Wire Size for 200 Amp Service
Find the copper or aluminum wire for a 200 amp service, main panel feeder or subpanel, and check the voltage drop for your run.
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Assumes NEC 2023 Table 310.16: copper or aluminum, up to 3 current-carrying conductors in a raceway or cable, 30 °C ambient, 75 °C terminals for a circuit above 100 A (110.14(C)), 3 % drop target; the dwelling service size follows NEC 310.12 (83 %, 75 °C); ground wire not included. Runs in your browser. Verify with your local code and a licensed electrician before you install.
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How to use the 200 Amp Wire Size Calculator
- Keep 200 in “Breaker rating (A)”, or type the rating of your main breaker or service.
- Enter the calculated or measured current in “Load current (A)”. Leave it empty to size for the full 200 A, which is the safe choice for a feeder. Use the electrical load calculator when you do not know the load.
- Tick “Continuous load (3 hours or more)” for EV chargers or heaters. The design current becomes 125 % of the load and must stay at or under 200 A.
- Pick the “Supply type” and enter “Voltage (V)”: 240 for a residential service, or the line-to-line voltage for three phase, for example 208.
- Type the “One-way length” in ft or m, measured along the conduit route from the meter or the main to the panel.
- Choose Copper or Aluminum under “Conductor” and the “Insulation temperature rating” printed on the wire, for example 75 °C for THWN or 90 °C for XHHW-2.
- Leave “Allowed voltage drop (%)” at 3 unless your project sets another limit.
- Open the advanced settings only when they apply: “Terminal temperature rating” (Auto uses 75 °C above 100 A), “Ambient temperature” and the number of current-carrying conductors.
- Read “Recommended wire size”, “Deciding limit” and the “Dwelling service or feeder” rows, then the steps and warnings.
The example buttons load a dwelling service, an aluminum service, an aluminum subpanel, a three phase feeder and two EV chargers. “Copy result”, “Copy link” and “Print / save as PDF” keep the answer.
What size wire do I need for a 200 amp service?
For the service or feeder conductors that supply all of a one-family dwelling at 120/240 V, NEC 310.12 permits 83 % of the rating: 166 A for a 200 A service. In the 75 °C column of Table 310.16 that is 2/0 AWG copper (175 A) or 4/0 aluminum (180 A). These are the sizes quoted for a typical house. Check that the utility’s service requirements and your inspector accept them. The service rows appear only when NEC 310.12 applies to your inputs: nominal 120/240 V single phase (not 208 V), a 100 to 400 A rating, a calculated load entered, conductors rated 75 °C or more, up to 3 current-carrying conductors and a 30 °C ambient. For three phase, 60 °C cable such as NM-B, more conductors, a hotter ambient or a rating outside 100-400 A, the tool says so and gives no smaller size. If your calculated load (125 % for continuous loads) is above the 83 % figure, the rows show the larger size that carries the load; with the load left empty they show no 83 % size and ask for it.
For a 200 A subpanel, a panel in a shop or a commercial feeder the 83 % allowance does not apply and the conductor has to reach 200 A:
| Settings (200 A breaker, 160 A load, 240 V, 50 ft) | Copper | Aluminum |
|---|---|---|
| Breaker-rated feeder (75 °C terminals above 100 A) | 3/0 AWG | 250 kcmil |
| Dwelling service or feeder, NEC 310.12 | 2/0 AWG | 4/0 AWG |
| Insulation rated only 60 °C | 250 kcmil | 350 kcmil |
How far can you run 200 amp wire?
At a 160 A load on 240 V, 3/0 copper reaches about 293 ft one way before the drop passes 3 %; at a full 200 A it reaches about 235 ft. Past that the calculator steps up a size.
| 240 V, 3 % target | One-way length | Result |
|---|---|---|
| 160 A load, copper | 100 ft | 3/0 AWG, 1.02 % drop |
| 160 A load, copper | 200 ft | 3/0 AWG, 2.04 % drop |
| 200 A load, copper | 300 ft | 250 kcmil, 2.57 % drop |
| 160 A load, aluminum | 120 ft | 250 kcmil, 1.36 % drop |
For the usual question of a 300 ft run from the meter to the panel at 200 A, the answer moves up to 250 kcmil copper. The size for the actual load is smaller than for the full 200 A, so enter your calculated load. The ground wire is separate: 6 AWG copper or 4 AWG aluminum for a 200 A breaker, from the equipment grounding conductor calculator.
Worked examples
| Input | Result |
|---|---|
| 200 A breaker, 160 A load, 240 V, 50 ft, copper 75 °C | 3/0 AWG (0.511 %) |
| 200 A breaker, 200 A load, 240 V, 30 ft, copper 75 °C | 3/0 AWG (0.383 %) |
| 200 A breaker, 160 A load, 240 V, 40 ft, copper 75 °C | 3/0 AWG (0.409 %) |
| 200 A breaker, 160 A load, 240 V, 150 ft, aluminum 75 °C | 250 kcmil (1.69 %) |
| 200 A breaker, 160 A load, 240 V, 40 ft, copper 60 °C | 250 kcmil (0.274 %) |
Calculated by the tool above; open it with the same values to see each step.
Questions, briefly answered
What size wire for a 200 amp service?
2/0 AWG copper or 4/0 aluminum for a one-family dwelling service, because NEC 310.12 lets the conductors be 83 % of 200 A. Other 200 A feeders need 3/0 AWG copper or 250 kcmil aluminum.
What size wire for a 200 amp subpanel?
3/0 AWG copper or 250 kcmil aluminum, plus an equipment ground. The 83 % service rule does not apply to a subpanel that serves only part of a building.
Is 2/0 wire good for 200 amps?
Yes as a dwelling service or feeder (175 A in the 75 °C column against 166 A needed). No as a feeder to a shop or a subpanel, where it falls short of 200 A.
What size aluminum wire for 200 amps?
4/0 aluminum as a dwelling service, 250 kcmil for other 200 A feeders. Aluminum needs lugs marked AL/CU and anti-oxidant at the connections.
What gauge wire for 200 amps at 300 feet?
For a full 200 A load, 250 kcmil copper keeps the drop at 2.57 % over 300 ft; 3/0 would drop about 3.8 %. With a real calculated load below 200 A a smaller wire may pass, so enter the load.
How far can I run 3/0 wire at 200 amps?
About 235 ft one way at 240 V with a full 200 A load and a 3 % target; at 160 A it is about 293 ft.
What size ground wire for a 200 amp panel?
6 AWG copper or 4 AWG aluminum for the equipment grounding conductor (NEC Table 250.122). The grounding electrode conductor of the service is a separate size.
Can I use 4/0 aluminum for a 200 amp subpanel?
Not at a full 200 A. Terminals above 100 A are judged in the 75 °C column, where 4/0 aluminum carries 180 A, so the answer is 250 kcmil (205 A). The 90 °C value of 4/0 aluminum does not help because the terminals cap it.