PAT Testing failures

[ckpr2]

I have designed a few SMPS.
On mine there is a resistor and capacitor to earth from the output ground line.
The resistor is 4M7 so should pass very little current.
The capacitor should only pass leakage current which again should be very small.

Some SMPS have capacitors from live and neutral to earth which will have some leakage but shouldn't be much.
These capacitors are usually small in value so they don't false trigger the ELCB.

[ckpr2]

Most of the SMPS I have seen have a lot of mains filtering.
SMPS (depending on type) can be noisy when switching. LLC SMPS is best as it alters the frequency rather than hard switch the rectified mains.
SMPS also have capacitors between neutral and live to earth.
If these capacitors go leaky then you will get a high leakage reading.