Wire Size Amp Chart
A compact starting chart that sends marginal or long-run work into the wire-size calculator.
- Source
- NEC ampacity and small-conductor overcurrent data
- Edition
- 2023
- Updated
- 2026-07-27
- Scope
- United States
Lookup Table
What is the quick ampacity starting point for common wire sizes?
| Size | Copper starting point | Aluminum starting point | Common limiter |
|---|---|---|---|
| 14 AWG | 15 A | - | Small-conductor rule |
| 12 AWG | 20 A | 15 A | Small-conductor rule |
| 10 AWG | 30 A | 25 A | Small-conductor rule |
| 8 AWG | 40 A | 35 A | Termination and derating |
| 6 AWG | 55 A | 40 A | Termination and derating |
This quick chart is a starting point. Ambient temperature, conductor count, terminal rating and voltage drop can all require a larger conductor.
Calculated against the NEC 2023 edition using 310.16, 240.4(D). Confirm the edition adopted by your AHJ, which may differ and may carry local amendments.
Not covered by this tool
- Local amendments and equipment markings can be stricter than this reference view.
- Marginal values should be checked directly against the adopted edition.
- This page is a routing aid and does not replace the owning calculator for project-specific inputs.
Data last verified