I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?

On Sat, 02 Feb 2019 11:10:18 +0000, Scott
wrote:

I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?

Most small PSU's carry surge protection anyway, or are so cheap and
cheerful that they don't need it.

The major risk to small appliances comes from Aerial inputs or
Telephone connections.

If the unit is easily dismantled, look at the innards. The surge
protection will in all likelyhood be a MOV, choke and fuse.

Providing the cable looks substantial enough, the fuse is of a
reasonable value and the MOV is mounted sensibly, ie away from easily
ignited components, then the unit is going to function as a good multi
way adaptor. Dont expect any sudden failiure of the supplied equipment
if you ditch it though.

A final point, I have found that if you change things electrically,
even turning off things that run 24/7, it seems to invite seemingly
none related problems, So if you get rid, and BBC1 starts showing
repeats................ :-)

AB

"Scott" wrote in message ...

I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?

You will had had thousands of spikes. Every time your 'fridge compressor
starts you'll get a detectable spike. Whether they are of significant
magnitude is the question.

The MOVs in surge suppressors do have a finite capacity for absorbing spike
energy, and at end of life can go s/c so always should have a fuse in line,
but in an extension it presumably is via a fused plug

Andrew

On Sat, 2 Feb 2019 12:53:20 -0000, "Andrew Mawson"
wrote:

"Scott" wrote in message ...

I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?

You will had had thousands of spikes. Every time your 'fridge compressor
starts you'll get a detectable spike. Whether they are of significant
magnitude is the question.

The MOVs in surge suppressors do have a finite capacity for absorbing spike
energy, and at end of life can go s/c so always should have a fuse in line,
but in an extension it presumably is via a fused plug

Andrew

The MOV's are VDR's, and as long as they are not called on to
dissipate more than their rating, they will work forever.

They are simply a Voltage dependent resistor. They have an infinite
lifespan if not overloaded.

The vertical oscillator/ output stage in old valve TV's used them on
the triode feed from the boost rail, specifically to stabilise the
Voltage. These never, ever failed.

There was one more in the frame stage, the thing would be across the
primary of the field output transformer. This handled spikes, lots of
them, 25 per second. They never failed either.

VDR's or MOV's do not simply fill up with spikes and fail in their
twilight years.

They are a Voltage dependent resistor and whereas your 10K is always
10K whether it has one or ten Volts across it, a VDR is what it say's,
"Voltage dependent".


AB



AB

In article ,
Scott writes:
I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?

Metal Oxide surge suppressors are a fire risk.
Seen a couple of socket blocks that would have started
fires if there was something flammable nearby.

They are also almost completely pointless. They only
came about because manufacturers found they could add
a component costing 10-20p, and charge £5 more for the
product.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 02/02/2019 13:16, Archibald Tarquin Blenkinsopp wrote:


The MOV's are VDR's, and as long as they are not called on to
dissipate more than their rating, they will work forever.

But their rating is often for as little as 10 to 100 spikes.


They are simply a Voltage dependent resistor. They have an infinite
lifespan if not overloaded.

That's the key "if not overloaded". Define an overload.


VDR's or MOV's do not simply fill up with spikes and fail in their
twilight years.

MOVs have a capacity to deal with a specified number of spikes (of a
certain energy) before they fail. The problem is often the mechanical
construction of the circuit. When a MOV fails it often blows apart. If
it is mechanically constrained by other components and is still held
physically together and can start sparking.


They are a Voltage dependent resistor and whereas your 10K is always
10K whether it has one or ten Volts across it, a VDR is what it say's,
"Voltage dependent".


But the characteristic is the wrong way around for infinite life.

High value resistance at lower voltages = low power dissipation
Low value resistance at higher volatges = high power dissipation -= bang!


--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On Sat, 2 Feb 2019 14:44:25 +0000, alan_m
wrote:

On 02/02/2019 13:16, Archibald Tarquin Blenkinsopp wrote:


The MOV's are VDR's, and as long as they are not called on to
dissipate more than their rating, they will work forever.

But their rating is often for as little as 10 to 100 spikes.


They are simply a Voltage dependent resistor. They have an infinite
lifespan if not overloaded.

That's the key "if not overloaded". Define an overload.


VDR's or MOV's do not simply fill up with spikes and fail in their
twilight years.

MOVs have a capacity to deal with a specified number of spikes (of a
certain energy) before they fail. The problem is often the mechanical
construction of the circuit. When a MOV fails it often blows apart. If
it is mechanically constrained by other components and is still held
physically together and can start sparking.


They are a Voltage dependent resistor and whereas your 10K is always
10K whether it has one or ten Volts across it, a VDR is what it say's,
"Voltage dependent".


But the characteristic is the wrong way around for infinite life.

High value resistance at lower voltages = low power dissipation
Low value resistance at higher volatges = high power dissipation -= bang!

In a domestic situation, the life would be infinite. Pulse levels of
hundreds of Amps have to flow before a cumulative effect takes place.
By the time cable resistance and plug contact resistance is taken into
account, there just wouldn't be hundreds of Amps available.

I have never seen one obliterated in a domestic environment. They do
get zapped on factories where the wiring is more substantial and noise
levels are high, even so I have yet to see a periodic maintainance
ticket for MOV replacement anywhere.


AB

Don't see why? They can only start to get hot, at which time one hopes the
fuse blows and there you are. If there are some which are not protected,
then I'd not want to use them anyway. I found back in the 70s a little vdr
in the plugs was OK and protected against mode spikes, after all they are
short lived and hence the current they take is not going to be an issue, and
in any case if the over voltage lasted the fuse would once again blow. I do
however like the ones with a filter as well as surge protection as they seem
to stop digital stuff misbehaving due to noise getting in from the mains. I
guess this is increasingly an issue with all these internet over the mains
adaptors which should all be outlawed in my view.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Scott" wrote in message
...
I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?

Yes indeed. The only failure mode, assuming no lightning strikes or similar.
I have encountered is going open circuit due to the wire becoming internally
detached. Far more common are failure of the filters that often are used as
well. In these the capacitors go leaky and heat up making usually magic very
smelly smoke before the fuse pops.
A very dangerous device from many years ago, though I never realised it
till it failed was the pifco rechargeable torch. It had a two pin plug on
one end withed a cover and inside a 'lossless' dropper in the form of a
capacitor, then a tiny circuit that made around 7.5v which charged up some
nicads. Fine until one day the capacitor went down. put huge mains on the
semiconductor and the batteries and the whole room filled with smoke and
gunge started to leak from the torch dripping onto the carpet.
Luckily I way in at the time, but oh, the smell was in my nose for days.
the torch had partially melted.
No no fuse just a resistor across the pins to discharge any charge left
when you unplugged it.
I have also found that many shops are being duped into stocking stuff that
has CE on it but is rubbish. Take shaver adaptors with no fuse at all, or
wall warts with no fusible link, or ones secured together by screws as short
as those used for cassette tapes.
All very dangerous. Then there was the Eaton PSU from Maplin that dropped
all of 1 foot onto a floor and the two halves came apparently seemingly
being glued in two little places, exposing the mains terminals of the
transformer.
I could go on, but really I think worrying about an older adaptor is not
what you should be worrying about its the new stuff you need to watch for.
My old torch had lasted over 10 years before it died, but many of the
current wall warts seem to be good if they last three years.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Archibald Tarquin Blenkinsopp" wrote in
message ...
On Sat, 2 Feb 2019 12:53:20 -0000, "Andrew Mawson"
wrote:

"Scott" wrote in message
. ..

I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?

You will had had thousands of spikes. Every time your 'fridge compressor
starts you'll get a detectable spike. Whether they are of significant
magnitude is the question.

The MOVs in surge suppressors do have a finite capacity for absorbing
spike
energy, and at end of life can go s/c so always should have a fuse in
line,
but in an extension it presumably is via a fused plug

Andrew

The MOV's are VDR's, and as long as they are not called on to
dissipate more than their rating, they will work forever.

They are simply a Voltage dependent resistor. They have an infinite
lifespan if not overloaded.

The vertical oscillator/ output stage in old valve TV's used them on
the triode feed from the boost rail, specifically to stabilise the
Voltage. These never, ever failed.

There was one more in the frame stage, the thing would be across the
primary of the field output transformer. This handled spikes, lots of
them, 25 per second. They never failed either.

VDR's or MOV's do not simply fill up with spikes and fail in their
twilight years.

They are a Voltage dependent resistor and whereas your 10K is always
10K whether it has one or ten Volts across it, a VDR is what it say's,
"Voltage dependent".


AB



AB

On Sun, 3 Feb 2019 08:50:02 -0000, "Brian Gaff"
wrote:

Yes indeed. The only failure mode, assuming no lightning strikes or similar.
I have encountered is going open circuit due to the wire becoming internally
detached. Far more common are failure of the filters that often are used as
well. In these the capacitors go leaky and heat up making usually magic very
smelly smoke before the fuse pops.
A very dangerous device from many years ago, though I never realised it
till it failed was the pifco rechargeable torch. It had a two pin plug on
one end withed a cover and inside a 'lossless' dropper in the form of a
capacitor

There was a Thorn mains portable TV that used this principle.
Brilliant when it worked, it dropped the Volts nicely and enabled the
TV to fit into a very small cabinet that was fairly portable.
When the cap shorted, the valves and no doubt CRT heaters would
compete with the Xmas tree for a "short" while :-)

Nearly everything I buy from Ebay has a CE mark. I do get the
impression that these are just stamped on as part of the manufacturing
process.

At least they seem to have seen the limit with my recently purchased
dimmer. No tools needed for disassembly, a circuit bare of any frills
like suppression, in fact it could be a direct copy from a textbook.

At least LW wireless is out of fashion now, it would play havoc with
the shipping forecast.

The CE mark has become a "CCCe" mark.

"Chinese Copied Ce" perhaps ?


AB

On 03/02/2019 10:59, Archibald Tarquin Blenkinsopp wrote:


The CE mark has become a "CCCe" mark.

"Chinese Copied Ce" perhaps ?



I think you might be confusing the CE mark with the CE mark where the
former is a confirmation of European conformity and the other means
Chinese Export. Wikipedia has an article on the difference between the
two: I believe there is something like a one pixel alteration between
the symbols so technically they are different.

Nick

Nick Odell wrote:

On 03/02/2019 10:59, Archibald Tarquin Blenkinsopp wrote:


The CE mark has become a "CCCe" mark.

"Chinese Copied Ce" perhaps ?



I think you might be confusing the CE mark with the CE mark where the
former is a confirmation of European conformity and the other means
Chinese Export. Wikipedia has an article on the difference between the
two: I believe there is something like a one pixel alteration between
the symbols so technically they are different.

Nick

I think that is an urban myth. Tne CE mark from China is still a claim
to meet EU standards, whatever the font. If a lot of firms use it
dishonestly it loses all value, but the context of use is such that
conformity to EU standards is being claimed even if the graphic
implementation is sloppy. And they use it because the CE mark is
compulsory and can easily be checked, while actual compliance checking
is harder.
--

Roger Hayter

On Sun, 3 Feb 2019 11:16:36 +0000, Nick Odell
wrote:

On 03/02/2019 10:59, Archibald Tarquin Blenkinsopp wrote:


The CE mark has become a "CCCe" mark.

"Chinese Copied Ce" perhaps ?



I think you might be confusing the CE mark with the CE mark where the
former is a confirmation of European conformity and the other means
Chinese Export. Wikipedia has an article on the difference between the
two: I believe there is something like a one pixel alteration between
the symbols so technically they are different.

Nick

Thank you! I wasn't aware of the difference, I assumed that the stuff
was being traded as something produced to EU standards.

That explains a lot.

On the plus point it seems that we have "control" already, we are
still in the EU and freely importing junk :-)


AB

In article ,
Archibald Tarquin Blenkinsopp wrote:
On Sun, 3 Feb 2019 08:50:02 -0000, "Brian Gaff"
wrote:

Yes indeed. The only failure mode, assuming no lightning strikes or similar.
I have encountered is going open circuit due to the wire becoming internally
detached. Far more common are failure of the filters that often are used as
well. In these the capacitors go leaky and heat up making usually magic very
smelly smoke before the fuse pops.
A very dangerous device from many years ago, though I never realised it
till it failed was the pifco rechargeable torch. It had a two pin plug on
one end withed a cover and inside a 'lossless' dropper in the form of a
capacitor

There was a Thorn mains portable TV that used this principle.
Brilliant when it worked, it dropped the Volts nicely and enabled the
TV to fit into a very small cabinet that was fairly portable.
When the cap shorted, the valves and no doubt CRT heaters would
compete with the Xmas tree for a "short" while :-)

Nearly everything I buy from Ebay has a CE mark. I do get the
impression that these are just stamped on as part of the manufacturing
process.

At least they seem to have seen the limit with my recently purchased
dimmer. No tools needed for disassembly, a circuit bare of any frills
like suppression, in fact it could be a direct copy from a textbook.

At least LW wireless is out of fashion now, it would play havoc with
the shipping forecast.

The CE mark has become a "CCCe" mark.

"Chinese Copied Ce" perhaps ?

The Ce bit means "Chinese Export".

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On Sun, 03 Feb 2019 11:51:17 +0000 (GMT), charles
wrote:

In article ,
Archibald Tarquin Blenkinsopp wrote:
On Sun, 3 Feb 2019 08:50:02 -0000, "Brian Gaff"
wrote:


The CE mark has become a "CCCe" mark.

"Chinese Copied Ce" perhaps ?

The Ce bit means "Chinese Export".

So I gather!

A bit of enlightenment I have Mr Odell to thank for.

Just when you think you know everything, someone comes along to tinkle
on One's bonfire :-)

AB

"Brian Gaff" wrote in message
...
Yes indeed. The only failure mode, assuming no lightning strikes or
similar. I have encountered is going open circuit due to the wire becoming
internally detached. Far more common are failure of the filters that often
are used as well. In these the capacitors go leaky and heat up making
usually magic very smelly smoke before the fuse pops.
A very dangerous device from many years ago, though I never realised it
till it failed was the pifco rechargeable torch. It had a two pin plug on
one end withed a cover and inside a 'lossless' dropper in the form of a
capacitor, then a tiny circuit that made around 7.5v which charged up some
nicads. Fine until one day the capacitor went down. put huge mains on the
semiconductor and the batteries and the whole room filled with smoke and
gunge started to leak from the torch dripping onto the carpet.
Luckily I way in at the time, but oh, the smell was in my nose for days.
the torch had partially melted.
No no fuse just a resistor across the pins to discharge any charge left
when you unplugged it.
I have also found that many shops are being duped into stocking stuff
that has CE on it but is rubbish. Take shaver adaptors with no fuse at
all, or wall warts with no fusible link, or ones secured together by
screws as short as those used for cassette tapes.
All very dangerous. Then there was the Eaton PSU from Maplin that dropped
all of 1 foot onto a floor and the two halves came apparently seemingly
being glued in two little places, exposing the mains terminals of the
transformer.
I could go on, but really I think worrying about an older adaptor is not
what you should be worrying about its the new stuff you need to watch for.
My old torch had lasted over 10 years before it died, but many of the
current wall warts seem to be good if they last three years.

Never had a wall wart fail and I've got heaps of
them and leave them plugged in all the time too.

"Archibald Tarquin Blenkinsopp" wrote in
message ...
On Sat, 2 Feb 2019 12:53:20 -0000, "Andrew Mawson"
wrote:

"Scott" wrote in message
...

I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?

You will had had thousands of spikes. Every time your 'fridge compressor
starts you'll get a detectable spike. Whether they are of significant
magnitude is the question.

The MOVs in surge suppressors do have a finite capacity for absorbing
spike
energy, and at end of life can go s/c so always should have a fuse in
line,
but in an extension it presumably is via a fused plug

Andrew

The MOV's are VDR's, and as long as they are not called on to
dissipate more than their rating, they will work forever.

They are simply a Voltage dependent resistor. They have an infinite
lifespan if not overloaded.

The vertical oscillator/ output stage in old valve TV's used them on
the triode feed from the boost rail, specifically to stabilise the
Voltage. These never, ever failed.

There was one more in the frame stage, the thing would be across the
primary of the field output transformer. This handled spikes, lots of
them, 25 per second. They never failed either.

VDR's or MOV's do not simply fill up with spikes and fail in their
twilight years.

They are a Voltage dependent resistor and whereas your 10K is always
10K whether it has one or ten Volts across it, a VDR is what it say's,
"Voltage dependent".


AB



AB

On Sunday, 3 February 2019 08:50:05 UTC, Brian Gaff wrote:

No no fuse just a resistor across the pins to discharge any charge left
when you unplugged it.
It is perfectly possible for a wall-wart containing a mains transformer
to have no fuse but still comply with the relevant safety standards.
For this to be the case the transformer itself must be rated to have
an acceptable temperature rise when its output is shorted.

John

On Sunday, 3 February 2019 11:00:03 UTC, Archibald Tarquin Blenkinsopp wrote:

The CE mark has become a "CCCe" mark.

"Chinese Copied Ce" perhaps ?

Not quite. It is the certification required for selling products in China.
The standards are very similar to CE however, with just enough difference
to add some friction to trade.

www.china-certification.com/en/

John

On 04/02/2019 15:05, wrote:
On Sunday, 3 February 2019 11:00:03 UTC, Archibald Tarquin Blenkinsopp wrote:

The CE mark has become a "CCCe" mark.

"Chinese Copied Ce" perhaps ?

Not quite. It is the certification required for selling products in China.
The standards are very similar to CE however, with just enough difference
to add some friction to trade.

www.china-certification.com/en/

John


It's very clear that many items on Ebay from China costing a couple of
quid (incl postage) and have a CE mark have never been near any
certification process.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On Monday, 4 February 2019 18:04:34 UTC, alan_m wrote:
On 04/02/2019 15:05, wrote:
On Sunday, 3 February 2019 11:00:03 UTC, Archibald Tarquin Blenkinsopp wrote:

The CE mark has become a "CCCe" mark.

"Chinese Copied Ce" perhaps ?

Not quite. It is the certification required for selling products in China.
The standards are very similar to CE however, with just enough difference
to add some friction to trade.

www.china-certification.com/en/

John


It's very clear that many items on Ebay from China costing a couple of
quid (incl postage) and have a CE mark have never been near any
certification process.

True enough. However, the Chinese are very strict about certification
of products exported from Europe to China, hence the requirement for
CCC marking on such goods. In other words, you would not be allowed
to re-import many Chinese electronic products sold in Europe back into
China.

I have also seen Chinese power supplies sold by a reputable UK supplier
where the internal design changed substantially from one batch to the
next without any evidence of re-certification. There was no change in
part number.

One automotive USB charger I looked at had conducted emissions more than
20dB above the allowed limit. It had component footprints for filtering
capacitors on the pcb but they had not actually been fitted. This was
bought from a major UK supermarket. The first batch of samples might
well have been certified and then subsequent production "cost reduced".
The savings would have been one or two pence in a product sold for
around £10 at the time.

John

On 02/02/2019 11:10, Scott wrote:
I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?


That fire risk was related to the story of surge supressors being used
on a boat, where electrics could be done different - earth found
floating halfway between live and neutral, that would place a constant
voltage across the device, and a constant source of heat (and risk).

Inland it is not a worry - heat only occurs when a surge is absorbed.


--
Adrian C

On Tue, 5 Feb 2019 11:30:14 +0000, Adrian Caspersz
wrote:

On 02/02/2019 11:10, Scott wrote:
I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?


That fire risk was related to the story of surge supressors being used
on a boat, where electrics could be done different - earth found
floating halfway between live and neutral, that would place a constant
voltage across the device, and a constant source of heat (and risk).

Inland it is not a worry - heat only occurs when a surge is absorbed.

Okay, thanks. This reassures me. The storyline was indeed on ship. I
didn't know about the earthing situation there.

I remember as a child being told that ship's equipment never worked on
shore because of superstition. However, I fairly soon found out it
was not because of superstition but because if was DC.

On Tuesday, 5 February 2019 11:30:17 UTC, Adrian Caspersz wrote:
On 02/02/2019 11:10, Scott wrote:
I have a surge protection extension in the kitchen, used for TV,
decoder box and radio. It is very old. I read here recently that
these devices may present a fire risk. To my knowledge we have never
had any surges or spikes. Should I be ditching this device?


That fire risk was related to the story of surge supressors being used
on a boat, where electrics could be done different - earth found
floating halfway between live and neutral, that would place a constant
voltage across the device, and a constant source of heat (and risk).

Inland it is not a worry - heat only occurs when a surge is absorbed.

bzzzt.

On Tuesday, 5 February 2019 11:30:17 UTC, Adrian Caspersz wrote:

That fire risk was related to the story of surge supressors being used
on a boat, where electrics could be done different - earth found
floating halfway between live and neutral, that would place a constant
voltage across the device, and a constant source of heat (and risk).

Inland it is not a worry - heat only occurs when a surge is absorbed.

Why would having the earth floating between live and neutral be worse than
the usual "inland" situation where one or other of the common mode surge
suppressors will usually have the full mains voltage across it?
It should make no difference at all for suppressors between live and neutral.
John

On 05/02/2019 14:57, wrote:
On Tuesday, 5 February 2019 11:30:17 UTC, Adrian Caspersz wrote:

That fire risk was related to the story of surge supressors being used
on a boat, where electrics could be done different - earth found
floating halfway between live and neutral, that would place a constant
voltage across the device, and a constant source of heat (and risk).

Inland it is not a worry - heat only occurs when a surge is absorbed.

Why would having the earth floating between live and neutral be worse than
the usual "inland" situation where one or other of the common mode surge
suppressors will usually have the full mains voltage across it?
It should make no difference at all for suppressors between live and neutral.
John


Some types are wired delta, and the working voltage rating of the part
connected neutral to ground *might* be low (expected inland, but not on
a boat)

https://www.littelfuse.com/~/media/e...ation_note.pdf

Perhaps. I don't pretend to understand US coastguard paranoia,
particularity where I can't find an authoritative statement exactly why
they must have the precaution in place. So the above is mine. YMMV.

Meanwhile, I'll offer US travellers a conversion service for their
onboard electrical devices. $100 a snip ;-

--
Adrian C