The wire is No. 12, but the double pole breaker is only 15 amps. I measure amperage only on the black wire in the breaker box. Seems to me that this is just 1 circuit for both the kitchen and the bath with its lights and vent fan heater. I understand the need for the fan, light, heater fan to be on one 20 amp circuit, but not sure how to segregate one circuit with just a red, black and bare ground wire used. I must run a second 12-2 and substitute 2 20- amp or 1-20 and 1-15 for the existing double pole 15.

Please don't start a new thread to continue a conversation. Here is the other thread: https://www.askmehelpdesk.com/electrical-lighting/wire-2-pole-breaker-438323.html