Breaker Size and Wire Size Chart
Common breaker-to-wire pairings, with reminders for derating, continuous load and terminal limits.
- Source
- NEC ampacity and overcurrent data
- Edition
- 2023
- Updated
- 2026-07-27
- Scope
- United States
Lookup Table
Which breaker and conductor sizes commonly pair together?
| Breaker | Common copper | Common aluminum | Caution |
|---|---|---|---|
| 15 A | 14 AWG | 12 AWG | Small-conductor limit |
| 20 A | 12 AWG | 10 AWG | Small-conductor limit |
| 30 A | 10 AWG | 8 AWG | Small-conductor limit |
| 50 A | 6 AWG | 4 AWG | Terminal rating often governs |
| 100 A | 3 AWG | 1 AWG | Check voltage drop |
Calculated against the NEC 2023 edition using 240.4, 240.4(D), 240.6(A), 110.14(C). 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