Following on from playing with the Hi-link HLK-PM01 I got this generic even cheaper board from Ben Dooks, after carefully wiring it up, I shoved it on the Kikusui TOS 8650 Withstand Voltage Tester:

This shows the cheap chinese powersupply breaking just below 2 kVac.

The following photos are from a Chinese seller via the Aliexpress link:

Looking at the bottom of the PCB, we can see that the clearance between the Primary (AC Side) and the Secondary (DC Side) sides is less than the 6 mm required for BS EN 60335 – “Household and similar electrical appliances. Safety. General requirements” or any similar standard we wish to use.

The Gap is bridged by three components:

  1. Transformer
  2. Opto Isolator
  3. Capacitor.

The Capacitor is not a Y1 rated capacitor, and as such does not comply with the requirements of class II (class 2/double) insulation double insulated.

Unlike the HLK-PM01 I would not be willing to use this in a project, and given that it failed at this point in just a mostly visual inspection, I don’t feel that there is any point in seeing how it handles Emissions testing.