On 04/04/2017 20:13, The Natural Philosopher wrote:
> On 04/04/17 17:55, rickman wrote:
>> Why are people obsessed with having an earth pin on power connectors.
>> Most of the appliances don't have anything to ground!  Why have an earth
>> pin if the product has no metal parts on the outside?  That's what
>> double insulation is about.
>
> You must be very young. I remember the electric fire that tingled when
> we touched its metal case
>
>
His world and environment is perfect and only contains new items and he
wouldn't do anything stupid. Therefore nobody else needs protecting. :-)

The UK plug design is 70+ years old and when it appeared many houses in
the UK were just being wired. My parent's house was not wired till 1947
despite living in a large city. In those days you may only have 1 socket
in a room and few items to plug in, the size of the plug was not an
issue. Now we have many items and the size is an issue. However, unlike
US and European plugs, you cannot easily pull a UK plug out of the
socket by the cable removing a possible failure mode. The fused plug is
to prevent cable issues to the device as the use of a ring main circuit
means that circuit may be able to provide 30A.

Modern ELCB and RCD render some of the 70 year old concepts moot. But
they were a royal pain in the arse when incandescent lamps were used.
Normally a failing lamp filament going OC would trip out the whole
consumer unit rather than just the circuit involved. I've seen this
happen on several consumer units. The move to CFL and LED bulbs means
when they fail, the whole house supply isn't dumped and I don't have to
reboot and recover half a dozen computers.

--- SoupGate-Win32 v1.05