So I’m now concerned by having them in a wall surrounded by insulation and starting a fire. Eg 40 degree day, in wall temp could be 70-80 degrees (I was going to get them installed behind the light switch, as in ceiling installation would be tricky)
Has anyone installed these in wall?
Do they aeotec or Fibaro get hot? I could potentially spring for these, but the are 3x the cost, and I’d need to get a zwave stick
As long as the device operates within its specifications and has certification, what is there to worry about? The safety cut out is at 90 degrees so it well within spec.
It has been designed by engineers to fulfil design requirements which have been achieved.
They have been sold worldwide yet there have not been any safety alerts or recalls. I’d be more worried about the sparky who installs them.
90 degrees is hot for humans but not for a lot of electrical/electronic devices or wood, plaster, insulation, or anything else used in house construction. Remember the book ‘Fahrenheit 454’,the temperature at which paper will burst in to flames.
125°C is the usual limit for silicon junctions. Because of the thermal resistance between the junction and the component package, the package temperature limit is usually a lot lower. I’d say if your dimmer enclosure was reaching 90°C you have a legitimate concern.
Silicon semiconductors are prone to thermal runaway. The hotter they get the more they conduct, so they get hotter, etc… until failure.
Yes, but the temp sensor on the PCB will shut it down when the board hits 90 degrees. The likelihood of the case reaching 90 degrees is remote. I reiterate; 90 degrees won’t set anything in house construction on fire.
As has already been pointed out this is not the normal operating temperature of the device.
At best you are advising people to destroy their devices, electrolytic caps wont last long at those temperatures.
At worst you are relying on a fail-safe that may not work. Especially if those electrolytic caps I mentioned have dried out causing excessive ripple and failure of the sensing circuit to do its job.
Tom, I don’t want to argue, however, there are many 125 degree C rated electros and they are far more common than in the past. If there is an abnormally high temp, I think Shelly may be more interested in keeping their market without burning down houses.After all, this is the only market they have.
While I agree that electronics do tend to operate in what seem like quite high temperatures in their internal components (Pi 4 anyone?), I’d be wondering what exactly a dimmer or relay would be doing that would heat it to have an external temp of 63… and how much power would be being wasted by that.
My Aeotec Nano switches only get externally to 29C, and that’s on the one with 100w of bulbs attached, and the light circuit that has a comparable light load on it without one of the switches only operates about 2w less when on. It would be interesting to see a power comparison on a load with and without one of these, to see if they make have a cost in long term power wastage.
Probably wouldn’t be much of a difference, but still be interesting to see…
From that linked thread, the enclosure was hitting 63 degrees c, and the pcb was reporting 80 or so.
So I acknowledge that it’s not the enclosure hitting 90, but rather the pcb.
But if it’s hitting 63c in a well ventilated environment with 30c ambient temp - what about inside an insulated wall with western sun at 40c ambient temp??
External sensor, I stuck a MCP9808 in behind the switch plate and pinned it about 0.5cm from the middle of the Aeotec. Room temp ranged from 22-26C
Admittedly only had it in there for a day, might chuck it back in sometime for a longer block. Had a hard time keeping the cats from batting at the ESP hanging outside it
I assumed that would be it, though it would be interesting to know what they idle at with the load switched off/disconnected though.
That said, would dimmer relays be less efficient than binary relays? Since they have to move through a range instead of just completely on vs completely off?
That was me that posted the Shelly 2.5 overheating thread. It’s the ESP chip getting hot in conjunction with the the current measuring shunt resistor. The Shelly 2.5 outer case rises approx 30 to 35°C above ambient when loaded with two 8W LED downlights.
