Unused hot in multi gang switch box uses?

Moved into a new house recently and I have a 4 gang switch box with one switch that doesn’t control anything and Ive about given up trying to figure it out!

Can I repurpose the hot wire coming in and hook it up to an Innovelli switch and control a Hue light somewhere else in the house?

Does it have a neutral available? If so, you absolutely can use it as a controller.

Also, some of these mysterious switches will control a single outlet (one side of the outlet) in the room or even outdoor eaves outlets for Christmas lights. I’d try to find out where the switch goes first.

There are neutrals ganged in the box so good news that I can at least utilize the slot in some way.

There are 2 hot wires in there, a red and a black. The previous switch, which I suspect is defective was some sort of ancient Lutron on/off/dim controller that was tied into both these red and black wires and then a white going to the neutral bundle.

Previous owner said she thought that switch controlled an outlet in the same room but I have tested every one and cant find it. Also why would they have a dimmer switch on an outlet? For completeness sake I will probably pull out every outlet in the room to see if I can find the corresponding red wire to see verify it is in fact a switched outlet that maybe is defective or had been replaced and they forgot to remove the bridging tab?

OCD is not a good thing to have in a situation like this!

@harjms, just curious is there a reason I need a neutral if the red and or black in there is alway hot? Wouldn’t it just be providing constant power to the switch which I would then turn off local control and them pair it to my Smartthings hub?

So if there is no load connected, the power flowing in needs a way to flow out back to the grid; thus the need of a neutral. If you were to have a load directly connected (e.g. light), then you could use a Dimmer in a non-neutral setup. Originally it sounded like you wanted to use the spare slip for a dimmer/switch to trigger smart lighting that may or may not have been directly connected to the switch. Make sense?

Another reason you might have a switch that doesn’t do anything is if you have fans that have no lights. Electricians will typically install for both just in case you decide to add a light later.

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Thanks for the replies all! Great community!

Previous owner was pretty sure this switch controlled an outlet and I tend to think this is true since there is a hot red in there which would indicate it goes to a switched outlet somewhere?

And yes, if I cant figure out what this switch controls I wanted to use it exactly as you describe @harjms. Power the Innovelli switch, turn off local control (since I cant find out what load its controlling) and program it to control some Hue bulbs plugged in elsewhere.

Yep, if you have a 3-wire connected to two switches that would also be consistent with a switched SPLIT outlet. What you do is run the constant hot over the black and the switched hot over the red.

When you swap out the Inovelli, remove the Load wire and cap it off in the box. Don’t relay upon the switch to not power it. You don’t need a Load on the switch anyway.