"Jeff Layman" wrote in message
...
Well, when there is a heavy current involved (such as an instant heat
shower), you've got a switch which will have to take 40 amps or more, so
that will require some heavy-duty contacts and a pretty powerful spring to
make sure make/break occur cleanly.

Agreed: you want to move the contacts from fully separated to fully in
contact (or vice versa) as fast as possible. But for a light switch,
especially with modern low-current LED bulbs, there's not much current so
much less chance of sparking at the changeover point.

I wonder if modern switches are rated for much higher currents (a rating
which is almost never needed) whereas older switches were rated for lower
current for lighting circuits and didn't need such a strong (and noisy)
spring.