I am trying to figure out my options for installing a smart switch in my configuration without running a new wire with a neutral. This is quite similar to other questions I'll reference later, so apologies in advance if I am failing to take the right lessons from them.
Here's my configuration:
- Two circuits on adjacent breakers, one serving outdoor lights and the other serving outdoor outlets.
- A 2-gang box has two switches, a smart switch controlling the lights and a basic single-pole switch controlling the outlets. One of those switches is already a smart switch (controlling the lights). The other switch is a basic single pole switch.
- A junction box sits between the electrical panel and the switches
- A Black/red/white/ground cable goes to the panel, with black being hot for one circuit, red hot for the second circuit, and white a shared neutral.
- Two cables go from the the junction box to the box with the switches. A black/red/white/ground cable carries the hot/load/neutral for the smart switch and a black/white/ground cable carries the hot/load for the single pole switch.
- Two other cables (black/white/ground I believe) leave the junction box, one for the lights and another for the outlets.
Can I replace the single-pole switch with a smart switch and use the same neutral wire that the existing smart switch is using, given that the two circuits are sharing a neutral at the junction box? My impression from a few answers is that it should be a code problem more than an electrical one. My read of the answer to this question is that even if it would be electrically okay it's a code violation because the neutral for the smart switch isn't in the same cable as the hot between the junction box and the switch. On the other hand, nobody raised an objection to this question where it was deemed to take the neutral from another switch in the box as long as it was the right neutral and presumably they were not in the same cable, so maybe there's something okay here?
If I can replace the switch the easy way I will do that, but if I can't, another option would be to move the lights and outlets to the same circuit. The lights are now LEDs and the outlets will only be used to power LED lights, so they do not require much current. Is this viable/better?
Edit: Adding some pictures...