Care to be taken with aluminum wiring: Do not over-fuse aluminum wiring. The AWG (American Wire Gauge) rating of No. 12 aluminum wiring is equivalent to No. 14 copper wiring.

This usually increases the gauge size by one. For a 15-amp circuit, you would need a 14-gauge copper wire or a 12-gauge aluminum wire. (The smaller the gauge number, the larger the wire.) ...

The result was aluminum-bodied lugs used to terminate copper wire operated successfully, while copper-bodied lugs used to terminate aluminum wire failed. Three entire series of branch circuit device ...