I use about 10 such sockets in the smart home system. One of the outlets burned out, the load did not exceed 2 kW. I dismantled the burnt socket, found that on the printed circuit board the width of the track of the burnt part is much less than the one that remained intact. In general, to the right of the button, if you look at the connected socket from above, the width is larger, to the left it is smaller (photo attached). As a result, it is safer to connect all devices that will be permanently connected through this outlet so that the phase goes through the right plug, and zero through the left, and determine the phase with a screwdriver or multimeter.