Need help, what is the reason for the recess on Europlugs?

wikipedia says the pins aren't parallel, maybe the waist is to avoid some geometry problem.

B in the drawing below), and a recess on the middle of the pin where the di ameter is 3.5mm (point A in the drawing)

ally needed

ct resistance of the Europlug to be unchanged even if there are no recess. But it may be that in some obscure socket, the mating pins are dimensioned so that if the recess is not there it will increase the contact resistance (due to conflict with some mechanical part)

Yes, correct

As far as I can tell the reason for that is to comply with different socket s in different countries in order to have some spring force action if they do not fit perfectly

Cheers

Klaus

The narrower part is insulating. If it were a /larger/ diameter than the conducting part, it could, on a poorly toleranced socket, splay the socket contacts so they don't touch the pins.

So you mandate it as smaller just in case.

I just made that up, but it seems reasonable.

Cheers

I think you are correct. They define it at 3.5mm to be sure they never get close to 4mm. That way the middle section is always smaller than the tip

Thanks

Klaus