/0 aluminum SE cable (4/0-4/0-4/0-2/0 SER, or 4/0-4/0-2/0 SEU) is the most common residential choice because it is lighter and usually costs much less than the equivalent copper; compare current supplier prices for your run.

The 83% math

200 × 0.83 = 166 A. At 75°C, 2/0 copper is rated 175 A and 4/0 aluminum 180 A, so both qualify; 1/0 copper (150 A) and 3/0 aluminum (155 A) don't. A subpanel feeder must be rated for the full 200 A: 3/0 copper (200 A) or 250 kcmil aluminum (205 A). See the ampacity chart.

Grounding

• GEC (Table 250.66): with 2/0 or 3/0 copper, or 4/0 or 250 kcmil aluminum service conductors, the GEC is 4 AWG copper or 2 AWG aluminum.
• GEC to ground rods: never required to be larger than 6 AWG copper (250.66(A)).
• GEC to concrete-encased electrode (Ufer): never required to be larger than 4 AWG copper (250.66(B)).
• Equipment grounding conductor for a 200 A feeder: 6 AWG copper or 4 AWG aluminum (Table 250.122).
• Intersystem bonding termination at the service for communications grounds (250.94).

Meter-main to an indoor panel

Many new services use an outdoor meter-main, partly because the NEC now requires an emergency disconnect outside one- and two-family dwellings (230.85). The conductors from the meter-main to the indoor panel are then a feeder, not service conductors:

• If that feeder carries the entire dwelling load, Table 310.12 still applies: 4/0 aluminum or 2/0 copper.
• It must be four-wire: two hots, an insulated neutral and an equipment ground (4/0-4/0-4/0-2/0 aluminum SER is typical).
• At the indoor panel, the neutral is isolated and the bonding screw removed. The only neutral-to-ground bond is at the meter-main.
• A 40-foot run at 160 A on 4/0 aluminum drops 2 × 21.2 × 160 × 40 ÷ 211,600 = 1.28 V, about 0.5%. Voltage drop almost never controls here.

200 A feeder by distance (240 V)

Smallest conductor that meets both the 75°C ampacity for a 200 A circuit and a 3% voltage drop at 160 A (80% of the rating), 240 V single-phase, one-way distance. Percent drop in brackets. If the circuit uses NM-B cable or 60°C terminations, start from the 60°C column instead.

Services are usually short runs from the meter, so voltage drop rarely controls. It matters for long feeders to a detached building or a second house. For example, a 200 A feeder to a detached shop 180 feet away, carrying 160 A on 250 kcmil aluminum, drops 2 × 21.2 × 160 × 180 ÷ 250,000 = 4.88 V, or 2.0%.

Conduit size for a 200 A service

• Aluminum: three 4/0 conductors (two hots and a full-size neutral) total 3 × 0.3237 = 0.9711 in² using the THHN/THWN-2 areas in Chapter 9 Table 5. That's too much for 1-½" EMT (0.8144 in²), so use 2" EMT (40% area 1.3424 in²) or 2" PVC Schedule 40 (1.3164 in²). Even four 4/0 conductors (1.2948 in²) fit 2". XHHW-2 aluminum areas differ slightly from THHN, so confirm with Table 5.
• Copper: three 2/0 THHN total 3 × 0.2223 = 0.6669 in², which fits 1-½" EMT or PVC.

Details and other combinations are in the conduit fill chart.

Is 200 amps the right size?

For most new single-family homes, especially all-electric homes with heat pumps and EV charging, 200 A is the standard. Very large homes with multiple EV chargers, electric heat and pool equipment may need 320/400 A class service. A load calculation settles it. In the 2026 NEC the dwelling load calculation moves to Article 120, while Table 310.12 still sizes the conductors once the rating is set. Smaller homes may fit 150 A.

Common mistakes inspectors flag

• 2/0 aluminum on a 200 A service (that's the copper size).
• Three-wire feeder from an outdoor meter-main to the indoor panel.
• Bonding screw left in the indoor panel downstream of the service disconnect.
• 6 AWG GEC run to a Ufer, which needs 4 AWG copper with a 200 A service.
• 4/0 aluminum on a 200 A subpanel breaker without the load calculation that 240.4(B) requires (4/0 aluminum is 180 A at 75°C).

Frequently asked questions

Can I use 2/0 aluminum for a 200 amp service?

No. 2/0 aluminum is sized for about 150 A. A 200 A dwelling service needs 4/0 aluminum (or 2/0 copper).

What size copper wire for a 200 amp service?

2/0 AWG copper for a dwelling service under Table 310.12, or 3/0 copper where Table 310.16 applies.

What size ground wire for a 200 amp service?

4 AWG copper GEC in general, 6 AWG copper to ground rods, and 6 AWG copper for the equipment grounding conductor in a 200 A feeder.

What size conduit for a 200 amp service?

2" EMT or PVC for 4/0 aluminum; 1-½" for three 2/0 copper. Check the exact conductor areas in Chapter 9 Table 5 and the conduit fill chart.

Can I use 4/0 aluminum for a 200 amp subpanel?

Only under 240.4(B): 4/0 aluminum is rated 180 A at 75°C, and a 200 A breaker is the next standard size, so it's permitted when the calculated load is 180 A or less. Otherwise use 250 kcmil aluminum or 3/0 copper. The 100 amp service page explains the same service-vs-feeder split at a smaller size.

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Last updated: October 6, 2026. Based on NEC 2023. Service work requires a permit and utility coordination. Check results against the code edition and local amendments your jurisdiction enforces and with the AHJ; electrical work should be done by qualified people.