Are mains surge protectors needed in the UK?

[David Maynard]

But electronic devices are not connected directly to the mains they
are connected to a power supply which is *designed* to copy
with large cueernts.

I suppose you think that means something but it's irrelevant to the point
that electronic devices react to electrical faults hundreds of times faster
than any fuse can. More to the point, any current that could possibly blow
a fuse is the RESULT of a failure which, by definition, means the fuse
cannot 'protect' from it as it's already happened.

OK if you connect one leg of your 3GHz pentuim to the
mains live connection and the other leg to earth you will probably damage it
but I am not recommending that.





I dount there are many 100mw components in a PS and even if there
were and they did blow they would protect your computer.

For that to even begin to make sense you'd first have to consider a blown
power supply as the device still 'working', but I doubt most people do.

Further, I have no idea what makes you think a 'blown' component in the PSU
will 'protect' the computer. All one need imagine is the reference voltage
zener blowing, resulting in lord knows what voltage being thrown into the
system and destroying massive numbers of components. That is, of course,
why all decent PSUs include over voltage protection on the power rails. And
while you may gleefully scream "ah hah!," as if that means something to
your case, it isn't done with fuses because fuses are too slow to protect
electronic components.

The issue isn't 'where' the fault occurs in the device but that a fuse
simply cannot 'protect' from it (voltage induced failure).

However before it did blow it would probably required a
several fold increase in current for a substained period which
would obviously blow the fuse first.

This is where you are sorely mistaken as you seem to think that the only
way any device, of any kind, fails is by current induced heating but that
is simply not the case with electronic devices. Too much voltage, as
perhaps induced by a surge, will instantly destroy semi-conductor
components; after which they may simply do nothing or, more common, draw
excessive current. At which point, anything a 'fuse' detects is long since
after the fact.

(Heat can destroy them too but that isn't the mode we're talking about with
surge protection)

And if you are saying that semi conductor devices are inherently
sensitive to current then obviously we would make fuses out of them.

It is your mistaken notion that only 'current' causes failure that leads
you to invalid assumptions.

However semiconductors are make out of silicone which has
an extremly high melting point.

Which is irrelevant because that is not what causes device failure.

(we are basically talking about
sand) indeed silicone has replaced asbestos as a safer heat
resistant material.
http://www.candochefs.com/silbakmat1.html

" Use in up to 900 degrees F! "

Obvioulsy fuses are *designed* to melt quickly
at low temperatures.

Semiconductors materials are probably never damaged
by heat, at least not untill long after the metalic contacts have
vapourised.

'Melting' is not the failure mechanism of semi-conductor devices.

You don't have a huge backlog of expensive surge protectors to shift
by any chance?

I don't 'sell' anything nor is it any skin off my nose if your computer is
damaged because you think a fuse will 'protect' it.

 

[half_pint]

Long before computers existed in homes, why were LED clocks
and radios replaced daily?

Well mine were not replaced daily, or ever for that matter.

The only electrical devices I can ever recall failing are light bulbs.

Actually that is a lie, some electrical devices do fail and the ones
which fail are the supposedly robust 'older' electronics such
as vacuum cleaners, electric drills, TV's etc..which "don't need"
surge protectors. Of course they probably all failed because of
other reasons unrealted to power surges, not the 'probably' as
I have no idea why they failed.

If your clocks were failing daily I suggest you get a competant
electriction to look at the wiring in you house, some 'cowboy' amateur
may have been 'fiddling with it.

The only failures in such devices I can recall is wearing out of the
on/off and other switch contacts (and variable resistors).

 

[half_pint]

Or don't blow at all. Sister in Law is running a washing machine and
tumble drier off an extension. THe tumble drier developed a fault this
week. THe extension cable got red hot - too hot to touch. To get that
hot it had to have exceeded the plug fuse rating. Neither the fuse in
the extension chord or the fuse in the tumble drier mains plug blew.

Sounds like the extension cable was not rated highly enough.
Even a basic tumble dryer draws about 5kW so for say a 240V supply
and working on W=I X V or I=W/V =5000/240 =18.75 Amps!!!!
(you can throw another 4 amp in for the washing machine too!!)
If you are on a 120V supply as in the USA? then you are up to
the 50 Amp mark!!!!

Most extension cables are rated 13amp some 10amp (some even lower
but probably illegal!!). Some may not even be fused at all. In my shopping
catalogue there is nothing above 13 amp even those rated 'heavy duty'.

I would imagine somewhere in the unread manual for the dryer it says
something like:-

DO NOT RUN THIS APPLIANCE FROM AN EXTENSION CABLE.

Obviously the dryer has its own fuse but the one in the extension cable was
probably replaced with something more 'stable' some time ago, probably
the aforementioned 4mm bolt. (or more realistically "one suitable for a
dryer"), by an amateur electrician.

Most extension cables are rated 13amp some 10amp (some even lower
but probably illegal!!). Some may not even be fused at all.

You sister-in-law is probably a very luck woman, wet washing rooms
and underrated cables, drawing huge currents are an extremely dangerous
combination. There would have been some fireworks if the plastic outer
cladding had melted, I can guarantee you that.

 

[half_pint]

Must be some odd problem of yours as I've never had one fail.

Same here.

 

[David Maynard]

Since you don't understand that both sides of a 230/115 V branch circuit
are on the same phase, you may not understand how such circuits are
wired.

No, I understand they're on the same phase but it is sometimes useful in
the electronics realm to note they're 180 degrees out from each other and I
misspoke. So sue me.

They are completely in accord with any current electrical codes.
A "multiwire branch circuit" is defined in the codes. It can supply two
115V circuits with two "hot" wires and a common neutral wire. Any U.S.
home with 230 V entry service has at least one.

Of course, the mains connection.

The branch circuit you refer to is the type 3, but that's not the circuit
for lighting and receptacles, type 1, that I was referring to.

 

[David Maynard]

Sounds like the extension cable was not rated highly enough.
Even a basic tumble dryer draws about 5kW so for say a 240V supply
and working on W=I X V or I=W/V =5000/240 =18.75 Amps!!!!
(you can throw another 4 amp in for the washing machine too!!)
If you are on a 120V supply as in the USA? then you are up to
the 50 Amp mark!!!!

In the U.S., a dryer of that rating would be on a 240 volt circuit too.

Most extension cables are rated 13amp some 10amp (some even lower
but probably illegal!!). Some may not even be fused at all. In my shopping
catalogue there is nothing above 13 amp even those rated 'heavy duty'.

I would imagine somewhere in the unread manual for the dryer it says
something like:-

DO NOT RUN THIS APPLIANCE FROM AN EXTENSION CABLE.

Obviously the dryer has its own fuse but the one in the extension cable was
probably replaced with something more 'stable' some time ago, probably
the aforementioned 4mm bolt. (or more realistically "one suitable for a
dryer"), by an amateur electrician.

Most extension cables are rated 13amp some 10amp (some even lower
but probably illegal!!). Some may not even be fused at all.

You sister-in-law is probably a very luck woman, wet washing rooms
and underrated cables, drawing huge currents are an extremely dangerous
combination. There would have been some fireworks if the plastic outer
cladding had melted, I can guarantee you that.

 

[half_pint]

I suppose you think that means something but it's irrelevant to the point
that electronic devices react to electrical faults hundreds of times faster
than any fuse can. More to the point, any current that could possibly blow
a fuse is the RESULT of a failure which, by definition, means the fuse
cannot 'protect' from it as it's already happened.

No we are talking about a surge in current from outside the house
so to speak. That surge must go through the fuse first, strictly speaking,
well, at leaaast at the same time anyway.

For that to even begin to make sense you'd first have to consider a blown
power supply as the device still 'working', but I doubt most people do.

Further, I have no idea what makes you think a 'blown' component in the PSU
will 'protect' the computer. All one need imagine is the reference voltage
zener blowing, resulting in lord knows what voltage being thrown into the
system and destroying massive numbers of components.

A zener diode is already 'blown' so to speak, thats how they work.
The voltage across them is basically the same whatever the input voltage.
Essentially it is a grain of sand, its not going to melt, at least not
before
other metal components vapourise. And the first component to vapourise
will be the fuse in the plug, you can be sure of that.

That is, of course,
why all decent PSUs include over voltage protection on the power rails.

Ah hah!!

And
while you may gleefully scream "ah hah!," as if that means something to
your case, it isn't done with fuses because fuses are too slow to protect
electronic components.

I think you will find 99% of surge protectors contain a fuse, which is a bit
odd really if they are surplus to requirements?

The issue isn't 'where' the fault occurs in the device but that a fuse
simply cannot 'protect' from it (voltage induced failure).


This is where you are sorely mistaken as you seem to think that the only
way any device, of any kind, fails is by current induced heating but that
is simply not the case with electronic devices. Too much voltage, as
perhaps induced by a surge, will instantly destroy semi-conductor
components; after which they may simply do nothing or, more common, draw
excessive current. At which point, anything a 'fuse' detects is long since
after the fact.

No that current has to come in via the fuse which is designed to fail as
quickly
as possible, as opposed to other components which are designed *not* to
fail.

(Heat can destroy them too but that isn't the mode we're talking about with
surge protection)


It is your mistaken notion that only 'current' causes failure that leads
you to invalid assumptions.

But I am right of course, *only* current *ever* causes electrical failures.
A semiconductor device, or any electrical device will work quite happilly
a 1 billion volts.

Which is irrelevant because that is not what causes device failure.

Heat is the only cause of device failure. Ever. Period.

'Melting' is not the failure mechanism of semi-conductor devices.

Yes it is.

I don't 'sell' anything nor is it any skin off my nose if your computer is
damaged because you think a fuse will 'protect' it.

Nice try buddy, uk.comp.vendors, pull the other one, I wasn't born
yesterday.

There of dozen of devices in my home which contain IC's none has ever
failed due to a power surge, zilcho.

There are also many IC's in my car which regularly gives me a big zap of
static electricity, I can assure you that the shock has effected me far more
than
my car stereo etc....

I have also worked in enviroments where there are dozen's upon
dozens of computers, no surge protection and no failed computers.

I get the feeling that someone here is trying to shift a job lot of surge
protectors on ebay, either that or having a larf.

Think I will go and take a look

 

[half_pint]

But not *that* large...and they too contain semiconductor devices.


For semiconductor devices, the sustained period is a lot shorter than
for a fuse.

No it isn't otherwise fuses would be made from semiconductors.

No, silicon. Not the same. How many semiconductor-packed breasts do you
know of?

I don't wear breast implants, but good luck with the 'op' anyway ;O)

Perhaps not the base material, but semiconductor materials are a bit
more complex than that (hint: look up 'doping').

Maybe I should look up 'dope' :OP we are basically talking about very
stable elements, similar to silicon which are 'woven' into the silicon
lattice they will form a very stable structure.

 

[David Maynard]

No we are talking about a surge in current from outside the house

No, we're talking about a voltage surge.

so to speak. That surge must go through the fuse first, strictly speaking,
well, at leaaast at the same time anyway.

There will be no current unless something conducts.

I.E. If there were no devices plugged in (or wired in) the only effect
would be a voltage spike on the interior power lines, but no current flow
per see (besides leakage).

If, however, a susceptible device is connected to the power line and the
voltage spike is sufficient to cause electrical breakdown then the device
fails and may pull excessive current as a result of the failure, which, if
severe enough, will blow the fuse. But the failure has already occurred by
the time the fuse sees anything, much less blows.

damage it



A zener diode is already 'blown' so to speak, thats how they work.

No, it isn't.

The voltage across them is basically the same whatever the input voltage.

An obvious contradiction, as stated.

A zener conducts when the voltage across it reaches a certain level,
otherwise is does not conduct, and the source better be current limited,
most commonly by a series resistor, or else the zener will self destruct.
In that case, by over heating.

Essentially it is a grain of sand,

Not hardly.

its not going to melt,

'Melting' has nothing to do with it.

at least not
before
other metal components vapourise. And the first component to vapourise
will be the fuse in the plug, you can be sure of that.

No offense but you really don't understand semi-conductors at all.

Ah hah!!




I think you will find 99% of surge protectors contain a fuse, which is a bit
odd really if they are surplus to requirements?

No one ever said they were 'surplus'. The problem is you don't understand
the nature of electronics and the purpose of various protection devices.

A fuse blows on a sustained current fault and breaks the connection: a
preferable situation to continuing to draw fault current because, for one,
it prevents fires.

That has nothing to do with 'protecting' what is already a damaged device
causing the current fault.

No that current has to come in via the fuse which is designed to fail as
quickly
as possible, as opposed to other components which are designed *not* to
fail.

You're never going to understand it till you get it out of your head that
'excessive current' is the only thing that damages semi-conductors.

But I am right of course, *only* current *ever* causes electrical failures.
A semiconductor device, or any electrical device will work quite happilly
a 1 billion volts.

Surely you jest.

Why in the word do you think power supplies, much less multi-voltage units,
even exist if electronics works 'quite happily' at just any old voltage?

Heat is the only cause of device failure. Ever. Period.

Just plain wrong.

Really now, even your own decryption, as misguided as it is, contradicts
THAT absurdity because, if it were true, there would never ever be an
electronic failure, unless someone shoved it inside a 900F oven. And that
is clearly not the case.

Yes it is.

No, it isn't. And I'd advise you to go learn something about
semi-conductors before you make such statements because they make it rather
obvious you have no idea how they work.

Nice try buddy, uk.comp.vendors, pull the other one, I wasn't born
yesterday.

I'm posting from alt.comp.hardware.pc-homebuilt.

There of dozen of devices in my home which contain IC's none has ever
failed due to a power surge, zilcho.

And you think that 'proves' what?

There are also many IC's in my car which regularly gives me a big zap of
static electricity, I can assure you that the shock has effected me far more
than
my car stereo etc....

Oh, really? And what were you doing with the case to these devices open so
that you were getting a 'static discharge' from the 'ICs'?

But since you bring it up you could expand your horizons by doing a web
search on ICs and static electricity and, in particular, ESD protection.

Here's one to get you started:
http://www.informit.com/articles/article.asp?p=21704&seqNum=3

"In general, MOS devices are sensitive to voltage spikes and
static-electricity discharges. This can cause many problems when you have
to replace MOS devices, especially complementary-symmetry metal-oxide
semiconductor (CMOS) devices. The level of static electricity on your body
is high enough to destroy the inputs of a CMOS device if you touch its pins
with your fingers."

I have also worked in enviroments where there are dozen's upon
dozens of computers, no surge protection and no failed computers.

Which you think 'proves' what?

I get the feeling that someone here is trying to shift a job lot of surge
protectors on ebay, either that or having a larf.

Think I will go and take a look

Have fun.

 

[David Maynard]

No it isn't otherwise fuses would be made from semiconductors.




I don't wear breast implants, but good luck with the 'op' anyway ;O)




Maybe I should look up 'dope' :OP we are basically talking about very
stable elements, similar to silicon which are 'woven' into the silicon
lattice they will form a very stable structure.

And they're still nice 'stable elements' after the device has failed too,
it just isn't a working device anymore.

 

[Mike Tomlinson]

[snip pointless attempt to reason with half_pint]

David, you're wasting your time arguing with half_wit. He's a regular
poster on uk.legal, where the quality of his "advice" is on a par with
his knowledge of electronics. I have him killfiled everywhere he pops
up.

 

[Mike Tomlinson]

That article is so filled with hysterical hyperbole that I can't tell how
much, if any, of it deserves serious consideration.

It was amongst the first hits I got when I googled for "third world
computer recycling" or similar. The original article I was thinking of
was printed in the Guardian, a liberal UK newspaper. These reports are
more even-handed:

http://www.guardian.co.uk/weekend/story/0,3605,849530,00.html

http://www.guardian.co.uk/international/story/0,3604,725756,00.html

 

[Lem]

And if you are saying that semi conductor devices are
inherently sensitive to current then obviously we would make
fuses out of them. However semiconductors are make out of
silicone which has an extremly high melting point. (we are
basically talking about sand) indeed silicone has replaced
asbestos as a safer heat resistant material.

Are you perhaps confusing silicon with silicone?

 

[Bob Eager]

No it isn't otherwise fuses would be made from semiconductors.

Of course it is...fuses have to cope with switch on surges WITHIUT
blowing.

I don't wear breast implants, but good luck with the 'op' anyway ;O)

Missed the point (sigh)

 

[Johannes H Andersen]

[...]

As said before, voltages also kills semiconductor devices. Why do you
think there are such things as electrostatic bags?

To protect semiconductors from static electricity as opposed to
mains electricity.

LOL! How much do you know about electricity?

 

[half_pint]

"Johannes H Andersen" <[email protected]>
wrote in message

[...]

As said before, voltages also kills semiconductor devices. Why do you
think there are such things as electrostatic bags?

To protect semiconductors from static electricity as opposed to
mains electricity.

LOL! How much do you know about electricity?

I have forgotten far more than you will ever know.

 

[half_pint]

And they're still nice 'stable elements' after the device has failed too,
it just isn't a working device anymore.

No because the metalic contacts have evapourated.
Replace the contacts and it would be fine.

 

[half_pint]

Of course it is...fuses have to cope with switch on surges WITHIUT
blowing.

As do semiconductors.

 

[half_pint]

Are you perhaps confusing silicon with silicone?`

Welll prehaps you are, silicone is based upon silicon
just as many semiconductors are based upon silicon.
Silicone like semiconductors in ICs does not occur naturally
however both are based upon silicon (or similar) and have
very high melting points.

 

[Bob Eager]

Silicone like semiconductors in ICs does not occur naturally
however both are based upon silicon (or similar) and have
very high melting points.

And they are completely different. Silicon is an element, and silicone
is a synthetic polymer compound. Therefore, saying that semiconductors
use silicone is rubbish.