What Size Wire for 150 Amps?
- Load
- 150 A
- Distance
- 0 ft entered
- Band
- Service / large feeder
- Defaults
- Non-continuous, 75 C lugs, 86 F, 240 V single-phase
- Conductor count
- 3 current-carrying
Computed Starting Point
The table uses common defaults. Change the calculator inputs for the actual installation.
| Material | Computed size | OCPD | Usable ampacity | Governing constraint | Default check |
|---|---|---|---|---|---|
| Copper | 1/0 AWG | 150 A | 150 A | Termination rated 75 C | Passes defaults |
| Aluminum | 3/0 AWG | 150 A | 155 A | Termination rated 75 C | Passes defaults |
What 150 A ChangesAt 150 A, the displayed copper row has no extra ampacity above the 150 A rating under the 75 C default, while aluminum shows only a small margin. Equipment limited to 60 C will move both displayed conductor results larger, and conductor product, ambient or bundling derating, and utility requirements can also change the final size.
Adjacent Amp Ratings
See whether stepping one standard size up or down forces a conductor jump under the same defaults.
| Load | Copper size | Copper OCPD | Aluminum size | Aluminum OCPD |
|---|---|---|---|---|
| 125 A | 1 AWG | 125 A | 2/0 AWG | 125 A |
| 150 A (this page) | 1/0 AWG | 150 A | 3/0 AWG | 150 A |
| 175 A | 2/0 AWG | 175 A | 4/0 AWG | 175 A |
A plateau means neighboring amp ratings share a conductor size under these defaults. A jump means a standard breaker change often needs a larger wire; confirm with your real ambient, length and terminations.
150 A Opens the Service / Large-Feeder Band
Service / large feeder context for a 150 A circuit.
A 150 A wire-size search often means a service upgrade, large subpanel, ADU feeder, shop feeder, or panel swap between the 125 A and 200 A decisions. At this size, the answer is less about a branch-circuit habit and more about the exact conductor product, equipment lugs, and utility or AHJ requirements.
Under the displayed 75 C termination defaults, copper moves from 1 AWG at 125 A to 1/0 AWG here, and aluminum moves from 2/0 AWG to 3/0 AWG. The next 175 A page moves both materials larger again, so a 150 A plan should be checked before it drifts toward a 175 A or 200 A service decision.
What Changes This Answer
Checks that can change the starting conductor under the displayed defaults.
Confirm service or feeder product
Service-entrance cable, raceway conductors, and feeder cable assemblies can follow different product listings and termination limits. Do not treat the AWG result as approval for every product type.
Watch the tight 150 A margin
The copper row shows 150 A usable ampacity under the displayed 75 C defaults. If conditions change, or if either end is limited to 60 C, rerun the calculator before relying on 1/0 AWG copper.
Check 60 C equipment limits
The displayed 1/0 AWG copper and 3/0 AWG aluminum results are 75 C defaults. Equipment limited to 60 C will force larger conductors for a full 150 A feeder or service.
Do not reuse the 125 A feeder
Under these defaults, 125 A uses 1 AWG copper and 2/0 AWG aluminum. This 150 A page moves to 1/0 AWG copper and 3/0 AWG aluminum.
Load calculation owns the service size
A 150 A conductor answer assumes 150 A is the correct service or feeder rating. Confirm the dwelling, feeder, or equipment load before selecting wire.
Check utility and AHJ requirements
Service work can be constrained by utility standards, meter and disconnect lug listings, grounding and bonding requirements, and local review.