12-gauge.txt 9/24/2020 2100 12-gauge - A 20-amp circuit, protected by a 20-amp breaker or fuse, must be served by 12-gauge or 10-gauge wire. USE 12 GUAGE. Use SOLID 14 Guage wire for 15 amp 120 VAC house wiring. Why are homes wired using solid wire rather than stranded ****** https://diy.stackexchange.com/questions/5901/why-are-homes-wired-using-solid-wire-rather-than-stranded The main advantage of stranded is that it's more flexible. You generally don't need this in home wiring because it's all put in place once and hidden behind walls/floors/ceilings. When you screw a solid wire into a switch or receptacle, you can tell if it's secure. https://learn.sparkfun.com/tutorials/working-with-wire/stranded-vs-solid-core-wire Since stranded wire is more flexible than solid core wire of equal size, it can be used when the wire needs to move around frequently, in a robot arm for example. Conversely, solid wire is used when little or no movement is needed, such as prototyping circuits on a breadboard or protoboard.