What is needed to provide protection from surges on the line when you
are using cable broadband? Any recommendations for products to choose
from?

McSpreader wrote:
Earth ground provides the protection. Any wire (not just phone wire)
that enters the building must connect to a single point ground - either
by a direct hardwire connection or through a surge protector.

Others are easily deceived by inferior protectors manufacturers into
believing the protector is protection. The protector and protection
are two different component of a surge protection system. All
protection systems require protection: single point earth ground. Some
systems also use surge protectors to make that essential 'less than 3
meter' connection to earth.

Surges can enter on any utility wire. Electronics are damaged when a
transient finds a path to earth ground via electronics. Electronics
already contain effective protection. But a transient not earthed at
the service entrance can overwhelm protection already inside appliances
- including that modem.

One common source of damaged modems is a surge incoming on AC
electric, through the modem, then outgoing to earth ground via the
telephone line protector. First electricity flows through everything
in that path. Then something in that path fails. Or incoming on a
phone line, destructively through modem, then outgoing via AC electric.
Notice one prerequisite. To be damaged, the electronics must have
both an incoming and outgoing path. After all, surges are electricity.
Electricity that seeks earth ground destructively.

This example demonstrates two points. First, every wire of every
utility must be earthed before it can enter the building. This is
called a 'whole house' protector for AC electric and phone. Or ground
block connects coax cable directly to earth ground - no protector
required.

Second, if utilities enter at different locations and therefore use
different earth grounds, then those different grounds can still create
surge damage. This figure from the NIST is used to demonstrate a fax
machine damaged due to multiple and separated earth grounds:
http://www.epri-peac.com/tutor*ials/sol01tut.html

Bottom line is this: single point earth ground is protection.
Plug-in protectors don't provide this most essential component. How to
identify a protector that is not effective? 1) No dedicated wire for a
less than 3 meter connection to earth ground. 2) Manufacturer avoids
all discussion about earthing.

A protector is only as effective as its earth ground. No short
connection to earth ground means no effective protection. A protector
is only as effective as its earth ground. Effective proetction earths
destructive transients before they can enter the building. Earth
ground is the only component of a surge protection system that is
absolutely essential. All connections to earth ground (via hardwire or
surge protector) best make a 'less than 3 meter' connection to the same
earth ground.

On 6 Jul, in article
<1120655345.241731.244290@g49g2000cwa.googlegroups .com>
w_tom1@usa.net "w_tom" wrote:

I've no argument with the basic thesis of the article, but anyone
reading this should remember that the regulations on electrical
installations may differ significantly. I am not an electrician, nor do
I play one on TV, but I am let to understand that ground-earths are
currently frowned on in the UK.




--
David G. Bell -- SF Fan, Filker, and Punslinger.

"I am Number Two," said Penfold. "You are Number Six."

On 6 Jul 2005 06:09:05 -0700, "w_tom" <w_tom1@usa.net> wrote:

Not in the UK - please be aware that people you reply to may not live
in the US and therefore different regulations will apply.

Posted is earthing that applies throughout the world. Some countries
with better codes even require this earthing. Others with less safe
electrical systems do not require it. But earthing for lightning
enhances what is required by human safety earthing.

They are not selling products that contradict local codes. Products
for N American protection may not meet the same safety codes in other
nations. Lightning protection earthing systems, sold in every country,
would meet those local requirements. Still, the concept of single
point earthing - an enhancement of the earthing system as required in
most western nations - has been routinely installed even long before
WWII to eliminate lightning damage. Concepts of protection are that
well proven and installed that routinely in buildings where no
electronics damage is acceptable.

An example of how earthing for lightning protection exceeds local code
requirements. Some codes may permit multiple earthing. But for
lightning protection, that earthing must be single point meaning all
utilities must enter the building at a common serive entrance.

Bottom line: purchase every surge protector sold in the country. But
if the building does not have a single point earth ground, then all
those surge protectors are ineffective. Earthing - and not surge
protectors - define transistor protection. Earthing is also installed
where human life would be endangered by AC electricity. Nations with
superior safety codes specifically require earthing - for human safety.
For lightning protection, code requirements sometimes are exceeded.
The earthing system, installed for human safety, may be enhanced for
transistor safety. And yet there is no way around that fact. Earthing
defined transient protection.

Any wire that can be directly earthed requires no surge protector.
For example, not every incoming AC wire can be earthed. Therefore the
earthing is provided by a 'whole house' protector. Utility makes a
connection to earth only during the potentially destructive transient.


A surge protector is only as effective as its earth ground.
Ineffective (and grossly overpriced) protectors simply enhance their
profits by avoiding any mention of THE most critical component in any
earthing system - single point earth ground.

"David G. Bell" wrote:

"w_tom" <w_tom1@usa.net> wrote in news:1120655345.241731.244290
@g49g2000cwa.googlegroups.com:

And that means short-circuiting everything. Are you sure you
understand this electrickery stuff?

Apparently the concept of earthing was not understood.
Since this pre-WWII concept is new, the technical explanation
requires reading multiple times. Anything technically good
and new (such as IEEE papers) required multiple readings.

Previously posted was:
That obviously means that earthing need not short circuit
every thing. Go back and read that post again. This is
technology so well proven that virtually every telephone
switching station uses it. Commercial radio stations do
this. Earthing of the antenna and other equipment essential
so that the station stays on the air and does not suffer
damage from direct lightning strikes. How do they do that if
the antenna is earthed? Again reread that above paragraph.

McSpreader wrote:

On Wednesday, in article <42CC62A6.313B254F@hotmail.com>
w_tom1@hotmail.com "w_tom" wrote:

As I've said, I'm not an electrician.

I wouldn't be surprised if American jargon was different from British
jargon.

I suspect there's some critical component being missed from the
description, some sort of voltage-dependent resistance at its simplest,
which shorts each wire of every utility to earth when a lighting-induced
surge hits.

It's possible he means something different by "earthed".

There's no way that you can directly connect both live and neutral to an
earth. You can't do it with both conductors of an aerial feed, because
the aerial wouldn't work. And on a transmitter the SWR could get high
enough to blow the power stage of the RF amplifier.







--
David G. Bell -- SF Fan, Filker, and Punslinger.

"I am Number Two," said Penfold. "You are Number Six."

Earthing an antenna or AC power via a surge protector, in
normal operation, means the surge protector is open circuit.
In normal operation, the protector acts as if it does not even
exist. When a destructive transient occurs, the protector
shunts to earth. This 'shunt' is not destructive and conducts
electricity only during the transient. Once a transient
terminates, then the protector returns to its 'open circuit'
state (assuming the protector was properly sized so as to not
fail catastrophically). It was assumed that the reader
understood what is meant by 'earthing a wire via the
protector'.

When I said the AC electric wire is earthed through a
protector, that does not mean the AC electric wire is always
conducting electricity to earth. Why? Protectors are open
circuit during normal voltage operation and shunt (short
circuit, close like a switch, etc) during excessive voltages.

If one did not understand what a shunt mode protector does,
then this below quote might lead one to assume that AC
electric wire was always shorted to and conducting electricity
into earth:
electricity into earth when voltage is excessive. This
voltage dependency characterizes shunt mode surge protectors.

If one assumes a plug-in protector blocks, stops, or absorbs
transients from wall receptacle into appliance, then one has
been deceived as to what surge protectors actually do. Then
that person would not comprehend what is meant by 'earthing
the AC electric wire through a protector'. A surge protector
conducts nothing - no current - until that rare time when
voltage is excessive. During that excessive voltage, the
protector acts like a switch; shunts (shorts) all wires
together. Shorting action has diminished effectiveness if
protector is not shunting wires 'less than 3 meters' to earth
ground.

If one properly understands the function of shunt mode
protectors (ie 'whole house' protector), then earthing the
incoming utility line does not mean that utility line is
always conducting electricity to earth. Sentence assumes the
reader comprehends what a protector does.

"David G. Bell" wrote:

McSpreader <invalid@hotmail.com> wrote in
news:Xns968ADDCE7DDF7McP@194.168.222.121:

Leaving aside the rambling theoretical discussion disappearing down a
rathole, can we get back to the topic, please?

For the avoidance of doubt:
- assume that the choice of where and how utility feeds (phone,
cable, power) enter a house are not open to choice by the
householder.
- similarly, earthing practices are dictated by IEE (not IEEE)
regulations, and are not open to personal preferences.
- is there even a significant risk, given the cable feed is
underground and short - to the nearest 'junction' box where it
becomes fibre.

I think I've got this sorted out. Partly my misunderstanding, though I
think the original article could have been clearer. It seemed to use a
lot of words to say "Surge protectors don't work without a good earth".

Further comments at the end.

On Thursday, in article <42CCACAD.CAE0F428@hotmail.com>
w_tom1@hotmail.com "w_tom" wrote:

I think you may have assumed a little too much knowledge on the part of
your audience, and I doubt you're familiar with current British
electrical practices.

The impression I have is that a good deal of American domestic
electrical wiring doesn't have an earth accessible at the socket.
British houses get a single-phase supply (live) at 240 volts, with a
return (neutral), and the fixed wiring also has an earth. Standard
sockets are three pin; live, neutral, and earth.

This isn't a good earth, by your definition, but a plug-in surge-
protector strip will be using that earth, it won't be floating. And
your insistence on a single earth point within 3 metres may be a little
impractical. I suppose this is where your whole-building protection
comes into it.

Perhaps another part of the problem is that we have other rules about
telephone wiring, and rigging an earthed protector on the line coming
into a house is non-trivial in other ways, regulatory and practical.

It's a long while since I had any involvement with an electrical
installation process. At that time, the earthing was done by the supply
company, through the neutral conductor. They didn't want to rely on a
local ground-earth of unknown quality, and such earthing wasn't
installed in new construction. But surge protection wasn't so
significant in those days; rules and practices may have changed.


--
David G. Bell -- SF Fan, Filker, and Punslinger.

"I am Number Two," said Penfold. "You are Number Six."

What he was saying about protection using Earth is the same as your house,
if you look around you will see some yellow/green wires attached to pipes
and metal surfaces. These protect you against electrical shock by making
the path easier to go to earth than through you and kill you.

The same applies to the electronic devices have a path to earth so it does
not go through the device and burn a component out.

I am no expert either but this is basic knowledge.



"McSpreader" <invalid@hotmail.com> wrote in message
news:Xns968C5F6DDFC1CMcP@194.168.222.122...

It's Me <spam@spam.spam> wrote:
"supplementary bonding", it's only mandatory (by IEE wiring regulations)
in the bathroom. The point of these wires is to make sure all the
conductors you can touch in the bathroom are at the same potential,
then you can't get a shock *even if* those conductors are not at earth
potential.

--
Chris Green

UK wiring, like wiring in so many countries, has three
prongs: live, neutral, and earth. (American wiring has long
had three prongs which is essential to modern safety.) Where
does that wall receptacle earth wire go to? It must go to
earth ground. Actually the wall receptacle 'earth' is only a
safety ground (for reasons explained below). So even that
becomes confusing in both countries.

Lightning protection in the UK is based upon concepts
defined by BS6651 - a British standard. This standard is
similar to an American standard C62.41. Why? Protection
techniques are standard worldwide. BS6651 is introduced at:

http://www.keison.co.uk/bowthorpe/do...on%20Guide.pdf

Meanwhile, a British company (in Nottingham?) that provides
protection also introduces same concepts that are used in N
American and also used by BT to protect their computers:
http://www.furse.com/esp/whenpro4.htm

Companies that provides telephone line protection for UK
are:

http://www.one.co.uk/catalogue/teleb...otect/22PX.HTM
http://www.keison.co.uk/furse/furse11.htm
http://www.citelprotection.com/engli..._B380_B480.PDF
These products for the UK do same as in other nations AND
perform as I described previously. The concept are world
wide. Details of that application are unique for each nation
and provided by local suppliers.

Meanwhile, the power strip protector may be connected to
wall receptacle safety ground. To AC electricity (50 Hz),
that is a connection to earth. But to higher frequency
transients such as lightning, wire impedance means that power
strip protector is all but disconnected from earth. Even
worse, lets assume the plug-in protector were to earth a
transient down the safety ground wire. That safety ground
wire is bundled with other wires. Now that transient has
induced transients on all those other wires. So where is the
protection? Plug-in protector manufacturers therefore forget
to mention earthing.

Too much wire impedance (because wire is too long) and
induced transients are simply two of so many reasons why the
power strip manufacturer hope you never learn why earthing is
the protection. Their profits are quite substantial. Why
would they threaten those profits by providing facts about the
most essential component in a surge protection system - earth
ground?

Even that above cited telephone protector manufacturer notes
earthing connection must be short:
http://www.telebyteusa.com/catalog/manuals/m0161.htm

Because British wiring standards don't address transistor
safety, then code requirement to make effective protection
possible are less practiced in the UK. For example, for
effective protection, the telephone line, TV cable, and AC
electric must enter at a same location to be earthed to a
common point. In the US, newer code requirements now make
that mandatory. Even BT stopped putting protectors inside the
Master Socket. I would not be surprises how often
thunderstorms cause damage in the UK since the only real
protection is that inside the appliance. Protection that is
overwhelmed if the transient is not earthed before entering
the building.

"David G. Bell" wrote:

The rambling has defined specific solutions. Products to
accomplish the solution are even listed in a reply to David G.
Bell. Earthing is defined by BS6651 - a British standard.

Even underground wires are a source of destructive
transients. As usual, this answer would be nothing more than
urban myth if I did not cite sources and underlying concepts.
Every wire entering the building connects to a single point
earth ground (either via hardwire or a surge protector)
including the buried phone wire:

http://www.erico.com/public/library/...es/tncr002.pdf
Buried phone wire (like any utility wire) can carry
destructive transients into the building. Polyphaser makes
the same point in their application note:
http://www.polyphaser.com/ppc_TD1026.aspx

When the utilities are installed to make transistor damage
more likely (not at a common service entrance), then surge
protectors for each utility could be earthed (connected to a
buried ground wire) as demonstrated by the 'right' picture in:
http://www.cinergy.com/surge/ttip08.htm
Its not a 'preferred' solution, but it does provide a single
point earth ground.

Meanwhile, coax cable is earthed by hardwire and a ground
block. Effective coax protection is obtained simply by
connecting its shield to earth ground. A principle often
cited by industry sources is that an earthed shield will then
protect the inner core wire from transients due to leakage in
the insulating material. No coax protector required that
would also degrade broadband signals. But again, its the
earth ground that defines cable protection.

McSpreader wrote:

On Thu, 7 Jul 2005 19:26:10 UTC, w_tom <w_tom1@hotmail.com> wrote:

Actually, that's line, neutral and earth.

In most modern houses (and a lot of older ones) it goes to neutral, at
the 'cutout' (where the incoming cable and service fuse are).

--
[ 7'ism - a condition by which the sufferer experiences an inability
to give concise answers, express reasoned argument or opinion.
Usually accompanied by silly noises and gestures - incurable, early
euthanasia recommended. ]

Put anti-surge in a Usenet header and the troll awakens.

Although Belkin products get slagged by the 'techies' mine
worked in the recent electrical storms the protector blowing
instead of my equipment. I sent the 4 year old protector to Belkin
under lifetime warranty and they replaced it FOC with the equivalent
latest product.

Chris

What Real Ale forgot to mention that is most damning.
Electronics appliances without any adjacent surge protector
survived. What protected his fire detector, his dishwasher,
his microwave oven, clock radio, furnace control system,
dimmer switches, etc? A device we call the 'missing
protector'?

Ineffective protectors are promoted by undersizing them.
When a transient too small to damage an adjacent appliance,
instead, damages the undersized surge protector, then Real
Ale will recommend that overpriced and undersized protector.
Why were those other appliances protected by a 'missing
protector'? Protection already inside appliances protected
all his appliances. The 'missing protector' also worked as
designed.

Meanwhile, effective protectors shunt destructive surges to
earth ground AND remain functional. His protector was so
grossly undersized as to fail during only one surge.
Unacceptable. But it worked as designed. It got Real Ale to
recommend that undersized protector. It failed, leaving
internal protection already inside his equipment to protect
itself. Kudos to the 'missing protector' that also provided
protection. Real Ale forgot to recommend all those 'missing
protectors' that protected his other appliances.

The Belkin got Real Ale to promote a myth AND to not
recommend 'missing protectors'. How do we know that Belkin
was not effective? First and foremost, where was its short
connection to earth ground? No earth ground means no
effective protection. Second it failed catastrophically.
Properly sized protectors degrade - don't fail
catastrophically. Fortunately the transient was too small to
overwhelm protection already inside his equipment - but large
enough to damage the undersized protector. Effective
protectors don't fail catastrophically during one transient
(as demonstrated by those 'missing protectors').

Real Ale wrote:

The neutral and safety ground meet at a common location, as
Bob Eager has noted. That common point also must have a
connection to earth. If that earthing connection did not
exist, then all three AC electric wires could float to
voltages as much as 1000 volts different from earth. That 1000
volts is a serious human safety threat.

That earthing was my earlier point. Somewhere that earth
prong on the wall receptacle must make a connection to earth -
first and foremost for human safety reasons. This human
safety requirement is true on both sides of the pond and
throughout the world.

Bob Eager wrote:

On Fri, 8 Jul 2005 02:57:30 UTC, w_tom <w_tom1@hotmail.com> wrote:

But the connection to earth is provided by the electricity supply
company, at multiple points. The system is known as Protective Multiple
Earthing, the technical version of earthing known as TN-C-S. So its
failure is very unlikely indeed.

--
[ 7'ism - a condition by which the sufferer experiences an inability
to give concise answers, express reasoned argument or opinion.
Usually accompanied by silly noises and gestures - incurable, early
euthanasia recommended. ]