On Tue, 02 Apr 2013 22:27:33 +0100, Tim Watts wrote:

On Tuesday 02 April 2013 19:41 Major Scott wrote in uk.d-i-y:

People with fuses aren't so worried about quick trips.

You ****ign well should be - you are required to meet the 0.4second
disconnection time, with an overcurrent device. The type of device is
irrelevant.

Required am I? I'll make the decisions around here, not a committee.

--
What do you call an Amish man with his arm up a horse's ass?
A mechanic.

On Tue, 02 Apr 2013 22:28:37 +0100, Tim Watts wrote:

On Tuesday 02 April 2013 22:07 Major Scott wrote in uk.d-i-y:


Put a match to your wallpaper. Or plasterboard.

Yes. And?...

FIRE!

--
What do you call an Amish man with his arm up a horse's ass?
A mechanic.

On Tue, 02 Apr 2013 22:43:46 +0100, Alexander Lamaison wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 21:02:20 +0100, Alexander Lamaison
wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 18:21:49 +0100, John Rumm
wrote:

On 02/04/2013 13:27, Major Scott wrote:














1) An unfused spur is restricted to a single accessory. That limits the
maximum load to 26A.

If you fit a decent cable that can handle 30A, it's protected by the
CU fuse and you can add more than one item to it.

You seem to be thinking of the items in an electrical installation as
having ratings indicating a magic boundary: a '30A cable' that's
protected by a '30A fuse', in your mind, is good while a '20A cable'
protected by a '30A fuse' is bad.

That's not how it works. Think of the ratings on these things as more
like names than numbers. You can't match circuit components and
protection using the number on the back, like painting-by-numbers.

In case you are still sceptical, consider the difference between a 30A
rewireable fuse and a 30A cartridge fuse which have different protective
'strength' (a 30A rewireable fuse has about the same ability as a 22A
cartridge fuse - if they existed).

It's a good guide. You wouldn't use lighting wire then fit a 30A
fuse.

It should be a guide. The problem seems to be you're using it as a rule
and ignoring what the regs actually say.

If it's labelled as x it should do x, or it's mislabelled.

--
Did you hear about the little Indian chief who didn't know the difference between heads and tails?
He was always bringing home scalps with holes in them.

On Tue, 02 Apr 2013 22:58:01 +0100, Alexander Lamaison wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 21:37:55 +0100, John Rumm
wrote:

On 02/04/2013 18:12, Major Scott wrote:
On Tue, 02 Apr 2013 17:58:37 +0100, John Rumm
wrote:

On 02/04/2013 11:57, Major Scott wrote:












You are falling into a common trap of conflating overload protection and
fault protection, and also assuming that it falls to the circuit
protective device to proved both for "everything".

In the case of a general purpose socket circuit, the protective device
at the origin of the circuit needs to provide both fault and overload
protection for the circuit as a whole, but not provide overload
protection for each individual accessory, since that can be provided by
other means.

The test regime for double sockets requires a long term loading test
with a 20A load. This is a solid and sensible engineering practice that
reflects a maximum load that will be "higher than reality". While you
may think you can contrive ways to get larger loads onto a single socket
than that, you will find it far harder to achieve in practice. (the fact
that sockets are not melting all around the country every day indicates
that the design has been very well proven in practice).

Some socket makers (MK for example) claim to test their double sockets
with 26A of loading, however many will test only up to the level of that
required by the BS since that is all that is required to put the product
onto the market.

It must be pretty common for someone to plug 2 of a dishwasher, washing
machine, and tumble dryer into a double socket, and quite likely to run
both at once. They've all got pretty powerful heaters in them.

A 20A fuse would allow short term overloads already. Upping
that to 30A is too much.

There is nothing stopping you using 20A circuits if you prefer, however
in domestic environments they tent to prove far less flexible in high
load areas like kitchens.

I'd prefer just to have a double socket than can handle the same as two
single ones.

Buy MK ones then - they claim to test with 2 x 13A loads.

At least someone is doing it properly. So if you all think 20A is ok,
why do you think MK is testing at 26?

MK's USP is to go that extra step beyond what's required in order to
justify their price premium. Otherwise you'd you'd buy a cheap asian
import, as all (legal) manufacturers meet the minimum spec.

That'll be why they're so popular, they do things right.

For definitions of "easy" that include really rather difficult. The vast
majority of 13A loads that you can find to plug in, tend to be
relatively short term in real world cases.

I can run a tumble dryer for an hour and a half, more if I have a lot of
washing to do after coming back from holiday for example. Same applies
to the washing machine and dishwasher.

Look at the current draw profile and you will find none of them present
continuous 13A loads. Many appliances of that nature are designed with
10A maximum loads, and that will be reduced over time by the action of
the thermostats.

A tumble dryer draws full power continuously unless you select the
gentle low heat cycle.

13A (domestically, usually less) for a couple of hours. NBD. Even with
the dishwasher and washing machine elements occasionally joining in.

My care doesn't normally have to perform an emergency stop, but it's nice to know it can.

What not have a go at costing it and see? Over engineering things for a
one off solution is sometimes acceptable. However for common items that
will be deployed many hundreds of millions of times, a 20% increase in
manufacturing price may well be "too much", especially as the current
design has been proven to work so well and safely.

But double sockets are pennies. It's not like we're talking about £50
items here. They're nothing compared to the total cost of an installation.

Which re-enforces the point really. If you are buying for your own place
and need a few dozen, then you can splash out a hundred quid extra on
the higher quality ones.

A few dozen is a bit much, this house probably has 16 (2 bedrooms).
Anyway, I bought my (brass) double sockets for £3 each. I assume 26A
instead of 20A would make them maybe £3.50 each. That's £8 extra..

If on the other hand you are purchasing for a
new housing estate, the prospect of saving £20K by going for an item
that in all practical purposes will work just as well, is attractive..

£8 per house...... less than a tin of paint.

Although your argument sounds good, the proof is in the pudding. If it
made financial sense, more manufacturers would make their double-sockets
exceed the standard. But they don't, so it doesn't. Simples.

The world is full of skinflints.

--
A woman walks into a drugstore and asks the pharmacist if he sells size extra large condoms.
He replies, "Yes we do. Would you like to buy some?"
She responds, "No, but do you mind if I wait around here until someone does?

"Major Scott" writes:

On Tue, 02 Apr 2013 22:27:33 +0100, Tim Watts wrote:

On Tuesday 02 April 2013 19:41 Major Scott wrote in uk.d-i-y:

People with fuses aren't so worried about quick trips.

You ****ign well should be - you are required to meet the 0.4second
disconnection time, with an overcurrent device. The type of device is
irrelevant.

Required am I? I'll make the decisions around here, not a committee.

You rail at the very thought of a 20A double socket but are blaze about
a 0.4s disconnection time. Time to get out the hammer and knock those
priorities straight.

Alex

--
Swish - Easy SFTP for Windows Explorer (http://www.swish-sftp.org)

"Major Scott" writes:

On Tue, 02 Apr 2013 22:43:46 +0100, Alexander Lamaison
wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 21:02:20 +0100, Alexander Lamaison
wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 18:21:49 +0100, John Rumm
wrote:

On 02/04/2013 13:27, Major Scott wrote:














1) An unfused spur is restricted to a single accessory. That limits the
maximum load to 26A.

If you fit a decent cable that can handle 30A, it's protected by the
CU fuse and you can add more than one item to it.

You seem to be thinking of the items in an electrical installation as
having ratings indicating a magic boundary: a '30A cable' that's
protected by a '30A fuse', in your mind, is good while a '20A cable'
protected by a '30A fuse' is bad.

That's not how it works. Think of the ratings on these things as more
like names than numbers. You can't match circuit components and
protection using the number on the back, like painting-by-numbers.

In case you are still sceptical, consider the difference between a 30A
rewireable fuse and a 30A cartridge fuse which have different protective
'strength' (a 30A rewireable fuse has about the same ability as a 22A
cartridge fuse - if they existed).

It's a good guide. You wouldn't use lighting wire then fit a 30A
fuse.

It should be a guide. The problem seems to be you're using it as a rule
and ignoring what the regs actually say.

If it's labelled as x it should do x, or it's mislabelled.

You seem to think it does one simple thing. In fact it takes many
hundreds of pages of regs, not to mention other standards, to describe
what it does in different situations. How are they supposed to 'label'
that?

Alex

--
Swish - Easy SFTP for Windows Explorer (http://www.swish-sftp.org)

On Tue, 02 Apr 2013 23:19:07 +0100, Alexander Lamaison wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 21:42:22 +0100, Alexander Lamaison
wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 17:58:37 +0100, John Rumm
wrote:

On 02/04/2013 11:57, Major Scott wrote:












You are falling into a common trap of conflating overload protection and
fault protection, and also assuming that it falls to the circuit
protective device to proved both for "everything".

In the case of a general purpose socket circuit, the protective device
at the origin of the circuit needs to provide both fault and overload
protection for the circuit as a whole, but not provide overload
protection for each individual accessory, since that can be provided by
other means.

The test regime for double sockets requires a long term loading test
with a 20A load. This is a solid and sensible engineering practice that
reflects a maximum load that will be "higher than reality". While you
may think you can contrive ways to get larger loads onto a single socket
than that, you will find it far harder to achieve in practice. (the fact
that sockets are not melting all around the country every day indicates
that the design has been very well proven in practice).

Some socket makers (MK for example) claim to test their double sockets
with 26A of loading, however many will test only up to the level of that
required by the BS since that is all that is required to put the product
onto the market.

It must be pretty common for someone to plug 2 of a dishwasher,
washing machine, and tumble dryer into a double socket, and quite
likely to run both at once. They've all got pretty powerful heaters
in them.

Like I said yesterday, sockets aren't firecrackers. They don't burst
into flame in indignation that you exceeded their rating. Are you
running the elements of all three machines on full, simulatanously for
10 hours? No, you couldn't convince the machines to do that even if you
wanted to.

They'll get a bit hot though, and the contacts will wear down.

Cry me a river.

A 20A fuse would allow short term overloads already. Upping
that to 30A is too much.

There is nothing stopping you using 20A circuits if you prefer, however
in domestic environments they tent to prove far less flexible in high
load areas like kitchens.

I'd prefer just to have a double socket than can handle the same as
two single ones.

Its certainly your right to dream.

Or get an MK.

For definitions of "easy" that include really rather difficult. The vast
majority of 13A loads that you can find to plug in, tend to be
relatively short term in real world cases.

I can run a tumble dryer for an hour and a half, more if I have a lot
of washing to do after coming back from holiday for example. Same
applies to the washing machine and dishwasher.

Let's imagine this socket somehow protected 20A by a 20A fuse (your main
complaint is that it isn't) and that you convinced that lot to run at
26A for an hour and a half contiunously (you couldn't). That would not
even begin to tickle your 20A fuse - it would never blow.

It should eventually, or why call it a 20A fuse?

Good question. I think a 20A (non-rewireable) fuse is called a 20A fuse
because it can provide overload and fault protection for those circuits
with a design current of = 20A and a cable rating of = 20A. But that
cable rating of = 20A already takes into account the fact that the fuse
doesn't even think about blowing until about 30A so all is well.

But it can work just fine in a circuit with a design current of up to 30A too. I know you should allow for motors starting etc, but if the load is more than 20A for 5 minutes, it should blow.

And just because it provides overload protection for circuits with =20A
cable rating doesn't mean it can't provide fault protection for cables
with 20A rating as long as overload protection is handled by other
means. That is the situation we're in with the unfused spur where the
13A fuses in the socket combined with limiting it to feed one double
socket takes care of the overload side of things. Yes, it's technically
possible to overload it still but that's already been taken care of when
they designed the rule that said it was safe to do this. They didn't
just wing it.

I'm not sure why a 20A rewireable fuse is called 20A because it isn't
actually suitable for protecting a cable rating = 20A. Well, ok, it
is, but that's basically because they hacked the regs to make the use of a
rewireable fuse a cable derating factor. This forces it to realign
again. Why didn't they just rate them 0.725 lower in the first place?

Paperpushers like to complicate matters, it keeps them in a job.

--
For the really paranoid who want to destroy data there's nothing like taking the lid off the disk drive and rearranging the sectors with a hammer.

On Tuesday 02 April 2013 23:26 Alexander Lamaison wrote in uk.d-i-y:


Because the people who installed them a few decades ago made sure there
was an adequate PFC to blow them!!

You're wasting your fingers... He doesn't understand there are two aspects
to fusing.

--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal coverage

Reading this on the web? See:
http://wiki.diyfaq.org.uk/index.php?title=Usenet

On Tuesday 02 April 2013 23:39 Major Scott wrote in uk.d-i-y:

On Tue, 02 Apr 2013 22:28:37 +0100, Tim Watts
wrote:

On Tuesday 02 April 2013 22:07 Major Scott wrote in uk.d-i-y:


Put a match to your wallpaper. Or plasterboard.

Yes. And?...

FIRE!


Only in your deranged mind.

You are Drivel's mad brother and I claim my £5. At least he was slightly
funny.

--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal coverage

Reading this on the web? See:
http://wiki.diyfaq.org.uk/index.php?title=Usenet

On Tuesday 02 April 2013 23:39 Major Scott wrote in uk.d-i-y:

On Tue, 02 Apr 2013 22:27:33 +0100, Tim Watts
wrote:

On Tuesday 02 April 2013 19:41 Major Scott wrote in uk.d-i-y:

People with fuses aren't so worried about quick trips.

You ****ign well should be - you are required to meet the 0.4second
disconnection time, with an overcurrent device. The type of device is
irrelevant.

Required am I? I'll make the decisions around here, not a committee.


OK - go jump off the nearest tower block.

I'm sure you can prove Newton wrong. After all, you decide what happens.

--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal coverage

Reading this on the web? See:
http://wiki.diyfaq.org.uk/index.php?title=Usenet

On Tue, 02 Apr 2013 23:55:58 +0100, Tim Watts wrote:

On Tuesday 02 April 2013 23:39 Major Scott wrote in uk.d-i-y:

On Tue, 02 Apr 2013 22:27:33 +0100, Tim Watts
wrote:

On Tuesday 02 April 2013 19:41 Major Scott wrote in uk.d-i-y:

People with fuses aren't so worried about quick trips.

You ****ign well should be - you are required to meet the 0.4second
disconnection time, with an overcurrent device. The type of device is
irrelevant.

Required am I? I'll make the decisions around here, not a committee.


OK - go jump off the nearest tower block.

I'm sure you can prove Newton wrong. After all, you decide what happens.

It's not a law of physics I'm breaking.

--
There are 10 kinds of people in the world: Those who understand binary, and those who don't.

On Tue, 02 Apr 2013 23:55:02 +0100, Tim Watts wrote:

On Tuesday 02 April 2013 23:39 Major Scott wrote in uk.d-i-y:

On Tue, 02 Apr 2013 22:28:37 +0100, Tim Watts
wrote:

On Tuesday 02 April 2013 22:07 Major Scott wrote in uk.d-i-y:


Put a match to your wallpaper. Or plasterboard.

Yes. And?...

FIRE!


Only in your deranged mind.

You are Drivel's mad brother and I claim my £5. At least he was slightly
funny.

I prefer to keep heat away from flammable stuff.

--
I dialed one of those 900 numbers to get some financial advice. They advised me not to dial 900 numbers.

In message , Tim Watts
writes
On Tuesday 02 April 2013 23:39 Major Scott wrote in uk.d-i-y:

Required am I? I'll make the decisions around here, not a committee.


OK - go jump off the nearest tower block.

Please do a risk assessment first and erect suitable barriers around the
landing zone, taking into account windage on the day. It would be
truly irresponsible just to jump and risk landing on some poor innocent
passer by.



PS.
I witnessed, from about 2m away, someone doing just this, he effectively
landed at my feet, it is not pleasant, both the sight and sound of him
hitting the concrete will remain with me forever.

PPS
I wonder if the OP realised the devil that he was unleashing when he
asked his original, simple question?


--
Bill

On Tue, 02 Apr 2013 22:22:36 +0100, John Rumm wrote:

The electricity board assumes I will never use more than 100 amps.
But if I did, the fuse next to the meter would blow.

Unlikely on both counts...

They are assuming you will use an average of around 8A

Your fuse won't blow at 100A (unless its a 40A one)

Even then it's likely to take minutes, if not hours, to blow.

--
Cheers
Dave.

On Wed, 03 Apr 2013 00:16:03 +0100, Bill wrote:

In message , Tim Watts
writes
On Tuesday 02 April 2013 23:39 Major Scott wrote in uk.d-i-y:

Required am I? I'll make the decisions around here, not a committee.


OK - go jump off the nearest tower block.

Please do a risk assessment first and erect suitable barriers around the
landing zone, taking into account windage on the day. It would be
truly irresponsible just to jump and risk landing on some poor innocent
passer by.

Sounds like the kind of bull**** they come out with nowadays.

PS.
I witnessed, from about 2m away, someone doing just this, he effectively
landed at my feet, it is not pleasant, both the sight and sound of him
hitting the concrete will remain with me forever.

You're not one of those people that visits trick cyclists are you?

PPS
I wonder if the OP realised the devil that he was unleashing when he
asked his original, simple question?

In this group it is to be expected.

--
Acupuncturists do it with a small prick.

In message , Major Scott writes


PS.
I witnessed, from about 2m away, someone doing just this, he effectively
landed at my feet, it is not pleasant, both the sight and sound of him
hitting the concrete will remain with me forever.

You're not one of those people that visits trick cyclists are you?

I am trying very hard to understand the reasoning behind your question,
but have not found it.

I am assuming that you mean psychiatrists rather than circus performers.

I did go to a circus last year and very good it was too. The clowns
were most amusing.

As for psychiatrists, no, I've never had need to visit one, although I
do know one personally and through work at camh.




PPS
I wonder if the OP realised the devil that he was unleashing when he
asked his original, simple question?

In this group it is to be expected.

Not normally to this degree, it has gone from serious discussion to name
calling and positively aggressive suggestions, which if said face to
face could have ended badly.

--
Bill

On Wed, 03 Apr 2013 00:43:58 +0100, Bill wrote:

In message , Major Scott writes


PS.
I witnessed, from about 2m away, someone doing just this, he effectively
landed at my feet, it is not pleasant, both the sight and sound of him
hitting the concrete will remain with me forever.

You're not one of those people that visits trick cyclists are you?

I am trying very hard to understand the reasoning behind your question,
but have not found it.

"Psychological harm".

I am assuming that you mean psychiatrists rather than circus performers.

Indeed.

I did go to a circus last year and very good it was too. The clowns
were most amusing.

I didn't think circuses still existed. Are they similar to what they were 20 years ago?

As for psychiatrists, no, I've never had need to visit one, although I
do know one personally and through work at camh.

PPS
I wonder if the OP realised the devil that he was unleashing when he
asked his original, simple question?

In this group it is to be expected.

Not normally to this degree, it has gone from serious discussion to name
calling and positively aggressive suggestions, which if said face to
face could have ended badly.

Oh that always happens in here. Not that I've seen anything remotely aggressive in this thread.

--
Women claim that they never pursue a man. Well, by the same token, a mousetrap never pursues a mouse, but the end result is
the same.

On 02/04/2013 22:16, John Rumm wrote:

You also need to watch your circuit lengths a bit more as the PSSC will
rise.

ITYM "fall" (Zs and disconnection time will rise). You know that, but
bear of small brain might be confused...

--
Andy

In message , Major Scott writes
On Wed, 03 Apr 2013 00:43:58 +0100, Bill wrote:

In message , Major Scott writes


PS.
I witnessed, from about 2m away, someone doing just this, he effectively
landed at my feet, it is not pleasant, both the sight and sound of him
hitting the concrete will remain with me forever.

You're not one of those people that visits trick cyclists are you?

I am trying very hard to understand the reasoning behind your question,
but have not found it.

"Psychological harm".

Ah ha, no need, just a memory that I would rather not have.



I am assuming that you mean psychiatrists rather than circus performers.

Indeed.

I did go to a circus last year and very good it was too. The clowns
were most amusing.

I didn't think circuses still existed. Are they similar to what they
were 20 years ago?

No idea, I've only visited them over the last couple of years.



As for psychiatrists, no, I've never had need to visit one, although I
do know one personally and through work at camh.

PPS
I wonder if the OP realised the devil that he was unleashing when he
asked his original, simple question?

In this group it is to be expected.

Not normally to this degree, it has gone from serious discussion to name
calling and positively aggressive suggestions, which if said face to
face could have ended badly.

Oh that always happens in here. Not that I've seen anything remotely
aggressive in this thread.

The suggestion about jumping off a tower block is not exactly a sign of
good will.



Any way, one can only take so much exposure to the internet, so I'm off
to bed.

Good night.


--
Bill

On Wed, 03 Apr 2013 00:52:03 +0100, Bill wrote:

In message , Major Scott writes
On Wed, 03 Apr 2013 00:43:58 +0100, Bill wrote:

In message , Major Scott writes


PS.
I witnessed, from about 2m away, someone doing just this, he effectively
landed at my feet, it is not pleasant, both the sight and sound of him
hitting the concrete will remain with me forever.

You're not one of those people that visits trick cyclists are you?

I am trying very hard to understand the reasoning behind your question,
but have not found it.

"Psychological harm".

Ah ha, no need, just a memory that I would rather not have.

Wouldn't bother me.

I am assuming that you mean psychiatrists rather than circus performers.

Indeed.

I did go to a circus last year and very good it was too. The clowns
were most amusing.

I didn't think circuses still existed. Are they similar to what they
were 20 years ago?

No idea, I've only visited them over the last couple of years.

I assume there are less animals due to animal cruelty concerns.

As for psychiatrists, no, I've never had need to visit one, although I
do know one personally and through work at camh.

PPS
I wonder if the OP realised the devil that he was unleashing when he
asked his original, simple question?

In this group it is to be expected.

Not normally to this degree, it has gone from serious discussion to name
calling and positively aggressive suggestions, which if said face to
face could have ended badly.

Oh that always happens in here. Not that I've seen anything remotely
aggressive in this thread.

The suggestion about jumping off a tower block is not exactly a sign of
good will.

It's only words.

Any way, one can only take so much exposure to the internet, so I'm off
to bed.

Good night.

I would be too, but I can't sleep unless I'm very tired, why can't we just sleep like we can breath or cough at will?

--
Confucius say man who sniff coke, drown.

On Tue, 02 Apr 2013 23:28:35 +0100, Alexander Lamaison wrote:

Actually paper ignites at 233C.

450C actually [1], but who's counting? And I was talking about the
match.

451 F as in Fahrenheit 451 by Ray Bradbury

[1] http://en.wikipedia.org/wiki/Autoignition_temperature

Which quotes both figures, 450 C and 218 - 246 C (424 - 475 F).

The talk page makes for interesting reading.

--
Cheers
Dave.

En el artículo , Tim Watts
escribió:

Don't bother replying, there will be no further debate on this point.

_________________
/| /| | |
||__|| | Please do |
/ O O\__ not feed |
/ \ the troll |
/ \ \ ________________|
/ _ \ \ ||
/ |\____\ \ ||
/ | | | |\____/ ||
/ \|_|_|/ | __||
/ / \ |____| ||
/ | | /| | --|
| | |// |____ --|
* _ | |_|_|_| | \-/
*-- _--\ _ \ // |
/ _ \\ _ // | /
* / \_ /- | - | |
* ___ c_c_c_C/ \C_c_c_c____________


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

On 03/04/2013 00:48, Andy Wade wrote:
On 02/04/2013 22:16, John Rumm wrote:

You also need to watch your circuit lengths a bit more as the PSSC will
rise.

ITYM "fall" (Zs and disconnection time will rise). You know that, but
bear of small brain might be confused...

Yes was just about to post a correction to that... must be something
about communicating with scotty, that is twice in the same thread now!



--
Cheers,

John.

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

On 02/04/2013 23:46, Major Scott wrote:
On Tue, 02 Apr 2013 23:19:07 +0100, Alexander Lamaison

Good question. I think a 20A (non-rewireable) fuse is called a 20A fuse
because it can provide overload and fault protection for those circuits
with a design current of = 20A and a cable rating of = 20A. But that
cable rating of = 20A already takes into account the fact that the fuse
doesn't even think about blowing until about 30A so all is well.

But it can work just fine in a circuit with a design current of up to
30A too. I know you should allow for motors starting etc, but if the
load is more than 20A for 5 minutes, it should blow.

Twaddle scotty, can you read a graph?:

http://wiki.diyfaq.org.uk/images/0/05/Curve-BS88.png

20A fuse - 40A load - time to blow 5 mins.

(it won't ever blow at 26A or 30A for that matter)

See if you can work out why that is not a problem.




--
Cheers,

John.

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

On 02/04/2013 22:47, Major Scott wrote:
On Tue, 02 Apr 2013 21:48:11 +0100, John Rumm

Note also that is the conductor temperature. There will be a temperature
gradient across the insulation, so the touch temperature of the
insulation on the outside will be lower.

I've got copper heating pipes in my airing cupboard that get that hot,
and I don't much like bottles of stuff being against them.

Are they covered in PVC insulation as well?

Do your "bottles of stuff" catch fire?

Is you house built from "bottles of stuff"?


--
Cheers,

John.

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On 02/04/2013 22:12, Alexander Lamaison wrote:
"Major Scott" writes:

On Tue, 02 Apr 2013 20:40:58 +0100, ARW wrote:

Major Scott wrote:
On Tue, 02 Apr 2013 17:53:00 +0100, ARW
wrote:
John Rumm wrote:
On 02/04/2013 11:59, Major Scott wrote:
On Tue, 02 Apr 2013 04:39:29 +0100, John Rumm
wrote:

On 01/04/2013 23:53, Alexander Lamaison wrote:
Tim Watts writes:

On Monday 01 April 2013 20:14 Major Scott wrote in
uk.d-i-y:
On Mon, 01 Apr 2013 18:31:04 +0100, Tim Watts
wrote:


A double socket is rated at 20A max total

Surely there would be thousands of people plugging in
two 3kW loads and
melting them.....


Apparantly not.

I'm sure Tim's right simply because I've seen the 20A
quoted so many times. But I'd love to know where it comes
from. Is this figure in BS 1363?

1363 part 2 1995. Its from the temperature rise test section,
where you are supposed to load a socket with 14A on one side,
and a further 6A on the other when testing a double. The load
is then maintained for a minimum of 4h, and up to a maximum
of 8h or when a stable temperature is reached (whichever
comes first). To pass, the temperature rise must be limited
to 52 deg C over ambient.

That's pretty hot. Lets say you have a warm room of 23C. That's
75C. I wouldn't want 75C sat in my wall. And that's only at
the 20A rating.

The temperature is decided by the typical temperature budget of
the cable feeding the socket, which if PVC insulated, would
normally be 70 deg C.

Needless to say the cable does not immediately fail if that
temperature is reached, however the lifetime of its insulation
will start to reduce with overheating.


More info here

http://electrical.theiet.org/wiring-...2.cfm?type=pdf

It's not just the cable that gets hot though. I don't want my
flammable wall that warm.

So you live in a caravan?

Put a match to your wallpaper. Or plasterboard.

So now this apocalyptic socket is running at 600C?

Perhaps his anal vibrator goes up to 11?

--
Cheers,

John.

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On 03/04/2013 00:43, Bill wrote:
In message , Major Scott writes


I wonder if the OP realised the devil that he was unleashing when he
asked his original, simple question?

In this group it is to be expected.

Not normally to this degree, it has gone from serious discussion to name
calling and positively aggressive suggestions, which if said face to
face could have ended badly.

Well from time to time drivel like clones pop up and spout their stuff.

While one might argue there is no need to respond to them at all in some
respects (since we know that scotty neither heeds any advice he asks
for, or proffers any information of value), there is an opportunity for
all of us to learn new stuff as the stream of nonsense often prompts
ever more detailed and thorough responses.

For example, just go read some of the IMM vs Andy Hall monster threads,
and you can learn lots just from the rebuttles of IMM/Drivel's scotty
like outpourings.



--
Cheers,

John.

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On 02/04/2013 22:30, Major Scott wrote:

In a portable appliance you don't fit a fuse higher than the flex is rated.

Erm, in fact its commonly done... (and safely)


--
Cheers,

John.

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"Dave Liquorice" writes:

On Tue, 02 Apr 2013 23:28:35 +0100, Alexander Lamaison wrote:

Actually paper ignites at 233C.

450C actually [1], but who's counting? And I was talking about the
match.

451 F as in Fahrenheit 451 by Ray Bradbury

He said "Fahrenheit" because he thought it sounded better even though he
knew it was Celcius.

Alex

--
Swish - Easy SFTP for Windows Explorer (http://www.swish-sftp.org)

On 03/04/13 10:38, Alexander Lamaison wrote:
"Dave Liquorice" writes:

On Tue, 02 Apr 2013 23:28:35 +0100, Alexander Lamaison wrote:

Actually paper ignites at 233C.

450C actually [1], but who's counting? And I was talking about the
match.

451 F as in Fahrenheit 451 by Ray Bradbury

He said "Fahrenheit" because he thought it sounded better even though he
knew it was Celcius.

Alex

Er no, he was an American ...

"Ray Bradbury, recipient of the 2000 National Book Foundation Medal for
Distinguished Contribution to American Letters, the 2004 National Medal
of Arts, and the 2007 Pulitzer Prize Special Citation, died on June 5,
2012, at the age of 91 after a long illness. He lived in Los Angeles."

....and they use Fahrenheit, and 'Celcius' is spelt Celsius..


And wiki list too entirely different values for autoignition, one at
450C and one at 450 F. One wonders if there was something lost in
translation.

I know I used to light fags off a weller soldering iron OK.


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On Wed, 03 Apr 2013 06:20:02 +0100, John Rumm wrote:

On 02/04/2013 22:30, Major Scott wrote:

In a portable appliance you don't fit a fuse higher than the flex is rated.

Erm, in fact its commonly done... (and safely)

Not safe at all. 5A flex, 13A fuse, for some reason the device goes wrong and draws 13A. Flex causes fire.

--
Hard work pays off in the future. Laziness pays off now.

On 03/04/2013 12:05, Major Scott wrote:
On Wed, 03 Apr 2013 06:20:02 +0100, John Rumm
wrote:

On 02/04/2013 22:30, Major Scott wrote:

In a portable appliance you don't fit a fuse higher than the flex is
rated.

Erm, in fact its commonly done... (and safely)

Not safe at all. 5A flex, 13A fuse, for some reason the device goes
wrong and draws 13A. Flex causes fire.

Bzzzzrt Is the wrong answer...

Now think a bit harder - all the information has been posted for you.

Imagine a table lamp, "3A flex", 13A fuse?

Or look at the IEC power lead in the back of your computer.... plenty of
those with 13A fuses - the cable is not 1.5mm^2 though.

Or imagine your appliance used in Germany, 16A MCB at the circuit
origin, no fuse in the plug at all, same "less than 13A capable" flex.

Yet it all still works and fails safe, how can that be?


--
Cheers,

John.

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In article , John
Rumm writes

IMM/Drivel's scotty
like outpourings.

He's currently infesting uk.railway (posting as "News") but they're
getting wise to him, there are fewer and fewer responses to his posts.
Rather amusing to see all the "News" dead ends when you view threads in
tree form.

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

On Wed, 03 Apr 2013 06:15:25 +0100, John Rumm wrote:

On 03/04/2013 00:43, Bill wrote:
In message , Major Scott writes


I wonder if the OP realised the devil that he was unleashing when he
asked his original, simple question?

In this group it is to be expected.

Not normally to this degree, it has gone from serious discussion to name
calling and positively aggressive suggestions, which if said face to
face could have ended badly.

Well from time to time drivel like clones pop up and spout their stuff.

While one might argue there is no need to respond to them at all in some
respects (since we know that scotty neither heeds any advice he asks
for, or proffers any information of value), there is an opportunity for
all of us to learn new stuff as the stream of nonsense often prompts
ever more detailed and thorough responses.

For example, just go read some of the IMM vs Andy Hall monster threads,
and you can learn lots just from the rebuttles of IMM/Drivel's scotty
like outpourings.

Incorrect. The only problem people have with me is I'm not a brainwashed health and safety moronic sheep like the rest of you.

--
Follow your dream! Unless it's the one where you're at work in your underwear during a fire drill.

On Tue, 02 Apr 2013 23:43:40 +0100, Alexander Lamaison wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 22:27:33 +0100, Tim Watts wrote:

On Tuesday 02 April 2013 19:41 Major Scott wrote in uk.d-i-y:

People with fuses aren't so worried about quick trips.

You ****ign well should be - you are required to meet the 0.4second
disconnection time, with an overcurrent device. The type of device is
irrelevant.

Required am I? I'll make the decisions around here, not a committee.

You rail at the very thought of a 20A double socket but are blaze about
a 0.4s disconnection time. Time to get out the hammer and knock those
priorities straight.

Fire concerns me more than electric shock.

--
In the UK, 17% of employees are health and safety officers.
Say NO! to health and safety in the workplace, before there are no real workers left!
Look out for yourself and stop blaming each other like 6 year olds!

On Tue, 02 Apr 2013 23:45:53 +0100, Alexander Lamaison wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 22:43:46 +0100, Alexander Lamaison
wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 21:02:20 +0100, Alexander Lamaison
wrote:

"Major Scott" writes:

















You seem to be thinking of the items in an electrical installation as
having ratings indicating a magic boundary: a '30A cable' that's
protected by a '30A fuse', in your mind, is good while a '20A cable'
protected by a '30A fuse' is bad.

That's not how it works. Think of the ratings on these things as more
like names than numbers. You can't match circuit components and
protection using the number on the back, like painting-by-numbers.

In case you are still sceptical, consider the difference between a 30A
rewireable fuse and a 30A cartridge fuse which have different protective
'strength' (a 30A rewireable fuse has about the same ability as a 22A
cartridge fuse - if they existed).

It's a good guide. You wouldn't use lighting wire then fit a 30A
fuse.

It should be a guide. The problem seems to be you're using it as a rule
and ignoring what the regs actually say.

If it's labelled as x it should do x, or it's mislabelled.

You seem to think it does one simple thing. In fact it takes many
hundreds of pages of regs, not to mention other standards, to describe
what it does in different situations. How are they supposed to 'label'
that?

Sack all the paperpushers.

--
The sensible in the world are doomed to be frustrated by petty, officious idiots.

On Tue, 02 Apr 2013 23:26:23 +0100, Alexander Lamaison wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 21:54:29 +0100, John Rumm
wrote:

On 02/04/2013 18:53, Major Scott wrote:
On Tue, 02 Apr 2013 18:48:10 +0100, ARW
wrote:

John Rumm wrote:


Stupid is as stupid does.

You think fuses are a bad idea? We were using them for decades before
these health and safety morons appeared.

No, we think people who put faith in fuses without also ensuring there
is adequate PFC to operate them, are either ignorant or morons.

A few decades ago, it was all we had. They worked fine.

Because the people who installed them a few decades ago made sure there
was an adequate PFC to blow them!!

Fuses are great, they don't have a hair trigger.

--
What does a Polish woman do after she sucks a cock?
Spits out the feathers.

On Tue, 02 Apr 2013 22:22:36 +0100, John Rumm wrote:

On 02/04/2013 19:43, Major Scott wrote:
On Tue, 02 Apr 2013 19:06:01 +0100, Tim Watts wrote:

On Tuesday 02 April 2013 18:48 Major Scott wrote in uk.d-i-y:

Read up about diversity factor.
http://en.wikipedia.org/wiki/Diversi...versified_Load

I'm not into gambling.


The you should probably ask your electricy company for a 150A supply
depending of whether you have an electric shower and cooker.

And a road with 100 houses should be supplied with 5000A 3 phase cables.

etc etc.

No, it's fine as long as there is adequate protection. The electricity
board assumes I will never use more than 100 amps. But if I did, the
fuse next to the meter would blow.

Unlikely on both counts...

They are assuming you will use an average of around 8A

Your fuse won't blow at 100A (unless its a 40A one)

You know what I mean, obviously I can have surges.

But assuming nobody will ever draw 26 amps from a double socket, and
having no protection if it did happen, is daft.

Just as well no one makes that assumption then.

The sockets are only tested at 20A.

--
How many potheads does it take to change a light bulb?
Two. One to hold the bulb against the socket, and the other to smoke up until the room starts spinning.

On Tue, 02 Apr 2013 23:28:35 +0100, Alexander Lamaison wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 22:12:21 +0100, Alexander Lamaison
wrote:

"Major Scott" writes:

On Tue, 02 Apr 2013 20:40:58 +0100, ARW
wrote:

Major Scott wrote:


So you live in a caravan?

Put a match to your wallpaper. Or plasterboard.

So now this apocalyptic socket is running at 600C?

Actually paper ignites at 233C.

450C actually [1], but who's counting? And I was talking about the match.

[1] http://en.wikipedia.org/wiki/Autoignition_temperature

I was going by the name of the film - Fahrenheit 451. Wikipedia quotes your and my figure and just writes "or". Presumably different paper types?

--
The squaw on the hippopotamus is equal to the sons of the squaws on the other two hides!

On Wed, 03 Apr 2013 05:59:10 +0100, John Rumm wrote:

On 02/04/2013 23:46, Major Scott wrote:
On Tue, 02 Apr 2013 23:19:07 +0100, Alexander Lamaison

Good question. I think a 20A (non-rewireable) fuse is called a 20A fuse
because it can provide overload and fault protection for those circuits
with a design current of = 20A and a cable rating of = 20A. But that
cable rating of = 20A already takes into account the fact that the fuse
doesn't even think about blowing until about 30A so all is well.

But it can work just fine in a circuit with a design current of up to
30A too. I know you should allow for motors starting etc, but if the
load is more than 20A for 5 minutes, it should blow.

Twaddle scotty, can you read a graph?:

http://wiki.diyfaq.org.uk/images/0/05/Curve-BS88.png

20A fuse - 40A load - time to blow 5 mins.

(it won't ever blow at 26A or 30A for that matter)

See if you can work out why that is not a problem.

The problem is calling something a 6A fuse when it will never blow at 7A. It should, that's why it's called 6A. The 6A fuse in that graph should be called a 9A fuse, as it will blow eventually at 10.

--
If sex is a pain in the ass, then you're doing it wrong.