Insteon Remote Control 2-Wire Dimmer Switch Qquestion

[bcdavis75]

Hi all.  I have a location (apparently the only one in my entire house) where I've got a witch with no neutral in the box.  I was just about to order my first 2wire dimmer when i noticed it explicitly says it's not compatible with LED's or CFL's.  It being 2019, the load on this circuit is 3 LED bulbs.

 

Just curious, why would the two wire version of the dimmer not be compatible with LED's when the normal 3 wire dimmers work fine (most of the time).  Is it just a minimum load issue?

[mwester]

Minimum load + nature of the load.  More specifically, modern electronics including LED bulbs are powered by a switching power supply.  This means that the current draw on the AC line does not actually follow the AC voltage sine wave, rather it draws very little power up until the voltage gets high enough, then it draws a LOT of power, up until the voltage drops on the other side of the curve to the point where it stops drawing power at all.  The net effect of this is that there's no nice clean simple way for non-neutral devices to get power -- their internal "vampire" power supplies need to be designed to handle this sort of nasty current draw waveform, and very few devices can actually do that (Insteon isn't alone in this).

Now some manufacturers have figured out that they can capitalize on consumer ignorance (or desperation, or whatever) -- instead of addressing the problem by replacing one of the bulbs with a low-wattage incandescent, they'll sell you (for a large markup) a simple power resistor that can suck enough power to make the 2-wire switch work (and of course, that resistor will waste that power as heat inside your wall box - yay! that's just what you need -- something to add heat to a sealed box containing an electronic switch!  what could possibly go wrong with THAT idea??? (put that resistor in the light fixture if you must use this hack!)).

Can you tell I hate these things?   If you must use one, just use an incandescent bulb in one of the sockets, that's the best way to solve the problem.

[Brian H]

They steal their power through the load. That should be an incandescent filament.

The stealing of the power through the load. Would also make the LED bulbs always glow or pulse.