I am trying to upgrade a switch that controls two wall outlets in a 2-gang switch box with a Kasa smart switch. The wall outlets controlled by the switch are split switched outlets.

Here's a diagram of my existing configuration (in the US, the house was built in 2013): Current configuration

I'd like to understand the function of the cables in this configuration and use that to install my new smart switch.

So far, the one thing I know for sure is that the (bare) copper cable is ground :). As per my research, I believe these statements are true:

  1. The white wires are neutral (the 2011 NEC mandates that a neutral wire be present in switch boxes).
  2. The top 3-wire cable connects the switch box to the fan.
  3. The bottom 3-wire cable connects the switch box to the wall outlets; I have split switched outlets with a switch loop, where the source is located at (one of?) the outlets.
  4. The hot wire coming from the switch loop is spliced and goes to both switches.

Is that accurate? What tests can I run with a multimeter to confirm this?

I'd be happy to report back with multimeter test results (once I know what tests to perform) if that helps with the identification. Thanks a bunch!

  • Is the box this is in made from plastic or metal? Nov 24, 2018 at 14:23
  • I think your copper wire is not right where it goes to the switches, it should only connect to the frame of the switch, not to the contacts.
    – Jasen
    Nov 24, 2018 at 18:40
  • @Jasen yes, of course! I should have clarified that in my sketch.
    – K Mehta
    Nov 24, 2018 at 20:49

1 Answer 1


Yes, what you say looks right. This work is competent. The white wire was brought up to supply the fan, not for the neutral rule.

Get my secret weapon, a 5-pack of nulticolored electrical tape. By happy accident, every wire is correctly color coded but one.

  • white is neutral
  • lower cable black is always hot
  • lower cable red is switched hot 1 (for the outlets)
  • upper cable black is switched hot 2 for the fan, mark it with blue tape
  • upper cable red is spare, tag it some other color e.g. Yellow

Of course you know the bare ground wire does not go to the same terminal as a hot...

  • Thanks for the response Harper. I'm a little confused about what you mean when you say "The white wire was brought up to supply the fan, not for the neutral rule." So does the white wire still function as a neutral wire? Since the Kasa switch requires a neutral wire, can I add the neutral wire from the switch to the white wires connected with the screw cap?
    – K Mehta
    Nov 24, 2018 at 20:41
  • It's a regular neutral and you can use it. I'm just saying they brought the neutral there out of practicality: because the fan actually needs a neutral, hence the splice. Nov 24, 2018 at 20:45

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