Breaker or Fuse (amps) Min. copper wire size (AWG) 15 14 20 12 30 10 40 8 55 6 70 4 For the full story, you'd have to start with table 310.15(B) (16) in the National Electric Code, but there are a ...

These branch circuits are different sizes, depending on NEC rules and what they're powering. Your kitchen and bathrooms, with high-watt appliances like hair dryers and microwaves, are on 20-amp ...