Date   : Sun, 13 Sep 2009 22:29:36 +0100
From   : philb@... (Phil Blundell)
Subject: Leccy @ Acorn World '09

On Sun, 2009-09-13 at 15:50 +0100, Mick Champion wrote:
> AlembicPrs@... wrote:
> > And why bother with 13mp fused plugs, if the consumer unit has RCB/MCB 
> > etc and trips at the slightest surge.

It is a bit of a stretch to describe most installations as tripping at
"the slightest surge".  A 30A type B MCB, which is the most sensitive
one that's likely to be used on a ring main, requires a current of at
least 90A, and maybe up to 150A, for an instantaneous trip.  For a type
C MCB the instantaneous-trip current might be as much as 300A.  Those
currents are much higher than a small appliance flex could be expected
to carry.

> I honestly don't think round sockets are any less safe than square 
> sockets in providing power.. As Phil pointed out, they are still allowed 
> for in the regulations.  Square plugs do have do have some extras though 
> such as a fuse and live / neutral shutters unlike Euro plugs that would 
> have a job seeing as the earth pin is attached to the socket. Who 
> thought that up? I know some UK round sockets do have shutters too.

Modern BS546 sockets are indeed equipped with shutters, and in fact the
Regulations require all socket outlets (irrespective of pin shape) in a
domestic installation to be shuttered.

> > I seem to remember that Australia, as well as Europe, has socket 
> > outlets, and normal wall light switches, in bathrooms. None of this 
> > pull-cord business. And the outlets are not shielded (or switched).
>
> You don't have to have a pull-cord, you can mount your wall switch 
> outside the bathroom. ;-)  Why do you want a socket in your bathroom?

Wall switches are legitimate in bathrooms so long as they aren't placed
within 0.6m of a bath or shower (and subject to various other general
conditions).  Pull-cord switches are traditional but not strictly
obligatory and, as Mick says, you can always mount the switch outside
the bathroom anyway.

p.