TP-link Kasa 2 way HS200 only controls 1 of 7 lights

Question

HELP for a SmartHome / Electrical noob here

Our kitchen has 11 recessed lights - 6+4 on the main roof and 1 over the sink. The 6+1 are controlled by one 2 way switch (A). The other 4 by a 3-way setup (switches B and C). Switch (A) and (B) are in a 2 gang plate. (C) is on the other end of the kitchen.

I replaced (A) - the 2 way switch that controlled 6+1 recessed lights in the kitchen - with the 2 way HS200 V3. It turns on fine, but only controls 1 of the 7 lights now - the one above the sink. The other 6 stay turned off. Switches (B) and (C) are working fine as usual and controlling the other 4 lights.

(A) had 3 wires as shown in the img below. The "white" wire was connected to the side screw and had black tape around it, so likely "hot". How do I wire this thing? The bulbs are all LED rated 8-11W / ~96mA. The HS200 I believe is rated 600W / 5A Incandescent and 600W / 15A LED.

Answer 1

This won't answer the reason why it worked-sort-of, nor exactly how you're wired - I'll leave that to the real electricians - but, I don't think you can use the HS200.

The HS200 requires a neutral for itself. Because it's a smart switch, and not just an expensive detachable piece of metal, it actually consumes current; so it can't just have a hot wire passing through it.

TPLink's page on installing the switch covers this in some (poorly written) detail.

If the black-wrapped wires (B1,W1) were solely going to the breaker, and the yellow-wrapped wires (B2,W2,copper) were solely going to the lights, then you could make it work - you'd have your neutral. But, that doesn't seem to be what you have, based on what you wrote - if that were the case then you'd not be able to turn on only the one light and not the others.

The yellow wrapped wire is irrelevant here - it is relevant to the lights it feeds, of course, but from the point of view of powering your switch, you need three wires plus ground: two wires that go back to the circuit breaker (one each, hot and neutral), and a third (hot) wire that goes to the light (with the light also having one go back to the breaker's neutral).

Consult an electrician, who can install a neutral wire for you to the switch, and fix the wiring of the current switches as needed.

You also could consider a smart switch that doesn't require a neutral, though I would bring an electrician in to make sure your wiring isn't wrong in other ways; but see for example this article about smart switches which do not require neutral, which also does have a nice bit explaining what your setup probably is like (disregarding the yellow-wrapped wires, which seems like they're just piggybacking on the black-wrapped ones).