There are not that many credible failure modes of LED lights or induction hobs that actually would trip a type A and not a type AC it needs a fault to earth after the rectifiers that does not actually blow the diodes to smithereens or open a series fusible resistor or similar weak link. Possible, but rare.

The other consideration is standing d.c. currents desensitizing a 30mA RCD intended for additional protection - so for example the RCD tripped at ≤40mA rather than ≤30mA - so someone touching a bare conductor or a picture nail driven into a concealed cable elsewhere on the circuit could now receive a >30mA shock without the RCD tripping (the actual shock current being limited by body resistance plus any anything else in the path - e.g. shoes).

   - Andy.

There won't be standing DC current to earth in either of the types of device described, unless faulty,. Leakage to earth through undamaged filter capacitors has no DC competent - it may not be sinusoidal but the capacitor will charge up to any mean DC offset and leave only the AC component flowing.

EVs actually use the CPC to carry a 'pilot' DC that detects the charger is connected to a real car, so there is slightly more possibility for confusion there. but even so to blind an RCD still requires a fault between true earth and the pilot wiring in the charger lead.

Mike

Maybe not just the filer capacitors to consider though. A lot of LED fittings are Class I with the LEDs in close contact with earthed metal - (I'm thinking of one bulkhead in particular where the light consists of LED tape stuck to a combined heatsink/reflector) with what I suspect is not an entirely galvanically isolated  driver. Any poor insulation between the two (damp, dirt...) carries a risk I would have guessed.

   - Andy.

Maybe not just the filer capacitors to consider though. A lot of LED fittings are Class I with the LEDs in close contact with earthed metal - (I'm thinking of one bulkhead in particular where the light consists of LED tape stuck to a combined heatsink/reflector) with what I suspect is not an entirely galvanically isolated  driver. Any poor insulation between the two (damp, dirt...) carries a risk I would have guessed.

   - Andy.

perhaps - but unless it fails an IRtest /PAT then it should be good for at least 500VDC between L//N and the CPC,   I agree there is some dreadful non-compliant rubbish on sale out there, but anything class I and legitimately CE/ UKCA  marked as suitable for use on the mains, will be fine on a 500V  insulation tester, and a high potential test for at least a minute will have been made at factory on samples of the product as part of the 'proof' it meets the low voltage directive - a requirement for CE and similar.

The tests to meet the low voltage directive are described informally here, as the actual standards themselves are surprisingly opaque and expensive for what they are.

And a surprisingly thin layer of insulation will hold off mains if not mechanically abused. Figures like 10-20kV per mm for polythene and PVC mean that even a single turn of undamaged cling film can be an adequate mains insulator, not that I'd actually recommend it. The hard part with such thin layers is the 'undamaged', as almost any handling introduces weakened regions from which failures can propagate.

Mike.