"ARWadsworth" wrote in message
...
dennis@home wrote:
"ARWadsworth" wrote in message
...
dennis@home wrote:
"ARWadsworth" wrote in message
...

Who knows, sometime in the future when all the old electricians
have retired rings will finally die.

Maybe, it is suggested everytime there is an update to the regs.

That would be because a lot of engineers don't think rings are safe.

But 60 years of history prove them wrong.

How does it?
Nobody knows how many faulty rings there are as the householder
doesn't know and very few are ever checked.
There could be 10 there could be 100,000, until people get hurt no one
cares.

Ditto for faulty radials.

Faulty radials are likely to be noticed by the householder, things like
sockets that don't work.
Most of the other faults can be found with a simple plug in tester from
Argos.


Are you going to clarify what you meant by

"That would be why they added radials with breakers that actually
match the cables because they didn't need to."

It is illogical to rely on downstream breakers to protect up stream
cables. It makes modification to the circuit potentially dangerous.

Only if you do not know what you are doing.

People do modify the circuits by putting the wrong fuse in plugs
(including nails) rendering them useless for protecting the upstream
circuit against overload.

Non of which alters the load on the spur or makes any difference at all to
a fault current on the spur.

Of course it can alter the load.
There is nothing to stop it.


There was even a large batch of "genuine" fuses for plugs that didn't
protect the circuit a few decades back.
These led to certification being required to show batch testing had
been done.
God knows how many of these faulty fuses are still out there.
Do you check the plug fuse for certification when you come across one?

And the relevance to spurs and radials is?

See above, its obvious once you realise that it can alter the load.
Without a working fuse in the plug there is nothing to stop you overloading
a spur.
There is even an argument that it could overload the ring itself if the plug
is in the "wrong" socket.

On Dec 16, 2:31*pm, "dennis@home"
wrote:

People do modify the circuits by putting the wrong fuse in plugs
(including nails) rendering them useless for protecting the upstream
circuit against overload.

Non of which alters the load on the spur or makes any difference at all to
a fault current on the spur.

Of course it can alter the load.
There is nothing to stop it.

You really are as thick as Jerry. I thought this was done to death a
few weeks ago.

Putting the wrong fuse or a nail in a plug top does NOT alter the
load. The load will draw whatever current it draws, regardless of
whether it does so through a fuse (correct or incorrect) or a nail. I
am, of course, assuming that the nail and all fuses in question are
rated for the normal load current.

Now, if you want to talk about what happens in the event of a fault...

MBQ

On 16/12/10 16:51, John Rumm wrote:
On 16/12/2010 12:09, Tim Watts wrote:
On 16/12/10 11:53, dennis@home wrote:

every time you disconnect the wire and reconnect it you work harden the
copper and make it more likely to fail due to passing traffic, etc. If
the consumer unit was correctly designed it would have test links so you
could do the tests without disconnecting the wires. But why do things
right when you can do them cheap?

Whilst I don't disagree with

the sentiment, a decently laid out CU isn't
too bad - and your idea would require at least 3 terminals per current
terminal (L,N and PE) all with per terminal links and test points - so
that's 9 links and test points per device.

And since screwed connections tend to be a failure point in circuits,
why introduce more of them!

I wish that all dimmers came with a small shorting plug though, that
could be inserted from the back of the device - that would save some
faffing.

or just design them all so they are "safe" to IR test.


You could do what Adam suggests and test LN-PE at 500V, then, just to
be pedantic, test L,L,PE in all combos at 250V.

But I suspect any decent electronics will be happy at 500V DC seeing as
that isn't much more than the top of the 240V sine plus a few spikes.

Part of the idea with the shorting link though, was to aid the R1+R2
(and R1+Rn) tests - means disturbing no terminals other than the CU.



--
Tim Watts

On 16/12/10 16:56, John Rumm wrote:
On 16/12/2010 12:10, ARWadsworth wrote:
wrote:
wrote in message
...

Who knows, sometime in the future when all the old electricians have
retired rings will finally die.

Maybe, it is suggested everytime there is an update to the regs.

That would be because a lot of engineers don't think rings are safe.

But 60 years of history prove them wrong.

More to the point, modern patterns of usage[1], are also very well
suited to ring circuits - so in a sense they are more rather than less
appropriate now than at any time in the past.

[1] a large number of small loads scattered over a wide area, and a few
larger loads that tend to be used intermittently in different places
around the house. The exception to that is a kitchen, but even there
assuming the layout is not unduly unbalanced, its a good way to supply a
shed load of power without making the physical aspects of wiring
particularly difficult.


Exactly my thinking.

I have one short ring[1] in the kitchen for 2 doubles and 3 fixed
appliances, another lower loaded but loads-of-sockets kitchen ring that
is shared with the adjacent bedroom, 3rd ring doing the other 2 bedrooms
and hall and potentially a 4th upstairs (in the dormer).

[1] This ring got special attention - one end finished right next to the
CU, the other end is 3m away. I actually ran both legs along the joists
to the opposing external wall (ring is on the centre wall), along a bit
then straight back to the CU - "wasting" about 8m cable per leg but
ensuring they remain balanced.

Testing with a clamp meter, each leg is balanced to about 45% vs 55%
which is pretty good - I had it loaded up with *all* my oil heaters -
total load 42A for 10 minutes. Cables just pereceptibly warm where they
went as a pair down a short bit of 20mm conduit into the top of the CU.

Dread to think how it would have behaved if I hadn't balanced it.

Others might have called for 2x20A radials there, but the rational was
the same - one radial might have had 20-ish A from a double socket plus
a tumble dryer for probably long enough to trip a 20A breaker, while the
other might have had a dishwasher and bugger all else. Depends on how
you layout the appliances, kettle and microwave...

--
Tim Watts

Tim Watts wrote:
On 16/12/10 16:56, John Rumm wrote:
On 16/12/2010 12:10, ARWadsworth wrote:
wrote:
wrote in message
...

Who knows, sometime in the future when all the old electricians
have retired rings will finally die.

Maybe, it is suggested everytime there is an update to the regs.

That would be because a lot of engineers don't think rings are
safe.

But 60 years of history prove them wrong.

More to the point, modern patterns of usage[1], are also very well
suited to ring circuits - so in a sense they are more rather than
less appropriate now than at any time in the past.

[1] a large number of small loads scattered over a wide area, and a
few larger loads that tend to be used intermittently in different
places around the house. The exception to that is a kitchen, but
even there assuming the layout is not unduly unbalanced, its a good
way to supply a shed load of power without making the physical
aspects of wiring particularly difficult.


Exactly my thinking.

I have one short ring[1] in the kitchen for 2 doubles and 3 fixed
appliances, another lower loaded but loads-of-sockets kitchen ring
that is shared with the adjacent bedroom, 3rd ring doing the other 2
bedrooms and hall and potentially a 4th upstairs (in the dormer).

[1] This ring got special attention - one end finished right next to
the CU, the other end is 3m away. I actually ran both legs along the
joists to the opposing external wall (ring is on the centre wall),
along a bit then straight back to the CU - "wasting" about 8m cable
per leg but ensuring they remain balanced.

Testing with a clamp meter, each leg is balanced to about 45% vs 55%
which is pretty good - I had it loaded up with *all* my oil heaters -
total load 42A for 10 minutes. Cables just pereceptibly warm where
they went as a pair down a short bit of 20mm conduit into the top of
the CU.

That is actually pretty neat.

Dread to think how it would have behaved if I hadn't balanced it.

A 33 to 67 balance/split is usually aceptable.

Others might have called for 2x20A radials there, but the rational was
the same - one radial might have had 20-ish A from a double socket
plus a tumble dryer for probably long enough to trip a 20A breaker,
while the other might have had a dishwasher and bugger all else.
Depends on how you layout the appliances, kettle and microwave...

And the daft thing is, I believe that a 4mm 32A radial is often ideal to
remove the high loads such as a washer and tumble dryer. I do not have
anything against radials when used correctly. Removing the loads from a
washer and drier makes the rest of the load on the kitchen ring irrelevant.
A kettle is used for a few minutes at a time and so is the microwave etc.
And there is no point in designing a circuit to suit the appliance layout if
you are married.

--
Adam

"Man at B&Q" wrote in message
...
On Dec 16, 2:31 pm, "dennis@home"
wrote:

People do modify the circuits by putting the wrong fuse in plugs
(including nails) rendering them useless for protecting the upstream
circuit against overload.

Non of which alters the load on the spur or makes any difference at all
to
a fault current on the spur.

Of course it can alter the load.
There is nothing to stop it.

You really are as thick as Jerry. I thought this was done to death a
few weeks ago.

Putting the wrong fuse or a nail in a plug top does NOT alter the
load. The load will draw whatever current it draws, regardless of
whether it does so through a fuse (correct or incorrect) or a nail. I
am, of course, assuming that the nail and all fuses in question are
rated for the normal load current.

You are the one being thick!
What if the nail is in a fourway strip?
Now go away and think about it.

Now, if you want to talk about what happens in the event of a fault...

With someone that doesn't even know multiway strips exist?
Why bother?

"John Rumm" wrote in message
...
On 16/12/2010 12:09, Tim Watts wrote:
On 16/12/10 11:53, dennis@home wrote:

every time you disconnect the wire and reconnect it you work harden the
copper and make it more likely to fail due to passing traffic, etc. If
the consumer unit was correctly designed it would have test links so you
could do the tests without disconnecting the wires. But why do things
right when you can do them cheap?

Whilst I don't disagree with the sentiment, a decently laid out CU isn't
too bad - and your idea would require at least 3 terminals per current
terminal (L,N and PE) all with per terminal links and test points - so
that's 9 links and test points per device.

And since screwed connections tend to be a failure point in circuits, why
introduce more of them!

Who said to use screws?

dennis@home wrote:
"Man at B&Q" wrote in message
...
On Dec 16, 2:31 pm, "dennis@home"
wrote:

People do modify the circuits by putting the wrong fuse in plugs
(including nails) rendering them useless for protecting the
upstream circuit against overload.

Non of which alters the load on the spur or makes any difference
at all to
a fault current on the spur.

Of course it can alter the load.
There is nothing to stop it.

You really are as thick as Jerry. I thought this was done to death a
few weeks ago.

Putting the wrong fuse or a nail in a plug top does NOT alter the
load. The load will draw whatever current it draws, regardless of
whether it does so through a fuse (correct or incorrect) or a nail. I
am, of course, assuming that the nail and all fuses in question are
rated for the normal load current.

You are the one being thick!
What if the nail is in a fourway strip?
Now go away and think about it.

Now, if you want to talk about what happens in the event of a
fault...

With someone that doesn't even know multiway strips exist?
Why bother?

The multiway strip will melt. Just as it usually does even when protected by
a 13A fuse.

--
Adam

"ARWadsworth" wrote in message
...

The multiway strip will melt. Just as it usually does even when protected
by a 13A fuse.

That's probably the best outcome, however Murphy says the cable will melt,
the PVC will emit lots of smoke killing the kids, the copper will spark and
the building will burn down cremating the dead. After all they won't have a
smoke alarm.

dennis@home wrote:
"ARWadsworth" wrote in message
...

The multiway strip will melt. Just as it usually does even when
protected by a 13A fuse.

That's probably the best outcome, however Murphy says the cable will
melt, the PVC will emit lots of smoke killing the kids, the copper
will spark and the building will burn down cremating the dead. After
all they won't have a smoke alarm.

And it will have nothing to do with a correctly installed ring (including
spurs) or radial circuit.

And your point about spurs from a ring was?

--
Adam

"ARWadsworth" wrote in message
...
dennis@home wrote:
"ARWadsworth" wrote in message
...

The multiway strip will melt. Just as it usually does even when
protected by a 13A fuse.

That's probably the best outcome, however Murphy says the cable will
melt, the PVC will emit lots of smoke killing the kids, the copper
will spark and the building will burn down cremating the dead. After
all they won't have a smoke alarm.

And it will have nothing to do with a correctly installed ring (including
spurs) or radial circuit.

A radial circuit will not do that, the breaker will trip before the cable
can melt as no cable is rated below the breakers rating.

A spur on a ring will be overloaded as the only thing preventing the
overload on the spur is the nail in the plug (and we all know how good they
are don't we?). The 2.5 mm cable is below the rating of the breaker so it
can be overloaded unless the plug fuse works.
I thought that was the obvious bit.


And your point about spurs from a ring was?

see the obvious bit above.

dennis@home wrote:


The multiway strip will melt. Just as it usually does even when
protected by a 13A fuse.

That's probably the best outcome, however Murphy says the cable will
melt, the PVC will emit lots of smoke killing the kids, the copper
will spark and the building will burn down cremating the dead. After
all they won't have a smoke alarm.

And it will have nothing to do with a correctly installed ring
(including spurs) or radial circuit.

A radial circuit will not do that, the breaker will trip before the
cable can melt as no cable is rated below the breakers rating.

Would you bet your life on that? I will happily bet my life that you are
wrong. You have never read BS 7671:2008 and you have never read the part on
32A radials.

--
Adam

On Dec 16, 7:07*pm, "dennis@home"
wrote:
"Man at B&Q" wrote in ...



On Dec 16, 2:31 pm, "dennis@home"
wrote:

People do modify the circuits by putting the wrong fuse in plugs
(including nails) rendering them useless for protecting the upstream
circuit against overload.

Non of which alters the load on the spur or makes any difference at all
to
a fault current on the spur.

Of course it can alter the load.
There is nothing to stop it.

You really are as thick as Jerry. I thought this was done to death a
few weeks ago.

Putting the wrong fuse or a nail in a plug top does NOT alter the
load. The load will draw whatever current it draws, regardless of
whether it does so through a fuse (correct or incorrect) or a nail. I
am, of course, assuming that the nail and all fuses in question are
rated for the normal load current.

You are the one being thick!
What if the nail is in a fourway strip?

Then you deserve all you get. You really ought to know better.

MBQ

On Dec 16, 7:28*pm, "dennis@home"
wrote:
"ARWadsworth" wrote in message

...

The multiway strip will melt. Just as it usually does even when protected
by a 13A fuse.

That's probably the best outcome, however Murphy says the cable will melt,
the PVC will emit lots of smoke killing the kids,

The whole dennis line wiped out for want of a fuse...

Man at B&Q wrote:
On Dec 16, 7:28 pm, "dennis@home"
wrote:
"ARWadsworth" wrote in message

...

The multiway strip will melt. Just as it usually does even when
protected by a 13A fuse.

That's probably the best outcome, however Murphy says the cable will
melt, the PVC will emit lots of smoke killing the kids,

The whole dennis line wiped out for want of a fuse...

Fingers crossed.

--
Adam

"ARWadsworth" wrote in message
...
dennis@home wrote:


The multiway strip will melt. Just as it usually does even when
protected by a 13A fuse.

That's probably the best outcome, however Murphy says the cable will
melt, the PVC will emit lots of smoke killing the kids, the copper
will spark and the building will burn down cremating the dead. After
all they won't have a smoke alarm.

And it will have nothing to do with a correctly installed ring
(including spurs) or radial circuit.

A radial circuit will not do that, the breaker will trip before the
cable can melt as no cable is rated below the breakers rating.

Would you bet your life on that? I will happily bet my life that you are
wrong. You have never read BS 7671:2008 and you have never read the part
on 32A radials.

So what have they done wrong in designing 32A radials then?

"Man at B&Q" wrote in message
...


Then you deserve all you get. You really ought to know better.

And what about the poor suckers that have fuses from that batches that
didn't blow at the correct current, I suppose they deserve it to for being
stupid enough to trust electricians with their lives?

dennis@home wrote:
"Man at B&Q" wrote in message
...


Then you deserve all you get. You really ought to know better.

And what about the poor suckers that have fuses from that batches that
didn't blow at the correct current, I suppose they deserve it to for
being stupid enough to trust electricians with their lives?

Did an elecrician buy or install the fuse?
--
Adam

dennis@home wrote:
"ARWadsworth" wrote in message
...
dennis@home wrote:


The multiway strip will melt. Just as it usually does even when
protected by a 13A fuse.

That's probably the best outcome, however Murphy says the cable
will melt, the PVC will emit lots of smoke killing the kids, the
copper will spark and the building will burn down cremating the
dead. After all they won't have a smoke alarm.

And it will have nothing to do with a correctly installed ring
(including spurs) or radial circuit.

A radial circuit will not do that, the breaker will trip before the
cable can melt as no cable is rated below the breakers rating.

Would you bet your life on that? I will happily bet my life that you
are wrong. You have never read BS 7671:2008 and you have never read
the part on 32A radials.

So what have they done wrong in designing 32A radials then?

You tell me. You claim to know it all.

Lets just say that a 32A radial uses 4mm cable apart from the 2.5mm unfused
spurs.

--
Adam

"ARWadsworth" wrote in message
...
dennis@home wrote:
"ARWadsworth" wrote in message
...
dennis@home wrote:


The multiway strip will melt. Just as it usually does even when
protected by a 13A fuse.

That's probably the best outcome, however Murphy says the cable
will melt, the PVC will emit lots of smoke killing the kids, the
copper will spark and the building will burn down cremating the
dead. After all they won't have a smoke alarm.

And it will have nothing to do with a correctly installed ring
(including spurs) or radial circuit.

A radial circuit will not do that, the breaker will trip before the
cable can melt as no cable is rated below the breakers rating.

Would you bet your life on that? I will happily bet my life that you
are wrong. You have never read BS 7671:2008 and you have never read
the part on 32A radials.

So what have they done wrong in designing 32A radials then?

You tell me. You claim to know it all.

Your the one claiming 32A radials are dangerous.


Lets just say that a 32A radial uses 4mm cable apart from the 2.5mm
unfused spurs.

Are you saying there are people stupid enough to spur off in 2.5 mm even
when they know its wrong on ring mains? Why don't they go the whole hog and
use 1.5 mm as that can supply a single spur without additional problems?

"ARWadsworth" wrote in message
...
dennis@home wrote:
"Man at B&Q" wrote in message
...


Then you deserve all you get. You really ought to know better.

And what about the poor suckers that have fuses from that batches that
didn't blow at the correct current, I suppose they deserve it to for
being stupid enough to trust electricians with their lives?

Did an elecrician buy or install the fuse?

Probably.

dennis@home wrote:
"ARWadsworth" wrote in message
...
dennis@home wrote:
"ARWadsworth" wrote in message
...
dennis@home wrote:


The multiway strip will melt. Just as it usually does even when
protected by a 13A fuse.

That's probably the best outcome, however Murphy says the cable
will melt, the PVC will emit lots of smoke killing the kids, the
copper will spark and the building will burn down cremating the
dead. After all they won't have a smoke alarm.

And it will have nothing to do with a correctly installed ring
(including spurs) or radial circuit.

A radial circuit will not do that, the breaker will trip before
the cable can melt as no cable is rated below the breakers rating.

Would you bet your life on that? I will happily bet my life that
you are wrong. You have never read BS 7671:2008 and you have never
read the part on 32A radials.

So what have they done wrong in designing 32A radials then?

You tell me. You claim to know it all.

Your the one claiming 32A radials are dangerous.

I am claiming so such thing. I am claiming that you do not know about
radials.

Lets just say that a 32A radial uses 4mm cable apart from the 2.5mm
unfused spurs.

Are you saying there are people stupid enough to spur off in 2.5 mm
even when they know its wrong on ring mains? Why don't they go the
whole hog and use 1.5 mm as that can supply a single spur without
additional problems?

There are people who spur off a 4mm 32A radial in 2.5mm. But you didn't know
that was allowed by the regs. Your lack of knowledge of the regs is showing
again.

--
Adam

dennis@home wrote:
"ARWadsworth" wrote in message
...
dennis@home wrote:
"Man at B&Q" wrote in message
...


Then you deserve all you get. You really ought to know better.

And what about the poor suckers that have fuses from that batches
that didn't blow at the correct current, I suppose they deserve it
to for being stupid enough to trust electricians with their lives?

Did an elecrician buy or install the fuse?

Probably.

Probably not. Most people do not call an electrician out to swap a fuse in a
plug.
--
Adam

"ARWadsworth" wrote in message
...


There are people who spur off a 4mm 32A radial in 2.5mm. But you didn't
know that was allowed by the regs. Your lack of knowledge of the regs is
showing again.

I don't need to know the regs allow that, I wouldn't do it as I consider it
no better than a ring and I don't like those either.
I prefer safety to cost savings.

dennis@home wrote:
"ARWadsworth" wrote in message
...


There are people who spur off a 4mm 32A radial in 2.5mm. But you
didn't know that was allowed by the regs. Your lack of knowledge of
the regs is showing again.

I don't need to know the regs allow that,

So stop incorrectly quoting the regs then.

--
Adam

"ARWadsworth" wrote in message
...
dennis@home wrote:
"ARWadsworth" wrote in message
...


There are people who spur off a 4mm 32A radial in 2.5mm. But you
didn't know that was allowed by the regs. Your lack of knowledge of
the regs is showing again.

I don't need to know the regs allow that,

So stop incorrectly quoting the regs then.

I didn't quote the regs.

dennis@home wrote:
"ARWadsworth" wrote in message
...
dennis@home wrote:
"ARWadsworth" wrote in message
...


There are people who spur off a 4mm 32A radial in 2.5mm. But you
didn't know that was allowed by the regs. Your lack of knowledge of
the regs is showing again.

I don't need to know the regs allow that,

So stop incorrectly quoting the regs then.

I didn't quote the regs.

Obviously, as you have never read them.

You just made comment on a radial that was incorrect.

--
Adam

"ARWadsworth" wrote in message
...
dennis@home wrote:
"ARWadsworth" wrote in message
...
dennis@home wrote:
"ARWadsworth" wrote in message
...


There are people who spur off a 4mm 32A radial in 2.5mm. But you
didn't know that was allowed by the regs. Your lack of knowledge of
the regs is showing again.

I don't need to know the regs allow that,

So stop incorrectly quoting the regs then.

I didn't quote the regs.

Obviously, as you have never read them.

You just made comment on a radial that was incorrect.

The comment I said was that people with sense don't put 2.5mm T&E cable into
32A circuits and that applies to rings and spurs and anything else. You may
regard it as wrong in which case I will still say its wrong. I am not alone,
there are many members of the IEE that also hold this view. I don't really
care what the regs say as I regard them as wrong and encouraging dangerous
practices just to save a miniscule amount of cash. What I propose does not
breech the regs and is an improvement on them which is something you cannot
deny.

dennis@home wrote:
So stop incorrectly quoting the regs then.

I didn't quote the regs.

Obviously, as you have never read them.

You just made comment on a radial that was incorrect.

The comment I said was that people with sense don't put 2.5mm T&E
cable into 32A circuits and that applies to rings and spurs and
anything else. You may regard it as wrong in which case I will still
say its wrong. I am not alone, there are many members of the IEE that
also hold this view. I don't really care what the regs say as I
regard them as wrong and encouraging dangerous practices just to save
a miniscule amount of cash. What I propose does not breech the regs
and is an improvement on them which is something you cannot deny.

That is not what you said. It is just lie after lie with you. That plus
careful snipping of posts so that your lies do not show up. What you said
was "That would be why they added radials with breakers that actually match
the cables because they didn't need to".

Is it easier for you to lie than just admit that you made a comment about
radials that was incorrect?

--
Adam

"ARWadsworth" wrote in message
...
dennis@home wrote:
So stop incorrectly quoting the regs then.

I didn't quote the regs.

Obviously, as you have never read them.

You just made comment on a radial that was incorrect.

The comment I said was that people with sense don't put 2.5mm T&E
cable into 32A circuits and that applies to rings and spurs and
anything else. You may regard it as wrong in which case I will still
say its wrong. I am not alone, there are many members of the IEE that
also hold this view. I don't really care what the regs say as I
regard them as wrong and encouraging dangerous practices just to save
a miniscule amount of cash. What I propose does not breech the regs
and is an improvement on them which is something you cannot deny.

That is not what you said. It is just lie after lie with you. That plus
careful snipping of posts so that your lies do not show up. What you said
was "That would be why they added radials with breakers that actually
match the cables because they didn't need to".

And where is that false?
They did exactly that but not with 32A breakers.


Is it easier for you to lie than just admit that you made a comment about
radials that was incorrect?


Well state which one was incorrect the one you quoted was correct.

So far you have been posting stuff calling me a liar while quoting stuff
that isn't a lie.

On Dec 18, 12:48*pm, "dennis@home"
wrote:
"ARWadsworth" wrote in message

...





dennis@home wrote:
So stop incorrectly quoting the regs then.

I didn't quote the regs.

Obviously, as you have never read them.

You just made comment on a radial that was incorrect.

The comment I said was that people with sense don't put 2.5mm T&E
cable into 32A circuits and that applies to rings and spurs and
anything else. You may regard it as wrong in which case I will still
say its wrong. I am not alone, there are many members of the IEE that
also hold this view. I don't really care what the regs say as I
regard them as wrong and encouraging dangerous practices just to save
a miniscule amount of cash. What I propose does not breech the regs
and is an improvement on them which is something you cannot deny.

That is not what you said. It is just lie after lie with you. That plus
careful snipping of posts so that your lies do not show up. What you said
was "That would be why they added radials with breakers that actually
match the cables because they didn't need to".

And where is that false?
They did exactly that but not with 32A breakers.

So it is an incorrect comment about 32A radials that you made then.
You just said radials and made no mention of MCB sizes. You are only
mentioning 32A radials now as you now have an idea how they can be
wired up, something that you did not know before I corrected you.

Is it easier for you to lie than just admit that you made a comment about
radials that was incorrect?

Well state which one was incorrect the one you quoted was correct.

Well your quote is in this post.

So far you have been posting stuff calling me a liar while quoting stuff
that isn't a lie.

Maybe your are stupid and not a liar then.


- Hide quoted text -

- Show quoted text -

--
Adam

On Dec 16, 8:18*pm, "dennis@home"
wrote:
"Man at B&Q" wrote in ...

Then you deserve all you get. You really ought to know better.

And what about the poor suckers that have fuses from that batches that
didn't blow at the correct current, I suppose they deserve it to for being
stupid enough to trust electricians with their lives?


So how do you test these made up in your imagination fuses then?

--
Adam

"Adam Wadsworth" wrote in message
...
On Dec 18, 12:48 pm, "dennis@home"
wrote:
"ARWadsworth" wrote in message

...





dennis@home wrote:
So stop incorrectly quoting the regs then.

I didn't quote the regs.

Obviously, as you have never read them.

You just made comment on a radial that was incorrect.

The comment I said was that people with sense don't put 2.5mm T&E
cable into 32A circuits and that applies to rings and spurs and
anything else. You may regard it as wrong in which case I will still
say its wrong. I am not alone, there are many members of the IEE that
also hold this view. I don't really care what the regs say as I
regard them as wrong and encouraging dangerous practices just to save
a miniscule amount of cash. What I propose does not breech the regs
and is an improvement on them which is something you cannot deny.

That is not what you said. It is just lie after lie with you. That plus
careful snipping of posts so that your lies do not show up. What you
said
was "That would be why they added radials with breakers that actually
match the cables because they didn't need to".

And where is that false?
They did exactly that but not with 32A breakers.

So it is an incorrect comment about 32A radials that you made then.
You just said radials and made no mention of MCB sizes. You are only
mentioning 32A radials now as you now have an idea how they can be
wired up, something that you did not know before I corrected you.

Is it easier for you to lie than just admit that you made a comment
about
radials that was incorrect?

Well state which one was incorrect the one you quoted was correct.

Well your quote is in this post.

And that quote is correct, no matter what you add to try and make it false
it is still true.
Try analysing it and then think about what radials they added last, a hint
it wasn't 32A radials it was radials designed about 2.5 mm cable with a
breaker that made it safe. Therefore what I stated is true.


So far you have been posting stuff calling me a liar while quoting stuff
that isn't a lie.

Maybe your are stupid and not a liar then.

Maybe you are deliberately trying to distort what I said?

"Adam Wadsworth" wrote in message
...
On Dec 16, 8:18 pm, "dennis@home"
wrote:
"Man at B&Q" wrote in
...

Then you deserve all you get. You really ought to know better.

And what about the poor suckers that have fuses from that batches that
didn't blow at the correct current, I suppose they deserve it to for
being
stupid enough to trust electricians with their lives?


So how do you test these made up in your imagination fuses then?

Well that would be the problem.

On Dec 18, 3:50*pm, John Rumm wrote:
On 18/12/2010 14:59, Adam Wadsworth wrote:

On Dec 16, 8:18 pm,
wrote:
"Man at *wrote in ...

Then you deserve all you get. You really ought to know better.

And what about the poor suckers that have fuses from that batches that
didn't blow at the correct current, I suppose they deserve it to for being
stupid enough to trust electricians with their lives?

So how do you test these made up in your imagination fuses then?

The same way he tests a match to make sure its not a dud... ;-)


vbg

To be fair you are pretty screwed if the fuses are illegal copies from
China with all the correct BS numbers stamped on them. However the 2.5
T&E unfused spur is not the bit that will suffer if they turn out to
be nails and not fuses, it will be the melting appliance or the
appliance flex.

--
Adam

"John Rumm" wrote in message
o.uk...
On 18/12/2010 15:17, dennis@home wrote:


"Adam Wadsworth" wrote in
message
...
On Dec 16, 8:18 pm, "dennis@home"
wrote:
"Man at B&Q" wrote in
...


Then you deserve all you get. You really ought to know better.

And what about the poor suckers that have fuses from that batches that
didn't blow at the correct current, I suppose they deserve it to for
being
stupid enough to trust electricians with their lives?


So how do you test these made up in your imagination fuses then?

Well that would be the problem.

Its pretty straight forward if you know anything about manufacturing
processes. You pull out a sample of production on a regular basis and
subject that to destructive testing against an agreed BS test procedure.
If they fail to meet spec, you bin or rework that batch of production
output.

Hence the asta certificate, there was a time when batch testing wasn't
mandatory.
Of course there may even be cases where the fuses are faked, sorry make that
we know there are cases where they have been faked.
http://www.theiet.org/forums/forum/m...VIEWTMP=Single

Do you really want to continue stating that making the plug fuse essential
for safety is a good idea?

dennis@home wrote:


"John Rumm" wrote in message
o.uk...
On 18/12/2010 15:17, dennis@home wrote:


"Adam Wadsworth" wrote in
message
...

On Dec 16, 8:18 pm, "dennis@home"
wrote:
"Man at B&Q" wrote in
...



Then you deserve all you get. You really ought to know better.

And what about the poor suckers that have fuses from that batches that
didn't blow at the correct current, I suppose they deserve it to for
being
stupid enough to trust electricians with their lives?


So how do you test these made up in your imagination fuses then?

Well that would be the problem.

Its pretty straight forward if you know anything about manufacturing
processes. You pull out a sample of production on a regular basis and
subject that to destructive testing against an agreed BS test
procedure. If they fail to meet spec, you bin or rework that batch of
production output.

Hence the asta certificate, there was a time when batch testing wasn't
mandatory.
Of course there may even be cases where the fuses are faked, sorry make
that we know there are cases where they have been faked.
http://www.theiet.org/forums/forum/m...VIEWTMP=Single

Do you really want to continue stating that making the plug fuse
essential for safety is a good idea?

But MCBs have been faked too

http://www.electriciansforums.co.uk/...-far-east.html

"Andy Burns" wrote in message
o.uk...

But MCBs have been faked too

http://www.electriciansforums.co.uk/...-far-east.html


True but there should be more chance of one being spotted by an electrician
than there is of the average person spotting a fake fuse. and they are
testable.

"dennis@home" wrote in message
...


"Andy Burns" wrote in message
o.uk...

But MCBs have been faked too

http://www.electriciansforums.co.uk/...-far-east.html


True but there should be more chance of one being spotted by an
electrician than there is of the average person spotting a fake fuse. and
they are testable.

There is an article in switchedON (issue 18) that may well have a bearing on
this debate..
"The national standard for extension leads, BS 1363-2: 1995, specifies
a maximum 'continuous use' rating of 13 A for the fitted plug and
socket-outlet. The test current is set marginally above this at 14 A for
type-testing, to determine compliance with the product standard.
Standard BS 1362: 1973, covering the fuse link, requires the fuse to
operate at 1.9 times rated current (that is 24.7 A) within 30 minutes,
and also that the fuse shall have a non-fusing current of 1.6 times
rated current (that is 20.8 A).
It is therefore possible for an extension lead to carry a total current of
20 A for an indefinite period. While this may not be a common
situation, the product testing undertaken was to determine whether
it is possible to overload extension leads such that they might pose a
fire hazard."

Assuming they have the figures correct..
it is quite easy to get 40A out of a double spur for an indefinite period
using two fully working extension sockets and some loads.
This would probably trip an MCB before any serious heating of the cable.
However it means that you could draw 32A indefinitely, this exceeds the
rating if the 2.5 mm cable by a significant amount and it requires no
circuit modification at all, not even a faulty fuse.
The only question is which melts first, the flex or the cable and that
depends on what they are made of and how they are cooled.
So I guess I was wrong, you don't need a fault to overload the spur just an
ignorant user (most of the population at a rough guess).

"John Rumm" wrote in message
o.uk...
On 18/12/2010 16:31, dennis@home wrote:


"John Rumm" wrote in message

It relies on the fuse in the plug to give overload protection to the
spur.
While this is fine in principle it isn't a good idea.

That's not true, since there is no requirement for any fuse in the
spur - the spur could quite legitimately have an unfused flex outlet
on the end of it, and everything would remain well protected. The
overload protection of the spur being enforced by controlling the size
of the load - not by fusing, and the fault protection being maintained
at the origin of the circuit by the 32A MCB.

So you think its permitted to wire in a four way without any plug or FCU?

No, an unfused spur can have a maximum of one single or one double socket.
I assume however you are referring to a 4 way trailing lead, which is not
designed to be "wired in" at all.

Earlier you stated "there is no requirement for any fuse in the spur - the
spur could quite legitimately have an unfused flex outlet on the end of it"
if so I can put a trailing socket on it.


The plug fuse is a user serviceable part and is going to be abused, we
know it is abused.

Is it equally easy to uprate your vacuum cleaner to 5kW for this non
sequiter to have any relevance?

Yes your could probably bodge a 4 way trailing lead and stick two 3kW
fan heaters on it, but as has been observed in testing the lead will
fail long before the fixed wiring is at risk.

You have no way to know this.

Actually I do.

Actually you don't as you can't define the flex type or how it is cooled.


Seen many extension leads with 4.0mm^2 flex?

I don't need 4 mm the spur is 2.5 mm so the flex would only need to operate
better than that.


Link?

To what?


It is not difficult to find 2.5 mm flex and then there is no reason why
it should suffer any more than the fixed wiring.

2.5mm^2 flex has a lower current carrying capacity than the fixed wiring,
and also is less likely to benefit from contact with masonry or other
building materials that will aid dissipation.

Commercial 4 way extension leads are almost exclusively wired with 1.5mm^2
flex however.

There are even heat resistant flexes about that will suffer no damage at
all while the main cable melts.

Clutching at straws dennis. If you are clued up enough to assemble an
extension lead with heavy gauge high temperature flex, you are also
unlikely to go replacing a fuse with a nail and plugging multiple fan
heaters into it. Assuming however for the sake of argument you do manage
to stick a sustained 40A load into a single socket, then its a pretty safe
bet the plug and or socket will give out before its supply cable.

Clutching at straws John?
I can easily put 40A into a double spur without needing a faulty fuse as
ordinary 13A fuses will run at 20A continuous.


The idea that something else will fail first is not reasonable unless
that something else is designed to fail first.

2.5mm^2 T&E with maximum current carrying capacity of 27A Vs cheap
thermoplastic 4 way socket (with dennis' patented nail in place of the
fuse) and 1.5mm^2 flex with a 15A max rating...

your call.

It also not tested. Virtually no PAT testing is done and even then they
seldom actually check the fuse is OK.
Electricians doing PIRs don't even care about the plug fuse despite it
being *essential* to protect the circuit they have just tested and
approved. The majority of householders don't even know its essential.

You seem to think that plug fuses are designed to protect against
overload, this is not the case. They are there for the fault
protection of the flex connected to them. The common exception to this
is with multiway extension leads, but this is not of relevance to the
fixed wiring.

Oh don't start..
the whole argument is about the plug fuse protecting the spur from
overload and you know that.

That seems to be *your* argument, however its based on an incorrect
assumption.

The plug fuse is not there to protect the spur from anything; overload, or
fault current. Its there to provide fault protection to the appliance
flex, that is all.

If the 32A breaker provided protection to stop the spur being overloaded
there wouldn't be any argument as it would be designed as I want it to
be.

I expect that most people want is a system designed to work and perform
safely in the real world. What we have evidently does so very well as
evidenced by our extremely low rate of accident and injury result from
fixed wiring.

If you want to do it differently, by all means do so, you don't need our
permission. However don't seek to justify this by making false claims
about proven engineered designs.

If we extend your argument to its logical conclusion, every table lamp
ought to have a 4mm^2 flex so that it matches the trip threshold of
the circuit breaker.

It is far more sensible to rate the breaker so that the cable is
protected whatever the householder does rather than saying well he
would

Which is exactly what the current circuit designs that permit 2.5mm^2
cable on 32A breakers do. The breaker provides fault protection at all
times. Overload protection some of the time.

But you just said the plug fuse doesn't protect the spur from overload

That's correct. It doesn't.

so now you think its OK to have part time protection.

No, the design requires full time protection.

But according to you it fails to do that.
A 32A breaker can't protect 2.5mm T&E from overloads so what do you think
does?


Don't design anything I have to use if that is OK to you.

Well since I am only advocating the use of standard designs as implemented
up and down the country, with a long proven track record of safety, its
not going to be a choice you get to make other than perhaps in your own
home should you choose to rewire it.

Just remember that the regs are the bare minimum that the IEE thinks are
safe enough at the cost they have decided upon.
The OSG provides guidence for those that can't or won't do the maths to
prove what they do is OK.
You obviously don't understand the design compromises or what protects what
in the circuits.
I recommend you don't continue with this debate until you get a clue..


However look on the bright side, many of the things I have designed are
intended to kill you, so you should be grateful for the remote possibility
that one might fail.

still be alive if he hadn't done something to the fuse in the plug.
Its like supplying a power press where the user has to fit parts to
make
it safe.


If overload protection is covered by another means then a 32A mcb will
in most circumstances provide adequate fault protection to 2.5mm2
cable. In fact there are situations where the use of 4mm2 cable
INCREASES the risk under fault conditions. The reason is that the cpc
conductor in 4mm2 cable is only 1.5mm2, so under fault conditions the
touch voltage will be higher than with 2.5mm2 cable.

That sounds more like a case to make the CPC bigger not to rely on the
consumer provided plug fuse to protect the circuit.

It highlights why rings tend to perform better than radials with
regard to earth faults. It also helps explain why when high integrity
earthing is use on a radial circuit, it is done by turning the
protective conductor into a *ring*

That's fine I haven't said you can't have a ring, just that the cables
shouldn't rely on it being a ring or to have spurs that need plug fuses
to prevent overload.

Which misses the fundamental point of the design in the first place. i.e.
that you can supply significant amount of power over a wide area, using a
cable that is easy to work with.

BTW AFAIK 32A radials are not the preferred radial, certainly not by
me.

A 32A radial in 4mm^2 T&E is a standard circuit. Just as is a 20A one
in 2.5mm^2 cable. The 32A version is however far more useful as a
general purpose socket circuit.

It is if you don't use 2.5 mm spurs anywhere.

Which would make no difference to performance since the load on each is
limited by the specification of only one single or double socket per
spur....

The fact that there is two sockets on a spur does not limit the current
below the cable rating.
It is quite obvious that it doesn't, you can even see it quoted in trade
magazines like switchedON issue 18 if you bother to loo;.
It is easy to get 40A continuously without blowing the plug fuses from a
double socket.


If you do then you may as well use a ring as its no safer.

A 4mm^2 radial for general purpose sockets will in many circumstances
perform less well than a ring since it tends to have a higher earth loop
impedance. Its also more difficult to wire and in many cases saves no
copper. Hence why its fairly rare to see in practice.

The 20A circuit doesn't rely on the plug fuse to prevent overloading the
cables like the others do.

None of the standard circuits rely on plug fuses to prevent overloading.

Yes they do, you are wrong and refuse to accept that you are wrong.
You cling to straws and keep changing the argument just to avoid admitting
it.
You are also a hypocrite as you accuse other of doing the same, even when
they don't.
You only have to look at this post to prove that this is true of you.

If the circuits were protected by breakers upstream we wouldn't have this
debate and if you really have designed stuff you know that its illogical to
protect the cable at the wrong end using something the householder controls.