Date   : Wed, 02 Sep 2009 09:22:05 +0100
From   : philb@... (Phil Blundell)
Subject: Leccy @ Acorn World '09

On Wed, 2009-09-02 at 03:37 +0200, Rick Murray wrote:
> David Hunt wrote:
> 
> > the socket ring main cable was rated for 45A continuous with a 32A
>  > breaker and a 10mA RCD, well within the 90A continuous load the cable
>  > was rated to.
> 
> The concept of a "ring main" causes great distress to the French.

It causes a certain amount of distress to a lot of folks in the UK as
well.  In many cases, ring final circuits are not obviously better than
radial ones and (as Rob seems to have recently discovered!) may indeed
be worse.

> I guess breakers are cheap over here, a modern installation would have many.

MCBs indeed don't cost much any more, maybe on the order of ?2 each
depending on what brand you want.  Compared to the cost of the labour to
install and test the circuit, the price of the breakers is basically
negligible.

> Doesn't this imply that such a setup is non-recoverable from a power 
> failure? I mean, if you have a blackout and the trips go upon power 
> being restored... won't be good for stuff in your freezer, or maybe a 
> server, whatever.

Yes, these kinds of nuisance trips are the reason that people tend to
put freezers, servers, fire alarms and suchlike on their own independent
circuits.

p.