In article ,
GB wrote:
Tell me, dennis, just why would there be any 'movement' in any part of a
properly installed final ring circuit?


Why do faults occur in electrical circuits if there is no movement?

There must be thermal expansion and contraction, surely?

As there is with any metal. But you don't expect the copper pipes in your
central heating to fail, so why expect wiring to do so?

--
*I couldn't repair your brakes, so I made your horn louder *

Dave Plowman London SW
To e-mail, change noise into sound.

On Wednesday, 27 May 2015 22:31:56 UTC+1, GB wrote:
On 27/05/2015 21:03, ARW wrote:
"GB" wrote in message
...


I did wonder whether the cable is overspecified to allow for this.
There must be loads of ring mains with breaks or dodgy connections,
but the number of electrical fires is fairly small.


Most ring circuits are underloaded. If there is a bad connection at a
socket then the socket usually packs up before the wiring (there may be
some small localised wire damage).
The minimum Iz of the cable for a ring is 20A. That's the maximum a
double socket can supply without burning out.

Let me ask a question to make sure I have understood correctly. A ring
main takes 30A. Any more and the circuit breaker trips. If there are no
glitches in the wiring that is carried over two cables with a minimum
current carrying capacity of 20A each, ie 40A total? So, there is a bit
of a safety margin.

20A rating, not 20A carrying capacity. We frequently had over 45A load on a 30A ring without any issue, as lots of kitchens do.


I leant an extension lead to a very experienced builder working in my
house stripping some wallpaper with a steamer. I just left him to it. 30
minutes later the power circuit failed. The steamer was well within the
power rating of the extension lead, but only if it was uncoiled, which
the builder had not done. The whole thing had melted, not just the cable
reel but the insulation off the wires. The insulation was the
consistency of custard. It's a bit frightening, actually.

So he had what, maybe 3x rated load for 30 mins for that to happen. I don't know anyone that runs 90A on a 30A ring for 30 mins.


NT

En el artículo , Dave Plowman (News)
escribió:

As there is with any metal. But you don't expect the copper pipes in your
central heating to fail, so why expect wiring to do so?

Your pipes aren't held together with screws, which loosen over time.

--
(\_/)
(='.'=)
(")_(")

On 27/05/2015 14:40, Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
On 27/05/15 13:55, Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
The ECC is the thinnest wire so most likely to break.

Questionable logic. Which breaks more easily? - a human hair or a
matchstick

And your 'logic' doesn't take the type of material into account?

which breaks more easily a human hair or a chicken feather quill?

same material

As in both animal products?

as in both made of Keratin



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 27/05/15 22:31, GB wrote:
If there are no glitches in the wiring that is carried over two cables
with a minimum current carrying capacity of 20A each, ie 40A total? So,
there is a bit of a safety margin.

Nope.

If the two lengths of cable feeding a given socket are of unequal
length, more current will go via the shorter (lower resistance) route in
proportion to the difference in length (in resistance, in fact).
The only way a ruing contributes to anything is by providing alternate
earth paths, and in the case of many distributed loads, slightly easing
current requirements, but anyone who fuses a ring at more than the
capacity of a single wire in the ring is a fool.


--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

On 28/05/2015 00:45, Dave Plowman (News) wrote:
In article ,
GB wrote:
Tell me, dennis, just why would there be any 'movement' in any part of a
properly installed final ring circuit?


Why do faults occur in electrical circuits if there is no movement?

There must be thermal expansion and contraction, surely?

As there is with any metal. But you don't expect the copper pipes in your
central heating to fail,

You may not expect it, and indeed I did not, but:

http://wiki.diyfaq.org.uk/index.php?...e_rubbing_pipe

so why expect wiring to do so?

That I expect more - however its only an issue on circuits that run at
near full load for extended periods IME.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
Mike Tomlinson wrote:
As there is with any metal. But you don't expect the copper pipes in
your central heating to fail, so why expect wiring to do so?

Your pipes aren't held together with screws, which loosen over time.

You've never come across a compression fitting, then?

--
*I'd kill for a Nobel Peace Prize *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
John Rumm wrote:
On 28/05/2015 00:45, Dave Plowman (News) wrote:
In article ,
GB wrote:
Tell me, dennis, just why would there be any 'movement' in any part of a
properly installed final ring circuit?


Why do faults occur in electrical circuits if there is no movement?

There must be thermal expansion and contraction, surely?

As there is with any metal. But you don't expect the copper pipes in your
central heating to fail,

You may not expect it, and indeed I did not, but:

http://wiki.diyfaq.org.uk/index.php?...e_rubbing_pipe

so why expect wiring to do so?

That I expect more - however its only an issue on circuits that run at
near full load for extended periods IME.

And the requirements of a final circuit ring is that it isn't. Devices
which take a high extended load - like say space heating or water heating
- are covered separately.

It's the beauty of a ring. It's eminently suitable for the sort of actual
use it gets in domestic premises. Lots of relatively low current devices
used intermittently. And a large number of outlets to avoid having
trailing cables.

The proof, as they say, is in the pudding.

--
*It was recently discovered that research causes cancer in rats*

Dave Plowman London SW
To e-mail, change noise into sound.

On 28/05/2015 10:17, Dave Plowman (News) wrote:
In article ,
Mike Tomlinson wrote:
As there is with any metal. But you don't expect the copper pipes in
your central heating to fail, so why expect wiring to do so?

Your pipes aren't held together with screws, which loosen over time.

You've never come across a compression fitting, then?

I could see that one coming. What are the screw joints made out of in
electrical work? Brass? How does the coefficient of expansion compare
with copper?

In article ,
GB wrote:
On 28/05/2015 10:17, Dave Plowman (News) wrote:
In article ,
Mike Tomlinson wrote:
As there is with any metal. But you don't expect the copper pipes in
your central heating to fail, so why expect wiring to do so?

Your pipes aren't held together with screws, which loosen over time.

You've never come across a compression fitting, then?

I could see that one coming. What are the screw joints made out of in
electrical work? Brass? How does the coefficient of expansion compare
with copper?

Compression fittings are brass. Tube copper.

Electrical fixing screws (and the terminal it screws into) are generally
brass. Cable copper.

Have you never done any DIY that you have to ask such a question?

--
*"I am " is reportedly the shortest sentence in the English language. *

Dave Plowman London SW
To e-mail, change noise into sound.

On 28/05/2015 11:25, Dave Plowman (News) wrote:

I could see that one coming. What are the screw joints made out of in
electrical work? Brass? How does the coefficient of expansion compare
with copper?

Compression fittings are brass. Tube copper.

Electrical fixing screws (and the terminal it screws into) are generally
brass. Cable copper.

Have you never done any DIY that you have to ask such a question?


I just wanted to check what material is used, as I have been accused
here of making assumptions. I thought it was generally brass, and
thanks for confirming.

The coefficient of expansion of brass is 18.7, whilst copper is 16.6
(10-6 m/(m K)), so they are fairly similar.

En el artículo , The Natural Philosopher
escribió:

anyone who fuses a ring at more than the
capacity of a single wire in the ring is a fool.

So the millions of rings installed since they were introduced were
designed and installed by fools? Rings are protected by 32A breakers,
yet each leg uses 2.5mm^2 cable rated to 16A.

What planet do you live on, again?

--
(\_/)
(='.'=)
(")_(")

On 27/05/2015 13:15, dennis@home wrote:
On 27/05/2015 10:53, Dave Plowman (News) wrote:
In article ,
charles wrote:
In article . com,
dennis@home wrote:
On 26/05/2015 23:05, wrote:


bad connection. Radials suffer much worse from them than rings.

A ring has more connections so a bad one is more likely.
The effects are different.

and if there is a break in a radial circuit it is very obvious. Not so
in a ring.

A break in the earth circuit in a radial is going to be obvious? Maybe
only when it kills you.

The ECC is the thinnest wire so most likely to break. With a ring there
are two. Unlike a radial.


I wouldn't make such statements without evidence.
The thin wire is more flexible so wont break so easy if it suffers
movement.

Every time I have found a discontinuity in a CPC, its been at a
termination. Typically either down to being lost in a mass of
connections and improperly sized sleeving such that one wire was never
actually pushed into the terminal, or, due to being over tightened such
that it fractured at the terminal.

Inspections probably find more earth faults because they show up in
tests while none working sockets get fixed before the tests.

True... although I rarely find a completely non working socket (and last
time I did, it was actually a non working MCB!)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 27/05/2015 20:36, dennis@home wrote:
On 27/05/2015 20:16, GB wrote:
On 27/05/2015 20:00, dennis@home wrote:
On 27/05/2015 14:10, GB wrote:


I did wonder whether the cable is overspecified to allow for this.

No it isn't in a 2.5 mm2 circuit.


I was merely inferring from the small number of fires that the 2.5 mm2
cable is probably more than needed in most circumstances. For example,
cable is more likely to overheat if the house is hot, but users are less
likely to have a high power appliance like an electric fire switched on
when the weather is hot. That sort of thing.

In any case, who would design a system without a sizeable safety factor
built in?

Apparently there are a set of rules you have to follow to ensure you
don't damage a ring.

Why do you persist in repeating this nonsense?


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 27/05/2015 22:31, GB wrote:
On 27/05/2015 21:03, ARW wrote:
"GB" wrote in message
...


I did wonder whether the cable is overspecified to allow for this.
There must be loads of ring mains with breaks or dodgy connections,
but the number of electrical fires is fairly small.


Most ring circuits are underloaded. If there is a bad connection at a
socket then the socket usually packs up before the wiring (there may be
some small localised wire damage).
The minimum Iz of the cable for a ring is 20A. That's the maximum a
double socket can supply without burning out.

Let me ask a question to make sure I have understood correctly. A ring
main takes 30A.

A modern one will be protected by a 32A MCB.

Any more and the circuit breaker trips.

That's not the way fuses or MCBs work in reality. They will take a
smallish sustained overload in excess of that indefinitely. Then they
will trip in ever decreasing time in response to a larger overload. You
need to look at the devices response curve to work out how long:

http://wiki.diyfaq.org.uk/index.php?...e-MCBTypeB.png

This curve is roughly designed to mimic the heating effect on the cable.
So to take the 32A device as an example, it will permit 50A of load for
around 1000 secs, 60A for 200 secs, 70A about 100 sec, and 100A for
perhaps 10 sec or so.

Once you get over 160A (i.e. 5x the nominal rating) then the magnetic
"fault" detection part of the trip kicks in, and they disconnect
"instantly"

The cable's current carrying capacity is defined by its maximum
sustained conductor temperature. For a PVC insulated cable this is 70
deg C. The circuit protection should ensure that this temperature is not
exceeded for an extended period (which would start to degrade the life
expectancy of the cable).

If there are no
glitches in the wiring that is carried over two cables with a minimum
current carrying capacity of 20A each, ie 40A total? So, there is a bit
of a safety margin.

The designer needs to ensure that the rated *installed* capacity (i.e.
taking into account the effects of insulation near the cable or other
factors that will lower its ability to shed heat and hence lower its
maximum current capacity) is at least 20A. In many cases it will be
higher than this. For cable buried in plaster or run on the surface, you
would get the highest rating of the cable. (which for 2.5mm^2 T&E is
around 27A). So the safety margin will vary from approaching 30% to
about 90%.

Note also that these are continuous ratings - in reality you will be
able to operate beyond those limits with no adverse effects due to the
nature of diversity.

http://wiki.diyfaq.org.uk/index.php?title=Diversity

I leant an extension lead to a very experienced builder working in my
house stripping some wallpaper with a steamer. I just left him to it. 30
minutes later the power circuit failed. The steamer was well within the
power rating of the extension lead, but only if it was uncoiled, which
the builder had not done. The whole thing had melted, not just the cable
reel but the insulation off the wires. The insulation was the
consistency of custard. It's a bit frightening, actually.

Indeed and a good example of the interrelationship between conductor
temperature, time, and current carrying capacity.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 28/05/2015 10:26, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
On 28/05/2015 00:45, Dave Plowman (News) wrote:
In article ,
GB wrote:
Tell me, dennis, just why would there be any 'movement' in any part of a
properly installed final ring circuit?


Why do faults occur in electrical circuits if there is no movement?

There must be thermal expansion and contraction, surely?

As there is with any metal. But you don't expect the copper pipes in your
central heating to fail,

You may not expect it, and indeed I did not, but:

http://wiki.diyfaq.org.uk/index.php?...e_rubbing_pipe

so why expect wiring to do so?

That I expect more - however its only an issue on circuits that run at
near full load for extended periods IME.

And the requirements of a final circuit ring is that it isn't. Devices
which take a high extended load - like say space heating or water heating
- are covered separately.

It's the beauty of a ring. It's eminently suitable for the sort of actual
use it gets in domestic premises. Lots of relatively low current devices
used intermittently. And a large number of outlets to avoid having
trailing cables.

The proof, as they say, is in the pudding.

Indeed - as a design it has endured because it works so well with modern
usage patterns.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 28/05/2015 12:08, Mike Tomlinson wrote:
En el artículo , The Natural Philosopher
escribió:

anyone who fuses a ring at more than the
capacity of a single wire in the ring is a fool.

So the millions of rings installed since they were introduced were
designed and installed by fools? Rings are protected by 32A breakers,
yet each leg uses 2.5mm^2 cable rated to 16A.

Rated at 27A down to a minimum of 20A



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm wrote:
It's the beauty of a ring. It's eminently suitable for the sort of
actual use it gets in domestic premises. Lots of relatively low
current devices used intermittently. And a large number of outlets to
avoid having trailing cables.

The proof, as they say, is in the pudding.

Indeed - as a design it has endured because it works so well with modern
usage patterns.

Yes. In this particular case the crystal ball worked. ;-)

--
*All men are idiots, and I married their King.

Dave Plowman London SW
To e-mail, change noise into sound.

"GB" wrote in message
...
On 27/05/2015 21:03, ARW wrote:
"GB" wrote in message
...


I did wonder whether the cable is overspecified to allow for this.
There must be loads of ring mains with breaks or dodgy connections,
but the number of electrical fires is fairly small.


Most ring circuits are underloaded. If there is a bad connection at a
socket then the socket usually packs up before the wiring (there may be
some small localised wire damage).
The minimum Iz of the cable for a ring is 20A. That's the maximum a
double socket can supply without burning out.

Let me ask a question to make sure I have understood correctly. A ring
main takes 30A. Any more and the circuit breaker trips. If there are no
glitches in the wiring that is carried over two cables with a minimum
current carrying capacity of 20A each, ie 40A total? So, there is a bit of
a safety margin.

I leant an extension lead to a very experienced builder working in my
house stripping some wallpaper with a steamer. I just left him to it. 30
minutes later the power circuit failed. The steamer was well within the
power rating of the extension lead, but only if it was uncoiled, which the
builder had not done. The whole thing had melted, not just the cable reel
but the insulation off the wires. The insulation was the consistency of
custard. It's a bit frightening, actually.



As you said, a normal ring circuit will use 2.5 T&E and a 32A MCB or 30A
fuse. The maximum current a 2.5 T&E can carry indefinitely without damage is
27A depending on how it installed eg if it is plastered into a wall it will
be 27A. Other factors can lower the CCC (grouping of
cables/insulation/temperature). eg A 2.5 T&E cable in an insulated wall but
touching the outer surface has a current carrying capacity of 21A.

Some new builds/refurbs need 4.0mm T&E ring circuits due to the insulation
in the building.


A 30/32A ring circuit must never use a cable that is installed so that it's
CCC drops below 20A. The MCB will also supply 40 odd amps for half an hour
or so before tripping. Short term overloads are allowed but long term small
overloads are not allowed.

Your extenstion lead is a classic example of a grouping factor - although I
would not call him an experienced builder if he fell for that one:-). Once
grouped around itself the CCC of the extention lead cable dropped from 13A
to say 5A.

Of course some people still bang on about balancing the loads on a ring
circuit and mention portable electric heaters to back up their statements.


--
Adam

On 28/05/2015 12:19, John Rumm wrote:

Apparently there are a set of rules you have to follow to ensure you
don't damage a ring.

Why do you persist in repeating this nonsense?


You and dave have both quoted some of the rules in this thread, try
reading what you said about space heating.

So its fine if I plug two (or more) 3kw heaters into adjacent sockets at
one end of the ring and it doesn't break any of the rules.

"dennis@home" wrote in message
eb.com...
On 28/05/2015 12:19, John Rumm wrote:

Apparently there are a set of rules you have to follow to ensure you
don't damage a ring.

Why do you persist in repeating this nonsense?


You and dave have both quoted some of the rules in this thread, try
reading what you said about space heating.

So its fine if I plug two (or more) 3kw heaters into adjacent sockets at
one end of the ring and it doesn't break any of the rules.

Doing that doesn’t damage the ring and doing that is
going to damage a ring less than a spur that uses the
same conductor wire too.

On 28/05/2015 18:56, ARW wrote:

Of course some people still bang on about balancing the loads on a ring
circuit and mention portable electric heaters to back up their statements.

They also ignore the point that a 20A protected radial could run
indefinitely with a pair of 13A fan heaters, and a cable de-rated to 20A
- but that would also spoil their argument. ;-)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 28/05/2015 23:23, dennis@home wrote:
On 28/05/2015 12:19, John Rumm wrote:

Apparently there are a set of rules you have to follow to ensure you
don't damage a ring.

Why do you persist in repeating this nonsense?


You and dave have both quoted some of the rules in this thread, try
reading what you said about space heating.

Dave correctly pointed out that a general purpose socket circuit is not
the ideal way to power a long term fixed load. This is true and applies
to radial and ring circuits that are feeding general purpose sockets.

General purpose socket circuits are intended to provide flexible power
for a wide range of diverse and distributed loads over a large floor
area. If you decide to power your swimming pool heater from one end of
the circuit, then all you do is reduce that flexibility.

So its fine if I plug two (or more) 3kw heaters into adjacent sockets at
one end of the ring and it doesn't break any of the rules.

Beyond using a bit of common sense, there are no "rules" that a user
need be aware of for any general purpose socket circuit type.

The reality is there is little difference plugging in a pair of said
heaters on a 20A radial, and right at the end of a ring. Depending on
the installation method of the cable, you may get a moderate overload on
a section of cable in both cases. The world will not end, the cable will
not burst into flames. You may degrade the cable with extended use, but
being realistic, how many months of the year do you need to run two fan
heaters in the same room with their thermostats disabled?

All that is required is a bit of common sense from the designer of the
circuit, and a user can do as they please.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 29/05/2015 01:40, John Rumm wrote:
On 28/05/2015 18:56, ARW wrote:

Of course some people still bang on about balancing the loads on a ring
circuit and mention portable electric heaters to back up their
statements.

They also ignore the point that a 20A protected radial could run
indefinitely with a pair of 13A fan heaters, and a cable de-rated to 20A
- but that would also spoil their argument. ;-)


Which cable is rated at 20A?
Not 2.5 mm T&E.

On 29/05/2015 11:20, John Rumm wrote:

All that is required is a bit of common sense from the designer of the
circuit, and a user can do as they please.


So three 3kW heaters on the end of a ring then?
How about adding in the combi microwave at 2kW for a hour while you cook
some chicken?

On Friday, 29 May 2015 19:02:54 UTC+1, dennis@home wrote:
On 29/05/2015 11:20, John Rumm wrote:

All that is required is a bit of common sense from the designer of the
circuit, and a user can do as they please.


So three 3kW heaters on the end of a ring then?
How about adding in the combi microwave at 2kW for a hour while you cook
some chicken?

Its common to have 45A or so load on a ring for a while most days, and harmless. 32A is the continuous rating.


NT

In article . com,
dennis@home wrote:
On 29/05/2015 01:40, John Rumm wrote:
On 28/05/2015 18:56, ARW wrote:

Of course some people still bang on about balancing the loads on a ring
circuit and mention portable electric heaters to back up their
statements.

They also ignore the point that a 20A protected radial could run
indefinitely with a pair of 13A fan heaters, and a cable de-rated to 20A
- but that would also spoil their argument. ;-)


Which cable is rated at 20A?
Not 2.5 mm T&E.

Indeed not, if the cable is run in conduit its only rated at 18.5A

--
From KT24 in Surrey

Using a RISC OS computer running v5.18

"dennis@home" wrote in message
web.com...
On 29/05/2015 11:20, John Rumm wrote:

All that is required is a bit of common sense from the designer of the
circuit, and a user can do as they please.


So three 3kW heaters on the end of a ring then?


Is that how you heat your house?

Is that how anyone heats their house?

That would be 9kW of localised heat.

--
Adam

On Friday, 29 May 2015 20:00:25 UTC+1, ARW wrote:
"dennis@home" wrote in message
web.com...
On 29/05/2015 11:20, John Rumm wrote:

All that is required is a bit of common sense from the designer of the
circuit, and a user can do as they please.

So three 3kW heaters on the end of a ring then?

Is that how you heat your house?
Is that how anyone heats their house?
That would be 9kW of localised heat.

and would thus be run for a very short time, which rings cope with.


NT

On 29/05/2015 20:00, ARW wrote:
"dennis@home" wrote in message
web.com...
On 29/05/2015 11:20, John Rumm wrote:

All that is required is a bit of common sense from the designer of the
circuit, and a user can do as they please.


So three 3kW heaters on the end of a ring then?


Is that how you heat your house?

Is that how anyone heats their house?

That would be 9kW of localised heat.


If that's what they please to do then why not?
John said thae can do as they please are you saying they can't?

"charles" wrote in message
...
In article . com,
dennis@home wrote:
On 29/05/2015 01:40, John Rumm wrote:
On 28/05/2015 18:56, ARW wrote:

Of course some people still bang on about balancing the loads on a
ring
circuit and mention portable electric heaters to back up their
statements.

They also ignore the point that a 20A protected radial could run
indefinitely with a pair of 13A fan heaters, and a cable de-rated to
20A
- but that would also spoil their argument. ;-)


Which cable is rated at 20A?
Not 2.5 mm T&E.

Indeed not, if the cable is run in conduit its only rated at 18.5A


Are you and dennis competing against each other for the thick **** of the
year award?

--
Adam

"dennis@home" wrote in message
web.com...
On 29/05/2015 20:00, ARW wrote:
"dennis@home" wrote in message
web.com...
On 29/05/2015 11:20, John Rumm wrote:

All that is required is a bit of common sense from the designer of the
circuit, and a user can do as they please.


So three 3kW heaters on the end of a ring then?


Is that how you heat your house?

Is that how anyone heats their house?

That would be 9kW of localised heat.


If that's what they please to do then why not?
John said thae can do as they please are you saying they can't?


Because only a thick daft **** would do it or try it.

Feel free to have a go. You fit the criteria.




--
Adam

On 29/05/2015 19:02, dennis@home wrote:
On 29/05/2015 11:20, John Rumm wrote:

All that is required is a bit of common sense from the designer of the
circuit, and a user can do as they please.


So three 3kW heaters on the end of a ring then?

Which part about the designer using common sense did you not get?

If you have a kitchen layout like mine, all the sockets are in the
middle of the ring since there is a 20m of cable run just to get there.
If you have a CU in the kitchen then you use a bit of common sense like
if you have a pair of adjacent utility spaces close to one end of the
ring, you make sure you wire the sockets on alternate ends and not
adjacent to each other.

How about adding in the combi microwave at 2kW for a hour while you cook
some chicken?

So what's that going to average out at? The equivalent of 500W
continuous load?


--
Cheers,

John.

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On 29/05/2015 18:59, dennis@home wrote:
On 29/05/2015 01:40, John Rumm wrote:
On 28/05/2015 18:56, ARW wrote:

Of course some people still bang on about balancing the loads on a ring
circuit and mention portable electric heaters to back up their
statements.

They also ignore the point that a 20A protected radial could run
indefinitely with a pair of 13A fan heaters, and a cable de-rated to 20A
- but that would also spoil their argument. ;-)


Which cable is rated at 20A?
Not 2.5 mm T&E.

Yes the 2.5mm T&E may be rated at only 20A (and that would be the lowest
acceptable de-rated value permitted in a 20A radial or a 32A protected
ring).

See for example 2.5mm^2 T&E, reference method A:

http://wiki.diyfaq.org.uk/index.php?...es#Cable_Sizes

You can also calculate any required de-rating based on circumstances.

It is explained it in great detail he

http://wiki.diyfaq.org.uk/index.php?...g_A_Cable_Size


--
Cheers,

John.

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wrote in message
...
On Wednesday, 27 May 2015 21:03:28 UTC+1, ARW wrote:
"GB" wrote in message
...


I did wonder whether the cable is overspecified to allow for this.
There
must be loads of ring mains with breaks or dodgy connections, but the
number of electrical fires is fairly small.


Most ring circuits are underloaded. If there is a bad connection at a
socket
then the socket usually packs up before the wiring (there may be some
small
localised wire damage).

The minimum Iz of the cable for a ring is 20A. That's the maximum a
double
socket can supply without burning out.

No, its the maximum current a double socket is rated to provide
continuously without getting hot. It takes more to burn it out.



Its the same for both. 20A is not a reserved number.

--
Adam

In article . com,
dennis@home wrote:
So three 3kW heaters on the end of a ring then?
How about adding in the combi microwave at 2kW for a hour while you cook
some chicken?

You have three 3kW heaters and a microwave oven in your kitchen?

--
*If at first you don't succeed, then skydiving definitely isn't for you *

Dave Plowman London SW
To e-mail, change noise into sound.

In article . com,
dennis@home wrote:
Is that how you heat your house?

Is that how anyone heats their house?

That would be 9kW of localised heat.


If that's what they please to do then why not?
John said thae can do as they please are you saying they can't?

If you actually owned 3 x 3 kW heaters it would suggest it's your only
form of heating. And space heating comes under a different set of regs.

--
*I'm already visualizing the duct tape over your mouth

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article . com,
dennis@home wrote:
Is that how you heat your house?

Is that how anyone heats their house?

That would be 9kW of localised heat.


If that's what they please to do then why not?
John said thae can do as they please are you saying they can't?

If you actually owned 3 x 3 kW heaters

I own a lot more of them than that.

it would suggest it's your only form of heating.

It isn't.

And space heating comes under a different set of regs.

Not when that sort of heater is used.

In article ,
Rod Speed wrote:
If you actually owned 3 x 3 kW heaters

I own a lot more of them than that.

Well, yes. But you live in a third world country which doesn't use final
ring circuits.

--
*Beauty is in the eye of the beer holder...

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
Rod Speed wrote:
If you actually owned 3 x 3 kW heaters

I own a lot more of them than that.

Well, yes. But you live in a third world country

Which actually has a higher standard level of wealth than you clowns do.

which doesn't use final ring circuits.

Wrong, as always.