I wonder why, since electrical codes in North America
and Britain require a ground connection at each outlet;
computer power cords are 3 wire?


(snip)

hot neutral ground

On May 5, 1:44*am, wrote:
In alt.tv.tech.hdtv bud-- wrote:| wrote:

| In alt.engineering.electrical Leonard Caillouet wrote:| | wrote in message

| ...
| | In alt.tv.tech.hdtv Franc Zabkar wrote:
| |
| |
| | The MOVs will act like conductors when they are clamping. *The surge will
| | take both paths ... the path through the MOVs, and the path going past the
| | MOVs. *In general, about 50% will go each way. *That can vary at higher
| | frequencies.
| |
| | Why would you assume that 50% will go each way when you don't know the
| | impedance of each direction? *When conducting, or at failure, the MOV has a
| | very low impedance.
|
| There is a distinction between "go each way" and "what comes back" due to
| the impedance. *It will be about 50% that goes each way _because_ the power
| itself does not (yet) know the impedance (at a distance), until it gets
| there.
|
| Another installment of Phil's Phantasy Physics using transmission line
| theory.

Not understanding it is your loss.


I have to agree that this is Phantasy Physics. We're supposed to
believe that a surge reaching a MOV is going to split 50-50, with half
of it going to the MOV path and half moving on down the line,
reagrdless of the impedance of the two paths? That would render all
surge protection about 50% effective.




| Two sources directly contradict Phil.

What sources? *Your truncated out of context quotes?

| Phil has provided no sources to support phantasy physics.

I don't care.

--
|WARNING: Due to extreme spam, I no longer see any articles originating from *|
| * * * * Google Groups. If you want your postings to be seen by more readers |
| * * * * you will need to find a different place to post on Usenet. * * * * *|
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

Ï "Tantalust" Ýãñáøå óôï ìÞíõìá
. ..
"NB" wrote in message
...
Who is W_TOM and why has he appeared in every single thread that has
contained those keywords since 2001???

He an obsessive-compulsive disorder victim, apparently driven by some kind
of bizarre fetish involving ground rods.


What kind of ground rods? I prefer steel core, copper clad ones:-) I even
have the special heavy hammer


--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr

On May 5, 10:54*am, "Dave" wrote:
I wonder why, since electrical codes in North America
and Britain require a ground connection at each outlet;
computer power cords are 3 wire?

(snip)

hot neutral ground


Meanwhile, I'm still waiting for an explanation from w_ about how
surege protection inside that computer can work? Where is that
direct connection to earth ground, without which w_ says surge
protection is impossible? Does the computer have a mythical earth
ground inside? The answer is it doesn't. It is acting under exactly
the same limitations and uses the same components, typically MOVs to
do what a plug-in surge supressor does. w-'s answer to this is to
claim that electronics, appliances, etc do not use MOVs, a claim
previously smashed, because of course they do. Plus it really has
nothing much to do with the question anyway, because the computer,
appliance, etc still HAS NO DIRECT EARTH GROUND, without which w- says
protection is impossible.

In article ,
Dave wrote:

I wonder why, since electrical codes in North America
and Britain require a ground connection at each outlet;
computer power cords are 3 wire?


(snip)

hot neutral ground


or, as we call it, Live, Neutral & Earth

--
From KT24 - in "Leafy Surrey"

Using a RISC OS computer running v5.11

On Mon, 5 May 2008 09:28:05 -0700 (PDT), wrote:

On May 5, 10:54*am, "Dave" wrote:
I wonder why, since electrical codes in North America
and Britain require a ground connection at each outlet;
computer power cords are 3 wire?

(snip)

hot neutral ground


Meanwhile, I'm still waiting for an explanation from w_ about how
surege protection inside that computer can work? Where is that
direct connection to earth ground, without which w_ says surge
protection is impossible? Does the computer have a mythical earth
ground inside? The answer is it doesn't. It is acting under exactly
the same limitations and uses the same components, typically MOVs to
do what a plug-in surge supressor does. w-'s answer to this is to
claim that electronics, appliances, etc do not use MOVs, a claim
previously smashed, because of course they do. Plus it really has
nothing much to do with the question anyway, because the computer,
appliance, etc still HAS NO DIRECT EARTH GROUND, without which w- says
protection is impossible.

I'm curous to know how surge suppression can work without a ground
(earth) of any sort. Does the "black box" detect overvoltage and
disconnect the power like an earth leakage safety switch?

This might be fine for a TV, but surely not for a computer.

I don't recall any computer I've owned that did not have a three wire
connection to the mains. That and a MOV is OK for smallish surges, but
I believe that for a large surge, the sort that will blow a telephone
off the wall, one needs a large, short-path earth for the surge
detector to dump the extra power down.

I've got a few plug in protectors here and there to sop up a small
spike, but when a storm is within a few km, I pull the phone wire out
of the ADSL router, and the plug out of the mains. If I'm working at
the time, I might just keep a watch on the weather radar and count
lightning fashes to thunder times. It's rare that I get interrupted. I
have underground power and phone lines so that gives a little extra
protection, I believe. I've been told that Australian phone lines are
the most vulnerable, and the most urgent to protect or disconnect.
I hope to be going wireless soon which obviates this problem.

jack

On Mon, 5 May 2008 19:21:16 +0300, "Tzortzakakis Dimitrios"
wrote:


Ï "Tantalust" Ýãñáøå óôï ìÞíõìá
...
"NB" wrote in message
...
Who is W_TOM and why has he appeared in every single thread that has
contained those keywords since 2001???

He an obsessive-compulsive disorder victim, apparently driven by some kind
of bizarre fetish involving ground rods.


What kind of ground rods? I prefer steel core, copper clad ones:-) I even
have the special heavy hammer

I'm on 2000' of sand, and at the moment, my house earth is the copper
water pipes, but the water corp keep adding plastic bits here and
there, so I don't really trust it. I was going to hammer in a 20'
length of 3/4" copper pipe under a large tree which gets the drain
from my grey water. Probably the best I can do.

I'm not a full bottle on earth loops yet so i don't know about leaving
the water mains connection still connected.
What's the best way to test an earth?
I heard once that a large electric radiator (fire) connected between
active (hot) and the earth will glow as per normal if the earth has
good capacity. Perhaps a current comparison between the earth return
and neutral return would be more informative?


jack

On Mon, 5 May 2008 09:24:41 -0400, "Tantalust"
wrote:

"w_tom" wrote

Yes, plug-in protectors do have limited protective functions.

Look at poor w_tom starting his back-pedalling.
Back-pedalling, back-pedalling, back-pedalling.


As I understand it, there is not "protection", or "no protection"
That is, it is not black and white, but degrees of protection, as
there are degrees of surge, or spike.

There is absolute protection of whole of house costing many thousands
of dollars, with tinfoil hats thrown in at no extra cost
And there is $7 protection against weeny little spikes/surges, and
then there is everything in between at varying prices.

The old saw "you get what you pay for" is generally bull**** IMHO
You get what the ******* will let you get away with IME

jack

In article , Jitt
writes

I wonder why, since electrical codes in North America
and Britain require a ground connection at each outlet;
computer power cords are 3 wire?

Many older domestic installations in N America are two-wire only (no
ground.)

In the UK and much of Europe, all outlets are grounded, so surge
protectors do work effectively. w_tom has been informed of this fact
many times but continues telling blatant lies, spreading FUD, and
misrepresenting what others write.

--
(\__/) Bunny says NO to Windows Vista!
(='.'=) http://www.cs.auckland.ac.nz/~pgut00...ista_cost.html
(")_(") http://www.cypherpunks.to/~peter/vista.pdf

wrote in message
...
On Mon, 5 May 2008 09:24:41 -0400, "Tantalust"
wrote:

"w_tom" wrote

Yes, plug-in protectors do have limited protective functions.

Look at poor w_tom starting his back-pedalling.
Back-pedalling, back-pedalling, back-pedalling.


As I understand it, there is not "protection", or "no protection"
That is, it is not black and white, but degrees of protection, as
there are degrees of surge, or spike.

There is absolute protection of whole of house costing many thousands
of dollars, with tinfoil hats thrown in at no extra cost
And there is $7 protection against weeny little spikes/surges, and
then there is everything in between at varying prices.

The old saw "you get what you pay for" is generally bull**** IMHO
You get what the ******* will let you get away with IME

jack

Yeah, but search google groups with the terms "plug in protectors".....
returning 33 instances clearly showing that wobbly_tom was bewildered on the
issue and he's back-pedalling now, as we expected.

In article ,
en writes

I'm curous to know how surge suppression can work without a ground
(earth) of any sort.

Surge suppressors usually have three MOVs: one between phase and
neutral, and one each from phase and neutral to earth.

On properly grounded outlets, such a suppressor can deal with an
incoming surge on phase or neutral in an effective manner by conducting
and diverting current to the other leg AND to ground, but their
effectiveness when used on ungrounded outlets is reduced, since the path
to ground doesn't exist.

w_**** chooses to conveniently ignore this fact and continues to peddle
his unique brand of lies, misrepresentation and FUD in his own
inimitable style, which another poster has described as "hostile".

It's telling that w_ was unable to understand that people perceive his
posting style as hectoring or hostile, which should give you some idea
of his mental state

Best place for w_'s posts is in the killfile.

--
(\__/) Bunny says NO to Windows Vista!
(='.'=) http://www.cs.auckland.ac.nz/~pgut00...ista_cost.html
(")_(") http://www.cypherpunks.to/~peter/vista.pdf

In alt.engineering.electrical wrote:
| On May 5, 1:44?am, wrote:
| In alt.tv.tech.hdtv bud-- wrote:| wrote:
|
| | In alt.engineering.electrical Leonard Caillouet wrote:| | wrote in message
|
| | ...
| | | In alt.tv.tech.hdtv Franc Zabkar wrote:
| | |
| | |
| | | The MOVs will act like conductors when they are clamping. ?The surge will
| | | take both paths ... the path through the MOVs, and the path going past the
| | | MOVs. ?In general, about 50% will go each way. ?That can vary at higher
| | | frequencies.
| | |
| | | Why would you assume that 50% will go each way when you don't know the
| | | impedance of each direction? ?When conducting, or at failure, the MOV has a
| | | very low impedance.
| |
| | There is a distinction between "go each way" and "what comes back" due to
| | the impedance. ?It will be about 50% that goes each way _because_ the power
| | itself does not (yet) know the impedance (at a distance), until it gets
| | there.
| |
| | Another installment of Phil's Phantasy Physics using transmission line
| | theory.
|
| Not understanding it is your loss.
|
|
| I have to agree that this is Phantasy Physics. We're supposed to
| believe that a surge reaching a MOV is going to split 50-50, with half
| of it going to the MOV path and half moving on down the line,
| reagrdless of the impedance of the two paths? That would render all
| surge protection about 50% effective.

You did not read very carefully. The reference to 50-50 split is about the
contribution of the MOVs themselves. That is an essential understanding of
the components so the whole system can be figured out. The impedance down
the paths is another separate component, which also has to be figured in
when determining the whole picture.

You have confused a component with the entire system. You need to read more
carefully. Or you need to understand the distinction of individual components
as they apply to the whole system

The whole wiring system is extrememly complex. It cannot be understood
properly without first understanding the components. And that includes
understanding that MOVs, when they conduct, do look to the propogating
energy as two paths to go down, and it will (initially) go both ways in
about an equal amount.

--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

"w_tom" wrote in message
...
People who are more than TV repairmen learn from their mistakes and
correct reasons for that failure. TV repairmen only fix defects -
never bother to learn how those failures can be avoided. Let's have
some fun. Let's reply using the same mockery and insult that Michael
uses. Except this post will be accurate about Michaels intelligence.

I am merely a TV repairman who happens to have quite a bit of education, and
has done much research on the matter. We began installing good basic MOV
based suppression on our clients' systems long ago, using system level units
that protect all incoming lines. We also pay close attention to proper
grounding. What we have found over many years of this practice in one of
the most lightning intense areas of the USA, is that our systems never take
damage. During times of high thunderstorm activity, however, we see several
times the repair volume, and invariably, the user did not use a surge
suppressor. Our clients are happy with the systems that we sell and with
the reliability. There are good reasons to suspect that system level surge
suppressors do work, but grounding cannot be ignored.

As for you w_tom, you have done far more to clutter groups than to provide
any useful information. While your emphasis on grounding is good advice,
much of the rest of your arguments are out of context and misleading.
Michael may be a crochety ass sometimes, but at least he consistently
provides useful information. Stick to preaching the importance of grounding
and give the rest a break.

Leonard

In article , Timothy Daniels
writes

Does that mean a combination of w_tom's "whole house protection"
and individual "surge protectors" at those "critical devices"? That's
what I've always felt would be prudent - not a single method of
protection, but a combination.

Yes, but the environment in which the protected dwelling is situated
should also be taken into account. For example, a house in Florida,
with its overhead power lines and frequent thunderstorms, would be a
more likely candidate for a combined approach to surge protection.

On the other hand, installing Florida-levels of protection in a house in
the UK with its infrequent storms, reliable underground power supply and
a decent electrical system with properly earthed sockets, would be a
waste of money.

It is those nuances that w_**** fails to explain when he spouts his one-
cure-for-all-ills religious mantra about every dwelling absolutely
requiring whole-house surge protection. Like another poster to this
thread has said, things are never black and white, but shades of grey.
The sensible approach is to evaluate the risk and install an appropriate
level of protection.

--
(\__/) Bunny says NO to Windows Vista!
(='.'=) http://www.cs.auckland.ac.nz/~pgut00...ista_cost.html
(")_(") http://www.cypherpunks.to/~peter/vista.pdf

wrote:
In alt.tv.tech.hdtv bud-- wrote:
| wrote:
| In alt.tv.tech.hdtv bud-- wrote:
| | wrote:
| | In alt.tv.tech.hdtv bud-- wrote:

| | For example, consider the high frequency issue. High frequency energy is
| | less common than low frequency energy. Partly this is because the chance
| | of a closer lightning strike is less than a more distant one. A strike
| | within 100 meters is only 1/8 as like as a strike outside of 100 meters
| | but within 300 meters. Some people then feel that they can dismiss high
| | frequency energy issues entirely.
| |
| | Francois Martzloff was the surge guru at the NIST and has many published
| | papers on surges and suppression. In one of them he wrote:
| | "From this first test, we can draw the conclusion (predictable, but too
| | often not recognized in qualitative discussions of reflections in wiring
| | systems) that it is not appropriate to apply classical transmission line
| | concepts to wiring systems if the front of the wave is not shorter than
| | the travel time of the impulse. For a 1.2/50 us impulse, this means that
| | the line must be at least 200 m long before one can think in terms of
| | classical transmission line behavior."
| | Residential branch circuits aren't 200m.
| |
| | Your response: "Then he flubbed the experiment." In another case you
| | have said Martzloff had a hidden agenda.
|
| I addressed this one elsewhere. You seem to have misunderstood him.
| He did not say that wiring systems do not exhibit transmission line
| characteristics.
|
| If you had actually read the quote:
| "*it is not appropriate to apply classical transmission line concepts to
| wiring systems*"
| and "*this means that the line must be at least 200 m long before one
| can think in terms of classical transmission line behavior*."
|
| Repeating: "Residential branch circuits aren't 200m."

You are now taking what Martzloff said out of context. He _qualified_
what he said in terms of a statement conditional. Following the part
you just now quoted is "... if the front of the wave is not shorter than
the travel time of the impulse." Then he added "For a 1.2/50 us impulse,
this means that the line must be at least 200 m long before one can think
in terms of classical transmission line behavior."

Hint: what "if" means is that if the conditional is not met, then the
statement does not apply.

Martzloff's statement is actually correct. Your quoting of it is wrong.
I suspect your understanding of it is weak or maybe even wrong. I believe
you are misapplying it. Then when _my_ statement contradicts _your_
incorrect understanding, you somehow think *I* am contradicting him.

His statement is qualified for a specific slow impulse rise time that
corresponds to a lower frequency. He has NOT said (in what you quoted
in earlier posts here) that no surge can ever have a faster rise time.
He has NOT said that you cannot think in terms of transmission line
behaviour for faster rise times, even on shorter wiring/circuits.

Previously you said Martzloff "flubbed the experiment".

Now you agree with Martzloff that branch circuit must be 200m for
transmission line behavior with 1.2 microsecond rise time.

You say that doesn't apply because surges are faster. Martzloff uses 1.2
us because that is a standard rise time for surges produced by lightning
as defined in IEEE standards.

w_' professional engineer source says 8 micoseconds with most of the
spectrum under 100kHz.


You still have *no sources that support your belief* that risetimes are
far faster.


| | You claim lightning induced surges have rise times about a thousand
| | times faster than accepted IEEE standards - which are experimentally
| | derived.
|
| So you are narrowing this statement to only induced surges?
|
| I intended "induced" meaning produced by including the most damaging -
| strikes to utility lines.

The most damaging strikes tend to be ones that are NOT induced. Do you
understand what induction and inductive coupling is?

Lightning does not have to directly strike the wire for there to be a
surge on it. That is induction when there is no direct strike. If the
strike _is_ directly on the wires, that's different (and has the exposure
of substantially more voltage/current).

Again you did not read what I wrote (what a surprise):
"I intended 'induced' meaning produced by including the most damaging -
strikes to utility lines."

--
bud--

w_tom wrote:

Both of Bud's citations - guides for laymen

The IEEE guide is aimed at "electricians, architects, technicians, and
electrical engineers who were not protection specialists."


Bud quotes from Martzloff
selectively. Meanwhile this conclusion is so fundamental that
Martzloff makes it the first point in his IEEE paper:

Quotes selectively? How pathetic. w_ forgets to mention that Martzloff
said in the same document:
"Mitigation of the threat can take many forms. One solution. illustrated
in this paper, is the insertion of a properly designed surge reference
equalizer [multiport plug-in surge suppressor]."

In 2001 Martzloff wrote the NIST guide which also says plug-in
suppressors are effective.

Also are those 'scary pictures of plug-in protectors

And lacking valid technical arguments w_ repeats the lie again.

Still missing - a link to any source that says UL listed plug-in
suppressors made after 1998 are a problem.

Still missing - a source that agrees with w_ that plug-in suppressors
are NOT effective.

Still missing - answers to simple questions:
- Why do the only 2 examples of surge suppression in the IEEE guide use
plug-in suppressors?
- Why does the NIST guide says plug-in suppressors are "the easiest
solution"?
- Why do all but one of w's "responsible manufacturers" make plug-in
suppressors?
- Why does SquareD say in addition to their "whole house" suppressors
"electronic equipment may need additional protection" from plug-in
suppressors.
- Why aren't airplanes crashing daily when they get hit by lightning (or
do they drag an earthing chain)?

For real science read the IEEE and NIST guides. Both say plug-in
suppressors are effective.

--
bud--

In alt.engineering.electrical Jitt wrote:
| In article 74683977-6a03-4695-a5a2-
| ,
| says...
| On May 3, 4:38?am, Franc Zabkar wrote:
| Can you elaborate on this by showing us the path taken by the strike
| through the TV?
|
| Path to earth was through the network and into a third computer.
| Through that third computer's motherboard, through modem, and to earth
| via phone lines. Semiconductors in these paths were damaged.
|
| We literally traced this path by replacing ICs. Some ICs (ie
| network interface chips) even had cracks on packages where surge
| current entered or exiting those ICs. Absolutely no doubt as to how
| surge currents found earth ground, destructively, via adjacent
| computers.
|
| I wonder why, since electrical codes in North America
| and Britain require a ground connection at each outlet;
| computer power cords are 3 wire?

What good is having the ground connection at each outlet if it is not used?
Are British power cords for computers only 2 wire?

2 of the wires are power conductors. Usually one of the is grounded somewhere
back along the path to the power system source. But it is possible for one to
have a connection with two hot wires (208V from three phase or 240V from single
phase in North America ... 400V from three phase in Europe ... I doubt any of
those 230/460 single phase systems are around anymore in Britain).

The 3rd wire is the groundING conductor. It is not supposed to carry any
current except in the case of a fault between a hot wire and the case or
frame of the computer (or whatever appliance is involved). While this is
a rare event, it is a more important protection in the case of appliances
that routinely get handled by people more than just being turned on and off.
An electric table lamp might not need the grounding conductor because of the
infrequent handling just to turn it on and off. A computer or cooker would
be handled more than a lamp. A computer would be subject to more handling
than the cooker, but the cooker would be subject to being wet. Both of them
are in far more need of the grounding protection than the lamp.

--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

Don Kelly wrote:
----------------------------
"Tony Hwang" wrote in message
news:dncTj.112858$rd2.31639@pd7urf3no...
wrote:
In alt.tv.tech.hdtv Michael A. Terrell
wrote:

| Bull****. Like ALL charges, it simply seeks a complete circuit to
| flow. You have absolutely no grasp of the basic concepts, yet you
| continue to spout your ignorance and lies.

Not true.

When you close a switch between a power source and a pair of wires that
go
out yonder, the electrical energy does not "know" whether the circuit is
complete or not. If it refused to flow, it would not be able to find
out.
It will flow, whether the circuit is complete or not. What happens after
that depends on what is at the other end, which could be an open
condition,
a short circuit, or some kind of resistive or reactive load.

You've claimed to have worked in broadcasting in an engineering role. So
you should understand what happens at the end of an open transmission
line.
The electricity flows to get to the open end. Yet it is not a "complete
circuit".

Hmmm,
You seem to be confused between current flow(energy) and voltage(poential)
Nothing flows in an open circuit. If not we have to rewrite Ohm's law.
Show your credential to make a stamement like that.
Shameful.
------------------------
Actually, you are showing some confusion. Phil is right in that he is
bringing out a point that normal lumped RLC circuit theory doesn't handle
because it essentially treats the speed of propagation of electrical signals
as if it were infinite- which isn't true.
.
2)Also, on energizing a line whether it is open or closed, there is a
current flow as the applied voltage "sees" the characteristic impedance of
the line (wire or whatever) so a current will flow-even on an open circuit-
until there is a modifying reflection from the termination. For a house the
distances are such that this may be of the order of 0.1-0.2 microsecond.
After all such reflections at terminations have ceased or are negligable,
conventional circuit theory is applicable.
In these situations, you are dealing with wave propagation rather than
conventional circuit theory.
This is the regime that is of interest in considering "surge protectors"

The last standards for simulating typical surge waveforms I have seen
(IEEE) were
1.2 us rise time, 50 us duration
8 us rise time, 20 us duration
a ring wave with a frequency about 100kHz.

All are long relative to 0.2 microsecond, so wave propagation should not
be relevant for household circuits.

A favorite article from w_ also uses a "8x20 us impulse as a very rough
representative pulse" with most harmonic content from 20kHz to 100kHz.

Martzloff, using the shorter rise time, has written: "For a 1.2/50 us
impulse, this means that the line must be at least 200 m long before one
can think in terms of classical transmission line behavior."

What reason is there to believe wave propagation is relevant to house
circuits?


As to the advantage of "whole house" vs local surge protection, "whole house
protection depends on distances to all "protected" items being small.

Longer distances make the system more subject to effects like direct
induction from lightning into the wiring. I don't see why, in general,
the distance has to be small.


--
bud--

In alt.tv.tech.hdtv bud-- wrote:

| Previously you said Martzloff "flubbed the experiment".

I remember that. You were telling me about some information he had
obtained from some experiment.


| Now you agree with Martzloff that branch circuit must be 200m for
| transmission line behavior with 1.2 microsecond rise time.

That's not a result of an experiment. I'm not so sure the exact distance
is 200m for that exact rise time. But that is a subjective thing. We are
likely not that far apart. It is a matter of degree to how different the
calculations come out when figuring them with transmission line issues and
ignoring those issues.


| You say that doesn't apply because surges are faster. Martzloff uses 1.2
| us because that is a standard rise time for surges produced by lightning
| as defined in IEEE standards.

Martzloff did not say that was a defined standard in the statement you
quoted. He just used it as an example to come up with the 200m figure.
Do you have some other statement from Martzloff or someone else about the
1.2 microsecond rise time?


| w_' professional engineer source says 8 micoseconds with most of the
| spectrum under 100kHz.

Even with 1 nanosecond rise time, most of the energy will be present in
the spectrum below 100 kHz. That means nothing when the surge is strong
enough to have energy above some frequency that is relevant to the whole
system involved that can do damage. That frequency might be 100 Mhz for
some thing, and 1 GHz for other things. Some surges, mostly from very
close direct strikes, can have damaging energy well above 1 GHz. It will
depend on how much inductance you have between the surge and the equipment
that needs to be protected. That's why I suggest that a good protection
scheme will include added inductance on the wiring at a level compatible
with the normal use (more can be added to power than to cable TV).


| You still have *no sources that support your belief* that risetimes are
| far faster.

I have experience and observation for that. I need no more.


| Again you did not read what I wrote (what a surprise):
| "I intended 'induced' meaning produced by including the most damaging -
| strikes to utility lines."

You are saying the most damaging strikes are induced? Or are you merely
adding the most damaging direct strikes in with the induced surges as a
set of surge classes that you want to consider together?

Your wording is so bad in that one sentence that I cannot tell what you mean.
It is vague and could satisfy more than one meaning.

--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

Mike Tomlinson wrote:
In article , Timothy Daniels
writes

Does that mean a combination of w_tom's "whole house protection"
and individual "surge protectors" at those "critical devices"? That's
what I've always felt would be prudent - not a single method of
protection, but a combination.

Yes, but the environment in which the protected dwelling is situated
should also be taken into account. For example, a house in Florida,
with its overhead power lines and frequent thunderstorms, would be a
more likely candidate for a combined approach to surge protection.

On the other hand, installing Florida-levels of protection in a house in
the UK with its infrequent storms, reliable underground power supply and
a decent electrical system with properly earthed sockets, would be a
waste of money.


Nice description. What you use depends on risk, and value of what you
are protecting.

The IEEE guide has, for max protection (not including lightning rods)
- adequate earthing
- short 'ground' wires from cable and phone entry protectors to the
'ground' at the power service (to limit the voltage between power and
signal wires)
- power service suppressor
- plug-in suppressor for high value "sensitive" electronics - especially
equipment with both power and signal connections (all wires to protected
equipment needs to go through the suppressor)



--
bud--

In alt.tv.tech.hdtv en wrote:

| I'm curous to know how surge suppression can work without a ground
| (earth) of any sort. Does the "black box" detect overvoltage and
| disconnect the power like an earth leakage safety switch?

Without a ground of any sort, not all types of surges can be protected against.
But some can.

If the surge is a differential one (some use the term transverse), then what
the surge suppressor can do is cancel it out by effectively short circuiting
it to itself. A differential surge involves two wires with the voltage on
each being of opposite polarity and equal level. The MOV component inside
the suppressor will normally not be conductive. But when the voltage is high
enough, it becomes a conductor. The arrival of a high voltage differential
surge will result in the MOV between those 2 wires to become conductive.

If the surge is a common mode one, AND if the surge has a slow rise time,
then a device that is interconnected to other wires or other devices can
be protected by allowing the surge to pass to all devices at the same level.
As long as the rise is not too fast, keeping all the incoming wires, and all
the interconnected devices, at the same level results in insignificant current
flows. That surge will either reflect back from the protected equipment to
the suppressor, and from there go back through all the connected wires (which
could be more than where the surge arrived from).

Most strikes have lower energy levels at high frequencies than what would
cause damage. The exact frequency level that needs to be considered depends
on the internals of the equipment. For example, where it has inductance to
one end of a sensitive component like a CMOS chip, and no inductance to some
other end, this could result in a very brief fast rise of voltage high enough
to damage the CMOS chip. In some cases an LC circuit can actually increase
the voltage level of high frequency components (at the resonant frequency).
For example if you have energy at some voltage at 200 MHz, an LC series
circuit resonant at 200 MHz will result in a higher voltage being present
at the connection between the L and the C. So even in cases where there is
not enough energy at high frequency in a surge to cause direct damage, it
can still happen on some devices (think of them as having a lower threshold
of damage to simplify this).


| This might be fine for a TV, but surely not for a computer.

If everything the computer is connected to is protected at a common point
in the same surge suppressor, you can have this kind of protection, even
on a computer. That does mean if you have a phone line connected to a
modem, you need to protect both the phone line itself and the power to the
modem, in common with the computer.


| I don't recall any computer I've owned that did not have a three wire
| connection to the mains. That and a MOV is OK for smallish surges, but
| I believe that for a large surge, the sort that will blow a telephone
| off the wall, one needs a large, short-path earth for the surge
| detector to dump the extra power down.

Such a surge is likely to have high levels of high frequency energy. The
effective protection against these rare events is a combination of somewhere
to divert the energy (like a ground path), and something (like an inductor)
to ensure the energy does get diverted.

One problem is that at the point of use, an alternate ground path is not
practical. The grounding wire of the power circuit coule be as much a source
of the surge as the neutral wire would be. The place to put the diversion
system is at the entrance to the building. Most surges that come in by other
paths besides the entrance to the building are induced surges that will not
have so much energy and even less at high frequencies.

Still, I have seen three incidents in which an induced surge damaged a device
that was not connected to anything at all (in two cases they were battery
powered devices, and in the third, it was disconnected before the storm but
suffered damage anyway).


| I've got a few plug in protectors here and there to sop up a small
| spike, but when a storm is within a few km, I pull the phone wire out
| of the ADSL router, and the plug out of the mains. If I'm working at
| the time, I might just keep a watch on the weather radar and count
| lightning fashes to thunder times. It's rare that I get interrupted. I
| have underground power and phone lines so that gives a little extra
| protection, I believe. I've been told that Australian phone lines are
| the most vulnerable, and the most urgent to protect or disconnect.
| I hope to be going wireless soon which obviates this problem.

Disconnecting provides even better (but still not 100%) protection. Yes, the
underground wiring helps. I don't know the issues with Australian phone lines.
I do the wireless thing myself and feel much more comfortable with it. Most
of the past damaging surges I've seen come in do that on phone and cable wires,
and much less often on power wires. That may be due to the more sensitive
aspect of equipment where it connects to these wires.

--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

In alt.tv.tech.hdtv bud-- wrote:

| The last standards for simulating typical surge waveforms I have seen
| (IEEE) were
| 1.2 us rise time, 50 us duration
| 8 us rise time, 20 us duration
| a ring wave with a frequency about 100kHz.

So now you are saying these figures represent a typical surge waveform,
as opposed to the worst case waveform you said a long time ago.

The term typical is generally accepted as a median. That means half of
the surges would have a slower rise time, and half would have a faster
rise time.

My concerns are not the typical surges. I suggest that half the surges
don't even need protection at all; they won't cause damage even if there
is no protection. But that also means half can be damaging and need the
protection. And a fraction of those surges need _substantial_ protection.


| All are long relative to 0.2 microsecond, so wave propagation should not
| be relevant for household circuits.

Maybe for the typical surge. How about for the most energetic 1% that are
the ones I'm most concerned with because they are hard to protect against.


| A favorite article from w_ also uses a "8x20 us impulse as a very rough
| representative pulse" with most harmonic content from 20kHz to 100kHz.
|
| Martzloff, using the shorter rise time, has written: "For a 1.2/50 us
| impulse, this means that the line must be at least 200 m long before one
| can think in terms of classical transmission line behavior."

And this statement is only using 1.2/50 us as an example. If you think
such a timing is the standard, why not offer a quote that actually says
that?

What does the "/" mean in that case, anyway? I never got to ask you that
before. Does it mean "divide 1.2 by 50"?


| What reason is there to believe wave propagation is relevant to house
| circuits?

The most damaging surges (not the typical ones) have substantial fast rise
high frequency energy (such as due to a very close direct contact strike).
In these cases, even if you can remove all of the low frequency energy, there
is still damaging energy in the higher frequencies that do follow transmission
line behaviour not only in wiring lengths of typical homes, but even in wiring
lengths inside a small appliance like a computer modem.


| As to the advantage of "whole house" vs local surge protection, "whole house
| protection depends on distances to all "protected" items being small.
|
| Longer distances make the system more subject to effects like direct
| induction from lightning into the wiring. I don't see why, in general,
| the distance has to be small.

I believe he was referring to the distance between the whole house protection
and the ground/earth electrode.

For things like the service drop distance and the branch circuit distance, it
can be a tradeoff between different kinds of surges. The longer wiring will,
through its self-inductance, reduce the high frequency energy and slew the
rise time of the wavefront ... especially for common mode surges. However,
that same longer distance increases the potential level of induced surges
where the wire is effectively an antenna.

--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

In alt.engineering.electrical bud-- wrote:
| wrote:
| In alt.tv.tech.hdtv bud-- wrote:
|
| | The last standards for simulating typical surge waveforms I have seen
| | (IEEE) were
| | 1.2 us rise time, 50 us duration
| | 8 us rise time, 20 us duration
| | a ring wave with a frequency about 100kHz.
|
| So now you are saying these figures represent a typical surge waveform,
| as opposed to the worst case waveform you said a long time ago.
|
| Still missing - your source that indicates nanosecond rise times and
| 100MHz spectrum.

Observation.


| What does the "/" mean in that case, anyway? I never got to ask you that
| before. Does it mean "divide 1.2 by 50"?
|
| It is standard notation in the surge field. 1.2 us risetime and 50 us
| duration

And what does the duration time have to do with high frequency energy?
Hint: nothing

--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

wrote:
In alt.tv.tech.hdtv bud-- wrote:

| The last standards for simulating typical surge waveforms I have seen
| (IEEE) were
| 1.2 us rise time, 50 us duration
| 8 us rise time, 20 us duration
| a ring wave with a frequency about 100kHz.

So now you are saying these figures represent a typical surge waveform,
as opposed to the worst case waveform you said a long time ago.

Still missing - your source that indicates nanosecond rise times and
100MHz spectrum.


What does the "/" mean in that case, anyway? I never got to ask you that
before. Does it mean "divide 1.2 by 50"?

It is standard notation in the surge field. 1.2 us risetime and 50 us
duration

--
bud--

wrote:
In alt.tv.tech.hdtv bud-- wrote:

| Previously you said Martzloff "flubbed the experiment".

I remember that. You were telling me about some information he had
obtained from some experiment.

| Now you agree with Martzloff that branch circuit must be 200m for
| transmission line behavior with 1.2 microsecond rise time.

That's not a result of an experiment.

"*From this first test*, we can draw the conclusion (predictable, but
too often not recognized in qualitative discussions of reflections in
wiring systems) that it is not appropriate to apply classical
transmission line concepts to wiring systems if ..."

As usual, you don’t know what was written.

I'm not so sure the exact distance
is 200m for that exact rise time. But that is a subjective thing.

Quit equivocating. Where is your cite. Like for nanosecond risetimes.


| You say that doesn't apply because surges are faster. Martzloff uses 1.2
| us because that is a standard rise time for surges produced by lightning
| as defined in IEEE standards.

Martzloff did not say that was a defined standard in the statement you
quoted. He just used it as an example to come up with the 200m figure.

He used it because 1.2/50 (voltage) is an IEEE standard. The 8us from
w_’s engineer is another standard (8/20 current).


| w_' professional engineer source says 8 micoseconds with most of the
| spectrum under 100kHz.

Even with 1 nanosecond rise time, most of the energy will be present in
the spectrum below 100 kHz. That means nothing when the surge is strong
enough to have energy above some frequency that is relevant to the whole
system involved that can do damage. That frequency might be 100 Mhz for
some thing, and 1 GHz for other things.

Still missing – your source. Nanosecond risetime. 100MHz spectrum.


| You still have *no sources that support your belief* that risetimes are
| far faster.

I have experience and observation for that. I need no more.

Lots of people have experience and observation with flying saucers.

The rest of us want a source.

--
bud--

Leonard Caillouet wrote:
"w_tom" wrote in message
...
People who are more than TV repairmen learn from their mistakes and
correct reasons for that failure. TV repairmen only fix defects -
never bother to learn how those failures can be avoided. Let's have
some fun. Let's reply using the same mockery and insult that Michael
uses. Except this post will be accurate about Michaels intelligence.

I am merely a TV repairman who happens to have quite a bit of education,
and has done much research on the matter. We began installing good
basic MOV based suppression on our clients' systems long ago, using
system level units that protect all incoming lines. We also pay close
attention to proper grounding. What we have found over many years of
this practice in one of the most lightning intense areas of the USA, is
that our systems never take damage. During times of high thunderstorm
activity, however, we see several times the repair volume, and
invariably, the user did not use a surge suppressor. Our clients are
happy with the systems that we sell and with the reliability. There are
good reasons to suspect that system level surge suppressors do work, but
grounding cannot be ignored.

As for you w_tom, you have done far more to clutter groups than to
provide any useful information. While your emphasis on grounding is
good advice, much of the rest of your arguments are out of context and
misleading. Michael may be a crochety ass sometimes, but at least he
consistently provides useful information. Stick to preaching the
importance of grounding and give the rest a break.

Leonard

Thank you, Leonard, for a breath of fresh air in this onerous thread
that w_tom perpetuates ad infinitum. This isn't his first, for newbies
trying to fathom his morass.

I've been a TV repairman. I'm now a "communications electrician" which
means I deal with telephone lines/switches, land-mobile radio, microwave
radio systems, security systems, and the like; in high-voltage
switchyards and substations. We deal with huge surges from switching
transients and direct lightning hits on the transmission lines. I know
first-hand what happens when surges hit. When I said "transmission
lines", I'm talking both from the 60hz side as well as the RF side as
the lengths are sufficient to act that way.

Define "ground" or "earth", Mr w_tom. Have you ever run an ANSI spec
ohms test on one? I think not. I've done grounding for military tactical
radio systems and complete commo systems. What you think is "ground" may
not be ground at all due to soil composition. I've seen ground rod
"farms" made up of 20+ vertical 8' rods on a 10 foot grid come up in the
500 kilohms range when the same rods in the same location would test
lower than 1000 ohms if those same stakes were buried sideways 18" below
surface.

Substations/switchyards have "ground mats" of heavy copper wire in a
grid spacing of 1-2 feet and about 6 feet under everything that's
covered with gravel. It's also cad-welded at all intersections to
prevent corrosion. This ground mat system is also used at well-designed
radio sites. Even with this elaborate grounding system, a major
malfunction at 230KV can create such a voltage differential to induce
fatal "step voltage" between your legs.
http://ballengearry.com.au/papers/St...004_090804.pdf

For 120Vac grounding on our equipment, we try our best to bring all
equipment grounds (racks and cable trays as well) to a single point that
*then* connects to the building's ground as close as possible. We do
have the advantage of most equipment running off DC at 24, 48, or 130
Vdc on huge battery racks that can absorb a lot of surge energy.....

In alt.engineering.electrical bud-- wrote:
| wrote:
| In alt.tv.tech.hdtv bud-- wrote:
|
| | Previously you said Martzloff "flubbed the experiment".
|
| I remember that. You were telling me about some information he had
| obtained from some experiment.
|
| | Now you agree with Martzloff that branch circuit must be 200m for
| | transmission line behavior with 1.2 microsecond rise time.
|
| That's not a result of an experiment.
|
| "*From this first test*, we can draw the conclusion (predictable, but
| too often not recognized in qualitative discussions of reflections in
| wiring systems) that it is not appropriate to apply classical
| transmission line concepts to wiring systems if ..."
|
| As usual, you don?t know what was written.

What what kind of surge did Martzloff use to carry out that test?


| I'm not so sure the exact distance
| is 200m for that exact rise time. But that is a subjective thing.
|
| Quit equivocating. Where is your cite. Like for nanosecond risetimes.

Observation.


| | You say that doesn't apply because surges are faster. Martzloff uses 1.2
| | us because that is a standard rise time for surges produced by lightning
| | as defined in IEEE standards.
|
| Martzloff did not say that was a defined standard in the statement you
| quoted. He just used it as an example to come up with the 200m figure.
|
| He used it because 1.2/50 (voltage) is an IEEE standard. The 8us from
| w_?s engineer is another standard (8/20 current).

The standard for what? The typical surge?


| | w_' professional engineer source says 8 micoseconds with most of the
| | spectrum under 100kHz.
|
| Even with 1 nanosecond rise time, most of the energy will be present in
| the spectrum below 100 kHz. That means nothing when the surge is strong
| enough to have energy above some frequency that is relevant to the whole
| system involved that can do damage. That frequency might be 100 Mhz for
| some thing, and 1 GHz for other things.
|
| Still missing ? your source. Nanosecond risetime. 100MHz spectrum.

Observation. Of course this is a concept you cannot understand.


| | You still have *no sources that support your belief* that risetimes are
| | far faster.
|
| I have experience and observation for that. I need no more.
|
| Lots of people have experience and observation with flying saucers.
|
| The rest of us want a source.

The only flying saucers I have seen are the ones I've tossed.

--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

bud-- wrote:

wrote:

In alt.tv.tech.hdtv bud-- wrote:

| The last standards for simulating typical surge waveforms I have
seen | (IEEE) were
| 1.2 us rise time, 50 us duration
| 8 us rise time, 20 us duration
| a ring wave with a frequency about 100kHz.

So now you are saying these figures represent a typical surge waveform,
as opposed to the worst case waveform you said a long time ago.


Still missing - your source that indicates nanosecond rise times and
100MHz spectrum.


What does the "/" mean in that case, anyway? I never got to ask you that
before. Does it mean "divide 1.2 by 50"?


It is standard notation in the surge field. 1.2 us risetime and 50 us
duration

Sloppy notation.

In article ,
says...
bud-- wrote:

wrote:

In alt.tv.tech.hdtv bud-- wrote:

| The last standards for simulating typical surge waveforms I have
seen | (IEEE) were
| 1.2 us rise time, 50 us duration
| 8 us rise time, 20 us duration
| a ring wave with a frequency about 100kHz.

So now you are saying these figures represent a typical surge waveform,
as opposed to the worst case waveform you said a long time ago.


Still missing - your source that indicates nanosecond rise times and
100MHz spectrum.


What does the "/" mean in that case, anyway? I never got to ask you that
before. Does it mean "divide 1.2 by 50"?


It is standard notation in the surge field. 1.2 us risetime and 50 us
duration

Sloppy notation.

s/sloppy/concise/

--
Keith

On Mon, 5 May 2008 19:19:16 +0100, Mike Tomlinson
wrote:

but their
effectiveness when used on ungrounded outlets is reduced, since the path
to ground doesn't exist.

I was going to ask whether this would help protect delicate components
in any way, but of course, the neutral is earthed nearby anyways, and
the third earth wire is just a backstop?

jack

In article ,
en writes

I was going to ask whether this would help protect delicate components
in any way,

Yes, as the surge protector is working to some extent, but it would work
far more effectively if it were plugged into a grounded outlet.

There's also the problem that using a surge protector in an ungrounded
outlet will cause the earth on the protector to rise in potential while
the protector is conducting a surge. Depending on the equipment plugged
into that strip, this has the potential to cause damage, as well as an
electrical shock to anyone touching a metal-cased appliance with a 3-pin
lead plugged into the strip.

Thus surge protectors should only be plugged into grounded outlets.
There will usually be a warning on the protector itself or in the user
instructions stating this.

but of course, the neutral is earthed nearby anyways, and
the third earth wire is just a backstop?

No. The earth pin, although bonded to neutral at the consumer unit
(=breaker box in US) should be regarded as a separate, third connection
from then on. The neutral is there to carry return current; the earth
is there for safety.

--
(\__/) Bunny says NO to Windows Vista!
(='.'=) http://www.cs.auckland.ac.nz/~pgut00...ista_cost.html
(")_(") http://www.cypherpunks.to/~peter/vista.pdf

----------------------------
"bud--" wrote in message
.. .
Don Kelly wrote:
----------------------------
"Tony Hwang" wrote in message
news:dncTj.112858$rd2.31639@pd7urf3no...
wrote:
In alt.tv.tech.hdtv Michael A. Terrell
wrote:

| Bull****. Like ALL charges, it simply seeks a complete circuit to
| flow. You have absolutely no grasp of the basic concepts, yet you
| continue to spout your ignorance and lies.

Not true.

When you close a switch between a power source and a pair of wires that
go
out yonder, the electrical energy does not "know" whether the circuit
is
complete or not. If it refused to flow, it would not be able to find
out.
It will flow, whether the circuit is complete or not. What happens
after
that depends on what is at the other end, which could be an open
condition,
a short circuit, or some kind of resistive or reactive load.

You've claimed to have worked in broadcasting in an engineering role.
So
you should understand what happens at the end of an open transmission
line.
The electricity flows to get to the open end. Yet it is not a
"complete
circuit".

Hmmm,
You seem to be confused between current flow(energy) and
voltage(poential) Nothing flows in an open circuit. If not we have to
rewrite Ohm's law. Show your credential to make a stamement like that.
Shameful.
------------------------
Actually, you are showing some confusion. Phil is right in that he is
bringing out a point that normal lumped RLC circuit theory doesn't handle
because it essentially treats the speed of propagation of electrical
signals as if it were infinite- which isn't true.
.
2)Also, on energizing a line whether it is open or closed, there is a
current flow as the applied voltage "sees" the characteristic impedance
of the line (wire or whatever) so a current will flow-even on an open
circuit- until there is a modifying reflection from the termination. For
a house the distances are such that this may be of the order of 0.1-0.2
microsecond. After all such reflections at terminations have ceased or
are negligable, conventional circuit theory is applicable.
In these situations, you are dealing with wave propagation rather than
conventional circuit theory.
This is the regime that is of interest in considering "surge protectors"

The last standards for simulating typical surge waveforms I have seen
(IEEE) were
1.2 us rise time, 50 us duration
8 us rise time, 20 us duration
a ring wave with a frequency about 100kHz.

All are long relative to 0.2 microsecond, so wave propagation should not
be relevant for household circuits.
----------------------------------------
Your point is true- the time interval is so small that for practical
purposes it can be ignored. I am not denying that. Obviously I gave that
impression- sorry for that.

I was simply pointing out that phil had it right in theory and Tony had it
wrong.

After this time for the wave to travel to the end and be reflected (and
other re-reflections die out) then conventional circuit theory is
applicable. The fact that the time is extremely small simply means that we
can pretend that it doesn't even exist.

While Matzloff is right in the time for a round trip is of the order of
200m, it is also dangerous to assume that one can ignore waves for shorter
distances. For example, a stroke to a tower of an EHV line (a lot less than
200m) will go down the tower, meet ground resistance and be reflected.
Such reflections have been found to be more likely to cause flashover than
direct strokes to the line (EPRI). Similarly, the practice in substations
is not "whole station" protection (where this is applicable, it must be done
considering a number of factors- quite interesting ) and putting specific
protection as near as possible to the protected apparatus-definitely within,
say, 10m. - It's not just the time to peak that is the critical factor. Do a
lattice diagram approach or use Bergeron's method (Hermann Dommel did a lot
of work with this at EPRI and has a lot of papers in IEEE- more dealing with
switching surges than lightning).
It's been a long time since I did any calculations in this area so I would
have to brush up.

Now - is this all germane to household protection? You say not and I agree
with you- because household equipment can ride through - at worst- doubling
of the clamped voltage for a very short time even though the clamped voltage
is relatively small compared to the peak of the incoming surge. --

Don Kelly
remove the X to answer


A favorite article from w_ also uses a "8x20 us impulse as a very rough
representative pulse" with most harmonic content from 20kHz to 100kHz.

Martzloff, using the shorter rise time, has written: "For a 1.2/50 us
impulse, this means that the line must be at least 200 m long before one
can think in terms of classical transmission line behavior."

What reason is there to believe wave propagation is relevant to house
circuits?


As to the advantage of "whole house" vs local surge protection, "whole
house protection depends on distances to all "protected" items being
small.

Longer distances make the system more subject to effects like direct
induction from lightning into the wiring. I don't see why, in general,
the distance has to be small.


--
bud--

On May 5, 1:05 pm, wrote:
I'm curous to know how surge suppression can work without a ground
(earth) of any sort. Does the "black box" detect overvoltage and
disconnect the power like an earth leakage safety switch?

This might be fine for a TV, but surely not for a computer.

I don't recall any computer I've owned that did not have a three wire
connection to the mains. That and a MOV is OK for smallish surges, but
I believe that for a large surge, the sort that will blow a telephone
off the wall, one needs a large, short-path earth for the surge
detector to dump the extra power down.

I've got a few plug in protectors here and there to sop up a small
spike, but when a storm is within a few km, I pull the phone wire out
of the ADSL router, and the plug out of the mains. If I'm working at
the time, I might just keep a watch on the weather radar and count
lightning fashes to thunder times. It's rare that I get interrupted. I
have underground power and phone lines so that gives a little extra
protection, I believe.

This will address some of your questions only in summary. Details
are provided in other posts.

First, much of this stuff was learned by earliest 20th century
hams. They would disconnect their antenna, put the lead inside a
mason jar, and still suffer radio damage. Even mason jars could not
stop or block lightning. But then the antenna was earthed, then damage
stopped. It's just like Franklin's lightning rod (air terminal).
Protection has always been about diverting "it to ground, where it can
do no harm". Disconnecting did not provide sufficient protection.
That wire had to be earthed.

Protection for the TV, computer, and all other appliances is same.
Computers contain some of the most robust protection. Computer grade
UPSes can output electricity so dirty (when in battery backup mode) as
to even harm some small electric motors. But computers are so robust
as to make even that 'dirty' electricity irrelevant. Do not assume
computers have less internal protection. Intel ATX standards require
computers to be more robust than what is standard for other
appliances.

No protection exists by disconnecting - the black box. Air is a
best insulator. Lightning travels through 3 miles of air to contact
earth. What magic black box do you own that can stop what three miles
of sky could not? Protectors do not stop, block, or disconnect from
lightning. Furthermore, a lightning surge does damage too fast. A
fastest disconnect relay takes milliseconds. Lightning surges do
damage in microseconds. Two of so many reasons why protection is not
achieved by disconnecting.

Try damming a river to stop a flood. Dam gets swept away. Move
that dam off to the side; call it a dike. Open a large channel
downriver. Protecting by disconnecting, blocking, or absorbing surges
is akin to that dam - useless. Instead, install (and earth) a 'whole
house' protector - akin to a large channel downriver. And then
install dikes - internal protection inside appliances or other
supplementary protection.

Even dikes (supplementary protectors) are useless without that large
channel downriver - the properly earthed 'whole house' protector.

MOVs are routinely installed where direct lightning strikes are
earthed - without damage to MOVs. MOVs used in properly sized 'whole
house' protectors. But when a plug-in protector is sold to maximize
profits (not for protection), then grossly undersized protectors also
create another problem - scary pictures:
http://www.hanford.gov/rl/?page=556&parent=554
http://www.westwhitelandfire.com/Art...Protectors.pdf
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html
http://tinyurl.com/3x73ol or
http://www3.cw56.com/news/articles/local/BO63312/

Routine is for direct lightning strikes to be earthed by a 'whole
house' protector. Routine is for a properly sized protector to earth
surges AND remain functional. A protector damaged by a direct
lightning strike - grossly undersized - is designed in direct
violation of MOV manufacturer's specs. MOV manufacturers are quite
clear about this. MOVs must only fail by degrading; not fail by
vaporizing. MOVs also do not work by sopping up surge energy. But
grossly undersizing a plug-in protector and a resulting explosive
damage gets the naive to recommend an obscenely overpriced protector.
Yes, grossly undersizing a protector can get the naive to recommend
more ineffective protectors.

An effective protector earths direct lightning strikes AND remains
functional. An effective protector means nobody knew the surge even
existed. But no explosive failure means some here would not recommend
that protector.

Above described secondary protection. Homeowners should also
inspect their primary inspection system:
http://www.tvtower.com/fpl.html

Buried wires do not provide effective protection. An industry
professional provides this application note. Notice even underground
wires must be earthed before entering the building. Even underground
wires can carry surges, destructively into the building. Any wire
that enters the building - overhead or underground - must connect to a
single point earth ground either directly (ie cable TV, satellite
dish) or via a protector (ie telephone, AC electric). The app note
shows two structures. Any wire into either structure first connects
to that structure's single point earth ground:
http://www.erico.com/public/library/...es/tncr002.pdf

And finally, it is posted multiple times including a reference to an
article for EE entitled "Protecting Electrical Devices from Lightning
Transients". That safety ground and neutral wire cannot provide
earthing for a long list of reasons.

Nobody described how much more earthing is installed in switching
centers (COs), electric substations, etc just to obtain a little
better earthing. A ten foot earth ground rod can be a massive
earthing improvement for surge protection. And then high reliability
facilities may spend $thousands more just to make that earthing but a
little better. Why so much extra conductors and labor for just a
little better ground? Because every little better earthing means that
much more surge protection. What makes a protector even more
effective? Better earthing.

So yes, where surge damage is not acceptable, then facilities will
do that much more work just to get a little better earthing. Earthing
is critical for direct lightning strikes without failure. Does that
mean a homeowner without a massive earthing mat should do nothing? Of
course not. Locating 3 meter ground rods (per post 1990 NEC
requirements) less than 10 feet from breaker box and telco provided
surge protector means significantly better protection. Anyone
building a new home should plan their surge protection where footings
are poured - see nobody's reference to cadwelding. Footings with
appropriately installed conductors (rebar) provide a home with
significant improvement (Ufer grounds). Protection should be planned
when the footings are poured. Better earthing (surge protection) for
so little money.

Nobody also discusses single point earth ground that is essential
for surge protection. Why? Again, a protector is only as effective
as its earth ground. Single point earth ground is essential to an
effective protector.

Some homeowners don't have that single point option due to failures
by the builder. One utility describes how to fix that defective
earthing:
http://www.cinergy.com/surge/ttip08.htm

Why do serious facilities do so much for their earthing system?
Earthing provides surge protection - where surge energy must be
harmlessly dissipated. And then, as Nobody notes, sometimes that
earthing system gets compromised by geology we did not know about.

What happens if damage occurs? We return to locate an earthing
defect. Even a nearby pipeline may adversely affect that earthing
system. If damage results, then discover a defect in the earthing
system. As Nobody demonstrates, so much labor to make earthing even
better because a surge protector is only as effective as that earth
ground.

BTW, battery racks do not absorb surge energy. Another concept even
taught in basic circuit theory - superposition. To surges, that
battery rack is equivalent to a short circuit. Batteries do not
absorb energy (if ignoring a battery's internal resistance). Those
batteries essentially connect surge currents to wires on both sides of
those batteries. To a surge, batteries are electrically equivalent to
a wire. Batteries are typically well earthed - meaning those
batteries will act just like a shunt mode surge protector - connecting
surge energy into earth. Batteries don't work as surge absorbers.
Batteries connect (shunt, divert, clamp) surge energy into earth.

On May 5, 6:31 pm, "nobody " wrote:
I've been a TV repairman. I'm now a "communications electrician" which
means I deal with telephone lines/switches, land-mobile radio, microwave
radio systems, security systems, and the like; in high-voltage
switchyards and substations. We deal with huge surges from switching
transients and direct lightning hits on the transmission lines. I know
first-hand what happens when surges hit. When I said "transmission
lines", I'm talking both from the 60hz side as well as the RF side as
the lengths are sufficient to act that way.

Define "ground" or "earth", Mr w_tom. Have you ever run an ANSI spec
ohms test on one? I think not. I've done grounding for military tactical
radio systems and complete commo systems. What you think is "ground" may
not be ground at all due to soil composition. I've seen ground rod
"farms" made up of 20+ vertical 8' rods on a 10 foot grid come up in the
500 kilohms range when the same rods in the same location would test
lower than 1000 ohms if those same stakes were buried sideways 18" below
surface.

Substations/switchyards have "ground mats" of heavy copper wire in a
grid spacing of 1-2 feet and about 6 feet under everything that's
covered with gravel. It's also cad-welded at all intersections to
prevent corrosion. This ground mat system is also used at well-designed
radio sites. Even with this elaborate grounding system, a major
malfunction at 230KV can create such a voltage differential to induce
fatal "step voltage" between your legs.
.http://ballengearry.com.au/papers/St...e_update_for_2...

For 120Vac grounding on our equipment, we try our best to bring all
equipment grounds (racks and cable trays as well) to a single point that
*then* connects to the building's ground as close as possible. We do
have the advantage of most equipment running off DC at 24, 48, or 130
Vdc on huge battery racks that can absorb a lot of surge energy...

On May 5, 2:35 pm, bud-- wrote:
The IEEE guide is aimed at "electricians, architects, technicians, and
electrical engineers who were not protection specialists."

IEEE and NIST state fundamental facts. Industry standard facts and
embarrassing questions.that Bud will ignore to lie and to promote plug-
in protector sales:

1) How does that plug-in protector provide protection without the
'always necessary' earth ground? What does a protector do? Bud
provides only two citations. Both disagree with his claims. The NIST
bluntly defines what a protector must do - Page 6:
You cannot really suppress a surge altogether, nor
"arrest" it. What these protective devices do is
neither suppress nor arrest a surge, but simply
divert it to ground, where it can do no harm.

Bud says his plug-in protectors somehow suppress or arrest surges.
Somehow, 'clamping to nothing' means that surge energy disappears?
Somehow protectors can work without earthing? NIST citation further
contradicts Bud on Page 17:
A very important point to keep in mind is that your
surge protector will work by diverting the surges to
ground. The best surge protection in the world can
be useless if grounding is not done properly.

2) Bud not only denies this also so important single point earth
ground. He also ignores what happens when a protector is too far from
earth and too close to appliances. Page 42 Figure 8: the surge
earthed 8000 volts destructively through appliances. This is the
second point from his citations that Bud must ignore.

3) So if a plug-in protector is effective protection, then
manufacturer specs will list each type of surge and protection from
that surge. Bud never provides that spec either. Why? Plug-in
protectors don't claim to protect from the type of surge that
typically causes damage. Not one plug-in protector manufacturer will
claim that protection - made obvious because Bud will not post those
specs and ignored over 400 requests for those specs.

4) No earth ground means no effective protection. A protector is
only as effective as its earth ground. Another reality that Bud must
ignore to post incessantly.

None of this is new. It is again posted because Bud continuously
ignores that even his own citations contradict him. Meanwhile w_tom
has provided many tens of professional citations that also contradict
Bud; that define how effective protection is routinely installed where
direct lightning strikes must not cause damage. We install effective
protection for lightning so that all other (and lesser) surges are
also made irrelevant. Surge protection is so routine for the past 100
years as to be traceable to human failure. Even the protector must
remain functional after a surge.

On May 5, 2:19 pm, Mike Tomlinson wrote:
On properly grounded outlets, such a suppressor can deal with an
incoming surge on phase or neutral in an effective manner by conducting
and diverting current to the other leg AND to ground, but their
effectiveness when used on ungrounded outlets is reduced, since the path
to ground doesn't exist.

Include facts taught in first year electrical engineering OR
described in both 'top of the front page' articled in Electrical
Engineering Times on 1 Oct and 8 Oct 2007 entitled "Protecting
Electrical Devices from Lightning Transients" at:
http://www.planetanalog.com/showArti...leID=201807127
http://www.planetanalog.com/showArti...leID=201807830

That wire from wall receptacle is too long, has too many sharp
bends, has spliced, is bundled with other wires, etc. More reasons
why that safety ground wire is not earth ground wire. Protectors
without earth ground is not effective as Mike says. And AC wall
receptacle does not provide an earthing connection - wire too long -
too much impedance. Page 42 Figure 8 also demonstrates that problem
resulting in 8000 volts being earthing, instead, through the adjacent
TV.

Breaker box earthing wire goes over top of the foundation and drops
down to an earthing electrode. Compromised protection. Wire is too
long and has sharp bends. Better protection means wire goes through
foundation and down to that earthing electrode. Few meters less wire
and without those sharp bends means improved protection. Why? See
"Protecting Electrical Devices from Lightning Transients".

If earthng wire must be every meter shorter, then how does a
receptacle safety ground wire do earthing? Safety wire has maybe 30
or 50 sharp bends, numerous splices, and maybe 15 meters too long?
Low impedance connection to earth typically means 'less than 10
feet', or then even shorter for even better protection.

Obviously wall receptacle safety grounds do not provide earth
ground. But then Mike Tomlinson also did not understand the
engineering numbers in that EE Times article entitled "Protecting
Electrical Devices from Lightning Transients". Note the numbers.
Wall receptacle safety grounds cannot provide a low impedance
connection to earth ground. Engineers would know this. Mike
Tomlinson obviously does not.

Literally every incoming wire must make that short (low impedance)
connection to earth ground. If that earthing wire is not separated
from other wires (if that earthing wire is inside a bundle of romex
cables), then that earthing wire induces surges on those other wires.
Just another reason why safety ground is not earth ground. Just
another engineering fact that Mike Tomlinson read and did not
understand.

AC wall receptable is not an effective earth ground. Protectors
best make a less than 3 meter (low impedance) connection to earth
which wall receptacles just cannot provide.

On May 5, 2:27 pm, Mike Tomlinson wrote:
It is those nuances that w_**** fails to explain when he spouts his one-
cure-for-all-ills religious mantra about every dwelling absolutely
requiring whole-house surge protection.

Mike Tomlinson has just posted in agreement. UK homes typically do
not need what is necessary in FL homes. UK homes need not be earthed
as central FL homes may be earthed:
http://members.aol.com/gfretwell/ufer.jpg

Many homes have more than enough protection with only one earthed
'whole house' protector - and nothing else. Especially in the UK.
That means spending tens (or maybe one hundred) times less money for
protection of everything.

UK homes may be more than sufficiently earthed with one 3 meter
ground rod. Then one surge protector can provide more than sufficient
protection for everything - eliminating maybe £500 or £2000 for plug-
in protectors.

On May 4, 9:09 pm, "Michael A. Terrell"
wrote:
The same thing we did in the studios and transmitter sites. Use a
combination of protection at the building's main disconnect, and
individual protection at each critical device. The only thing that I've
lost in the last ten years was when lightning hit a huge pine tree, and
cut the top half of it off. It landed on the ground right over the
buried telephone line, and a second strike blew out the modem and MOV
protection on the phone line.

You suffered damage from a lightning strike and call that effective
protection? Modems are most typically damaged by surges entering an
AC mains. Outgoing surge path would be the phone line to earth via a
telco installed 'whole house' protector. Damage from lightning is
effective protection? After spending how much for all those
protectors, you call that protection?

Phone lines do not use MOV protectors. Basic information that you
would have learned if not wasting time insulting people. MOVs have
too much capacitance. Phone line 'whole house' protectors use other
technologies with lower capacitance.

In alt.engineering.electrical Don Kelly wrote:

| Now - is this all germane to household protection? You say not and I agree
| with you- because household equipment can ride through - at worst- doubling
| of the clamped voltage for a very short time even though the clamped voltage
| is relatively small compared to the peak of the incoming surge. --

What if the surge is an extreme case (e.g. direct strike very near) and it is
arriving at protection devices in common mode (same polarity on all three
wires). Bud's assertion _seems_ to be that no surge could ever be of the
type with substantial energy at high frequencies. My belief is that they
can, and will at times. Lightning strokes have that energy, or else you
would not receive them on UHF. If the stroke is strong _and_ close (e.g.
less line inductance between the point of strike and where it is being
considered), then more of that UHF energy will arrive.

I have seen damage patterns in electronics that strongly suggests that there
were specific paths involved based on minor levels of reactance in the circuit.
A resistor would be melted along one path, but not so along another which had
a small inductor (3 turns in air) in the way. And this device (a VCR) was on
a surge protector along with a TV that was unharmed.

If Bud is just arguing about the _typical_ (median?) surge level, then maybe
we are arguing apples and oranges. I certainly don't intent to protect against
50% of surges. My target is better than 99%. I want to feel comfortable
sleeping through a severe thunderstorm while my computers and media center
remain plugged in.

I do agree that things can survive at the clamping voltage. But there has to
be a clamping situation. It's too easy for a surge to come in as a common
mode surge where the voltage difference across the MOVs would be (nearly) zero.
Then all we have is a propogating wavefront. And if it is strong and/or close
then we have very fast rise times. And it passes by the MOVs "laterally".

There's probably a big difference of opinion about just how much protection is
worth it. But one thing I do see in at least part of this thread is that Bud
focuses on quoting things other people say, and does very little to express
things in his own words. That suggests he reads but does not fully understand.
And that means I can't ask questions of what is said in the thread. Since Bud
can't (or won't) defend what he's saying in his own words based on his own
knowledge, it's not really a two way street. His "experts" are not involved
in the debate; they can neither defend their position nor be questioned about
it to get more details.

It also has brought some other comments from people who are either anti-social
insulting types, or those that just don't understand what is said (apparently
having never dealt with transmission line propogation), or both. But at least
I know who not to trust any technical opinions from when I have question to
ask about things I want to learn more about.

--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |

In article
..com, w_tom writes

Mike Tomlinson has just posted in agreement.

As usual, you're twisting things again. I'm certainly not agreeing with
_you_.

UK homes typically do
not need what is necessary in FL homes.

instead, YOU are agreeing with what I said...

UK homes need not be earthed
as central FL homes may be earthed:
http://members.aol.com/gfretwell/ufer.jpg

Those pictures do absolutely nothing to bolster your argument,
especially appearing as they do without any explanatory text.

Many homes have more than enough protection with only one earthed
'whole house' protector - and nothing else. Especially in the UK.

Nonsense. You live in Pennsylvania (thankfully, though I do feel sorry
for your neighbours and anyone else with whom you come into contact.)
It is not common practice to install whole-house protectors in the UK.

UK homes may be more than sufficiently earthed with one 3 meter
ground rod.

You have no idea. TT earthing (ground rod earthing) is relatively
unusual in the UK. The majority of buildings have a T-N-C-S supply from
the utility provider, who provide an earth point alongside the supply
cable where it rises out of the ground.

Then one surge protector can provide more than sufficient
protection for everything - eliminating maybe £500 or £2000 for plug-
in protectors.

Absolute crap. You have no idea how much surge protectors in the UK
cost.

w_ once again lies, distorts, and twists what others say to suit his own
bizarre beliefs and ideologies.

w_ continues to lead his one-man crusade and is unable to understand why
his dogmatic posts attract contempt and derision from many different
people with a wide spectrum of experience and knowledge of electrical
and electronic theory and practice.

w_ continues to believe that he alone is Right and everyone else is
Wrong, a classic sign of a sociopathic personality. w_**** needs to
consult a mental health professional.

--
(\__/) Bunny says NO to Windows Vista!
(='.'=) http://www.cs.auckland.ac.nz/~pgut00...ista_cost.html
(")_(") http://www.cypherpunks.to/~peter/vista.pdf