I recently purchased a TP-Link HS200 Smart Wi-Fi light switch that I would like to install so that I can set a schedule for my outside lights. However, the switch that controls my outside lights is beside a 3-way switch. The wiring is different than what I am used to seeing.

I have uploaded pictures to show what I am seeing. Switch 1 controls the outside lights (this is the switch I want to change to a Smart switch) and it appears to be a single pole switch. Switch 2 and 3 control the hallways lights and they appear to be 3-way switches. Switches 1 & 2 are in the same box and switch 3 is down the hallway.

I’ve also labeled the wires from each switch A to K and I’ve included details below on what happens when I disconnect each wire. I will start with switch 1, then switch 2, then switch 3. Please note that the ground wires are not connected for any of the switches.

Switch 1 (all black wires)
If I disconnect wire A, the outdoor lights no longer work, but the hallway lights still work
If I disconnect wire B, nothing changes and all lights still work (wire B goes into the back of the switch, not to one of the side screws)
If I disconnect wire C, the hallway lights don’t work, but the outside lights still work
If I disconnect wire D, no lights work

*when I turn the breaker on, only wire D has voltage with the switch removed



Switch 2 (two black wires, one red wire)
If I disconnect wire E (red wire), nothing changes and all lights still work
If I disconnect wire F, the hallway lights don’t work, but the outside lights still work (also note that wire F connects to wire C on switch 1)
If I disconnect wire G, the hallway lights don’t work, but the outside lights still work

*wire F is connected to a black screw on switch 2
*when I turn the breaker on, only wire F has voltage with the switch removed



Switch 3 (two black wires, one red wire)
If I disconnect wire H, nothing changes and all lights still work
If I disconnect wire K, the hallway lights don’t work, but the outside lights still work
If I disconnect wire J (red wire), the hallway lights cannot be turned on from switch 3, but they can be turned on from switch 2 and the outside lights still work

*wire K is connected to a black screw on switch 3
*when I turn the breaker on, only wire J (red wire) has voltage with the switch removed


So my question is, how do I go about replacing switch 1 with my new Smart switch? I’ve included a picture of the back of the Smart switch. It has 4 wires (one ground, two live/load, one neutral). There are 3 neutral wires in the box connected together at the end with a marette and not in use.

I hope this is clear to whoever is reading. I have replaced many light switches, but this is the first time I’ve encountered a 3-way switch. Thanks

 

I should have mentioned that wire F and C are the same wire (they are connected to both switches 1 & 2)

 

Just some general info to start. You are showing three way switches. The location of the wiring on the switch means nothing. There is a dark or black screw on the switch. That's common and the important connection.

Is switch 1 also a three way switch ?
If not sure..... does the switch say ON and OFF on the front.
If it is.... that switch won't work. You'd need a smart switch that says for 3 way use.

 

Switch 1 is not a three-way switch

 

Ok.... so it's a home handyman connected switch.

A = LOAD
B + C + D = HOT

Connect B, C, and D together and add one smart switch black wire.
Connect A to other smart switch black wire.
White needs to be connected to the neutral splice.
The white wires that match A and D will be in the neutral splice.

 

Thanks Pete. Okay I follow everything except your last line, "The white wires that match A and D will be in the neutral splice". I've never connected to the neutral wires before. I now notice there are 4 white wires connected together with a marette on the end (I'm assuming these are all neutral wires). How do I know which white wires match A and D? Unfortunately I can't seem to attach a picture of what I'm seeing unless I start a totally new thread.

 

Those four white wires are the neutral splice. Connect the smart switch white to that splice.

How-to-insert-pictures.

 

Okay now I understand. I will try this tomorrow and let you know how it goes. Thank you

 

Sorry one more question before I attempt to install the switch. I'm a bit confused by wire B in switch 1 (this wire is in the back of the switch). This wire doesn't seem to do anything as nothing changes when it's disconnected. Do you know what this wire's purpose is?

 

I don't know its exact purpose but I assumed it went to a nearby receptacle that was added in later. If it was dead now you wouln't notice it. If you left it disconnected I'd imagine you could find something dead.

 

Okay thanks Pete that makes sense

 

Thanks Pete everything is working great!

 

Good job. Thanks for letting us know how you made out.