Which is better?
Copper carries more current per size, terminates more forgivingly, and doesn't creep. Aluminum is roughly a third the cost and much lighter. Both are code-compliant when installed correctly.
What size wire for a 50A circuit?
- Copper: #6 AWG (THHN/THWN-2 or 6/3 NM-B w/ ground)
- Aluminum: #6 AL is rated exactly 50A at 75°C — legal but zero margin. #4 AL is the practical choice, especially on longer runs.
Is aluminum safe?
Modern AA-8000 series aluminum building wire is a different animal than the 1960s–70s branch-circuit aluminum that caused problems. What matters is the termination:
- Lugs/breakers listed for aluminum (AL9CU or CO/ALR)
- Anti-oxidant compound on the conductor
- Torqued to the manufacturer's spec with a calibrated tool (NEC 110.14(D))
When does aluminum make sense?
Long runs. A 100–150 ft feeder to a detached garage or a subpanel is where aluminum saves real money. For short runs inside the house, the copper premium is small enough that it isn't worth the extra care.
Does wire size change for EV vs. a stove?
It can. On a range you can sometimes lean on demand factors. On EV you're sizing for sustained full current, and voltage drop matters more because the load runs for hours. Keep it under 3% — on longer runs that often means upsizing one gauge regardless of ampacity.