I have an electrician friend I always consult before doing electrical work. I have always had a tendency to go up one wire size from what is recommended for a circuit. We were recently talking about that and his answer was that it really doesn’t help anything to do that because the specs are always one wire size over what is needed anyway. Is this true?
Yes, it’s true.
What do you think you are accomplishing?
You mean like using 12 AWG on a 15 A branch circuit, instead of 14 AWG?
There are advantages and disadvantages to using 12 AWG on a 15 A circuit:
Advantages
Easy to upgrade to 20 A in the future.
Slightly less voltage drop.
A little bit less heating at contacts in receptacles.
Disadvantages
Higher cost for the wiring.
More difficult to pull wiring during installation.
More difficult to bend wiring inside boxes.
The same applies to using 10 AWG on a 20 A circuit.
Also keep in mind that, for very long runs, you should increase the AWG of the wiring regardless of anything else.
Those are good examples on short runs I don’t worry about it as much but anything over about 20 ft I usually go up a size. Maybe I will change my criteria to 50 ft.
If you do upsize, make sure you upsize everything on that circuit. Sometimes people will see #12 wire and a 15 amp breaker and will just assume that they can upgrade the breaker to 20 amps, not realizing that there is some #14 wire elsewhere on that circuit.
Around 50 feet you’d want to bump it up to #12 anyway just because of voltage drop (and #10 at 100 feet if you ever go that far).
That makes good sense
20 amp wire doesn’t do anything for a 15 amp plug. Make sure you get the right plug. It looks a little different. If you do it properly your house can have slightly higher resale value. My dad’s did because he ran 20 amp circuits instead of the 15.