I'm really concerned about the safety of the Sonoff devices.
These photos show a TH-16 unit that was fed from a 13amp fused spur (240V) and feeding a 3kW fan heater. Total load was less than 13A, yet this is the second Sonoff that has self-destructed in 4 months. Although there has been a recall for the PCB track tinning, I believe the fault is with the fuse clips. That is where the charring of the board is the worst - the board has literally melted and the fuse bent over to touch the terminal block (by gravity).
What is the rating of the clips? Schurter of Germany make some of the best, and they are only rated at 10amp (http://uk.farnell.com/…/fus…/dp/1453528…)
Until this is sorted I am only running heaters on half power, and am tempted to short out the fuses, as they are protected by a 13A fuse at the spur.
Hi, I have just experienced the same problem with my TH16. In my case I was running a water heater rated at 3kW, 230V, I measured current independently at 13A. In this use case, the system as set up was operating for at about a month, and typical operation was relay open for 20 hours out of 24, and closed and under current for about 3 hours.
The TH16 date code appears to read 2017 - 2 - 10 but is partially damaged.
The unit was mounted sideways against a water cylinder, and there was almost nothing left of the fuse. It appears to have melted and burned a hole through the side of the housing on to the surface below, which is where I found a lump of solder mixed with glass and the remains of the fuse holder ends.
I have just had my 3rd Sonoff fail - again driving a heater. This one was only 2kW (230V), so way below the 16A rating. It also shows that it is the fuse clips that cause the problem, not the PCB tracks. The heat from the fuse/clip junction conducts back to the PCB and melts the solder under the clips.
I will be soldering a 2.5mm copper link across the fuse clips from now on. They are just not fit for purpose.
I am also concerned that there has been no comment at all from Itead on this matter - don't you care guys?
Looks like itead have listened - have a look at the new dual Mk2:
They are using a solid link to replace the fuse!