Arfa Daily wrote:
Explain why it's always the
neutral terminal screw that comes loose in a plugtop, for instance. Same
current flows in both pins.

I'd say the reason is mechanical.

The neutral pin shakes about by the action of the (UK) plug being placed
in / removed from the socket. This pin probably shakes about more than
the earth pin, as the user is more careful to locate that pin first
before slamming the rest in.

The Live connection is at the other side of the fuseholder which takes
up some of the movement energy.

--
Adrian C