What Size Wire for 200 Amps at 400 Feet?
- Load
- 200 A
- Distance
- 400 ft
- Band
- 200 A feeder / service
- Defaults
- Non-continuous, 75 C lugs, 86 F, 240 V single-phase
Computed Starting Point
Ampacity and voltage drop under common defaults for this amp and distance.
| Material | Computed size | OCPD | Usable ampacity | Governing constraint | Default check |
|---|---|---|---|---|---|
| Copper | 300 kcmil | 200 A | 285 A | Voltage drop | Passes defaults |
| Aluminum | 500 kcmil | 200 A | 310 A | Voltage drop | Passes defaults |
What 400 ft ChangesAt 400 ft, the page is the end of the published 200 A distance series. The default result moves from 250 kcmil copper and 400 kcmil aluminum at 300 ft to 300 kcmil copper and 500 kcmil aluminum here, so route and load assumptions deserve a fresh check.
Zero-Length vs This Distance
If the distance-adjusted size is larger, voltage drop governed under these defaults.
| Case | Copper size | Copper constraint | Aluminum size | Aluminum constraint |
|---|---|---|---|---|
| Ampacity only (0 ft) | 3/0 AWG | Termination rated 75 C | 250 kcmil | Termination rated 75 C |
| 400 ft (this page) | 300 kcmil | Voltage drop | 500 kcmil | Voltage drop |
Adjacent Distances at This Amp
Neighboring published lengths for 200 A under the same defaults.
| Distance | Copper size | Aluminum size | Copper constraint |
|---|---|---|---|
| 300 ft | 250 kcmil | 400 kcmil | Voltage drop |
| 400 ft (this page) | 300 kcmil | 500 kcmil | Voltage drop |
400 ft Is the Extreme 200 A Route
200 A feeder / service context for 200 A at 400 ft.
A 400 ft 200 A run is no longer a casual distance adjustment. It usually points to a remote shop, barn, equipment pad, detached building or long service-planning route where the site layout and electrical assumptions should be reviewed together.
Under the defaults on this page, the answer is another large step above 300 ft. The practical question is whether the full 200 A load really needs to travel the entire measured route, and whether the selected conductor can be installed cleanly.
What Changes This Long-Run Answer
Checks that matter for distance-governed sizing in this amp band.
Do not extend beyond 400 ft by guesswork
This is the last published 200 A distance page. If the measured path is longer, rerun the calculator with the real distance instead of extrapolating.
Recheck whether 200 A is the load
A service or panel rating is not always the operating current used for voltage drop. A lower calculated load can materially change long-run sizing.
Verify large-conductor constructability
300 kcmil copper and 500 kcmil aluminum affect conduit size, bends, pulling setup and terminations. Confirm the installation path before ordering.
Review equipment placement
At this distance, moving equipment, shortening the feeder, or splitting loads can be part of the planning conversation before accepting a very large conductor run.