Em wrote:
I added 14-gauge (15A) romex cable to a circuit that had 12-gauge
(20A) wire, indicating I had made a mistake, but it turns out to be a
15A breaker on the circuit with 12-gauge wire. Is that OK/safe? I
don't have to correct my mistake, right? Thanks

You already have answers to the same message you posted about 15 minutes
before this one.

--
Joseph Meehan

Dia 's Muire duit