"A.Lee" wrote in message
...
Mike Barnes wrote:

The subject of British ring mains came up in another group
(alt.usage.english). When it was said that nobody really knew the
history, one contributor came up with this explanation, which I
reproduce here for your entertainment.

Snip ring final circuits.

The real reason for its allowance is probably from one of the Technical
Committees who had a long lunch, one of their members could make 2.5mm
T+E cheaply, and make a good profit on it, so he persuaded the others to
go along with it.
There is speculation on why we have the 5 seconds disconnection rule for
distribution circuits - far too long, and pretty unsafe if you drill
through it, and the usual answer is that there were so many fuses out
there, British manufacturing couldnt make a Breaker to meet the 0.4
second rule, so 5 seconds was standardied, hence the power companies
could continue to use their 100A fuses.

I know someone who is sitting on the Tech. Comm. re-writing Guidance
Note 3 (Inspection and Testing), and they say it is comical some of the
things that come up, there is little reasoning behind some of the
articles, yet "it has always been done that way, so why change it?"

As for the RFC, there was a large consultation about circuits a couple
of years ago, (it is all in a file on the IET site, though I cannot find
it now), with a long presentation why RFCs should be removed for the
2011 Amendment, this gave the pros and (mainly) cons for them, with
recommendations that they be removed from the standard circuit
definitions, and only used for certain applications.
The pro voice was heard after dinner, and the vote taken that things
should stay as they are. When reading the minutes, it is pretty clear
that there is a good case for removing them, but, cable makers sell more
cable for rings, so they have a bigger voice.

I've listened to a number of people who know the various writers of the
Tech. Documents, and there are very few good remarks about them, the
typical one being "out of touch" or "not open to reason".

Alan.

You can post stuff like that you will upset the people that don't understand
the cons, those people have a name.. electricians.