How Many Amps Can 12 AWG Aluminum Wire Handle?
Verified against NEC 2023, checked against the 2026 edition · Last checked August 19, 2026
12 AWG aluminum wire carries 15 A at 60°C, 20 A at 75°C and 25 A at 90°C · Table 310.16. Which column applies depends on the termination rating · 110.14(C). No matter the column, the breaker on 12 AWG aluminum tops out at 15 A · 240.4(D).
Common landing spot: a 15 A breaker or feeder.
| Column · insulation examples | Ampacity | Basis |
|---|---|---|
| 60°C · TW, UF | 15 A | Table 310.16 |
| 75°C · THW, THWN, XHHW wet, USE | 20 A | Table 310.16 |
| 90°C · THHN, THWN-2, XHHW-2 | 25 A | Table 310.16 |
| Maximum breaker | 15 A | 240.4(D) |
THHW and XHHW are 90°C only in dry and damp locations; wet locations put them in the 75°C column. XHHW-2 and THWN-2 hold 90°C wet or dry · Table 310.4(1).
| Current-carrying conductors | Percent of table ampacity |
|---|---|
| 4 to 6 | 80% |
| 7 to 9 | 70% |
| 10 to 20 | 50% |
| 21 to 30 | 45% |
| 31 to 40 | 40% |
| 41 and more | 35% |
Ambient above 86°F applies a further correction from the band table of 310.15(B)(1). The free wire size calculator applies both automatically.
Derate it in seconds, offline.
The JobVolt app applies ambient correction, conductor adjustment and termination limits to 12 AWG aluminum with every step cited, then exports inspector-ready PDF submittals.
Common questions
- How many amps can 12 gauge aluminum wire handle?
- 15 A at 60°C terminations, 20 A at 75°C and 25 A at 90°C, per NEC Table 310.16 with no more than three current-carrying conductors at 86°F ambient. The overcurrent device still caps at 15 A · 240.4(D).
- What size breaker goes on 12 AWG aluminum?
- 15 A is the maximum · 240.4(D). Larger breakers are not permitted on 12 AWG aluminum outside specific rules like motor circuits · 240.4(G).
- Why does the chart say 25 A for 12 AWG aluminum but the breaker only 15 A?
- 25 A is the 90°C table ampacity, the starting point for derating. The small-conductor rule caps the overcurrent device separately · 240.4(D). Both are true at once.
- Is 12 AWG aluminum wire safe to use?
- Yes, at the ampacities above: 20 A at 75°C terminations. Modern aluminum branch and feeder conductors are AA-8000 alloy, not the 1960s wire, and terminate on lugs rated for aluminum.
- Does conduit fill change the ampacity of 12 AWG aluminum?
- Four or more current-carrying conductors in one raceway derate the table value · 310.15(C)(1). At 4 to 6 conductors, 12 AWG aluminum starts from 80% of the 90°C cell: 20 A before any further correction. Heat above 86°F derates it further · 310.15(B)(1).