Aluminum Wire: Separating 1968 from 2026

"Aluminum wiring" means two completely different things, and conflating them costs homeowners real money.

What actually went wrong

1965–1973 branch circuits used AA-1350 utility-grade aluminum in 12 and 10 AWG, landed on devices designed for copper. That alloy crept under screw pressure, its oxide is insulating, and thermal cycling loosened terminations until they arced. The fires were real — and they were a small-conductor termination problem, not an aluminum-conductor problem.

What changed

AA-8000 series alloys (required since NEC 1987 for building wire) creep like copper. Terminations are now rated and listed for aluminum (AL9CU lugs), torque values are specified and — since NEC 2017 110.14(D) — must be verified with a torque tool. Modern aluminum SER/SEU and feeder cable in 6 AWG and up has decades of clean service history.

The 2026 decision rules

• Branch circuits (15–30 A): copper, full stop. Aluminum below 12 AWG is not even listed, and device compatibility makes it pointless.
• Feeders and services (1/0 and up): aluminum is the market default — roughly two AWG sizes larger than the copper equivalent (see the comparison table) at a fraction of the price and a third of the weight.
• Existing 1960s–70s branch aluminum: not an emergency, but every termination is a maintenance item — COPALUM/AlumiConn repairs or rewire, evaluated by an electrician.

Voltage drop math is the one place aluminum always costs: 61% more resistance per size means the solver will hand you a bigger number. Buy it anyway — at feeder sizes, it is still cheaper.