I'm continuing to fix the issue introduced by someone else (Why run the same phase twice to a series of outlet?).
The other room they did has this setup:
- a 3-conductors cable brings the same phase twice, from a single breaker
- one device is a 120V heater/fan that requires 13A
- the rest is lighting and a power outlet
- everything is AWG 14
(so, with the heater/fan on, we go above 15A. And anyway, the heater spec asks for a 20A circuit)
I understand electricity well, but I know nada about code. Since I don't feel like running a new cable, I though this would work:
- split the 3-conductors cable into a MWBC 20A (I'll ask a competent electrician for this, I don't open panels)
- use 1 phase for the heater/fan (it only needs 120v, but has two switched inputs)
- use the other phase for everything else
Location is Quebec, Canada.
Update: There's another cable I had dismissed, 2 conductors and bare ground, in 12 AWG, but the wires are coloured Black and Red. So I expected this to be only meant for 240v. See second picture. Maybe I can use this dedicated circuit for the heat/fan.
Update 2: Thanks, many excellent answers. I added the diagram that show what I must change.