Heard a guy at the supply house say you should always use a bigger wire than the code minimum.

He was telling a new guy to run 10 AWG for a 20 amp circuit instead of 12. Said it was 'safer' and 'better for voltage drop'. I get the idea, but that's just wrong for most houses. Code minimum is safe, tested, and legal. Upsizing everywhere adds cost for no real gain. In a 50 foot run, the voltage drop difference is tiny. It also makes pulling harder and can mess with breaker trip curves. When have you actually needed to oversize wire in a normal residential job?

3 comments

3 Comments

hannahs451mo ago

I only upsize for really long runs, like out to a detached garage.

kai_park1mo ago

Guess you're not running power to the moon then.

claire_wells8723d ago

Used to be one of those guys who thought upsizing was always better. Then I actually looked at the math on a typical 20A circuit and realized the voltage drop is like 1% over 50 feet with 12 AWG. Running 10 AWG just makes the wire nuts harder to get on and the box tighter for zero benefit. Honestly, seeing the real numbers change my mind.