Switch – Odd wiring setup in light switch

lightsmart-switch

Hoping for some help after trying to get this setup to work. I’ve purchased a smart switch that requires two load wires, one neutral wire, and one ground wire.

When I took out my existing light switch I found it having the two load wires but also two neutral (white wires) connected to a ground wire (green). I unwrapped all the wires and hooked it into the smart switch but it didn’t work.

After some investigation it seems that the green wire must be touching one of the white wires for even the normal switch to work. Does anyone have any idea what’s going on here and what the right setup should be?

What’s very odd is that my white wires must be connected to green ones. If they are disconnected the switch doesn’t work.

Thank you.

smart switch
original switch
original wiring
closet switch
Back of box

Here is a wiring that does seem to work (note the white and green are touching):

enter image description here

The following wiring doesn’t work (white and green not touching):

enter image description here

UPDATES:

Thank you all for the advice and help, it works great:

final switch

Best Answer

Someone ran out of white wire

It appears the previous installers ran out of white wire to use for running neutrals, so they grabbed the spool of green wire off the back of the truck to keep the job going. As a result, you'll need to treat the green wires in your switch boxes as neutrals for the purposes of installing your smart switch. This is workable here because you're in Chicago, land of metal conduit everywhere, and metal conduit is usable as a grounding path all by itself.

So, what I'd do is wire up the line/load pigtails to the wires that went to the switch, attach the white pigtail to the existing bundle of white/green wires (making sure they're bundled together as before), mark the green wire as a neutral with white electrical tape (given that replacing it isn't an option at this time), and either leave the green pigtail capped off/unhooked (grounding the switch via its yoke) or terminate the green pigtail from the switch on a green 10-32 ground screw in the matching hole in the back of the switch box (grounding the switch to the box via its pigtail). If there are any other bundles of wires in the box (such as the bundle of reds in the first switch box), just leave them intact.

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