What Size Wire for a 150 Amp Service?
For a 150 A single-phase dwelling service, the NEC allows 1 AWG copper or 2/0 AWG aluminum (310.12 83% rule). A general 150 A feeder sized from Table 310.16 needs 1/0 AWG copper / 3/0 AWG aluminum.
Minimum wire size for 150 amps
| Application | Copper (75°C) | Aluminum (75°C) |
|---|---|---|
| Branch circuit / feeder (Table 310.16) | 1/0 AWG | 3/0 AWG |
| Dwelling service / main feeder (310.12) | 1 AWG | 2/0 AWG |
Assumes 75°C-rated terminations (NEC 110.14(C)). Both assume no more than three current-carrying conductors in a raceway at 30°C ambient. Derating, continuous loads, and local amendments can change the answer: confirm with a licensed electrician.
Ground wire for 150 amps
| Ground | Copper | Aluminum |
|---|---|---|
| Equipment ground, 150 A feeder to a subpanel (Table 250.122) | 6 AWG | 4 AWG |
| Electrode conductor, 1 AWG Cu service (Table 250.66) | 6 AWG | 4 AWG |
| Electrode conductor, 2/0 AWG Al service (Table 250.66) | 6 AWG | 4 AWG |
The electrode conductor runs from the service to the ground rods, Ufer or water pipe; to rods alone it never has to exceed 6 AWG copper (NEC 250.66(A)), and aluminum may not terminate within 18 in of the earth (NEC 250.64(A)). The equipment ground applies when the same rating feeds a subpanel. Every size, with a worked upsizing example, is in the ground wire size chart.
How far can you run it? (voltage drop)
Keeping voltage drop under the recommended 3% at a 120 A load (80% of the breaker), 1/0 AWG copper is good for roughly:
| System voltage | Max one-way run (1/0 AWG Cu) |
|---|---|
| 240 V | ≈ 245 ft |
Past these distances, step up one gauge. Run your exact length and load through the voltage drop calculator.
What runs on 150 amps
- Main service
- Whole-house feeder
Parts for a 150 A service
Since the 2020 NEC (230.67), a new or replaced dwelling service must have surge protection: a Type 2 SPD at the panel is how most 150 A services meet it.
We earn a commission if you buy through links on this page, at no extra cost to you. It does not change what we recommend. See our affiliate disclosure. As an Amazon Associate I earn from qualifying purchases.
Type 2 whole-house SPD
Siemens BoltShield FSPD140
Best for: The default whole-house pick on any brand of panel
Non-contact voltage tester
Klein Tools NCVT-3P
Best for: Confirming a circuit is dead before you open a device or box
Frequently asked questions
Ask AI about this
Open an AI assistant with a question grounded in this page.
Other amperages
Cite or link to this pageAPA · MLA · Chicago · HTML
Free to cite, quote and link. Copy a ready-made citation: the link back is all we ask.
- APA
WattSimple. (2026, August 16). What Size Wire for a 150 Amp Service? https://wattsimple.com/wire-size/150-amp
- MLA
"What Size Wire for a 150 Amp Service?" WattSimple, 16 Aug. 2026, https://wattsimple.com/wire-size/150-amp.
- Chicago
WattSimple. "What Size Wire for a 150 Amp Service?" Last modified August 16, 2026. https://wattsimple.com/wire-size/150-amp.
- HTML link
<a href="https://wattsimple.com/wire-size/150-amp">What Size Wire for a 150 Amp Service?</a> (WattSimple)