Will I need a bypass for my Fibaro FGD-212 install?

I’ve bought a Fibaro FGD-212, haven’t fitted yet, to go on a bank of 3 non-dimmable GU10 spot LEDs of 4W each.

I’m keeping the current toggle switch and it’s going to be used for security and convenience at night switching.

I’m a little confused on what I may need extra, if any.

Do I HAVE to have dimmable LED bulbs?
Do I HAVE to have the bypass?


They don’t have to be dimmable - you can disable dimming in the parameters.

Instructions say that you will need a bypass 2, but others have been fine without. Vesternet have a sale on today (Dimmer 2 and bypass 2).

Edit to add… if you have a neutral wire you won’t need a bypass.


How do you disable dimming? Where they are located I don’t have any need for dimmable ones.

Reading up it looks like need minimum of 50W or need bypass, below quoted from the Vesternet website…

“The Fibaro Dimmer 2 and Dimmer Bypass can only be used with lamps that are ‘dimmable’. Before buying this product, please confirm that your lamp can be dimmed”

I don’t have a neutral, eventually after buying incorrect products I found via ST forum, this was best and works with no neutral.

With the P+P charge, no free or slower postage option, makes them a bit to near Amazon price even the current discounted price though.

Parameter 32 on the device (you’ll need a custom handler to set this, there are plenty around on the board).

Parameter 32: On/Off mode. This mode is necessary when connecting non-dimmable light sources. Setting this parameter to 1 automatically ignores brightening/dimming time settings. Forced auto calibration will set this parameter’s value to 2. 0=disabled (dimming possible) 1=enabled (dimming not possible) 2=auto detect.

Vesternet are probably just covering their backs.

The bypass is just a resistor, it shouldn’t make any difference if your bulbs are dimmable or not.

Thanks John, I really need to read up, haven’t a clue how to set it up yet, or even wire it yet…

I’m just worried on the low wattage, mine being 12W when they say 50W, quite a discrepancy.

What’s worst that would happen? Not work? It’s not dangerous is it?

You don’t have the link for the newest/best/recommended handler please currently do you please?

Thanks again

@ hajar’s device handler and associated apps are the best there is. They really exploit the features built into the dimmer 2.

The reason for needing the bypass, is that the Dimmer 2 needs power to run. To power something you need a live and neutral. Unless you have a neutral wire, you need to use the neutral in the circuit, which effectively runs through the lights (this is usually called the ‘switched live’ as it needs the live switched to it in order to complete the circuit).

The Dimmer 2 can never be truly off, as it needs power to accept commands. It needs/consumes a very small amount of power, and is effectively at ‘minimum brightness’ rather than off. This minimum is enough to make some low power bulbs blink or stay on.

The bypass is just a resistor which absorbs this extra power, and doesn’t pass it on to the bulbs.

If it were unsafe, it wouldn’t be for sale. The amount of power going through the bypass is tiny when the lights are off. It really just goes to show how mega-efficient LED bulbs are.

Thanks again John, appreciate your comments and help. So I can still try safely, even with my only 3 non-dimmable LEDs, at around 12W, without the bypass first then?

I’ll have a look at that code, thanks for link, although had ST a few months, I’m not a coder, and when have to manually add, it’s a little difficult. I added some Lightify LEDs with the help, work great, but wife and kids switch off the switch, which renders my expensive, smart bulbs…very dumb!?!

So the procedure for the dimmer 2 is…

-Wire in (still have to do this!)
-add to ST (how initially?)
-change handler with code in the IDE
-change parameter 32 (easy?)


That’s pretty much it, yes.

For the initial add, just start the app looking for new devices, and flick the switch a few times. The device will install itself as a generic Z-Wave device, and you need to change this through the IDE.

Once you’ve got Hajar’s device handler installed, you’ll have his device type in the list, so you can just change to that.

Once you have this active, you can change all of the parameters directly in the app with no further IDE involvement.

And yes, it’s perfectly safe (bar all exceptions of being a DIY electrician) to try without using the bypass. All you will get at the worst is low power leakage to the bulbs. You’ll know whether you need one quite quickly.

Did you manage to install and get your dimmer2 working as expected with the bypass?
I’ve had the dimmer2 working for a week or so… the dimmer works and on/off as a toggle… but after i installed the dimmer bypass today i still have some light glow and flicker when set to “off” Ive done another calibration (actually a few) using both the parameter 13 options and using the Dimmer2 menu system… neither seem to sort it out.
How did your install go?

And does anyone else have any ideas on how to get this to work - from a wiring perspective, it seems you install the bypass either side of the lights neutral… is this correct?


Been so busy never even tried yet! Got some wire and connection block to install but never got around. Maybe next weekend now… Mmm…

I’m still unsure if I’ll need new dimmable bulbs and/or a bypass as well though

If you do decide to install the bypass I would be interested in your results :slight_smile:

I’ve tried this and it seems that I DO get low power leakage to the bulbs - when they are suppose to be OFF, they still keep flickering.
Is there a way to fix that without using the bypass? (simply because I don’t have one…)
Some configuration setting? Maybe a different module will behave differently? (I have a few extra dimmer modules)


The only other way would be to use something to absorb the current. For example, if you had 6 LED bulbs all flickering, change one to a conventional bulb and it should stop.

Or a resistor (which is pretty much what a bypass 2 is).

To do a proper job, you need the bypass.

Hi Guys,

So I initially setup up my dimmer 2 into a 2 wire wall switch and it works fine with a high wattage bulb.

I just ordered a bypass 2 and am looking to install it.

Can someone advise on how to install the bypass and whether I need to reset the dimmer 2 module?