The calculator is preset to a 200 amp whole-house service in aluminum. Enter the distance from the meter to the main panel to see whether a long run calls for more than the table size.
How to use this calculator
- Keep the rating at 200 amps, the main breaker.
- Choose aluminum for the usual SE or USE cable, or copper for an older or a commercial-style installation.
- Enter the one-way distance from the meter base or the service disconnect to the panel.
- Feeding a 200 amp subpanel or a second building instead? Switch to a circuit or a subpanel; that feeder carries the full rating and takes larger wire.
Worked examples
A panel on the other side of the meter wall
The wire feeds: A whole house (service) · Load current: 200 A · Circuit voltage: 240 V · One-way distance: 10 ft · Conductor: Aluminum
- Wire size
- 4/0 AWG aluminum
- Current the service wire must carry
- 166.0 A
- Rated for
- 180 A
- Voltage drop
- 0.17%
- Longest run within 3%
- 180 ft
An underground service from a pedestal
The wire feeds: A whole house (service) · Load current: 200 A · Circuit voltage: 240 V · One-way distance: 90 ft · Conductor: Aluminum
- Wire size
- 4/0 AWG aluminum
- Current the service wire must carry
- 166.0 A
- Rated for
- 180 A
- Voltage drop
- 1.50%
- Longest run within 3%
- 180 ft
A copper service entrance
The wire feeds: A whole house (service) · Load current: 200 A · Circuit voltage: 240 V · One-way distance: 25 ft
- Wire size
- 4/0 AWG aluminum
- Current the service wire must carry
- 166.0 A
- Rated for
- 180 A
- Voltage drop
- 0.42%
- Longest run within 3%
- 180 ft
Service conductor size for a 200 amp dwelling by distance
| One-way distance | Copper | Aluminum |
|---|---|---|
| 10 ft | 2/0 AWG | 4/0 AWG |
| 25 ft | 2/0 AWG | 4/0 AWG |
| 50 ft | 2/0 AWG | 4/0 AWG |
| 75 ft | 2/0 AWG | 4/0 AWG |
Each cell: the smallest conductor under the dwelling service rule that keeps the drop at full rated current within the branch-circuit limit. A longer run can go past the largest size this calculator lists; size it with an electrician.
Where 2/0 copper and 4/0 aluminum come from
The rule asks the conductors to carry 83 percent of the service rating. 2/0 AWG copper is rated 175 amps and 4/0 AWG aluminum 180 amps in the higher temperature column, and both clear that share of a 200 amps service. The calculator applies the same rule, so its answer for this rating matches the table row.
A 200 amp subpanel is a different answer
The allowance belongs only to the conductors that carry the whole load of one dwelling. A 200 amp feeder to a subpanel, a garage or a second house must carry the full rating from the regular table: 3/0 AWG copper is rated 200 amps, and aluminum goes beyond the largest size listed here. For a smaller feed see the 100 amp subpanel page.
Who installs the service
The service entrance belongs partly to the utility: they set the meter, often specify the meter base and the underground conductors, and will not energize a new service until the inspector signs it off. Plan the upgrade with them and a licensed electrician; the calculator is for knowing what to expect on the quote, and the 100 amp service page shows the smaller version.
Common questions
What size wire for a 200 amp service?
2/0 AWG copper or 4/0 AWG aluminum for the service of a single-family house, under NEC Table 310.12.
Is 4/0 aluminum good for 200 amps?
For a whole-house service, yes: it is rated 180 amps, more than the share of the rating the dwelling rule requires. For a 200 amp subpanel feeder it is too small.
Is 2/0 copper good for 200 amp service?
Yes, for a single-family service: 2/0 copper is rated 175 amps in the higher temperature column, and the rule asks for 83 percent of the rating.
What size wire for a 200 amp subpanel?
Larger than the service: a feeder to a subpanel carries the full rating, so 3/0 AWG copper, rated 200 amps, or a larger aluminum conductor.