Costco LED xmas bulbs and ACT dimmer

I’ve plugged a string of LED bulbs into an Schlage Dimmable module. I didn’t actually think they would dim, but to my surprise they do. The only catch is they never turn all the way off(about 5% on).

My assumption about their internal circuitry would be that the LED’s would stobe on and off from the triac. This is not the case.

Can someone fill me in on the internal circuit operation of the Schlage dimmer?

I am not sure about the dimmer but I have a intermatic plug in module that I have my balcony xmas lights plugged into… they are LED as well and they definately dim up and down as they turn on and off with the set scenes. I think its kind of cool and beats a timer any day.

The same thing happens with my Intermatic HA03 lamp module. The LEDs do remain on just a little bit when supposedly turned off.

I was worried that the low level of voltage could be damaging the LED circuity, so I took them off of the lamp module.

I don’t know about the intermatic specifically, but I may know what’s happening. I’ve noticed with my Leviton vizia rf wall dimmer, there is no neutral terminal on the switch, meaning the switch itself has no way to power the internal leds (night-light and dim-intensity leds) until the circuit is completed (i.e. screw in a lightbulb, or plug a lamp into the wall-outlet if dimmer is controlling an outlet). That being said, I believe the way leviton handles this is that it puts out a small voltage to complete the circuit to light the internal leds. This voltage is not high enough to light an incandescent, but perhaps is enough to light leds. This may also be attributed to load sensing capabilities (sends out a low voltage over the circuit to sense the load type). Again, I don’t know enough about the intermatic, but this may be what is happening.
One thing that may help if you’re really worried about it is installing a resistor downstream of the switch and upstream of the leds to drop the voltage down, although depending on the internal wiring of the intermatic, it may drop out the z-wave radio as well (hopefully not).


I’m not trying to curb your enthusiasm :wink: , but what you are describing is not exactly, but partially, correct. There were previous posts on the forum, explaining how incandescent in-wall dimmers work, e.g.:

But, that should not apply to the external Appliance or Light Plug-in Modules, discussed in this thread, as they plugged in the wall outlet and always powered, hence don’t have to keep the load circuit closed…

As of my own experience - I also got some new LED holiday lights this year and first plugged them into a Monster/Leviton Appliance Plug-in Module. I was very surprised, when they won’t turn completely off… I always assumed the Appliance module is relay-based and it breaks the circuit when off. Then I switched to a Sylvania Dimmable Light Plug-in Module and while LED lights appear to dim perfectly fine, they also switch completely off! What a mystery! :slight_smile:

@denix… interesting theory - i don’t think i agree with the open circuit 99% of the time… otherwise I would think the internal z-wave radio would only be operational 1% of the time… which is not the case with a lamp plugged in… I’ll check it out though - I’ll bring my meter home with me Monday…
Anyway, question - with the monster/leviton device, does the internal z-wave radio work when nothing is plugged into the module? I’m just curious…

@woodsby, it’s not a theory, it’s a fact! :slight_smile:
Check this very detailed explanation here, titled “How Dimmer Switches Work”:

Alternative Current (AC), triac, inductors and capacitors make it all work.
This all applies to dimmable part of the circuit. And in case of in-wall Z-Wave dimmers without neutral wire, the radio is also powered from the same circuit. Z-Wave radio is by nature a very low-power device, so being on only 1% of the cycle (we are talking about 60Hz AC, which anyway changes polarity or flickers 120 times per second…) is fine and can be mitigated with capacitors, if needed…

In case of the plug-in modules, the radio doesn’t even have to be powered from the same dimmable circuit, as plug-in modules are always plugged in to a power outlet, delivering hot and neutral.
That should answer your second question - yes, plug-in modules work all the time, even when there is no load, i.e. nothing is physically connected to them.

@denix… you’re absolutely right - I didn’t even think of that… if the circuit is closed on every cycle, than the devices on the circuit will see a constant voltage (for our intents and purposes)… guess it’s been a while since school…
Anyway, I understand what you’re saying about the isolated circuit - I was just suggesting that maybe leviton intentionally left it as a complete circuit. I mean, essentially, it would have been virtually just as easy to isolate the dim circuit on the wall-box dimmers - there’s a neutral already in the box. Essentially, it’s greener to keep the internal wiring in series, rather than paralled (or isolated) - why power a radio or led if there’s nothing plugged into it… you know? That still leaves me curious as to why the plug-in module doesn’t fully open the dimmed circuit when dimmed all the way down - seems like a waste of electricity… you know?

Actually, in many installations, there is no neutral in the wall box for normal in-wall manual switches. There are only 2 wires (not counting the ground), and both of them are hot! The switch breaks the circuit by disconnecting the hot wire to the light. The neutral comes directly to the light and does not appear in the wall box. That is the simplest installation and is widely used, as it’s sufficient for manual switches.

Check this page below, where they show side-by-side wiring for a light switch with neutral (Figure A) and without neutral (Figure B):

Since case B is so common, it’s hard to have Z-Wave switches and CFLs mixed - need to fish a separate neutral wire to be able to use a relay switch…

If you recall, I was saying that in my case, an Appliance Plug-in module, which uses a relay to isolate the circuits, kept my LED lights on, when powered down. That I cannot explain. :slight_smile:

I decided to attach aforementioned images for a single-pole switch wiring…

Figure A - with neutral in the wall box
Figure B - without neutral in the wall box

Just to add my two cents:

This may not be the legal terminology, but this is how some electricians refer to the following:
Figure A - with neutral in the wall box = HOT SWITCH
Figure B - without neutral in the wall box = COLD SWITCH

Here in California, most all new construction since 70’s uses HOT SWITCH wiring. Denix, both wires in the COLD SWITCH wiring shouldn’t be HOT, you may be picking up some voltage through the filament in the light bulb and the neutral it is attached to. Not that you are, but I want to say…DO NOT use one of those light pens to test for voltage, they should only be used to protect yourself from getting shocked (and even then I’d want to double check). I suggest getting a “Wiggy” or “Vol-Con” tester from Ideal or similar…a multimeter could work too if you know how to use one. This way you are accurately reading which wire has power when you test from the wire in question to a neutral or ground (if there is no ground in the box, run an extension cord from a nearby outlet and use its ground to test). The great thing about the “Vol-Con” is that it has a simple continuity tester as well, which is great for trouble shooting or tracking down wires (when you get continuity between neutral and ground this usually means the wire you are testing is a Home-Run to the panel, where neutral and ground are connected on the same bus bar).

As was mentioned, if you happen to have conduit (pipe) in the walls then pulling a neutral down to the switch location could be fairly easy.

@shady, thanks for the info!

Unfortunately, here on the East Coast, many of the 80s-90s constructions have COLD SWITCH wiring. Not sure about the very recent ones…