Close lightning destroyed the cordless phone at the weekend, now looking
to get some phone line surge protection. The adsl router survived.

One of the Belkin range seems ok for mains / BT telephone sockets
but I can't find anything for the RJ 11 lead between the BT ADSL
faceplate and the router.

... Or perhaps the ADSL part of the faceplate and / or the router have inbuilt
protection and no need to worry ?

Chris

First you are assuming electricity works like a wave
crashing on the beach. Does the transient enter on phone
line, destroy phone, then stop? Of course not. A transient
first flows equally through everything in a path from the
cloud to ground. Only when that current increases
sufficiently, does something in that path (ie. the phone)
fail.

Second, all appliances have internal protection. Protection
that can be overwhelmed if the destructive transient is not
earthed BEFORE it can enter the building.

To have a destructive transient, the transistorized
appliance must have two paths - an incoming and an outgoing
path. Portable phone base stations are particularly
vulnerable; two paths being AC electric and phone line. So
which line did the transient enter on? You have assumed it
was the telephone line. Why?

Furthermore, do you expect to stop what 3 kilometers of sky
could not? That is what ineffective plug-in protector
manufacturers hope you will assume. However in N America,
every incoming phone line already has a 'whole house'
protector installed free by the telco. Does it stop the
transient? Of course not. Effective protection does what Ben
Franklin demonstrated in 1752. He did not stop lightning. He
shunted (diverted) lightning to earth. You must do same.

A protector is not protection. An effective protector does
same thing as an earthing wire. An effective protector
connects the destructive transient to protection. The
protector is not protection. Earth ground is protection. The
protector is simply a connection from that utility wire to
protection. This is what plug-in protectors hope you never
learn.

You don't know if the transient entered on AC electric to
find earth ground via phone line; or visa versa. But we know
this. First, a plug-in protector hopes you will assume a
protector will stop what 3 kilometers of sky could not.
Forget the nonsense promoted by Belkin; who avoids all
discussion about earth ground. The concepts of RJ-11
protection were discussed extensively "RJ-11 line protection?"
on 30 Dec 2003 through 12 Jan 2004 in pdx.computing at:
http://tinyurl.com/2hl53

In the UK, providers of effective protectors for AC electric
are:
http://www.keison.co.uk/furse/furse06.htm
http://www.keison.co.uk/furse/pdf/ma...lies/m2_m4.pdf

For phone lines:

http://www.one.co.uk/catalogue/teleb...otect/22PX.HTM
http://www.keison.co.uk/furse/furse11.htm
http://www.keison.co.uk/furse/furse08.htm

Notice what every effective protector features: a dedicated
wire for a 'less than 3 meter' connection to single point
earth ground. An effective protector only connector the
transient to protection.

How might your phone have been damaged? This figure from
the National Institute of Standards and Technology
demonstrates how bad earthing caused fax machine damage:
http://www.epri-peac.com/tutorials/sol01tut.html

Again, the effective protector makes a 'less than 3 meter'
dedicated connection to earth ground. Same principle is why
BT, connected to overhead wires everywhere in town, need not
shutdown during any thunderstorm. You are strongly
encouraged to review that previous discussion entitled "RJ-11
line protection?". Earth ground (and not the protector) is
protection. No protector is going to stop, block, filter, or
absorb the transient that might damage that portable phone
base station. Therefore ineffective protectors avoid all
discussion about earthing - to make the sale.

The protector is only as effective as its earth ground.

Kris wrote:

Thanks for the techie stuff, conclusion ... I'll not bother with
anything, I could buy 2 adsl routers for the price of the pro
protectors.

Amazing how Belkin can claim to pay out for surge damaged equipment
if their products don't work. perhaps I'll read the small print.

Chris

Possible that trivial transient was just enough to damage
the phone but not enough to overwhelm ADSL internal
protection. Or the phone was protecting ADSL router by
earthing a transient. No phone and the next transient may
find a destructive path via that ADSL router. Its called a
'canary in the coalmine'. If lightning exists, then spend
less money (per protected appliance) for recommended protector
or something equivalent. The protector sold by Belkin is
typically tens of times more money per protected appliance and
does not provide what every appliance requires.

All appliances have internal protection. Protection that
assumes you have earthed the incoming transient. Earthing
that transient so that internal protection is not
overwhelmed. Nothing techie about it since I did not even
post numbers. It's really quite simple. Effective protection
for about £1 per protected appliance.

What protects your dishwasher? RCDs. Your clock radio.
Dimmer switches. Smoke detector. Furnace and central air
controls. Effective protector costs about £1 per protected
appliance. 'Whole house' protectors being so inexpensive that
N American phone companies install them for free. Without it,
next time the ADSL router may not have a portable phone to
protect it - or computers adjacent to the ADSL router may not
be so lucky.

What is one potentially outgoing and destructive path from
an ADSL router? Through household computers. That damaged
portable phone may be a 'canary in a coalmine'. Effective
protection from direct lightning strikes being so inexpensive.

What is not mentioned by Belkin is so damning. Which type
of transient does it protect from? An effective protector
provides protection from all types of transients. A plug-in
protector does not claim protection from the typically
destructive type of transient, and therefore avoids all
discussion about earth ground.

How to identify an ineffective protector. 1) Has no
dedicated connection to earth ground. 2) Manufacturer avoids
all discussion about earthing. Again, a protector is only as
effective as its earth ground.

Meanwhile, potentially destructive transients occur maybe
once every eight years. A number that varies significantly
based upon geology and other factors beyond the scope of this
discussion. Are you in a high transient location, or is that
frequency of transients so low that another may not occur for
over 10 years? Just another consideration.

Kris wrote:

On Tue, 24 May 2005 17:41:51 -0400, w_tom <w_tom1@hotmail.com> wrote:

<snip waffle>

http://tinyurl.com/7e9us

You talk endlessly on newsgroups about power related stuff, but you
haven't worked out how to bottom post yet.

Jake

w_tom wrote:
Thanks w_tom, I'm now losing the will to live ... do you continually
search Usenet for 'surge protection' ? get a life mate ... and top posting
irritates many users.

"w_tom" <w_tom1@hotmail.com> wrote in message
news:42939F9E.67ED367E@hotmail.com...
Hurry up and find your tweezers and magnifying glass and get off this ng
ffs.

If you did not want the answer, then why did you ask the
question?

Kris wrote:

On Wed, 25 May 2005 17:07:05 -0400, w_tom <w_tom1@hotmail.com> wrote:


Does the facepalce have inbuilt protection?
Do I need to get protection?
If I do, what do I need to buy?

I am sure the OP did not want a thesis on the electical bollocks you
gave.

A simple yes/no/"this is what you need" would have sufficed.

"Kris" <chris.howland@ukgateway.net> wrote in message
news:42937bb2$0$93743$ed2619ec@ptn-nntp-reader01.plus.net...
If you are able to use a surge protector between the incoming BT line and
your ADLS filter e.g. at the master socket then one surge protector will
provide protection for both telephone and ADSL equipment. This is by far the
best place to position it. You don't need one explicitly for the RJ11 ADSL
connection. There are other surges that come through the mains and the
Belkin devices also filter these out as well.

I should ignore much of the information you have been given in another part
of this thread. There will be no effective protection against a direct
lightening strike but electrical storms give rise to voltage surges in
telephone wires even if the strike is some considerable distance away from
any of the telephone wiring between yourself and the exchange. The amount of
energy involved is almost impossible to comprehend. The voltage transients
created can be hundreds of thousands of volts (or more) close to a strike
and no affordable protection will survive that. The surge dissipates with
distance but can still cause transients that damage equipment several miles
from the actual strike.

The protection devices from Belkin however come with a "Connected Equipment
Warranty" so that even if your equipment is damaged at least it will be
replaced - has anyone tried to claim by the way? My Mastercube provides
warranty protection for £35,000 of connected equipment which is more than
enough for normal domestic use. Professional surge protectors may give more
protection but I am comfortable with the Belkin unit together with the
warranty. By the way it did not affect my ADSL performance when I inserted
the surge protector!

John Steele
www.soroban.co.uk

If they don't post the numbers, then first assume they are
lying. Most people don't want the numbers. A lying president
knows this. He too never provides facts for his
proclamations. Therefore the mentally weak routinely believe
him. No numbers. No supporting facts. Therefore America has
even justified torture in Guantanamo and Abu Ghriad.
Meanwhile some neighbors who get angry when numbers are
provided also claim torture did not happen. Rush Limbaugh
told them. For many, Rush Limbaugh and not the facts are more
than sufficient.

If I did not post that supporting information, then even I
would not believe me. I also did not believe a president who
could not be bothered to provide honest facts and numbers.
Never trust those who cannot provide numbers nor say why.

The OP need not understand those facts and numbers - be it
Iraq or surge protectors. He skims down to the only paragraph
provided for his benefit. Provided were specific examples
that solve his problems at tens of times less money. Who else
demonstrated technical knowledge to justify their
recommendations? No one.

To be honest, one must first commit to numbers. Others who
recommend ineffective plug-in protectors commit to nothing and
demonstrate no technical knowledge. They recommend based on
junk science reasoning.

I provided numbers because realists demand numbers - even if
they (today) have 'not a clue' what those numbers mean. No
numbers means a recommendation comes from junk science
reasoning.

Listed again are the OP's solutions. Only this paragraph
applies to those who never need know why:
http://www.keison.co.uk/furse/furse06.htm
http://www.keison.co.uk/furse/pdf/ma...lies/m2_m4.pdf

http://www.one.co.uk/catalogue/teleb...otect/22PX.HTM
http://www.keison.co.uk/furse/furse11.htm
http://www.keison.co.uk/furse/furse08.htm

BTW, there is no "yes or no" answer to his question. His
question was based upon wild speculation and a fictional
perspective. A nearby lightning strike did not cause that
damage. That nearby strike would be a direct connection to
his transistors. Why? Previously explained - which is why a
"yes or no" answer would only be 'lying by telling half
truths'.

Harry wrote:

You post is true if a protector is properly earthed; not
between incoming BT line and ADSL filter. An effective
protector sits between the incoming BT phone line and single
point earth ground. A protector between incoming BT line and
ADSL equipment will only work if it can stop, block, or absorb
what 3 kilometers of sky could not. Even Belkin does not
claim to do that. Show me any protector that even claims to
do that?

Should you disagree, then post facts and numbers. Even
those plug-in protector manufacturers don't claim to stop or
block such destructive transients.

If no protection exists from a direct strike, then which
year was your BT service down for a whole week while they
replaced that central office computer? We routinely divert
direct strikes without damage at telco switching stations, BBC
broadcasting sites, in mobile base stations, in high voltage
transmission equipment - and 25 times every year to FM and TV
electronics atop the Empire State Building. Even Ben Franklin
demonstrated the concept in 1752. Please explain why all
those locations are not routinely destroyed? You made the
claim. Provide facts. Show me that you did not wildly
speculate.

As for that Belkin warranty: first read it. It is so chock
full of exemptions that the warranty is routinely not
honored. Others here get mad when I post examples. So you
prove why that warranty is always honored. Show us how those
many exceptions are not exercised. Prove me wrong. Provide
supporting facts with your assertions. Or need I again
provide examples of what that overhyped warranty is really
mythical?

John Steele wrote:

On Thu, 26 May 2005 23:57:16 -0400, w_tom <w_tom1@hotmail.com> wrote:


We dont trust the US because they are Americans and they voted a chimp
as their leader. Numbers have nothing to do with it, as they are
usually twisted or false or incomplete.

crashed. But I am smart enough to realise that most of that detailed
information goes completely over the customers head. I simplify the
detail into a short summary of the reason and not a large amount of
waffle that serves no purpose.

If, and only if, they ask for more details do I give them the
necessary information. Of course I will offer the detail to them, but
99% of the time they only want the summary reason and solution.
electricity here. We are talking about a surge protector.
send us you wise words of numeric wisdom.
good." How patronising is that?!?
You are just too much of a geeky boffin to be posting to us mere
mortals.

The OP was asking about protection against destructive effects of electrical
transients arriving via a telephone line and I focussed on answering that
question in a plain and straight forward manner. I still stand by the advice
I gave.

You are substantially confusing the issue by introducing other effects
which, in domestic premises, there is usually no effective protection
provided.

Here is a more complete answer:

There can be direct protection against lightening strikes - these are
typically referred to as lightening conductors. This minimise the risk of a
direct strike to buildings or to exposed metallic surfaces attached to
buildings. If I recall my physics/electrical engineering correctly (and it
is a long time ago that the principles of lightening and its protection were
explained to me when I did a degree course in electrical engineering given
by the late Prof Eric Laithwaite, I haven't been into the loft to recover my
university notes) a lightening strike starts with a stream of electrons
being emitted from an object connected to Earth attracted towards the
positively charged cloud. Such a stream is most efficiently emitted from a
sharp point rather than a flat plate which is why lightening conductors have
sharp points. They are designed to provoke a strike.

If the potential difference is high enough between the charged cloud and the
electron emitter the stream of electrons reaches the cloud and the discharge
starts back down the path formed by the electron stream ionising the air and
forming a low impedance short circuit to the source of the electron stream.
This will be the lighting conductor or tree or whatever.

The current flows down the lightening conductor (a thick copper strap)
directly into the ground and then dissipates in a spherical pattern into the
ground. The very high currents flowing (millions of amps) form a potential
difference from the entry point to other locations at increasing distance
from the strike. It is this potential difference that can cause damage even
without a direct strike. As Laithwaite put it in one of his lectures - if
you stand under a tree which is struck by lightening you can be electrocuted
by current flowing through your body caused by the potential difference
between your two legs arising from the current flow. He claimed (I have not
tested the theory!) that if you stood on one leg then you would not be
electrocuted.

The current flow is very high, builds very quickly and lasts for a short
time. The potential difference (voltage) (which causes the damage) between
the strike and more distant parts follows the well known inverse square law.
Telephone interface circuits used to have to withstand at least 4 Kilovolt
spikes to receive an "approval" sticker. I am not aware of the regulations
in force now as it is some time since I designed equipment to interface to
telephone lines.

If a lighting strike happens near a telephone exchange then there will be a
difference in the earth potential between the earth exchange and earth at
the domestic premises. The effect of this is that the common mode of the
pair of telephone wires (i.e. both wires of the pair) will follow the
potential of the earth at the exchange whereas the premises equipment will
be at the earth potential of the local earth. In the extreme situation of a
lightening strike these "earths will transiently be at sufficient potential
difference to cause damage.

There are other effects arising from induced voltages and currents that can
be induced into particularly overhead telephone wires which result from fast
changes to electrical signals which occur with the pulse arising from the
strike so the situation can get much more complex.

I repeat my observation that a direct strike was not the real cause of the
original poster's damage to the electronic equipment. It was almost
certainly caused by the effect I outlined in my post and explained in more
detail above. I agree that the surge protection needs to be earthed. The
local mains earth provided by the local ring main is not ideal for this
purpose but does provide a significant additional degree of protection. I
agree the ideal would be for a telephone surge filter to be placed at the
point of entry for the telephone wires with an earth taken directly to an
earth spike in the ground. The situation must be treated as a risk
mitigation. Does the Belkin unit add to the protection? answer YES. is the
solution perfect? Answer NO but much better than nothing, not very
expensive, does not cause any harm, and there is a warranty.

I have not tried to claim against the Belkin warranty, but it reads as
follows:

Connected Equipment Warranty: Belkin will repair or replace any equipment
damaged by a surge, spike or lightening strike while properly connected to a
Belkin surge protector, up to the maximum value stated on the package.

I bought it primarily as a mains surge suppressor but am using it to protect
against the telephone line. That is why I asked whether anyone had tried to
claim against the Belkin warranty. I have not personally experienced any
lightening damage although I do know people who have. (None of these had
filters but that is not statistically significant!)

I have not seen any of your posts before as I read this group sporadically.
Perhaps you regard an understanding of the physics and engineering involved
as speculation. I do not intend to extend this particular discussion any
further or provide attempt to provide any supporting facts as I do not have
any. I will leave the group to judge whether my observations and analysis,
based on science and engineering, and supported by over 40 years of
professional design experience are as valid than yours. I have given
stuffiest information (on my web page), for anyone who chooses, to check out
my experience and credentials. I will continue however to provide answers,
in this and other groups, where I can which are also based on sound
engineering and experience.

John Steele
www.soroban.co.uk

"w_tom" <w_tom1@hotmail.com> wrote in message
news:42969C78.E18A11D0@hotmail.com...

"John Steele" <jcs.ng@NOSPAMsoroban.co.uk> wrote in news:42987419$0
$13905$ed2619ec@ptn-nntp-reader01.plus.net:

In this context it is lightning. Lightening may be the effect on your
hair colour if you suffer a direct hit :-)

"Kinell" <w@invalid.jp> wrote in message
news:Xns9664A0B488E85kxxx@62.253.162.202...
That's what comes of typing too quickly and trusting the spell checker!

John has correctly targeted the principles although some
details are in error. For example, lightning is not millions
of amps. A most typical strike being 20,000 amps - and for a
very short period.

Also sharp points have been demonstrated to be inferior to
blunt pointed rods.

As John demonstrates, the currents in a lightning strike are
a connection from charges in clouds to other charges in
earth. Those cloud borne charges can be positive or negative
- both types of lightning exist.

John also discusses what is called equipotential.
Equipotential beneath a building contributes to protection.
As John noted, voltage potential is not same everywhere in the
CG strike path. A million volts in the sky does not mean even
10,000 volts exist as that same current passes through a
building. Good conductivity of that grounding wire and
equipotential beneath a building, both, means that million of
volts stay in the sky and very little voltage appears across
earthborne electronics. The single point earth ground is
commonly installed for better equipotential and good
conductivity. The two objectives of earthing.

We single point earth ground for the same reasons that John
demonstrates with an electrocuted human standing beneath the
tree. To not be harmed, the human must stand with feet
together. With feet apart, then earth beneath him is no
longer equipotential. Equipotential also why we say the
protector is only as effective as its earth ground.

The OPs question cannot be answered only in terms of a phone
line. Electricity requires a complete circuit. A phone line
provides no complete circuit. Without an outgoing (second)
wire, then no electricity exists. One cannot discuss
destructive effective of electrical transients without
discussing a complete circuit - ie incoming on phone line and
outgoing on what - AC electric? To pretend that only a phone
line carried a destructive transient (that no outgoing circuit
exists) is akin to learning advanced physics from an article
in a tabloid newspaper. Nothing useful can be extracted.
Discussion of destructive transient must define both incoming
and outgoing circuits. Anything less only distorts the issue
into deception and confusion.

As John noted, lightning conductors protect by earthing a
transient so that no large voltage exists in a building.
'Whole house' protectors, such as those recommended twice
previously, perform that function on each incoming utility
wire. But the Belkin does not even claim to protect from
these typically destructive transients. Obviously. The
Belkin does not provide an earthing connection. No earth
ground means no effective protection. As John demonstrates,
earthing is essential to the protection system. Protection
being only as effective as earthing that a Belkin protector
does not provide.

As John noted, protection is in earthing the transient. The
Belkin could only protect if it stopped, blocked, or absorbed
what 3 kilometers of sky could not.

John Steele wrote:

Thanks John, the problem I have is the BT master faceplate which has a
BT phone socket and a separate ADSL socket. The only solution for the
ADSL socket to router would be an inline RJ11 protector like these......
http://www.phonapart.com/surge_page5.html
they are less than a tenner but a complete waste of money ?

The BT phone socket to phones now has a Belkin protector on it.

:-) I tried to understand it ( for what it's worth I have a degree in Industrial
Chemistry),
but ,sadly, it's beyond me.

Chris

"Kris" <chris.howland@ukgateway.net> wrote in message
news:4298c688$0$579$ed2619ec@ptn-nntp-reader03.plus.net...
If you able to use an ADSL filter using the filtered BT socket instead of
the faceplate filter then your ADSL line will also be protected. That is in
effect what I am suing.

John Steele

In article <42965e05$0$13868$ed2619ec@ptn-nntp-reader01.plus.net>,
"John Steele" <jcs.ng@NOSPAMsoroban.co.uk> writes:
Some of the BT sockets have provision for a GDT protector to be
plugged in the back, although you have to unscrew the whole faceplate
to see this, not just the bottom cover. If yours has, you will see
3 small pin sockets in a row and an earth screw connection (which will
have nothing connected to it). You might find it already has a
2-terminal GDT device plugged in to the pin sockets (middle socket not
connected). What you could do is buy a 3-terminal GDT protector to plug
into the pin sockets, and make a good earth connection to the earth
terminal, the other end ideally going to the house main earthing
terminal via a short thick earth wire. (The 2-terminal GDT devices don't
protect against a common-mode voltage spike, which is what you're more
likely to see if there is a lightning strike nearby. The 3-terminal GDT
device does, but requires a very good earth connection to work well.)

--
Andrew Gabriel