I have 7 outlets on one circuit. It has a 15amp breaker and is wired from one to the other in 14/2 My question is, I have a small(6' section) where I have to change around, and I will need about 6' of wire to connect this outlet. Question is I have a whole bunch of 12/2 romex and want to know if i can use the 12/2 for this 6' section. It is still just outlets in a series. Thanks
It is perfect to use 12/2(or larger) on a 15 amp circuit.
The code only states the minimum size gauge to use on a circuit. 14 gauge is the minimum on 15 amps.
You cannot add 20 amp breaker if any wire is smaller than 12 gauge, must all 12 gauge or larger.
Most devices have a maximum gauge that will fit on it's connection points.
So long as the breaker is 15A, because there is 14Ga wire on the circuit, you can use 12Ga (or 10, or 8, or whatever larger size you like, though it becomes inconvenient in practice) on the circuit as well. 14Ga is a minimum size, and 15A is a maximum size if there is any 14Ga. 12Ga is larger than minimum, and perfectly safe/acceptable.