On Mon, 27 Aug 2007 22:53:14 +0100, "Doctor Drivel"
wrote:
"Peter Parry" wrote
However, the consequential hazards are not.
A characteristic of many continental installations is that there are
a smaller number of sockets in a house than for a house of similar
age in the UK and consequently much more use of trailing extensions.
Not the fault of the radial system.
Yes it is as it is both more expensive to fit radials initially and
much more difficult and expensive to add them later. A Dutch friend
of mine has recently returned to a brand new house in Holland after
several years in the UK. In the UK their office room had 15 double
sockets which took a day to retrofit. Their new house in Holland
includes an "office" room which has 5 single sockets. To fit 30
outlets in the new room would cost him well over £3,000 including the
extensive re plastering and redecoration required throughout the
house after fitting the new cables.
These are inherently more hazardous than wall sockets and contribute
to far more fires of electric origin than does fixed wiring. The
lack of any form of appliance lead protection coupled with high trip
currents
High trip current? 16A MCBs or RCBOs on 8 sockets is not high.
Yes it is, it is more than high enough to allow a 2A flex to burn for
some time and start a fire. How many sockets you have is
inconsequential. 16A on a single socket won't trip a residual
current device or a circuit breaker but will start a fire in a faulty
lead. The consequence is that you have an inherently unsafe
installation.
If a simple
fuse fails in a plug the protection is a 32A MCB (or fuse)
Fuses, which are 13A maximum, don't fail short circuit - only open
circuit. In safety terms usually the simpler things are the safer
and more reliable they are.
One of the problems CENELEC faced when told by their EU paymasters to
introduce a new EU plug and socket system (amazingly without anyone
having bothered with any estimation of cost of implementation) was
that for political reasons it had to be more or less the same as the
German system and for technical reasons safer than all other systems.
During 5 years of large lunches the best they could come up with was
an astonishingly complex proposal with mini distribution boards in
every room which by their own admission was no safer than the UK
system and in some respects less safe. The IEC continue to peddle IEC
60906-1 which manages to be as unsafe as the dreadful American
system.
All countries using the CEE 7/4 (Shuko) plugs tend to have a number
of child fatalities each year caused by objects being poked into the
unprotected openings. The UK has virtually no such accidents with
the shielded 13A socket.
There are unprotected openings now in some sockets I have seen.
Only if your fellow bodgers have been at them with a drill. Shutters
are required to be operated by the earth pin or by pressure of both
shaped pins on both L and N at the same time (MK have used this
system). There is also a marked difference between a system which
has a few unshielded sockets caused by damage and one which by design
has none whatsoever.
Another issue with the continental two pin plugs is that the wiring
of the live and neutral is random (and even if it were not the plugs
can be inserted any way around).
There is a standard to where live should be connected, but most don't stick
to it.
There is no standard for wiring of Shuko sockets, there would be no
point as they are not polarised. There is supposedly one for CEE
7/7.
The improved safety of the ring over the radial stems largely from
secondary effects of the greater number of fixed sockets and fuse
protection of the appliance lead.
"improved safety of the ring" Where?
In its design, in the proper certification of devices to use with it
and with its proven inherently lower risk of causing fires.
A radial circuit with RCBOs, tripping
on neutral and live, on each circuit is much safer.
No it isn't. Tripping of both sides occurs in current imbalance on
both types of circuit. In overload, tripping on both sides has no
safety advantage.
The UK ring system
trips on 32A and only the live. Most new Continental systems have RCBOs.
My Dutch friends brand new just finished house doesn't.
Together these reduce the number
of fires caused by overloaded and damaged extensions.
This is where you display your profound ignorance. A 16A circuit will
dissipate about 3.7kW which is more than enough to turn an extension
or appliance lead into a red hot fire source.
Most fires are caused by overloads which do not trip high current
protective devices.
Fires in the UK are caused by the same problem. Most homes I see have
trailing extension leads, especially around computers, TVs, etc.
Indeed, and each appliance plugged in has a low value fuse. Contrary
to your ignorant assertion that most fuses are 13A most low current
devices have moulded on plugs and the same (correct) fuse they were
originally supplied with as they rarely fail.
On a Shuko system there is no protection at all other than the main
16A fuse or circuit breaker.
There would be. A 16A RCBO at the CU, rather than a 32A RCBO. 1363 relies
on old hat fuses in plug tops.
As fuses are cheaper and inherently more reliable than RCBO's what is
wrong with that?
If I did a re-wire, it would have radials and RCBOs.
For some reason you never seem to put your money where your mouth is.
Do you use _any_ of the aberrant ideas you suggest to others
yourself?
--
Peter Parry.
http://www.wpp.ltd.uk/