When the surge protection LED on a power strip won't light, is it likely to be a blown var...

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When the surge protection LED on a power strip won't light, is it likely to
be a blown varistor?

My *&^#$(*&@ Belkin unit (that I paid way too much for) isn't in protection
mode anymore, and I don't want to have to send it away for weeks to get a
repair.

Thanks

-Markus



Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?


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Best speak to your local dealer , I cant remember the last time I heard
of one being damaged , all the gear is ok ?

Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?


Seems to be

Markus

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Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?


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  Indicator does not report what you assumed.  For example, notice that
MOVs can even be removed and indicator lamps declares a protector as
still good:
   http://www.zerosurge.com/HTML/movs.html

  MOVs that fail so catastrophically as to cause a light change mean
the design was grossly and unacceptablely undersized.  Effective
protectors degrade as defined by numbers in manufacturer datasheets -
do not vaporize and do not cause that fuse to open.  But Belkin is not
selling effective protection.

  How to identify an ineffective protector:  1) no dedicated earthing
wire and 2) manufacturer avoids all discussion about earthing.
Meanwhile look at its numerical specifications (and not the subjective
propaganda). Where is each transient type listed with numbers that
define protection?  No such numbers exist because protectors without
earthing hope you don't learn what is necessary for effective
protection.

  They will not even define what that lamp reports so that other will
promote myths based upon no facts.  Those scary pictures with all MOVs
removed should start you asking embarrassing questions - such as how do
protectors degrade and why is a vaporized protector not effective
protection.


Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?



w_tom wrote:
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The best information I have seen on surge protection is at
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
- w_tom provided the link to this guide
- the title is "How to protect your house and its contents from
lightning: IEEE guide for surge protection of equipment connected to AC
power and communication circuits"
- it was published by the IEEE in 2005
- the IEEE is the dominant organization of electrical and electronic
engineers in the US

A second guide is
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf
- this is the "NIST recommended practice guide: Surges Happen!: how to
protect the appliances in your home"
- it is published by the National Institute of Standards and
Technology, the US government agency formerly called the National
Bureau of Standards
- it was published in 2001

Both guides were intended for wide distribution to the general public
to explain surges and how to protect against them. The IEEE guide was
targeted at people who have some (not much) technical background.

Both say plug-in surge suppressors are effective. They protect
primarily by CLAMPING all wires (including phone, ...) to a common
ground at the surge suppressor, NOT EARTHING.

One (or both?) of the guides show that the protected load may, or may
not, be disconnected if a MOV is disconnected. There are advantages
both ways and one should decide accordingly, What indicator lights mean
varies with manufacturer.

bud--


Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?



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The LED indicator shows that a Thermal Fuse (which is wired in series with
the MOV) Has failed.
This Thermal fuse is there to protect against the MOV becoming Leaky
(Degraded) and breaking down at the rated Voltage (240V) - when this happens
the MOV dissipates way more power (i.e. over a couple of watts) than it is
designed to and becomes a Fire hazard.
in other words the Thermal fuse failing indicates that the MOV has failed.

MOV Failure is normal - it happens - hopefully it holds on long enough to
provide some sort of protection - usually it just joins the list of failed
components following a Direct or near strike.

This is why charlatans* like the Links w_tom has given can show pictures of
surge arrestors with the MOVs removed and the 'Protection working' LED still
lit - because the LED does not show the presence of the MOV but rather that
the Thermal fuse that stops the MOV causing a fire is intact.

btw it is safer to ignore most Ravings from w_tom who although he seems
strangely attracted to the subject of Surge arrestors, seems to know almost
nothing about the subject (as demonstrated by his lack of understanding of
how/why the 'Protection working' indicator functions). I find it Ironic that
w_tom has linked to a site that points out the Failings of MOVs when he has
spent so long defending them ;-) It is also Interesting to note that where
w_tom has spent so long bagging out anything other than 'whole house
protection' he is now linking to the site of a manufacturer who makes plug
in protection.

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Unless you are in an area highly prone to Surges with little multiple mains
earthing (i.e. a Rural area) then MOV based protection typically provides no
real extra protection than the MEN Mains distribution system already offers.

The Surge arrestor industry is based on Hype and Hysteria for example you
will note that Surge arrestors are rated for 8/20 uS whereas a real
Lightning strike (single stroke) Lasts typically 4 or 5 times this long and
usually consists of several Strokes - no MOV built can withstand a Direct or
Near strike without frying itself and allowing damage to the equipment
supposedly protected by it.

a Surge arrestor should be considered line of last resort protection only
and should not replace common sense such as unplugging valuable equipment
when a storm threatens - I have seen to many computer and Data comms
installations damaged by Lightning (many of which had 'surge arrestors') to
give equipment in a near or direct strike a snowballs chance in hell of
surviving.
Ironically most Lightning damage that I have seen to Computer installations
comes not from the M.E.N AC Mains - which contrary to popular belief is in
fact extremely well earthed but through phone and data lines and Radio
aerials this is for two reasons:
 1) Because the Multiple Earthed Neutral System provides the best Earth you
are likely to get without  an Extensive (and expensive) Earthing system
covering half an Acre or more.
2) Because Under ground phones lines are in fact very susceptible to Earth
Potential Rise in the event of a Lightning strike and are actually more
prone to Lightning damage being buried.

So the moral of the story is unplug your Modem from the phone line when it
is not in use and unplug from the AC mains if a Lightning storm is
approaching.

* I have called folk who run the page w_tom has linked to "charlatans" based
on there mis-representation of the efficacy of the 'Protection working'
LED - This is patently dishonest! however scanning their website they don't
seem quite as retarded as most of the surge arrestor manufacturers ......

Regards
Richard Freeman



Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?


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  If Richard Freeman had consulted MOV manufacturer datasheets,  he
would learn that MOV failure by vaporizing is completely unacceptable.
Vaporizaton is not even listed in those charts for life expectancy.
MOVs fail by degrading.  Manufacturers provide charts with
relationships of pulse times, current, and number of pulses.  When an
MOV's  Vb voltage changes 10%, then an MOV has degraded excessively.
Notice after so many transients, the MOV only degrades so much as to
require replacement.  Vaporization does not occur.  It means Richard
first consults datasheets before he somehow knows.  He did not.

  We do what Richard Freeman cannot.  Using numbers from an MOV
manufacturer datasheet, a 240 volt MOV has a curve that ends at 900
volts for highest currents.  Currents well beyond those charts mean
vaporization - possible fire.  We know from charts that this MOV will
safely shunt up to 5000 amps.  What happens when a surge is a typical
10,000 or 20,000 amps?  MOV voltage rises somewhere well above 900
volts.  IOW appliance is exposed to well over 900 volts because MOV was
grossly undersized - and also vaporized.  Richard called that effective
protection.

  If that MOV was properly sized, then voltage would never rise that
high and MOV would not vaporize.  But then this post uses numbers from
manufacturer datasheets; not rumors that so often promote grossly
undersized protectors.

  MOV protectors that vaporize (and change that indicator lamp) are
grossly undersized.  After so many fires, protectors now have thermal
fuses as a final safety device to disconnect the MOV.  Only disconnects
the MOV.  The appliance is left connected and exposed to the surge.
Thermal fuse does not disconnect an adjacent appliance.   What kind of
protection is that?  Grossly undersized and ineffective.  But that MOV
vaporization does get the naive to recommend and buy more grossly
undersized protectors.  Notice what Richard Freeman has just
recommended.

   A surge too small to overwhelm an adjacent computer can vaporize a
grossly undersized protector.  Then the naive declares, "My protector
sacrificed itself to save my computer."  In reality, the computer saved
itself.   But the naive will recommend that grossly undersized and
overpriced protector because its MOV vaporized - potentially could have
created a house fire.  Where does that be an honest recommendation?

  Reference to  www.zerosurge.com  web site (obviously) was not a
recommendation of their products.  Zerosurge, as do others,
demonstrates why grossly undersized protectors can be dangerous:
 http://www.hanford.gov/rl/?page55%6&parent55%4
 http://www.westwhitelandfire.com/Articles/Surge%20Protectors.pdf
 http://www.ddxg.net/old/surge_protectors.htm

  That thermal fuse is a last backup layer of protection.  Why would
you buy a protector so grossly undersized as to routinely depend on
that thermal fuse (backup protection)? Richard Freeman says protection
from a backup protection function is normal.  View the scary pictures
to appreciate why Richard Freeman would disparage this poster rather
than post numbers from datasheets.


Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?



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I think you are both missing the point re MOV's. Considering most
equipment these days uses SMPS with MOV built in, the equipment itself
can usually survive minor surges (ie, like spikes from the washing
machine solenoids etc), however I think you will find the common
misconception is that a MOV wil protect you from a lightning strike,
and I think thats what most people beleive.

So what you should tell the OP is that if he wants real surge
protection from old mate crashing his car into power pole and 3.3kv
falling onto 110/220v lines, then go buy a commercial online UPS with
a good isolation spec.

If the OP wants lighting protection, then follow Freemans advice and
pull the plug when a storm is coming, because I can assure the OP will
not want to pay for real lightning surge protection.

Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?


  Once MOVs were installed in appliances.  For example Apple II
contained MOVs.  No longer.  MOVs were too close to transistors, too
far from earth, and too undersized.

  Electronic appliances contain internal protection which is why minor
transients are irrelevant even to dimmer switches and smoke detectors.
But a major transient such as lightning may overwhelm internal
appliance protection.  So we eliminate such transients where utilities
enter the building; less than 10 foot to earth.  Effective 'whole
house' surge protection so that protection inside appliances is not
overwhelmed.

  Disconnecting a plug is too unreliable.  Humans are not available
every minute of every year to pull the plug - far too unreliable.  Wall
receptacles have limited number of dsconnections.   Meanwhile a 'whole
house' protector concept has been providing effective protection even
to telephone COs (switching computers) for longer than any reader has
existed. Technology is that well proven and that standard where direct
lightning strikes cause no damage.   Does a telco, connected to
overhead wires everywhere in town, disconnect their $multi-million
computer to protect it from lightning?  Of course not.  How often are
you without telephone service for four days because lightning destroyed
that computer? Never.   'Whole house' type protection means telephones
work without damage during every thunderstorm.  Effective protection is
that well proven.  Earthing before transients can enter the building.

  Protectors sold for less than $50 in Lowes and Home Depot will
provide minimally sufficient lightning protection - and remain
functional after that direct strike - in direct contradiction to what
The Real Andy has posted..

The Real Andy wrote:
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Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?




Look I do not reply directly to w_tom nowadays as he/she/it is so full of
crap that he/she/it makes an unflushed public lavatory look pristine.
however if someone makes the mistake of giving w_tom a reply I will find it
necesary to insert corrections.
So corrections to w_toms ravings below....

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As per usual when w_tom has lost the argument he starts misquoting my post
....
w_toms link talked about vaporised MOVs - I talked about degrading, then
burning MOVs different kettle of fish entirely.....

- ironically this is kind of also what w_tom is talking about (however since
he is completely ignorant of the subject w_tom does not realise this)

- it all comes down to the definition of the term "degradation" the IAEI
however do have an article on the subject at
http://www.iaei.org/subscriber/magazine/04_b/04_b_brown.htm

- let me quote the pertinent sentences :

 "When MOVs degrade they become more conductive after they have been
stressed by either continuous current or surge current."

and

"The degradation manifests itself as an increase in idle current at the
maximum normal operating voltage in the system. Excessive idle current
during normal, steady-state operation will cause heating in the varistor.
Because the varistor has a negative temperature coefficient, the current
will increase as the varistor becomes hotter. Thermal runaway may occur,
with consequent failure of the varistor."

What this means is that a Degraded MOV is going to Start conducting current,
and as those of us who know basic physics will realise this means that the
MOV will heat up and ultimately become a Fire hazard.

This BTW is what happened to Markus's surge arrestor the MOV would have
degraded then the Thermal fuse would have tripped.

To stop the surge arrestor becoming a fire hazard they typically have a
Thermal fuse inside which will disconnect the MOV when it heats up.
In order to let the user know that the has happened the manufacturer does
one of two things:
1) wire a light across the MOV so that when the Thermal fuse is intact the
Light is on - as a 'protection working' indicator
2) wire a light across the thermal fuse so when the fuse goes open the light
comes on and warns the user that the surge arrestor needs to be replaced

If w_tom had the slightest clue what he was talking about he would have
realised this.

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I have to admit though that I have seen plenty of vapourised MOVs following
Lightning strikes - maybe w_tom could suggest a MOV that would not suffer
serious damage in a Lightning strike (I know he used to talk about 1KJ
MOVs) - he does not. because he knows he cannot. They are all prone to
failure in a near or direct strike not surprisng really with a typical
Lightning strike


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I note that w_tom has not referenced the Data-sheet - he must be making this
up again!
altough I note that he fails to discuss the slow response times of MOVs.
And of course he also fails to mention that for all MOVs the voltage across
them rises as the current through them increases - this is not linear as
with a resistor but MOVs are not perfect clamps either

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More evidence that w_tom knows he has lost the argument so again he
misquotes me I have never ever claimed that MOVs were adequate or effective
protection! - quite the contrary I have always claimed that they should be
considered ' line of last resort' protection only - ie better than nothing
but in the scheme of things unlikely to provide better protection than
nothing.

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Ah well this is merest fantasy when you bear in mind that a typical strike
is several strokes  lasting 20/100uS (20uS rise/peak and 100uS follow on) in
the order 30,000-50,000 Amps per stroke although up to 150,000 Amps is not
uncommon and 500,000,000 to 1,000,000,000 Joules typically per stroke it is
difficult to imagine a 20,000 Amp at 1,000 Joule MOV Rated to last 8/20uS
being worth considering.....


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or degraded and trying to clamp AC mains unrealistically low ..... In fact
all MOVs will ultimately degrade I do not care how big they are it is in the
nature of a MOV to degrade!

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At Last !!!!
w_tom gets something right !!!!!!
(but only because I pointed it out and it obvious from the rest of his
claims he does not understand this point)

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Yes Please!
 Note what Richard Freeman has/has not recommended .... Once again w_tom is
clutching at straws I did not recommend MOV based protection as anything
other than LOLR

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Routinely ????? the thermal fuse trips once and that is that!
 next trip will lead us to the deep fried stench of computer equipment.....

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Read the misrepresentations from a BS site to understand why I believe the
surge protection industry is full of crap! I disparage w_tom because he is
full of crap and pushes a naive and dangerous view that MOVs protect against
Lightning - they do not protect adequately against near or direct strikes!!!

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Well actually that pretty well is the point I am making - that a MOV does
not protect against Lightning Strikes. I
 have seen way to much Lightning damage to suffer from that belief.

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Actually a one to one isolation Transformer - particularly a Toroid with a
Circuit breaker does a pretty good Job in this regard and protects against
most other spikes and surges as well ....

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Damn right !

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Especially not the extensive Earth system required for that - and even then
Lightning damage can and will occur to even the best protected
installations - I have seen damage in Telephone exchanges (and they are as
well protected as you can get) and Radio (and TV) Transmitters.

Regards
Richard Freeman



Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?


 Because effective protection is so easily implemented, then no reason
to disconnect anything for protection.  That fact has been demonstrated
by every telephone switching station for generations and in direct
contradiction to what Richard Freeman has posted.  Will effective
residential protection be 100% perfect?  Of course not.  But when
destructive surges occur typically once every eight years and since
minimally effective protection eliminates well over 90% of the threat,
then disconnecting for protection is clearly a misguided
recommendation.

  Richard provides a good IAEI article on MOVs - the fundamental
component in most surge protectors.  In direct contradiction to
Richard's claim, that article defines degadation and vaporization
separately.  Three failure modes are defined:
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 Failure (1) becomes failure (2) according to the Note.  Failure (2) is
MOV vaporizing (either partially or wholly).  Failure (1) leads to
failure (2) and vaporization.  Neither failure is acceptable.   A
failure so problematic as to be demonstrated by numerous scary pictures
from multiple sources (posted previously), and so unacceptable that
industry standards were created to avoid resulting fires (ie UL1449).

  In direct contradiction to Richard Freeman, failure (1) and (2) are
unacceptable, are conditions beyond what the MOV manufacturer intended,
and are a threat to human life.  A danger so unacceptable that a
thermal fuse is now installed as a last layer of human protection.
Failure (1) and (2) also means an adjacent appliance is left to protect
itself from well over 900 volts as an undersized MOV vaporizes.

  Failure (3) is degradation - a slow change of MOV parameters.
Degradation is definitely not as Richard misrepresents.  Richard
intentionally misrepresents his own citation by changing the definition
of degradation.  He speculates:
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  Richard defined vaporization as degradation.  This will be
demonstrated as wrong five times over.  However, you may skip to the
Fourth quote to appreciate how wrong Richard is.  First, manufacturer's
datasheet  (and multiple following quotes) defines degradation
differently:
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  Second, a degraded MOV is not vaporized.  Degradation means a change
of threshold or let-through voltage.  MOV remains functional.
Richard's own citation says same:
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  The MOV remains functional with grain size changed. This means a
still functonal MOV has a changed voltage (Vb).  MOV defined by IAEI
remains functional in total agreement with quote from MOV manufacturer
datasheet.  After 10,000 impulses, its Vb voltage changes 10% -
degraded but still functional.  No vaporization because vaporization is
not an acceptable failure mode - in direct contradiction to what
Richard Freeman posts.

  Third, requoting exactly what Richard quoted from the IEAI article:
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  Again correct. MOV only degraded; its Vb voltage changed 10%.   Why a
measurable 10% voltage change?  Because a degraded MOV does not
vaporize and may be tested with more impulses.

  Fourth, another quote from Richard Freeman's own IAEI article
(entitled Metal Oxide Varistor Degradation):
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  This time, Richard's own article bluntly contradicts his
speculations.  No wonder he must post insults - hoping you don't read
the IEAI article that, instead, confirms posts from w_tom.

   Fifth, and Richard Freeman was that much in error: consult an
application note from another MOV manufacturer:  Littelfuse and their
application note  AN9772:
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  Why do grossly undersized power strips fail the same way?  Need I
repeat the obvious: grossly undersized?  That short circuit or
resulting open circuit occurs "when subjected to surges beyond their
peak ... ratings".  This happens to grossly undersized (ineffective)
plug-in protectors.  Again, MOV operated well beyond its "peak
current/energy ratings."

  Unfortunately one here learned only from what retail store shelves -
where grossly undersized protectors are sold.  When confronted by
numbers from manufacturer datasheets, quotes from IAEI article, or from
application note from an MOV manufacturer, then Richard must attack
(insult) the messenger.  Richard will not reply directly.  He did not
learn the technology.  Therefore he must insult w_tom in a hope that
lurkers will neither learn the technology nor read his own cited IEAI
article at:
 http://www.iaei.org/subscriber/magazine/04_b/04_b_brown.htm

  Apparently he has never read an MOV datasheet and therefore cannot
challenge the numbers.  So Richard responds with another insult:
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 Acceptable failure mode for MOVs is degradation - change of grain size
and therefore 10% change of voltage.  MOV remains functional, only
degrades.  Catastrophic failure - vaporization - is a totally
unacceptable failure mode.  Power strip protectors, often grossly
undersized, fail catastrophically.  Undersized MOV fails by vaporizing
- not by acceptable degradation.  All this in direct contradiction to
what Richard Freeman posts and, ironically, in complete agreement with
Richard's IAEI article.  Richard should have read the article before
posting insults of w_tom.

Richard Freeman wrote:
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Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?



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Evidence that w_tom knows nothing about Telecommunications and has never
worked in the industry.

I on the other hand have worked in Data communications for over 20 Years and
can assure you that contrary to w_toms fantasy world - In the real World
damage can and does occur to equipment in Telephone exchanges - I have seen
equipment damaged by Lightning located in Telephone exchanges and this is
despite some of the best and most extensive protection available. Likewise
w_tom also likes holding up Radio Transmitters as another fine example of
'Lightning proof installations' however again Radio and TV Transmitters are
also damaged by Lightning.

Ironically MOVs are not considered anywhere near reliable enough or Fast
enough for use in Telecommunications equipment and Gas Discharge Arrestors
and Transzorbs (Semi-conductor spike supression - look it up) are usually
used in combination with a High(ish) Series impedance to the Line - but then
w_tom would have difficulty understanding this Technique and this is not
applicable for use in Low impedance systems such as AC mains distribution.

bottom line is that anyone who makes claims of 100% protection from
Lightning is merely demonstrating their total complete and absolute
ignorance of the subject

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Nope disconnecting for Protection is the only 100% effective protection


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As per usual when w_tom has lost the Argument and is making himself look a
fool he resorts to Lies and misquoting my posts once more for the dummies
let me repeat myself :
"w_toms link talked about vaporised MOVs - I talked about degrading, then
burning MOVs different kettle of fish entirely....."

Note that I said that I Talked about degrading (then burning) MOVs - I did
not say if the article did or not and in point of fact I have NOT even
stated that MOVs do not vaporise - I have seen them with the living $#!|
blown out of them (effectively vaporised) however the most common Failure
mode for a MOV is that it Degrades and goes into Thermal runaway.

Further more Despite w_toms claims the Article in question does not use the
term vaporisation (or even the American ? spelling Vaporization) It talks
about the usual Failure modes (many of which lead to self incineration ....)
and I quote "The significant MOV failure mechanisms include: electrical
puncture, thermal cracking, and thermal runaway" So once again w_tom lies
and misquotes an Article.

In actual fact I pointed to the article for a definition of the term
degraded which w_tom was bandying about in a way that made it obvious he did
not understand the term - degradation ultimately results in the Destruction
of the MOV. w_tom pretends it is some kind of loss of effectiveness of the
MOV only.



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w_tom adding his own words in an effort to win an argument that did not
exist until w_tom invented it this is not a quote from the article this is
w_tom paraphrasing - the MOV burns at 1 leading to 2 - however he has also
missed the MOV degades definition.

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once again w_tom misquotes I never stated that this was acceptable - this is
just w_toms fruitcake fantasy and In fact I pointed out that MOVs required
thermal Fuses to protect against these Failures - w_tom pretended that MOVs
do not fail in this mode.

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w_tom talks glibly about undersized MOVs - problem is he cannot name any
that will withstand a near or direct strike - for the simple reason that
there are none.

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It is obvious that w_tom has not taken the Time to read the link I
referenced - as it was this link that defined Degradation not me.

As per usual when w_tom is shown wrong he carefully avoids the quote from
the article so he misquotes me and straight out lies - I guess he is so used
to spouting crap that he does not even notice that he is lying.

Let me quote directly from the Article that w_tom is having so much trouble
understanding :

"When MOVs degrade they become more conductive "

Pretty clear eh? - except to a moron like w_tom

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Well actually I never mentioned the MOV vaporising - what I did show was how
degredation led to the overheating and incineration of the MOV

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"When MOVs degrade they become more conductive " then "the MOV draws in
excess of 1 mA of current during each half-cycle of the sine wave voltage, a
condition tantamount to thermal runaway"

But then I wouldnt expect w_tom to understand a simple concept like Thermal
runaway - or how this leads to the destruction of the MOV

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selective quoting where he carefully avoids the point I was making

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"When MOVs degrade they become more conductive " then "the MOV draws in
excess of 1 mA of current during each half-cycle of the sine wave voltage, a
condition tantamount to thermal runaway"

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Again more fantsy from w_tom about vaporisation

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But w_tom carefully avoids the result of this increase in conductivity and
how this leads to thermal runaway and the destruction of the MOV
 "the MOV draws in excess of 1 mA of current during each half-cycle of the
sine wave voltage, a condition tantamount to thermal runaway"

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"When MOVs degrade they become more conductive " then "the MOV draws in
excess of 1 mA of current during each half-cycle of the sine wave voltage, a
condition tantamount to thermal runaway"

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Please w_tom you cretin read the Article - read it slowly, Take time to
understand it, Take time to think about Leakage current and Thermal runaway

No wonder w_tom resorts to posting lies - hoping you don't read what has
really been written in the article and how it explains what degradation is
and how it leads to the destruction of the MOV

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I dont know why w_tom is quoting this as it goes against his argument that
MOVs degrade in some kind of unexplained mode that does not result in
incineration of the MOV

Maybe he is just off his scone and thoroughly confused and needs a good lie
down ??? - how does this match w_toms earlier claim : "Because a degraded
MOV does not  vaporize and may be tested with more impulses." - a short
circuited mov will certainly get rather hot if connected to AC mains

Goodness I dont even need to try to point out how wrong he is he does it
himself ;-)

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what w_tom is avoiding mentioning here is that all surge arrestors will be
exposed "to surges beyond their peak ... ratings" in a near or direct strike

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when confronted by Data and quotes from IAEI article w_tom invents things
and tells lies as per usual...

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w_tom does not quote Data sheets because he cannot find one for a MOV that
will withstand a near or direct strike and that I will hold it up for
ridicule.
He knows that any Data sheet he finds will be easily shown to be seriously
incapable of withstanding a near or direct strike so he just pretends or
makes stuff up as usual.

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quoting again from the IAEI article:
"When MOVs degrade they become more conductive " then "the MOV draws in
excess of 1 mA of current during each half-cycle of the sine wave voltage, a
condition tantamount to thermal runaway"


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Catastrophic Failure is ultimately the normal Failure mode for a MOV
because:

"When MOVs degrade they become more conductive " then "the MOV draws in
excess of 1 mA of current during each half-cycle of the sine wave voltage, a
condition tantamount to thermal runaway"


Quoted text here. Click to load it

But remember Folks what Degradation is (according to the IAEI article):
"When MOVs degrade they become more conductive " then "the MOV draws in
excess of 1 mA of current during each half-cycle of the sine wave voltage, a
condition tantamount to thermal runaway"

Quoted text here. Click to load it

Well actually all this in complete support of what I said and in complete
contradiction to w_toms fantasy world

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Yep lets see what the IAEI article has to say on degradation again :
"When MOVs degrade they become more conductive " then "the MOV draws in
excess of 1 mA of current during each half-cycle of the sine wave voltage, a
condition tantamount to thermal runaway"

Quoted text here. Click to load it

What is w_tom on about ???
- he has this fantasy that bigger MOVs do not heat up when they Fail - is
this supported by manufacturers data sheets ?
Nope all MOVs Degrade and what happens to a MOV when it Degrades again?

"When MOVs degrade they become more conductive " then "the MOV draws in
excess of 1 mA of current during each half-cycle of the sine wave voltage, a
condition tantamount to thermal runaway"

That's Right they become more conductive then they heat up and Go into
Thermal Runaway - more Detail from that IAEI article that w_tom completely
Fails to understand:

"MOVs degrade gradually when subjected to surge currents above their rated
capacity. The end-of-life is commonly specified when the measured varistor
voltage (Vn) has changed by + 10 percent.4 MOVs usually are functional after
the end-of-life, as defined. However, if an MOV experiences sequential surge
events, each causing an additional 10 percent reduction of Vn, the MOV may
soon reach a Vn level below the peak recurring value for the applied Vrms.
When this state is reached the MOV draws in excess of 1 mA of current during
each half-cycle of the sine wave voltage, a condition tantamount to thermal
runaway. In nearly all cases, the value of Vn decreases with exposure to
surge currents. The degradation manifests itself as an increase in idle
current at the maximum normal operating voltage in the system. Excessive
idle current during normal, steady-state operation will cause heating in the
varistor. Because the varistor has a negative temperature coefficient, the
current will increase as the varistor becomes hotter. Thermal runaway may
occur, with consequent failure of the varistor."

So what it is saying then is that a MOV is considered by the manufacturer to
have reached end of life when vn has changed by 10% unfortunately in the
real world no-one actually knows when the MOV has reached this state - or
does w_tom offer a vn testing service "Measure your MOVs once a week" ?

In the real world (not w_toms fantasy world) MOVs either Fail short Circuit
or suffer degradation which ultimately leads them to suffering Thermal
runaway and incinerating themselves - this failure mode is actually used by
the Manufacturers deliberately to blow a fuse and indicate when the surge
arrestor no longer offers even the minimal protection it usually does - even
the big MOV based surge arrestors installed in fuse boxes (such as w_toms
much loved 'whole house protection' ) contain a fuse as these MOVs also
breakdown and overheat

face it w_tom you do not have a clue what you are on about ...





Re: When the surge protection LED on a power strip won't light, is it likely to be a blown varistor?


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  Richard makes more claims not based in technical reality.  MOVs have
long been fast enough for telecommunication protection which is why Gas
Discharge Tubes (GDTs) were replaced by MOV similar devices.   Because
a traditional MOV has too much capacitance, then telcos manufactured an
MOV similar device that was standard at homes even in 1960 North
America.   Protector was fast enough even that long ago. This lower
capacitance version of an MOV was often called 'carbons' and is still
found in many older telephone installations:
    
http://www.inwap.com/inwap/chez/Phoneline.jpg

  Technical fact posted even with a 1960 era example.

  Traditional avalanche diodes such as transzorbs also have too much
capacitance - also in direct contradiction to what Richard posts. The
carbons have been obsoleted by other semiconductor based protection;
again manufactured so that capacitance is lower.  If Richard knew
technical facts, then he would have known that transzorbs have too much
capacitance:
   http://www.semtech.com/pc/downloadDocument.do?id53%2
Quoted text here. Click to load it

  Unlike other regions, North American telcos have routinely installed
effective protection on their customer's subscriber lines; now
installed in a box called the NID.  North American electrical codes
even define how this telephone protector must be earthed.  Australian
should upgrade their telephone installations with the most important
component in transistor protection:  earthing.

  Now Richard claims MOVs are too slow for telephone line protection.
How silly. He does not even know of MOV like protectors that were
standard as telephone line protection even in the 1960s - and since
obsoleted by semiconductor protectors.  Somehow a nanosecond response
time is too slow?   But again, Richard posts attacks; does not know
basic technology.  He even assumed MOVs are too slow without first
learning what has been standard for generations.

  North America has been installing properly earthed protectors on
customer phone lines as long as any lurker can even remember.
Protection that has not been standard in so many other countries AND is
necessary in any building that contains transistors.  The lurker is
warned of those who post with acidity and who don't even know that MOVs
are more than fast enough.   Richard does not even know of THE most
critical component in any protection system - single point earth
ground.

  LED on a power strip can report a defective protector.  It does not
report a protector as good or effective.  To sell power strip
protectors on myths, the manufacturer is even vague about what that
light reports.  Consumer is cautioned about power strip protectors that
have some nasty side effects as demonstrated by scary pictures in:
 http://www.hanford.gov/rl/?page55%6&parent55%4
 http://www.westwhitelandfire.com/Articles/Surge%20Protectors.pdf
 http://www.ddxg.net/old/surge_protectors.htm

  The lurker is also reminded how some recommending plug-in protectors
also use insult as technical proof.

  How to identify ineffective protectors:  1) it has no dedicated wire
for that 'less than 3 meter' connection to earth, and 2) its
manufacturer avoids all discussion about earthing.

  Better protection, standard even in telco switching centers, earths
before transients can enter a building.  One 'whole house' protector
for every appliance verses maybe 50 or 100 plug-in protectors.
Effective protection costs maybe one dollar per protected appliance AND
does not leave a homeowner worried about scary pictures:
 http://www.zerosurge.com/HTML/movs.html


yep w_tom is still full of CRAP !!!!



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Once again when w_tom is incapable of arguing a point he makes up Facts by
showing a Picture of something dating Back to the 1960's - what this thing
is I could not say - but it is definitely not a Line module of any sort out
of a modern exchange and certainly nowhere near small enough to fit in say a
modern DSLAM besides this is all pretty well irrelevant - at work we use
Marconi, Nokia (European I know) equipment which use clamping Diodes and
Adtran (North American) which again use semiconductor diodes for Protection
and I will have to have a look at the Stratacom/Cisco gear on Monday again I
bet it is all semiconductor  based - not a MOV in sight - contrary to
w_tom's claims.
- the main issue here is reliability (w_tom of course side tracks to the
speed of the device since he knows that he cannot argue that the MOV is more
reliable than a Transorb -BTW the MOV actually is slower than the
transzorb - again another fact that w_tom does not dispute because he knows
he cannot)

Now I know what w_tom will say that This North American Telco protection is
so fantastic, blah blah blah that Telco gear in the US never suffers from
Lightning damage and it would only happen in Australia - that is funny as
this is not the experience of Ron Potee Interim Director of IT for Public
schools in Huntsville Alabama in this document :
http://www.adtran.com/adtranpx/Doc/0/M7SVV0UP9DT4L6QGQ4S60GSI54/Document.pdf
when Ron potee talks about equipment failing often in "Lightning prone
Huntsville"

and I wonder why
http://www.adtran.com/adtranpx/Doc/0/9I7E9Q6C85FKTECK5FHVKP7G95/Video%20Access%20Network%20Architectures.pdf
talks about FTTP having a Greater immunity to Lightning - if Lightning
protection for Telco gear in the US is so perfect ?? (note I have quoted a
North american Telco manufacturer here) Butthere are further exampes of
death and Injury stats in the USA from folk using the Phone in North America
during thunderstorms


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strange they work then even on ADSL2+ services

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Hang on now one minute you are claiming it is all MOV based and now you are
saying that "Carbons" or MOVs have been made obsolete and that it is Diode
based protection nowadays ? - how w_tom twists and turns when he is on the
hook and being shown up as being full of crap.

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Hang on you are referencing an Application note which tells you how to
choose the right TVS for your application as proof of what ??? that they are
used in High speed data services ?

The whole point of this app note to advise the engineer on how to choose the
right TVS for their high-speed data applicationfrom ISDN BRI through to Fast
Ethernet (100Mbs) In fact this App note supports my claim that they are used
in High speed data Services.

What were you hoping that no-one would actually read the app note ??????

So here we find w_tom again misquoting and telling lies since he cannot
actually support his argument with any real documented Facts


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And North America - like every other Country that suffers Lightning still
has Telco equipment damaged by Lightning - This is Fact no matter what w_tom
claims
here is an example of Lightning damage to exchange equipment:

http://www.dpstele.com/dpsnews/success_stories/kevin_arthur_feature.html
And Utah - correct me if I am wrong but isn't that in North America ??

and according to 'Lightning fatalities in North Carolina 1972-1988 by R.L
Langley and K.A Dunn" - citing  the North Carolina medical examiners office
3% of Deaths due to Lightning during 1972 - 1988 time were of People Inside
a building using the Telephone. and isnt this North Carolina Place in North
America also?

In fact  Professor Martin A Uman (probably one of the worlds leading experts
on Lightning) was quoted in 1997 as saying that there were probably 100 or
more injured by Lightning while using a Telephone each year in the United
States (that is still North America isnt it ?) with 15-20 of these injuries
being serious.

And I wonder why the National Lighning Safety Institute would bother
recommending that you not use the phone during a Thunderstorm if Telco
protection is 100% effective as w_tom claims ?
http://www.lightningsafety.com/nlsi_pls/lst.html
In fact that is strange they say to unplug appliances, Computers, Power
tools and TV Sets - they dont mention "unless you have 'whole house
protection' as installed by w_tom" this Mob are based in Louisville CO -
wait isn't that Colorado in North America ???

Further more on the NLSI website at:
http://www.lightningsafety.com/nlsi_lls/incidents.html I find this Claim :
"A lightning strike traveled along phone lines and ruined several pieces of
equipment and damaged others in the Barrow County Detention Center, county
courthouse, Winder City hall, Police Department, Fire Department and legal
offices. The power surge associated with the lightning damaged the main
frame computer, several printers, telephones and monitors of the Winder
municipal offices."
then Later on the same page: "Lightning struck the central office tower at
the Monroeville Telephone Company leaving thousands without telephone
service and causing about $60,000 in damage." - That one is strange as w_tom
claims that Telephone exchanges are never ever damaged by Lightning

then again on http://www.lightningsafety.com/nlsi_lls/35_years_injuries.html
the NLSI claim that  2.4% of Lightning Deaths and Injuries around the USA
are Telephone-related.


but then w_tom will just ignore these Facts -as he always does with
inconvenient Facts juat as he has been unable to post a link to the Data
sheet for a MOV that can stand say even 1% of a Lightning strike without any
problems.

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Australian Lightning protection is as effective as in the USA


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MOVs take time to react - the higher the initial pulse the faster they
react - the lower e

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Standard for generations means nothing - The Horse and cart were standard
for generations - this means nothing SCDs are faster than MOVs end of
statement

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once again w_tom knows he has long since lost the argument so he makes
claims about what I do or do not know and once again shows his complete,
absolute and utter igorance of Surge protection only some one as ignorant of
lightning as w_tom would imagine that a Single ground stake was anything
near adequate for a Lightning strike - I guess he is not aware that a Single
Earth stake will Suffer an EPR in excess of 100KV during a Lightning Strike


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Dunno what his point is here - So new MOV based surge arrestors (including
those that go in the switchboard for 'whole house protection') are required
to have a thermal Fuse to stop a 'degraded' or blown  MOV burning the House
down - this is what I have been saying (and ironically w_tom has been
arguing against) all along - But w_tom has long since lost this argument so
he resorts to pretending it was about something else...

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Once again w_tom resorts to Lies and misquoting I never recommended plug-in
protectors - w_tom insults folks intelligence with the Lies and crap he
posts

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Any protection that claims 100% effectiveness - this is so obviously a Lie
that you would have to presume the rest of the claims were a Lie also oh
hange on that is what w_tom keeps claiming 100% effective protection - just
more proof you cannot believe a word he says.


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Re: yep w_tom is still full of CRAP !!!!


  The lurker is again cautioned about Richard Freeman posts.  For
example, the transzorb is faster then an MOV.  So what?  They are both
many times fast enough - responding in nanoseconds.  He posts half
truths that confuse the lurker and to attack w_tom.

  Provided previously were components used in surge protection that
Richard did not even know about. That point made to demonstrate how
little Michael really knows about protection.  Michael posts long about
damage that occurred - maybe even with surge protectors installed.
Again, Richard does as so many others who never learned the technology.
 They cite the exception and fail to first learn why that failure
happened.

    Protection is not just about the protector as Richard would have
you believe.  Knowledge of protectors is important.  But damage can
still result when earthing is insufficient. Richard would have you
believe protection - earth ground - was sufficient when so many (such
as Richard) don't even understand why earthing is so critical.  Why
were some on the phone harmed by lightning?  Did that short connection
to earth exist or was it disconnected by a naive homeowner?  The lurker
should be asking that same question.  Is earthing for each layer of
protection properly installed?  Not safety ground.  Earthing.

  Effective protection was even standard before the 1960s when Richard
Freeman said such devices were too slow.  Yes, some people are harmed
by talking on the telephone during a thunderstorm. Does that mean
protectors are too slow?  Nonsense.  Telephone, emergency response, and
corporate telephone operators take off headphones with each
thunderstorm?  Of course not.  Their earthed protection is minimally
sufficient - and inspected.  They don't just have protectors.  They
have something so essential - protection - single point earth ground.
What do plug-in protectors pretend is not necessary?  Earthing.  What
does Richard not ask?  Where is the earthing?

  Richard Freeman did not even know of protector technology from the
1960s. This paragraph demonstrates his problem:
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    MOV failure is directly traceable to a human who has installed
grossly undersized protectors (ie many power strips and UPSes).
Meanwhile effective protection uses sufficiently sized MOVs - do not
vaporize.  Protection is not just defined by MOVs.  The most critical
part of protection - the art of protection - is earthing.  Routine to
earth direct lightning strikes and the protector remain functional.
Numbers from manufacturer and experiences even in every telephone
switching center (connected to overhead wires everywhere in town)
demonstrates that reality for longer than Richard has even existed.

  An indicator lamp on a power strip protector can report the protector
defective.  But lamp cannot report a protector as good.  Meanwhile,
power strip protectors do not have a dedicated connection to earthing
AND do not even provide numbers that claim protection.  A damning fact
made obvious by a necessary short and dedicated connection to single
point earthing.

  Michael will prove his point with insults.  That proves to the naive
that plug-in protectors do something effective? Don't be so naive.
Those who really want effective protection don't look at an indicator
lamp.  Start with THE most critical component in surge protection - a
single point earthing electrode for that building.  Then each 'whole
house' protector makes a 'less than 3 meter' connection to that
earthing.  Earthing defines protection.

Richard Freeman wrote:
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Re: yep w_tom is still full of CRAP !!!!


w_tom wriggles and squirms like a fish on a hook then resorts to telling
Lies in order to pretend he has a valid point so let us work through w_toms
misinformation one point at a Time.

w_tom claims that a MOV based surge arrestor can provide 100% effective
protection.
Unfortunately there is not a MOV manufactured that can safely handle 1% of a
typical Direct Lightning strike - w_tom avoids posting links to Data sheets
for MOVs because he knows that I could point out that any MOV he could find
would have difficulty handling a near strike let alone a Direct strike.

w_tom claims that it is all in the Earthing....
Ironically w_tom actually speaks some truth here but what he neglects to
mention is that a single Earth stake will suffer an EPR (Earth Potential
Rise - I believe that in the USA this is known as GPR) of in excess of
100,000 Volts in a direct strike.
w_tom does not even understand the basic physics involved for Earthing -
this is why he so frequently refers to the 'Art of Earthing' because for
w_tom Earthing is an art not a science.
An Earth required to even begin to effectively shunt a Lightning strike with
a minimum EPR requires multiple Earth stakes bonded together with low
impedance cable/bussbars covering 1/4 of an Acre or more - is this practical
or cost effective in a Domestic situation ? nope ! - yet w_tom still claims
100% effective 'whole house protection' for domestic premises is not only
possible but inexpensive.

w_tom claims that Lightning does not come in via Phone lines as all Phone
lines in North America are adequately protected - this is another of his
100% Bullshit claims he then tries to squirm out and blame the home owner
when presented with evidence that a high number of injuries and some deaths
occour each year in North America due to folk using Telephones during
Thunderstorms.
Further more w_tom claims that Telephone exchanges never ever suffer
lightning damage - this in direct contradiction of the experience of anyone
who works in the Telecommunications industry. w_tom ignores the example
provided as an inconvenient Fact.

Next w_tom claims that MOVs have been adequate protection for Telephone
exchanges since the 1960's - he neglects to mention that the Exchange
Technology in the 1960's was mainly Relay based switching with a lot of
Step-by-step (and Strowger) equipment still in use. whereas modern exchanges
are primarily digital Micro-processor based and these Micro-processors
running at up to 200Mhz routinely deal with Signals lasting just nano
seconds. The VLSI integrated circuits used in these Exchanges are
susceptible to static charges so small that a careless Tech who is not using
antistatic precautions when handling the Circuit boards in the exchange can
cause damage without even feeling or noticing the discharge.
w_tom from his standpoint of complete and utter ignorance then asks how
Spikes from Lightning lasting mere nano-seconds could not possibly cause
damage.

Further more modern exchange equipment does not depend on MOVs for
protection as while they may have been adequate to protect Strowger switches
they are neither up to the task nor reliable enough to provide protection
for modern exchange equipment so w_toms claim that lack of damage to
Telephones proves the effectiveness of MOV Lightning protection is also
proved False.
Modern Exchanges equipment typically uses an impedance of some sort in
series with the line to limit the current to managable levels then typically
a Transzorb or equivalent (Transzorb is a registered Trade name of Vishay
semiconductor however the term is often used to refer in a generic manner to
clamping diodes used for spike supression) to clamp the surge. This though
is not a techniique that can be readily adapted for use on low imedance
circuits like the AC power mains.

Next w_tom claims that a decently sized MOV does not suffer degredation -
again he provides no links to such a MOV's data sheet because all MOVs
suffer degredation when they suffer from surges - especially surges outside
the MOVs stated limits. But again w_tom knows that I can show that any MOV
that he posts a link to the data sheet for will suffer degredation and
possibly destruction in the event of a direct strike (and even in the event
of many near strikes) so he carefully avoids this inconvenient Fact *.

w_tom also claims that degredation of a MOV does not lead to it's clamp
voltage changing and the MOV becoming leaky - which leads to thermal runaway
in the MOV and ultimately its destruction - this in contrary to the IAEI
experiences and discussion paper on MOVs at
http://www.iaei.org/subscriber/magazine/04_b/04_b_brown.htm
But this is inconvenient data so w_tom just avoids it or misquotes it.

Finally w_tom claims that I think plug in Power protectors are effective -
This is just an insult and a Blatent lie on w_toms part

Next there are some questions regarding statements that w_tom has told in
the past that he has still not answered :

Tell me again tom what a Thermal Fuse is.

Tell me the fairy tale again about how Lightning is a 'Low energy event'

Identify the 'direct connection between AC mains and the Integrated circuits
in a modern modem' for me.

explain how 0.6mm diameter single strand copper wire has a lower impedance
than 2.5mm square multistrand copper wire and therefore provides a better
earth.

Tell me again how Telco gear and TV/Radio Transmitters never ever suffer
Lightning damage.

Tell me how long your 1KJ mov lasts in a Direct Lightning strike ?

how long does a surge last ? - what is the definition of a surge ?

Remind me again when the MOV was developed ?

But then again I am probably assuming w_tom understands enough basic physics
to answer these questions.....

Now it would seem that w_tom is hallucinating and calling me the Arch angel
Michael - but then  it always was pretty obvious w_tom is completely off his
Tree ;-)

* Geez I am starting to feel like Al Gore for some strange reason...... ;-)

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Well I do not need to warn the Lurker about w_tom as it is obvious from his
Posts that he does not have a clue.

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w_tom has trouble understanding how Electronics that has issues with the
Static charge built up on the Human body and has no trouble handling signals
lasting 5 nano seconds (200Mhz) could have issues with Spikes lasting
nanoseconds - just more indications of how little idea w_tom has about
modern Electronics.

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so again w_tom resorts to telling lies as it was I who provided alternatives
and w_tom who had to quickly go and look them up.

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who is Michael ??? Looks like w_tom has completely lost it .... but then it
is obvious that w_tom has long ago lost it.

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The point of the (many) examples of injury, Death and Damage to Telco gear
were merely to highlight that w_toms claims of Nil Failure to Telco gear
were like almost all w_tom's claims completely false and especially like his
claim that the 'whole house protection' he installs is 100% effective.

when w_tom is proven to be incorrect he wiggles and squirms and pretends
that the issue is completely different

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As per usual when w_tom is shown to be wrong he invents facts to suit him -
w_tom does not understand how the Surge protection could fail so he
speculates - But remember it was w_tom



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Because he does not have a clue w_tom tries to pretend that I was saying was
that MOV protectors were to slow - Actually this is merely proof that -
contrary to w_tom's claims North America does not have 100% effective
protection against Lightning.

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well Actually modern call Centers are all fed by Fibre optic cable - which
does not conduct surges

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Once again w_tom pretends that I have been saying plug in protectors work -
this is a lie perpetuated by w_tom so that he has something to argue against

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w_tom is still unable to provide a data sheet for a MOV that does not
Degrade or one that can handle a near/direct strike so instead he pretends -
he is completely unable to support this claim with any published facts - so
he just makes this assertion and hopes that no one notices that as per usual


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Damn ! when a reality is inconvenient w_tom just reinvents reality -
experience in Telephone switching centres proves that damage can and still
does occur despite the best Earthing and protection available but w_tom just
chooses to ignore this and claims otherwise.

In fact the Earthing system in an Exchange is considerably  more comlplex
and expensive than is practical in a domestic situation as this Earthing
system often involves multiple earth stakes bonded together as Experience
has long shown that a Single Earth stake can suffer EPR and hence render
surge protection useless in the event of a Lightning strike.

Furthermore Phone lines are a High impedance service and typical surge
protection consists of an impedance in series with the Line to reduce Surge
current to manageable levels and then a Protection device - typically a
supression diode of some sort (be it the Vishay Semiconductor Transzorb or
another brand) which clamps the incoming spike on the Line card itself.

What this means is that actually the same protection Techniques used on
(relatively) High impedance Lines such as phone and data Services is not
Scaleable for use on Low impedance circuits such as AC power distribution.

Further more w_tom holds up Telephone exchanges as an example of the success
of MOVs but in fact Telephone Exchanges DO suffer damage and secondly Modern
exchange equipment us Transzorbs not MOVs.
Of the Telco equipment I have on Hand:

Modules from an ADTRAN DSLAM (North American built equipment)
Octal SHDSL Card (part no 1181403L2)   Line protection = ST Transil *1
Octal ADSL Card (part no 1181405L1) Line protection = ST Transil *1

Nortel DMS (Canadian - this is still North America)
2BIQ ( Basic rate) Line card Line protection = ST Transil *1

Nortel DMS 100 and 300 Line cards all prove to use Spike






*1 Note Transzorb is used as a generic name for a Transient supression diode
and is actually a Registered Trademark of Vishay semiconductor - Transil is
ST's equivalent
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w_tom is so divorced from reality by now that he has even forgotten who he
is dealing with - or is that Michael the arch-angel he can see after
consuming waaay to many drugs ......






Re: yep w_tom is still full of CRAP !!!!


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   Richard Freeman is so divorced from *why* as to even claim that call
centers use fiber optic cables.  Yes?  Call centers in the 1930s used
fiber optics?  His diatribe is chock full of such spin.  Even in the
1930s, earthing where phone lines entered the building meant operators
need not remove headsets during thunderstorms.  Effective protection
was that well proven that long ago.  Protection has always been defined
by earthing.

  Damage to telephone switching centers is so rare and so unacceptable
that damage is a major news story.  Connected to overhead wires
everywhere in town, a switching station that suffers direct strikes
every year must never suffer damage.  An informed technician would have
known this.  Numbers for direct strikes without damage were published
even in Oct 1960 by Bodel and Gresh in the Bell System Technical
Journal using data from New Jersey, Georgia, Maryland, and Michigan.
Effective and earthed protectors were standard that long everywhere.
Hundreds of surges were detected and measures - without damage to any
equipment.  That is how standard protection - using earthing - has been
proven.  This in direct contradiction to Richard's post - that provides
neither numbers nor citations.

   What does a telephone switching center do so that direct lightning
strikes every year do not cause damage?  Every wire inside every cable
is earthed via 'whole house' type protectors located best up to 50
meters distant from the $multi-million computer. In 1960, that was the
MOV similar device that Richard says is too slow.   That up to 50 meter
separation increases protection.  Since earthing is so essential, then
every telephone company has long technical manuals on how earthing must
be installed, upgraded, and maintained.  Earthing defines protection.

  By this point, every lurker should know:  no earth ground means no
effective protection.   Richard Freeman is still posting four letter
insults so that you don't learn that fact and corresponding numbers.

  No earth ground means no effective protection.  Earthing - as
demonstrated by Ben Franklin even in 1752 - is the most essential
component of a surge protection system.


Re: yep w_tom is still full of CRAP !!!!



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I dont know what your experiece is with telco gear, nor do I know
where you are getting your info from. But I suspect with your endless
references to circa 1960 that you don't really understand how a modern
exchange works and what gear they use. A substantial amount of info
you have posted is completely incorrect. Furthermore, I notice that
you keep steering the topic in a new direction with every post, which
leads me to beleive that once again, you are misunderstandg the
issues.

Re: yep w_tom is still full of CRAP !!!!


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  If The Real Andy could dispute what was posted, then he would have
cited technical sources, provided numbers, or described engineering
concepts. Instead he uses lawyer type logic.   He is critical of a
paper just on this subject from the Bell System Technical Journal -
where real world experiences and research defined lightning protection?
  Andy did as he did previously.  He claims multiple reasons for
effective protection are wrong.  He does not even acknowledge a single
posted reason. He does not challenge a single number or citation.  He
only says tens of reasons are all wrong.  One sentence again proves his
point?  Yes if one believes lawyer logic or politicians.

  Why was a 1960 Bell System Technical Journal paper cited?   Why does
no one else cite a technical reference?  Why did Bodle and Gresh do
that research?  Question was whether electronic telephone exchanges
would be more susceptible to lightning damage. Question was whether
well proven lightning protection from long before WWII was sufficient
for transistor protection.  Anyone who knows about surge protection
learns from early 1900s research AND again in 1950s and 1960s research
for semiconductor protection.  Their first sentence:
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  Obviously anyone who learns surge protection would read this paper.

  Learned is why (when) lightning does not damage transistors.
Principles of effective protection is pre-1960 research.  Those who
know protection would also know why that 1960 paper is so appropriate.
Effective protection is that old and well proven no matter how many
times Richard Freeman posts insults and spins half truths.

  Bottom line fact - protection is provided by earthing.  No earth
ground means no effective protection.  What is the essential component
in every protection system?  No a power strip protector.  Not a
protector's indicator lamp nor MOV inside that protector.  Earthing -
as demonstrated by Franklin in 1752 - is the most essential protection
component in every telephone CO (switching station).  Even the Bodle
and Gresh paper demonstrates why earthing is so critical where damage
is not acceptable.

  Forget the protector's LED indicator.  A protector without a
dedicated earthing connection AND whose manufacturer avoids all
discussion about earthing:  ineffective. Well, at least one poster
first learned well proven technology and did this stuff.  So well
grounded that even Richard Freeman insults do no damage.


Re: yep w_tom is still full of CRAP !!!!



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That is strange w_tom accusing someone else of his own Tactics.....

w_tom is unable to point to a Data sheet of a MOV capable of diverting a
Direct (or even near) strike with out suffereing degredation and damage

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One that does not exist let me repeat myself  once more for the retard :

Must have been a damn thin issue of the Bell system Technical Journal In
October 1960!

Because we go from Volume 39 Issue 5 In September of 1960 which has the
contributer acknowledgements starting page 1379 to the Next article
("Signalling Systems for the control of Telephone switching") in Volume 39
Issue 6 starting page 1381 on November 1960.

It looks suspiciously like they did not publish a Bell System Technical
guide in October 1960!

By the way none of the volumes I could find from 1960 had such an
article....

Sounds like w_tom is making stuff up again!


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He knows that it is pretty well pointless I just respond to the moron to
highlight to other posters what an ignorant cretin w_tom is.

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Because w_tom was hoping that no-one was able to check if the article
existed or not

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They have been cited but w_tom just ignores them as inconvenient Facts that
get in the way of his fantasies

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They may have done the research (if they exsisted) but we only have w_toms
word for what conclusion was reached....

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Was this Transistor protection before WWII ????

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Yes? and so ? this line does not actually state any conclusions.


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We cannot because the paper does not exsist where w_tom says it is - and
those of us who have followed w_toms ravings before know well that he has a
propensity for reaching the opposite conclusion from a paper that the Author
reached - as an example w_tom recently referred to data sheet for TVS Diodes
on how to select the appropriate TVS for your high speed data service as
proof that TVS's were not appropriate for use on high speed data


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once again w_tom assumes that protecting Strowger switch gear is the same as
protection for a Modern digital exchange
But really w_tom is sidetracking the gentle reader as w_tom holds protection
of Exchange equipment up as an illustration of how effective  MOV protection
is when in fact modern exchanges do not use MOVs and MOVs have not ever
really been particularly popular for exchange protection (not even before
they were invented around the 1960's ;-)

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w_tom is the one who insults the readers intelligence by posting misquotes
and lies

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Time and Time again I point this out to w_tom but he still misses the basic
ohms law :

a Good ground resistance for a single earth stake is considered to be 5-10
Ohms
the current in a typical Lightning strike is 30,000 to over 200,000 Amps
Lets take the lowest Figures of 5 Ohms at 30,000 Amps

5*30,000 gives us an EPR of 150,000 Volts

what this means is that in the event of Lightning being shunted to the Earth
stake then the Earth stake will rise to 150,000 Volts above ground (at best!
at worst try about 2,000,000 Volts).

w_tom accuses others of note quoting numbers but ignores them when they are
thrown at him as incovenient.


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Yes forget the LED indicator as only w_tom ever brings this up in
conversation - But at least it tells you when your MOV is stuffed - oh thats
roight w_tom is still having trouble with MOVs degrading and reckons that if
you get a big enough one it will last for ever - shame he cannot provide a
link to the Data sheet for this mythical MOV...

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Well maybe the manufacturer is merely being realistic and not pretending
that a Single Earth stake is adequate ....

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Who ??? Not w_tom thats for sure he obviously does not  have a clue ..

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oh dear looks like he has Blocked me - Damn shame ;-)




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