Date   : Thu, 10 Sep 2009 21:39:21 +0100
From   : philb@... (Phil Blundell)
Subject: Leccy @ Acorn World '09

On Thu, 2009-09-10 at 21:00 +0100, Mick Champion wrote:
> Jonathan Graham Harston wrote:
>> [someone else wrote:]
> >> kept, our 2  amp round pin and 5 amp round pin socket outlets (brown and
> >>     
> >  
> > Bad installation practice.
> >   
> Not when it was first installed maybe? Do round plugs have grandfather 
> rights? 

Round plugs (or, rather, the sockets for them) to BS546 are still
explicitly permitted by the Regulations.  There's no need for any
grandfather rights in this situation. 

That said, with the exception of lighting circuits, I can't think of any
particularly good reason why one would want to include BS546 sockets in
a new installation.  Using round pin plugs on regular appliances is
perfectly legitimate but it would be a strange thing to want to do.

> Regulations only apply to new installations, but what does a 
> safety certificate cover?

There isn't really any such thing as a single "safety certificate" for
electrical installations in the same sense as there is for (say) gas
appliances.  If the installation is being tested, either following
alterations or just as a periodic check, the resulting documentation
will specify the exact scope of the tests that were carried out.

> >> By the way, I have never understood why we can't have socket outlets in
> >> bathrooms, etc, yet France and Gernmany, for example, have no such qualms.
> >>     
> > As
> >  
> > 'cos electricity and water don't mix!
> >   
> Agreed 100%

Funnily enough, the current regulations do in fact permit socket outlets
in bathrooms (though still subject to some constraints).  The blanket
prohibition on such outlets was abolished in the 17th edition.

> Is a 
> round plug with no fuse but has a 5 amp fuse at the fuse box (6amp MCB 
> breaker at the distribution unit) any safer than the same piece of 
> equipment with a appliance cable rating of 3 amps with a 13 amp fuse and 
> 32 amp breaker? I don't think so. Would it pass a safety test..... Pass 
> (that is I've passed on the answer) ;-)

The former (round-plug) scenario probably is slightly safer in that
situation, although in practice the risk of an appliance overloading its
own flex is fairly low so even the latter scenario is not very likely to
result in disaster; a 3A flex protected by a 13A fuse is, after all,
about the same level of protection as most small appliances enjoy in the
rest of Europe.  But of course that doesn't make it good practice, and
indeed the appliance would fail a PAT inspection if it was fitted with a
13A fuse on a 3A flex.  

p.