Blue dimmer, no neutral, Hue lights = Won't work

[rohan]

@makahlow

Bottom line - since Ohm’s Law hasn’t been repealed, this series/parallel resistor Ohm’s Law visualization is too simple to explain what I’m seeing. There’s something about the interaction between the lights and the switch which causes the switch not to operate… and now I’m in handwaving territory. The light bulb load might have a substantial inductive component, for instance (and probably does). There are several voltage converters with a lot of funky frequencies which can bleed back and forth. And I know that my picture of the switch as a simple resistor (or even a second load parallel across a resistor) is too simplistic. All of which is beyond my background, although I might be able to follow someone else’s explanation.

Ohm’s law as you’ve described only works for DC circuits. AC circuits are a lot more complicated to model mathematically because of impedance. V = I x Z (Impedance) is the correct formula for an AC circuit. I personally don’t want to go through the math and reasoning in further depth.

@makahlow

So here’s the heart of my question. Either I’m seeing an engineering/manufacturing flaw (I’ve got bad switches), a design issue (I’m working outside of the parameters for which the switch is designed), or a configuration issue (there’s some little box setting a parameter that I need to set). Which one (or more than one) of those three am I looking at?

I think you’re operating at an edge case of the what the switch is designed for.

1. It will operate best with a neutral.
2. With dumb bulbs, it will operate fine with one or multiple bypasses.
3. With smart bulbs, you’ll need to add more bypasses until it starts working.

The options moving forward are as follows:

1. Install additional bypasses with your smart bulb setup until the dimmer remains powered when the bulbs are off in Smart Bulb mode.
2. Rewire at the light to pass a hot/neutral between the switch box and the fixture.
3. Add a new wire between the switch box and the fixture so you have 3 conductors (line/load/neutral).
4. Switch from Smart Bulbs to dumb bulbs and disable smart bulb mode.

I don’t recommend option 3 since it’s going to be considerable rewiring and potentially making holes in drywall.

Option 4 isn’t ideal since you lose your smart bulbs.

That leaves you with Option 1 and Option 2.

@makahlow

edit - Rewiring to bypass the switch isn’t really a good option. My goal with these switches is to set the house up so that my spouse & friends can come in and operate everything with the wall switches. I want my smart house to be able to work like a dumb house if needed - it shouldn’t need a Ph.D. in home automation, or be dependent on remembering the names of every one of 50+ light bulbs.

If your smart bulbs are Zigbee (Hue are) and directly controlled by the same Zigbee hub as the one controlling your light switches (which I assume is true since you are running Home Assistant). You can directly bind your switch(es) to individual or groups of bulbs. This will mean that they will operate perfectly normally with the wall switches without any dependencies on remembering smart bulbs or not. It just works, whether your hub is online or not.