2 switch question with 14/3 and 14/2 connected

So I was hoping to move an underused circuit over to a different switch. The circuit currently powers 1 outlet in my garage and nothing else. I removed the drywall between a 2-switch box and the outlet of the underutilized circuit with hopes to just run a junction over to one switch and have my garage lights now powered by a different circuit than the rest of the garage (garage door opener, exterior lights, outlets). When I opened up the box, I found this:

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I am assuming that the 14/2 cable (right side) is the power coming in. The switch on the right turns an exterior light on and off. The switch on the left turns the interior garage lights on and off.

By the way, the red unconnected wire snapped and was connected to the loose red single wire on the right switch. The original wiring is old aluminum (I need to swap out these wire nuts for the purple Al/Cu nuts while the box is opened up).

Would anyone know the proper way to connect the switch on the left to a different power source while retaining the use of the switch on the right powered by its current source?

My guess is that the red on the 14/3 is the hot for the outside light and the black is the hot for the inside lights while they share the negative with the power source. I was going to bring the new power source in and connect the hot to the black on the 14/3; the old hot to the red on the 14/3 and connect all 3 whites and all 3 grounds. Would this solve my issue?

Help would be much appreciated!

 

Since the two loads share a neutral this can't be done just by shifting the hots. You would need to run a new cable from the switch to the load that is to be separated because it needs to be supplied by its own hot and neutral in the same sheath. The existing neutral can't be used.

 

Thanks for the quick response Ray. The issue I have here is that the current load (controlled by the switches) is split somewhere inside a finished wall. I'm wondering if the easiest solution is just to power both loads from the new source. It's a 15A circuit and currently only powering a chest freezer (about 600W). What I was hoping to do was to run 16 can lights (75W max on each) off this circuit but that would put me past a max load on the circuit (1200W for the can lights + 200 on the outside lamps plus the freezer). Am I missing an easier solution?

 

You have a splice inside a finished wall?

Need to resolve that code violation anyway, all splices need to be accessible.

 

I'm going to have a fun time finding where they put the splice. I think it's in a box behind the wall somewhere. At least I hope it's in a box. Once I have that sorted out, would I be ok running the new power source over and powering this entire load for both switches and then running the old power source back over to the receptacle and powering my freezer? This seems to be the only way to get the ~1200W I need for the new lights. It seems every time I open up a j-box I find some nasty surprise like this. The kitchen was a nightmare!

 

Assuming that the 'underused' circuit is feeding a receptacle and not another switch, it should be GFCI protected because it's in the garage.

First, it is rare to find a stand-alone GFCI device in a home. The extra expense of adding that protection leads installers to combine load taps. If there is only one cable entering the box then it is end-of-line. When you turn the power off to it at the breaker, check to be certain that you still have power at all the other locations where GFCI protection is required. Receptacles in bathrooms, attics, unfinished basements, and outside are some of those locations.

Second, GFCI protection does not play well with nonlinear loads such as fluorescent lighting and electric motors. So if you were going to use that circuit to feed the switch for your interior garage lights, you would need to tap off of it before the GFCI protection was applied. And that might be at the breaker.

This is in addition to what Ray said about needing a new cable to one of the loads.

 

This appears to be a circuit only powering this 1 receptacle. I have not been able to find any other outlets on it. It's not GFCI protected as it appears to be pretty old. If I run the power source that's currently powering both switches here over to that receptacle as its new power source, I don't believe there is anything downstream of it (i'll verify) so I could install GFCI there to bring that receptacle up to code unless I'm missing something else. That receptacle would still be end-of-line at that point. I don't believe there would be any issues with fluorescent as everything in the garage will be incandescent or LED.

 

If you don't see a GFCI receptacle behind the freezer and the breaker protecting that circuit is not a GFCI breaker, you can test for GFCI protection upstream with a GFCI tester.

If you install a GFCI and plug a freezer into it, the freezer motor may trip the GFCI when it cycles on. A single receptacle without GFCI protection might be acceptable in that location. Or you could try mounting a GFCI receptacle and seeing if it'll hold.

If you haven't amp-clamped the wires attached to the breakers in your panel while maximizing load, then you don't know how much load a circuit has now, nor how much capacity it has left. Do you have an open space in your panel where you could mount a new breaker to power your lights?

If you decide that you have enough capacity on the circuit feeding the receptacle where the freezer is plugged in to power both the freezer - a relatively small load, typically - and your lights, and you want to install a GFCI there, I would terminate the new cable feeding the light switch to the LINE terminals of the GFCI along with the panel feed. That will keep GFCI protection off the lights and avoid any problem with that.

 

As a side note, although the Ideal Twister 65 wire nut is U.L. Listed for aluminum to copper connections, it isn't U.L. Listed for aluminum to aluminum connections and not recommended by the Consumer Product Safety Commission to be used at all. I'd use the AlumiConn connectors.

Approved by CPSC to prevent aluminum wire fire hazards | KingInnovation