Shelly 1PM Mini Gen3 and compact fluorescent tubes

[Perkovich]

Dear Forum Members,

After having faced some destroyed Shellys I identified the very likely root cause to be a flourescent tube in another room but same circuit causing voltage spikes. The Shellys were in same circuit but did not switch the fluorescent tube. In another forum I found following explanation: https://smarthome-forum.eu/thread/19953-totaldefekt-durch-ausschalten-einer-leuchtstofflampe/ 

The fluorescent tube I replaced now by LED tube so this issue should be solved.

My question now: I have several exterior housing lights which have all these compact fluorescent tubes (see attached pictures). All of these lights I intend to be switched by Shellys. In fact I already do so and so far no damage.  Will it be a matter of time that all Shellys will be destroyed due to same reason like above described? Means shall I replace all compact fluorescent tubes by LED to be on safe side or is electrical behaviour of these compact tubes different compared to this of long tubes?

Thanks for your support!

BR Perkovich

 

[thgoebel]

With every starting process of the fluorescent tube, high voltage transients travel through the in-house network. This leads to a stepwise degradation of the transient absorber component in the Shelly (VDR, Varistor). At the end of the day (not literally!), the VDR turns into a low resistance state, which causes the internal fuse of the Shelly to trip. Now, the Shelly seems dead (cause no one does repair defective Shellies).

Unfortunately, it is not possible to predict the time period after that a Shelly gets faulty. Hence, you’re in a conservative position if you avoid incandescent tubes as possible.

[Perkovich]

Thanks for quick reply. Is my understanding correct that it does not matter whether I have the standard fluorescent tubes or the compact ones in bulb style like shown in picture in my in-house network? Means they have both same electrical behaviour in regard of high voltage transients and the small ones will also damage the Shellys?

[thgoebel]

This was my first thought too. But the circuit diagram at the label of the Tridonic lamp convinced me that the starting is done with the „old fashioned“ method: Current through a coil is interrupted by a contact which produces the high voltage to ignite the fluorescent tube.

Otherwise, the OSRAM Dulux lamp is operated with an electronic ballast, which should not exhibit high voltage spikes.

Edited July 7 by thgoebel