Fusing theory

The flex to the lamp does not need to be capable of taking the full output of the circuit *continuously*, it just needs to be able to survive the full prospective short circuit current[1] for long enough to open the circuit protective device.

So here, that would usually be to survive until the 13A fuse in the plug blows, and elsewhere, until the 16A breaker in the CU trips. (so in reality, not that different)

That is what the adiabatic calc will attempt to predict.

That was me !!! And indeed, this is what I was wondering about (as well as the 2.5A rated Europlug).

If it is a 13A fuse. When I was a boy, we used 2, 3 and 5 amp fuses for the smaller appliances. I still fit the smaller fuses where I know I can (as I have a big stock of them).

Nothing wrong with using more closely matched fuses and it is still good practice. However these days a maker of an appliance will want to sell it in multiple markets, and so has to accept that in many of those, the plug fuse won't be there.

Hence why you design your product so that when bad stuff happens it still fails safe.

This was my understanding of the term 'harmonised' employed by the EU.

I take your point entirely about knowledge. I remember at my first conveyancing lecture, the professor said that any citizen is entitled to do their own conveyancing 'just as you are entitled to take out your own appendix but this does not mean it is a good idea'.