A lot of this information that is given on this thread is wrong and tread lightly when listening to some of this. Most new construction will use 14g wire for 15 amp lines and most use 12g wire for 20 amp, never smaller but you can use 10g. Never assume anything. No builder is going to pay a premium of using 12g wire for 15amp circuits. I have purchased and built 5 new homes in the last 18 years and every builder in every state has done this. We are building a new custom house now and this builder does the same as the other 5. If unsure, open your panel and verify the wire used. Another thing you should do is have either an electrician or your local utility come out and place a device over your circuit to show exactly how many amps you are drawing on the line. There are guidelines on how many max amps you want to draw. For example, on a 15 amp line, you don’t want to go over 10 amps, this is just an example, not sure 10 is accurate, it might be less or more, but never close to 15.
in my latest custom house in my dedicated audio room, I have 6 dedicated 20amp circuits. Cheap to do when building. Large monoblocks, used to use 2 large powered subwoofers, 2 large motor hanss t-60 tt, pre, dac, and other equipment, and the circuits can go fast. Without the subs, I use 4 circuits. Overkill, maybe
