Fibaro dimmer and Fibaro bypass connection

Other Devices & Integrations Lighting & Load Control
1

Hi all,

I will try to setup a 3 wire connection (with a Neutral from a power plug) with my Fibaro dimmer for my dimmable LED bulb.
Can I connect the bypass straight to the N en the O of the dimmer? Actually it is also parallel connection on the lamp. In that case I have everything behind my wall socket.

Or is it required to connect the bypass close to the lamp holder as it is stated in the manual.

Thanks!

Jasper

2

That should work.

So long as the dimmer bypass is in parallel with the LED then the bypass will do its job.

This application note shows how to install it in a 2-wire set-up, I know it’s not the same but you’ll see the general idea.

http://www.vesternet.com/resources/application-notes/apnt-24

3

It was my understanding that the bypass was only required in situations where there was no neutral, in order to supply enough current to the dimmer…?

4

Is that true? I will find this out next week with and without the bypass including a neutral

5

[quote=“monions, post:2, topic:175948”]That should work.

So long as the dimmer bypass is in parallel with the LED then the bypass will do its job.

This application note shows how to install it in a 2-wire set-up, I know it’s not the same but you’ll see the general idea.

http://www.vesternet.com/resources/application-notes/apnt-24[/quote]

Thanks! I will give it a try!

6

The Bypass is required for any installation that has a load below the minimum 25W. This includes 2-wire (no neutral) and 3-wire (neutral) installations.

The Fibaro dimmer requires a minimum load of 25W, if you use it on a circuit with a load less than this you will typically see the issues you have - flashing and refusing to switch off.

The Bypass acts as a dummy load and increases the load above the 25W minimum, it also soaks up the small current that causes the flickering of the LEDs.

Mark
Vesternet

7

[quote=“monions, post:6, topic:175948”]The Bypass is required for any installation that has a load below the minimum 25W. This includes 2-wire (no neutral) and 3-wire (neutral) installations.

The Fibaro dimmer requires a minimum load of 25W, if you use it on a circuit with a load less than this you will typically see the issues you have - flashing and refusing to switch off.

The Bypass acts as a dummy load and increases the load above the 25W minimum, it also soaks up the small current that causes the flickering of the LEDs.

Mark
Vesternet[/quote]

Quoted cos this is the truth (and Vesternet should now!). So many misconceptions about the dimmer bypass…

8

it should not soak up the small current if connected right in the 2-wire setup.

9

[quote=“monions, post:6, topic:175948”]The Bypass is required for any installation that has a load below the minimum 25W. This includes 2-wire (no neutral) and 3-wire (neutral) installations.

The Fibaro dimmer requires a minimum load of 25W, if you use it on a circuit with a load less than this you will typically see the issues you have - flashing and refusing to switch off.

The Bypass acts as a dummy load and increases the load above the 25W minimum, it also soaks up the small current that causes the flickering of the LEDs.

Mark
Vesternet[/quote]

Hi Mark,

Thanks for reply. I am using a bypass icm with a 2 wire connection. That works great but the LED bulbs starts to flicker when it is switched off. Hopefully it will be solved with a neutral wire including the bypass ofcourse.

10

Yes I know but I know for sure that I carried out the setup correctly… hopefully the flickering will be solved with a neutral

11

i found that a 3-wire setup works better . for the dimming range and also for the flickering trouble therefor i recommend this as being a better practice. it also prevents that the fibaro is out of order when changing the lightbulb in case you do not use a extra load.

12

Hi all,

Thanks all for your support! I used the 3 wire setup including the bypass. No flickering anymore!

Cheers,

Jasper

13

@Da-JoJo

it should not soak up the small current if connected right in the 2-wire setup.

How do you mean that it will not soak the current?

In the 2-wire system, the dimmer sends a small current via N & O through the load and then to Neutral. Otherwise the dimmer would have no power to work while the load is ‘off’.

The Bypass is wired in parallel with the load (switched live from O and the load’s neutral)

Therefore as the Bypass has a higher load or low impedance (however you look at it), this will help soak some of the residual current - it will not remove it, but help reduce flickering across the LED.

I agree a 3-wire set-up is better but in most UK homes and many in Europe that’s not a possibility without channeling the wall and installing a neutral down to the switch.

14

your right, but the used current for the dimmer to work should not exceed the lower level that makes the light go on. its the load that makes the lower level go up to the point the light goes on i guess, without load it does not exceed the threshold but it makes the dimming function to not function properly. it is not a problem most of the time to put the fibaro under the light itself where it has a 3 wire or neutral. imho no use to exchange it with the light-switch as all lights are connected to a mains supply in a box above the light itself or some other place. the switch can also be used in this setup. switch can even be wired also to key 2 and switch other lights with it as well. works a lot better like this.

15

Hi All

I’ve just bought a few Fibaro dimmers and Bypass(es) (damn you Vesternet 20% off sale!!) for some LED lights.

Please can someone help me understand where the bypass needs to go when you have a low voltage transformer in the middle ?

See attached

I have two of these units and two dimmers so they can be managed independently. They will need to be wired to a mains power socket via a plug, so two wires Live, Neutral & Earth - there is no need for a light switch, just wired directly.

All suggestions welcome

Thanks

16

The Bypass device should be wired across the load - on the 240V side. Its function is to prevent the small quiescent current that flows when the dimmer is off from activating the light. It is mostly required in two-wire circuits (with no neutral connection) but may help even when a neutral is connected.

You could connect it at the module or at the load. There is probably more room at the load end. In your pictured device, you could connect it to the brown and blue wires on the small terminal block.

17

Thanks @Rex

Vesternet also responded today to say they …

don't recommend using the Fibaro Universal Dimmer with transformer based lighting systems as they usually conflict - you essentially have 2 electronic dimmers in-line with each other. Typically this results in buzzing noises or flickering in the lighting.

I wonder if anyone has used the bypass successfully with a transformer in the middle ?

18
I wonder if anyone has used the bypass successfully with a transformer in the middle ?

I don’t think the Bypass is your issue. It is really a question of whether your lights are suitable for dimming with the FGD211. Do they claim to be dimmable? You may just have to wire one up and see.

19

[quote=“monions, post:6, topic:175948”]The Bypass is required for any installation that has a load below the minimum 25W. This includes 2-wire (no neutral) and 3-wire (neutral) installations.

The Fibaro dimmer requires a minimum load of 25W, if you use it on a circuit with a load less than this you will typically see the issues you have - flashing and refusing to switch off.

The Bypass acts as a dummy load and increases the load above the 25W minimum, it also soaks up the small current that causes the flickering of the LEDs.

Mark
Vesternet[/quote]

I am not sure that I fully understand this. Firstly I would think that the 2-wire configuration is suitable for a load that is (more or less) resistive like an old fashion light bulb. In this configuration the dimmer get its neutral connection trough the light bulb all the time. That is obviously not the case with a LED lamp that is an active device that when dimmed, only conducts short periods of the 50 Hz (or 60 Hz) cycle.

I do not have any bypass installed for my LED lamps, at least not yet. However the bypass isn?t really a 25 W dummy load, I mean it would not make sense? Correct me if I am wrong, but from what I understand, what the bypass really does is that it enables a small current to flow through the circuit during the whole 50 Hz cycle (regardless of the load) enabling the dimmer to get enough power to operate continuously?

I am lucky to live in a building with a neutral wire at each switch and my personal experience is that this solves many dimmer problems. Currently I have only LED lamps (except for one) and all of them are working fine. But as you say, this can depend on the type of lamps used. Adding a neutral wire is sometimes not that difficult since you will for sure find it where the connection for the lamp is so it might not be needed to redo the wiring from the fuse box.

20

The Fibaro Bypass is not a resistive dummy load. I have not opened one up but I suspect it contains both active and reactive components. The device dissipates very little heat so it is probably drawing current out of phase with the voltage. It does, as you say, pass the small quiescent current required to operate the dimmer in a two-wire circuit without it passing through the load. It can also be used with non-incandescent lamps even when the dimmer has a neutral connection. It does two things when used this way: It diverts the small current that flows through the electronic switching element even when it is turned off; It draws sufficient reactive current to meet the dimmer’s minimum load requirement when it is turned on. Both of these are important when switching CFLs and LEDs and for dimming LEDs.

I have used the FGD211 in two-wire circuits feeding CFL lamps. Without the bypass, the lamps could not be turned off but would flicker. With the bypass fitted across the load, the FGD211 switched them on and off perfectly. For this application, the dimmer must be configured so that it only operates at 0% and 99%.