wrote:
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.

I can attest to vhf/uhf content in lightning strikes. I worked for a
communications outfit. We owned and maintained a number of comm sites
with towers and antennas. One strike on an antenna destroyed the LDF rf
cable all the way to the polyphaser at the bottom of the tower. It had
blowouts at about 1 foot intervals all down it's length suggesting a
1/2 wave of about 1 foot or approx 460 mhz. That's one hell of a lot of
energy at that frequency..
Eric

In article ,
says...

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

I suppose I phrased the question badly. I wonder why a surge
would wander around looking for ground, when its available
in the box!

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


Ï "Tantalust" Ýãñáøå óôï ìÞíõìá
m...
"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

2000'? I am only 5'10":-)

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.

Perhaps you should get a proper earthing electrode, with a spiked end and a
stell core? It would be really difficult to hammer 20' of 3/4" copper pipe.
They are not that expensive.
I'm not a full bottle on earth loops yet so i don't know about leaving
the water mains connection still connected.
The earth loops matter only in electronic circuits, like amplifiers and the
like. In electricity, the play no role, in fact they reduce even further the
earth resintance.
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?

Although the neutral is at zero potential, still carries a large current.
The earth not. Since the neutral point of the LV side of the local
substation is earthed, for the electricity "is all the same" between neutral
and earth, depending on the neutral earthing system.


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

w_tom wrote:

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?


Where did I say HOW was protected? It was my second week at that
station, and the chief engineer took off on a long overdue vacation. If
you would learn to read, rather than just do mindless rants you wouldn't
look so stupid. At that time the building had a UFER ground, and a
three phase protection system at the meter CTs. That didn't prevent the
damage, as you claim it should.



Phone lines do not use MOV protectors. Basic information that you
would have learned if not wasting time insulting people.


Sorry, _wacko_ but you are the one slinging insults and ignoring
proof from hundreds of people.


MOVs have
too much capacitance. Phone line 'whole house' protectors use other
technologies with lower capacitance.


Gee, _wacko_ you've never seen ANY modern business telephone
equipment? Gas tubes are fragile and very expensive. The protection
isn't to save the privately owned telephones, it it to limit damage to
the building. Even that mid '60s 1A2 system had every output of the
power supply fused to prevent a fire. Explain why an MOV's capacitance
is high enough to affect a phone line. Never mind. I have a Nitsuko/NEC
DX2NA-32SYTEMEM KEY TELEPHONE SYSTEM in front of me, and every CO line
in it has a MOV across the line. Once more, you're preaching lies and
using deceit to try to make others look bad.

,http://refurbishednitsuko.net/productInfo.aspx?productID=75978489-9ac8-40c1-9496-559bfc01b4d3
is the Central Office line card for four telephone lines. See the black
MOVs to the right of each pair of fuses?

http://refurbishednitsuko.net/productInfo.aspx?productID=f5453e33-047e-4726-8631-50a929aabedf
is the card for four standard 2500 type telephones, or equivalent
equipment. See the pairs of black MOVs over the blue connectors at the
bottom of the screen? They are all japanese, with no brand markings.

http://www.epcos.com/web/generator/Web/Sections/Publications/PDF/SIOVMetalOxideVaristors,property=Data__en.pdf;/SIOVMetalOxideVaristors.pdf
is the Epcos MOV databook, with datasheets for Telecom applications.
page 213 list the TELECOM MOV data.


Every line into that studio building had a long distance call device
diverter in the line that had MOV across the phone line. Every one of
them survived the direct hit to the building and STL tower. That's more
than can be said of your ability to use reason, and learn new things.

You need to get your head out of 1920 and learn modern electronics.
The one thing we learned today is that you don't know any more about
Telecom that you do lightning protection, or reading comprehension.

--
http://improve-usenet.org/index.html


Use any search engine other than Google till they stop polluting USENET
with porn and junk commercial SPAM

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm

Jitt wrote:

In article ,
says...

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

I suppose I phrased the question badly. I wonder why a surge
would wander around looking for ground, when its available
in the box!


They don't discriminate. They look for every possible path to
ground.


--
http://improve-usenet.org/index.html


Use any search engine other than Google till they stop polluting USENET
with porn and junk commercial SPAM

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm

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

| | 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.

Observation proves flying saucers and magic.

Without supporting sources it is Phil's Phantasy Physics.
Where is a source that supports your belief in nanosecond risetimes and
100MHz spectrum?

--
bud--

wrote:
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. --

My belief is that they
can, and will at times.

People believe in flying saucers.
Where is a source that supports your belief?


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".

Where is a source that supports your belief in nanosecond risetimes and
100MHz spectrum?

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.

I focus on the real world. You focus on your beliefs.

Where is a source that supports your belief in nanosecond risetimes and
100MHz spectrum?

--
bud--

w_tom wrote:
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."

Industry standard facts and
embarrassing questions.that Bud will ignore to lie and to promote plug-
in protector sales

Lacking any valid technical arguments poor w_ has to try to discredit
opponents. My only association with surge protectors is I have some.


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:

What does the NIST guide really say about plug-in suppressors?
They are "the easiest solution".


2) Bud not only denies this also so important single point earth
ground.

If w_ could only read he would have seen my emphasis on a *short*
'ground' wire from phone/cable entry protectors to the 'ground' at the
power service. w_ appears to want all wires run to the grounding
electrode. That does not provide the minimum voltage between power and
signal wires. Martzloff has written "the impedance of the grounding
system to 'true earth' is far less important than the integrity of the
bonding of the various parts of the grounding system."

And the case where phone/cable entry points are too far distant from
power service, IEEE guide says "the only effective way of protecting
the equipment is to use a multiport [plug-in] protector."

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.

The illustration has 2 TVs. The IEEE says the point of the illustration
is "to protect TV2, a second multiport protector located at TV2 is
required." Way to complicated for w_.


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.

"Each type of surge" is nonsense. w_'s favored SquareD service panel
suppressors do not have specs for "each type of surge". Lacking valid
technical arguments has to invent problems.

Plug-in
protectors don't claim to protect from the type of surge that
typically causes damage.

Complete nonsense.

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.

Over 400 requests - another hallucination.
Specs posted often and ignored.


4) No earth ground means no effective protection. A protector is
only as effective as its earth ground.

w_'s religious belief (immune from challenge) in earthing has been the
elephant in the closet. w_ believes a surge protector must directly
earth a surge. Thus in his view plug-in suppressors (which are not well
earthed) can not possibly work.

The IEEE guide explains plug-in suppressors work by CLAMPING the voltage
on all wires (signal and power) to the common ground at the suppressor.
The voltage between the wires going to the protected equipment is safe
for the protected equipment. Plug-in suppressors do not work primarily
by earthing (or stopping or absorbing). The guide also explains earthing
does occur, just not primarily through the plug-in suppressor. (Read the
guide starting pdf page 40).

For accurate information on surges read the IEEE and NIST guides. Both
say plug-in suppressors are effective.

There are 98,615,938 other web sites, including 13,843,032 by lunatics,
and w_ can't find another lunatic that says plug-in suppressors are NOT
effective. All you have is w_'s opinions based on his religious belief
in earthing.

Embarrassing questions that w_ will igno
- 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)?

--
bud--

w_tom wrote:
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.

Last I heard UK phone entry protectors did not clamp the voltage to
earth. That allows high voltage between power and phone wires. w_’s
favored service panel suppressor provides no protection from this hazard.

--
bud--

Don Kelly wrote:
----------------------------
"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.

I am real glad the probability of a direct house strike is low. I have
some appreciation for the earthing/bonding required in a substation
(also referred to by nobody).


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. --

The effect Martzloff was specifically looking for in experiments was
doubling of voltage.

As an aside, several of the experiments done by Martzloff were at EPRI.

--
bud--

In alt.engineering.electrical bud-- wrote:
| wrote:
| In alt.engineering.electrical bud-- wrote:
| | wrote:
| | In alt.tv.tech.hdtv bud-- wrote:
|
| | | 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.
|
| Observation proves flying saucers and magic.
|
| Without supporting sources it is Phil's Phantasy Physics.
| Where is a source that supports your belief in nanosecond risetimes and
| 100MHz spectrum?

Since you seem unwilling to just discuss technical aspects of things, I have
to conclude that you simply do not understand what it is you read and quote.
Too many times you quote out of context. I don't know where that is because
you are trying to be manipulative or simply on account of ignorance. There
is that old sayind "Do not ascribe to malice that which can be explained by
ignorance". I don't know if I should follow it's advice.

There is no point in spending the effort to find some quotable source because
you wouldn't know what to do with it. How could you possibly comprehend what
I would give you if you can't even comprehend what you post.

After this round of followups, I'm done with this thread and I'm done replying
to you. If curing your ignorance is in your future, it will have to be from
someone else.

--
|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 Eric wrote:

| I can attest to vhf/uhf content in lightning strikes. I worked for a
| communications outfit. We owned and maintained a number of comm sites
| with towers and antennas. One strike on an antenna destroyed the LDF rf
| cable all the way to the polyphaser at the bottom of the tower. It had
| blowouts at about 1 foot intervals all down it's length suggesting a
| 1/2 wave of about 1 foot or approx 460 mhz. That's one hell of a lot of
| energy at that frequency..

Apparently you had some kind of resonance involved. Maybe the antenna itself
can cause that. Or the output tank circuit in the transmitter. Once you have
the resonance to narrowband the energy, it would only take a reflection back
up the line and you turn a propogating surge into standing waves.

--
|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:

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

w_ can't understand his own hanford link. It is about "some older
model" power strips and says overheating was fixed with a revision to
UL1449 that required thermal disconnects. That was 1998. There is no
reason to believe, from any of these links, that there is a problem with
suppressors produced under the UL standard that has been in effect since
1998.
But with no valid technical arguments all w_ has is pathetic scare tactics.

For reliable information on surges and protection read the IEEE and NIST
guides. (Both say plug-in suppressors are effective.)

--
bud--

In alt.engineering.electrical bud-- wrote:
| wrote:
| 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. --
|
| My belief is that they
| can, and will at times.
|
| People believe in flying saucers.
| Where is a source that supports your belief?

My observations support my belief. I don't expect YOU to believe it on the
basis if MY observations, as I certainly won't believe things on the basis
of YOUR observations. What I am posting about is for you to UNDERSTAND what
I believe, not that you have to believe it. Maybe someday you will come to
understand it, and then you might realize how you have misread what it is
you have been quoting online.

Since you spend all your keystrokes making person attacks or insisting on
something being cited, or make quotes that are often truncated incorrectly
or misapplied, I can only conclude you have no actual understanding of what
it is you have been quoting. What good would me citing anything do for you
if you can't understand it.


| 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".
|
| Where is a source that supports your belief in nanosecond risetimes and
| 100MHz spectrum?

Another poster followed up to my post you just followed up to that also has
experienced the same thing. That might not be some published citation that
you want. But that doesn't matter. It seems you can't comprehend what this
is about regardless of whether it is observed by others, or yourself, or by
the experts you cite.


| 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.
|
| I focus on the real world. You focus on your beliefs.

You focus on citing and quoting things you do not understand well enough to
just talking about them in technical terms.


| Where is a source that supports your belief in nanosecond risetimes and
| 100MHz spectrum?

See above.

And after this round of followups, I'm done with this thread and with your
posts on this subject. You can have the last say, but I will not even read
it.

--
|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) |

On May 5, 2:20*pm, wrote:
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.

Maybe you should review what you actually stated in the context of
current surge supression discussion:
"
"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. "

That sure sounds like 50% of the surge is going through the MOV and
the other 50% is going on past it to the protected equipment.

And that I would have to agree with Bud on, it's phantasy physics,
because if it were true, no type of surge protection would work,
because it would only be 50% effective.




--
|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.engineering.electrical Eric wrote:

| I can attest to vhf/uhf content in lightning strikes. I worked for a
| communications outfit. We owned and maintained a number of comm sites
| with towers and antennas. One strike on an antenna destroyed the LDF rf
| cable all the way to the polyphaser at the bottom of the tower. It had
| blowouts at about 1 foot intervals all down it's length suggesting a
| 1/2 wave of about 1 foot or approx 460 mhz. That's one hell of a lot of
| energy at that frequency..

Apparently you had some kind of resonance involved. Maybe the antenna itself
can cause that. Or the output tank circuit in the transmitter. Once you have
the resonance to narrowband the energy, it would only take a reflection back
up the line and you turn a propogating surge into standing waves.

Pretty much what we determined. Also in another thread I stressed that
the rise time by itself does not determine frequency content. One needs
to know the rate of change, or slew rate, to determine that. A
lightning pulse may have a rise time of 1.2 microseconds but in that
short time the current can rise to thousands of amps, generating a large
amount of vhf,uhf energy.
Eric

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


Can you trim W_tom with that?? Or is he incurable?

On May 6, 12:08*pm, "Michael A. Terrell"
wrote:
w_tom wrote:

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?

* *Where did I say HOW was protected? It was my second week at that
station, and the chief engineer took off on a long overdue vacation. If
you would learn to read, rather than just do mindless rants you wouldn't
look so stupid. *At that time the building had a UFER ground, and a
three phase protection system at the meter CTs. That didn't prevent the
damage, as you claim it should.

* Phone lines do not use MOV protectors. *Basic information that you
would have learned if not wasting time insulting people.

* *Sorry, _wacko_ but you are the one slinging insults and ignoring
proof from hundreds of people.

*MOVs have
too much capacitance. *Phone line 'whole house' protectors use other
technologies with lower capacitance.

* *Gee, _wacko_ you've never seen ANY modern business telephone
equipment? *Gas tubes are fragile and very expensive. The protection
isn't to save the privately owned telephones, it it to limit damage to
the building. *Even that mid '60s 1A2 system had every output of the
power supply fused to prevent a fire. Explain why an MOV's capacitance
is high enough to affect a phone line. Never mind. *I have a Nitsuko/NEC
DX2NA-32SYTEMEM KEY TELEPHONE SYSTEM in front of me, and every CO line
in it has a MOV across the line. *Once more, you're preaching lies and
using deceit to try to make others look bad.

,http://refurbishednitsuko.net/productInfo.aspx?productID=75978489-9ac....
is the Central Office line card for four telephone lines. See the black
MOVs to the right of each pair of fuses?

http://refurbishednitsuko.net/productInfo.aspx?productID=f5453e33-047....
is the card for four standard 2500 type telephones, or equivalent
equipment. See the pairs of black MOVs over the blue connectors at the
bottom of the screen? They are all japanese, with no brand markings.

http://www.epcos.com/web/generator/Web/Sections/Publications/PDF/SIOV...
is the Epcos MOV databook, with datasheets for Telecom applications.
page 213 list the TELECOM MOV data.

* *Every line into that studio building had a long distance call device
diverter in the line that had MOV across the phone line. Every one of
them survived the direct hit to the building and STL tower. That's more
than can be said of your ability to use reason, and learn new things.

* *You need to get your head out of 1920 and learn modern electronics.
The one thing we learned today is that you don't know any more about
Telecom that you do lightning protection, or reading comprehension.


W_ denies MOVs are commonly used in typical electonics or modern
appliances too. He had to, because he can't answer the obvious
question of how MOVs can be used effectively in these applications,
yet they can't work in plug-in protectors and the only way to get any
protection is to have a nearby direct earth ground. Faced with the
problem of MOVs providing protection in electronics/appliance without
an earthground, he simply denies MOVs are used in electronics and
appliances. Here's the references that I provvided him on that one:

Here, from Appliance Magazine and Appliance Design websites:

http://www.appliancedesign.com/CDA/A.../BNP_GUID_9-5-...


"New thermally enhanced MOVs help protect a wide variety of low-power
systems against damage caused by over-current, over-temperature and
over-voltage faults, including lightning strikes, electrostatic
discharge (ESD) surges, loss of neutral, incorrect input voltage and
power induction.


These devices help provide protection in a wide range of AC line
applications, including AC mains LED lighting systems, PLC network
adapters, cell-phone chargers, AC/DC power supplies (up to 30 VA as
input power for 230 VAC input voltage), modem power supplies, AC
panel
protection modules, AC power meters, and home appliances. "


http://www.appliancemagazine.com/pri...zone=1&first=1


"Protecting increasingly sophisticated and complex control boards
from
misconnection, power surges, or short circuit damage is of particular
concern to the equipment manufacturer. Although appliance
transformers, their enclosures, and connections are capable of
withstanding higher voltage transients, the use of sensitive solid-
state devices on the board necessitates improved overcurrent,
overtemperature, and overvoltage control.


Coordinating overcurrent and overvoltage protection can also help
designers comply with safety agency requirements, minimize component
count, and improve equipment reliability. A metal oxide varistor
(MOV)
overvoltage protection device used in a coordinated circuit-
protection
strategy with a line-voltage-rated PPTC overcurrent device helps
manufacturers meet IEC 6100-4-5, the global standard for voltage and
current test conditions for equipment connected to ac mains."

In article , bud--
writes

Martzloff has written "the impedance of the grounding
system to 'true earth' is far less important than the integrity of the
bonding of the various parts of the grounding system."

Indeed. This is an important principle of the UK wiring code. It's
referred to as "equipotential bonding." Such a concept, of course,
would be far beyond the understanding of w_'s lone brain cell.

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

In article , bud--
writes

Last I heard UK phone entry protectors did not clamp the voltage to
earth.

You're quite correct. It's a practice that the GPO (forerunner to
British Telecom) abandoned in the 1960s, showing how up to date w_'s
"knowledge" is.

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

wrote:

Mike Tomlinson wrote:

... This is an important principle of the UK wiring code. It's
referred to as "equipotential bonding."

I wonder if "ring mains" (an extra wire from the last outlet to make
a loop back to the fusebox) are legal in the US. Seems like a nice way
to improve voltage regulation with a little extra wire, and if the ring
wire only breaks in one place, all the outlets keep working.


No, the are not legal in the US.


--
http://improve-usenet.org/index.html


Use any search engine other than Google till they stop polluting USENET
with porn and junk commercial SPAM

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm

wrote:

W_ denies MOVs are commonly used in typical electonics or modern
appliances too. He had to, because he can't answer the obvious
question of how MOVs can be used effectively in these applications,
yet they can't work in plug-in protectors and the only way to get any
protection is to have a nearby direct earth ground. Faced with the
problem of MOVs providing protection in electronics/appliance without
an earthground, he simply denies MOVs are used in electronics and
appliances. Here's the references that I provvided him on that one:

Here, from Appliance Magazine and Appliance Design websites:

http://www.appliancedesign.com/CDA/A.../BNP_GUID_9-5-...


"New thermally enhanced MOVs help protect a wide variety of low-power
systems against damage caused by over-current, over-temperature and
over-voltage faults, including lightning strikes, electrostatic
discharge (ESD) surges, loss of neutral, incorrect input voltage and
power induction.

I had a microwave oven that had a MOV across the 120V line ahead of the
power switch. The other side of the 120/240 20A circuit supplied a
refrigerator. The loss of the neutral applied a good part of the 240V
across the MOV when the refrigerator attempted to start.

The MOV didn't last long! It would probably have been OK on the load
side of the switch.

I know that refrigerators should be alone on a "home run" circuit, and
neutrals shouldn't be connected with wire nuts, but that wasn't how it was!

My only complaint with some plug-in protectors is that the MOVs are
often much too small. I've also seen some with only a line-line MOV.

--
Virg Wall, P.E.

Mike Tomlinson wrote:

... This is an important principle of the UK wiring code. It's
referred to as "equipotential bonding."

I wonder if "ring mains" (an extra wire from the last outlet to make
a loop back to the fusebox) are legal in the US. Seems like a nice way
to improve voltage regulation with a little extra wire, and if the ring
wire only breaks in one place, all the outlets keep working.

Nick

In alt.engineering.electrical wrote:

| Mike Tomlinson wrote:
|
|... This is an important principle of the UK wiring code. It's
|referred to as "equipotential bonding."
|
| I wonder if "ring mains" (an extra wire from the last outlet to make
| a loop back to the fusebox) are legal in the US. Seems like a nice way
| to improve voltage regulation with a little extra wire, and if the ring
| wire only breaks in one place, all the outlets keep working.

It is not legal in the US. It is also considered technically unsafe.

You could wire a ring circuit with AWG #14 CU rated at 15 amps and protect
it with a 30 amp breaker under the theory that the current would be split
across the 2 paths between the source (breaker) and the load. This is the
most unsafe configuration because if one of the wires breaks, the breaker
will not detect it, and you won't notice until a fire starts.

You could wire the same circuit to two separate 15 amps breakers. In this
case it is somewhat safer because if one wire breaks, you can't get any use
via one of the breakers, effectivly reducing the current that would trip
the circuit via the remaining breaker. This is still unsafe because the
broken wire could merely be loose, and shutting off one breaker would leave
the circuit potentially live via the other breaker as the wire could come
back in contact.

There could also be confusion with separate breakers. The breakers have to
be on the same pole (phase), an issue not present in the single pole single
phase home wiring most homes have in UK. The USA, however, has two pole
single phase wiring. One way around that would be a "tandem" breaker with
the two handles fused together.

The safest case would be wiring both ends of the ring into the same breaker
rated for the current capacity of the wire as if used in a regular branch
circuit. Even this would have a safety issue. If the wire became loose at
one point in the ring, it would still be a potential hot spot that would be
not as easily noticed as a similar loose wire in a branch circuit. That hot
spot could then start a fire.

So far I have only described issues with the hot wiring. There are issues
with the neutral wiring as well. In all the above configurations, a neutral
would have to be wired in from both ends of the ring, and each be wired in
a separate hole (not doubled up) in the neutral bus bar. A loose neutral in
all these cases would go unnoticed just like a hot wire. But in cases where
the total current available (either the 30 amp single breaker, or tandem 15
amp breakers, described above) exceeds the wiring (when neutral is AWG #14 CU)
a wiring overheating problem exists.

The grounding wire would also have to be wired correctly from both ends.

An even greater double hazard potential exists when the neutral on one end is
broken while the hot on the other end is broken (or shut off at the breaker).
This creates a large inductive loop which can energize other wiring and cause
various problems with many metallic constructions.

Very little is gained by doing this over direct branch circuits. The issue
of voltage stability is addressed by keeping branch circuits short. It is
my understanding that UK ring circuits tend to be longer and run all around
the portion of a house (often an entire floor). Branch circuits in the USA
tend to be shorter.

Very long circuits can have voltage issues. An example is a home with a 1000
foot long driveway into the property, and a string of many lights along the
way. The more distant lights would be dimmer. This can be addressed to at
least balance out the dimming by using a loop-back circuit, which is still a
branch circuit. This is a more expensive circuit that is done by having an
extra hot wire run with the circuit in the same cable or conduit. Each lamp
is connected between the extra wire and the neutral. The extra wire is then
connected to the fed hot wire at the last lamp in the string. There is no
other connected to the fed hot wire other than the last lamp and the source
controlling switch. With this loop-back circuit, each lamp has the same
circuit length, and thus will have the same voltage drop.

The above technique was discussed on electrical-contrator.net a while back,
but they have since changed web site software, and my old links do not work.

--
|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 VWWall wrote:

| I had a microwave oven that had a MOV across the 120V line ahead of the
| power switch. The other side of the 120/240 20A circuit supplied a
| refrigerator. The loss of the neutral applied a good part of the 240V
| across the MOV when the refrigerator attempted to start.
|
| The MOV didn't last long! It would probably have been OK on the load
| side of the switch.
|
| I know that refrigerators should be alone on a "home run" circuit, and
| neutrals shouldn't be connected with wire nuts, but that wasn't how it was!

How would you connect a neutral? Doubled up on a receptacle device screw?
The usual practice is to wire the neutral in a wire nut so it can feed the
device in that box, as well as connect up and down stream, even if the
device is removed.

OTOH, I don't like wire nuts. I've seen them come loose even when wired
together well. Maybe it was a defective nut. I definitely will try to
avoid them when my new house gets built (a lot of bad electrical things
will be avoided in it).


| My only complaint with some plug-in protectors is that the MOVs are
| often much too small. I've also seen some with only a line-line MOV.

You had a plug-in protector for a double line (240V) circuit? Or are you just
referring to the neutral as one of the lines?

I'm still on the hunt for a plug-in surge suppressor power strip for 240V
with NEMA 6-15P plug and NEMA 6-15R outlets. The MOVs between each line
and ground need to be the ones appropriate for 120V (330V clamp rated) and
the ones between the two lines appropriate for 240V (660V clamp rated).

--
|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 Eric wrote:
| wrote:
| In alt.engineering.electrical Eric wrote:
|
| | I can attest to vhf/uhf content in lightning strikes. I worked for a
| | communications outfit. We owned and maintained a number of comm sites
| | with towers and antennas. One strike on an antenna destroyed the LDF rf
| | cable all the way to the polyphaser at the bottom of the tower. It had
| | blowouts at about 1 foot intervals all down it's length suggesting a
| | 1/2 wave of about 1 foot or approx 460 mhz. That's one hell of a lot of
| | energy at that frequency..
|
| Apparently you had some kind of resonance involved. Maybe the antenna itself
| can cause that. Or the output tank circuit in the transmitter. Once you have
| the resonance to narrowband the energy, it would only take a reflection back
| up the line and you turn a propogating surge into standing waves.
|
| Pretty much what we determined. Also in another thread I stressed that
| the rise time by itself does not determine frequency content. One needs
| to know the rate of change, or slew rate, to determine that. A
| lightning pulse may have a rise time of 1.2 microseconds but in that
| short time the current can rise to thousands of amps, generating a large
| amount of vhf,uhf energy.

In some plots of voltage rises I've seen in the past, the rise was not at all
a smooth one. It went up in steps. Of course if one _thinks_ there will be
no VHF or UHF energy and does measurement with a ssytem only capable of lower
frequencies, that would smooth out how the rise appears.

--
|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) |

On May 6, 2:45 pm, Sjouke Burry
wrote:
Can you trim W_tom with that?? Or is he incurable?

He is incurable as long as others post outright lies and myths while
denying what really provides surge protection. Now to discuss what is
relevant.

If in sand, a single ground rod is probably insufficient earthing.
For example, a FL couple suffered repeated direct lightning strikes to
their bathroom wall. They have lightning rods installed. Lightning
again struck that exterior wall. Lightning rods were earthed by 8'
ground rods only in sand. Plumbing inside that wall connected to
deeper (more conductive) limstone. Lightning found a better
connection to deeper limestone via the bathroom wall.

What will provide sufficient earthing? Without knowledge of the
underlying geology, some will expand that earthing with a buried wire
around the entire building (halo or ring ground). Others will may
install a large and interconnected network of ground rods. Do you
need that much? Expanding the earthing may be easier than learned
later it was not sufficient. Also useful is to canvas the
neighborhood to learn what others have experienced for ten or more
years.

Reducing earth resistance is not as important as creating single
point ground with a shorter connection, more conductive (impedance)
than any other path, AND creating equipotential beneath the building.
Too many assume a water pipe is better because it is longer. But a
better earth ground meets two slightly different criteria -
conductivity and equipotential. IOW some ground rods located short to
all 'whole house' protectors may be superior earthing than the water
pipe. Appreciate that wire length may be more critical than the size
of an earthing electrode.

On May 6, 5:01 pm, Mike Tomlinson wrote:
Indeed. This is an important principle of the UK wiring code. It's
referred to as "equipotential bonding." Such a concept, of course,
would be far beyond the understanding of w_'s lone brain cell.

UK wiring code alone does not provide sufficient earthing for
something not intended to address. Code addresses earthing for human
safety. Proper earthing for surge protection must both meet and
exceed code requirements. Essential for surge protection is that all
utilities be earthed very short to the same earthing electrode. UK
code does not require that. In fact, many UK master sockets have no
earthing connection meaning no phone line protection.

Mike Tomlinson posts insults when he does not have facts. Those who
would promote magic box plug-in protectors are same who also post
these insults. Same technique used by Rush Limbaugh to prove Saddam
had WMDs.

Single point earth ground remains essential to surge protection -
which only makes people like Mike Tomlinson post more insults. A
protector is only as effective as its earth ground. An effective
protector makes a 'less than 10 foot' connection to that earth ground
rod.

On May 6, 1:00 pm, bud-- wrote:
w_ can't understand his own hanford link. It is about "some older
model" power strips and says overheating was fixed with a revision to
UL1449 that required thermal disconnects. That was 1998.

Bud will only challenge the hanford link because he cannot challenge
those 'scary pictures'. One is a Boston building fire last year
created by a plug-in protector. Another is a fire marshal describing
why plug-in protectors can create house fires. And pictures from fire
departments showing a problem seen too often.

And then Bud posts a half fact. UL1449 was created on 28 Aug 1985 -
not in 1998 as Bud claims. Why would Bud do this? Profits are at
risk - another fact that Bud must avoid admitting.

So where is this plug-in protector spec that claims to provide
protection? Oh. It does not exist because plug-in protectors do not
even claim to provide this protection. Bud refuses to post a
specification for one simple reason. There is no plug-in spec that
claims what Bud is posting. So Bud posts insults. In reply, this is
what Bud is really promoting - these '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/

Pictures of protectors typically located on a pile of desktop papers
or buried in dust balls on a rug.

On May 6, 10:54 am, Jitt wrote:
I suppose I phrased the question badly. I wonder why a surge
would wander around looking for ground, when its available
in the box!

If all grounds are same, then connect lightning rods into a
motherboard ground. That would be perfect building protection because
a lightning rod is grounded?

Ground inside a stereo is different from ground inside a TV is
different from ground on the computer case is different from ground on
a wall receptacle is different from ground inside a cell phone is
different from a ground inside a breaker box is different from ground
in earth. Most all those grounds are interconnected and are still not
the same ground.

Electricity is different at both ends of a wire. That 100 amp surge
seeking earth from a wall receptacle may leave the wall receptacles at
12,000 volts - again, due to wire impedance. That plug-in protector
on Page 42 Figure 8 was so far from earth ground (via AC electric
wire) as to be 8000 volts - a destructive path via an adjacent TV to
earth.

The EE Times article entitled "Protecting Electrical Devices from
Lightning Transients" defines why a ground in a box is not a ground to
surges. Why electricity at both ends of a wire is always different.
Why that difference during a surge is so important that an effective
protection makes a 'less than 10 foot' connection to earth. Only
relevant 'ground' is the one that is ground to a surge. That is not
an 'inside the box' ground.

Typically destructive surges are an electrical connection from a
cloud to earthborne charges maybe miles away - the relevant ground.
If any part of that connection is via an appliance, then the appliance
may be damaged. Surge protection has always been about diverting a
connection from cloud to earthborne charges so that current need not
pass inside the building.

A protector is only as effective as its earth ground so that surges
need not enter a building. No earth ground means no effective
protection; means a surge creates connections to earth destructively
inside a building. Any facility that installs effective protection
does earthing connected, very short, via a 'whole house' type
protector.

Polyphaser makes a protector that has NO earth ground connection.
Earthing is so critical that their protector mounts directly ON the
earthing electrode - zero feet from earth ground. Distance to earth
ground is critical for effective protection. Which ground? Earth
ground is not found and not provide in three wire AC wall
receptacles. That is a safety ground.

On May 6, 12:08 pm, "Michael A. Terrell"
wrote:
Where did I say HOW was protected? It was my second week at that
station, and the chief engineer took off on a long overdue vacation. If
you would learn to read, rather than just do mindless rants you wouldn't
look so stupid. At that time the building had a UFER ground, and a
three phase protection system at the meter CTs. That didn't prevent the
damage, as you claim it should.

Lightning created damage. Since Michael Terrell says it had an Ufer
ground, that means grounding was properly installed and not
corrupted? Therefore the resulting damage proves, "Woe is me.
Nothing can protect from lightning."? Nonsense.

Damage was created by a surge. A responsible human locates the
defect in that protection system. Michael Terrell was defeatist. He
'knew' nothing can earthing lightning without damage.

Then Michael posts nonsense about other protectors so he need not
admit this fact: MOVs are not used on telephone lines. Why discuss
fuses? Fuses obviously are not for surge protection - when one has
basic electrical knowledge. Effective protectors (even gas discharge
tubes - GDTs) earth direct lightning strikes and remain functional.

So why is Michael now discussing GDTs and fuses? Michael has again
been caught posting in error. MOVs are not used for telephone line
surge protection due to excessive capacitance. This has long been
common knowledge among those who post facts - not insults. Nnoted and
finally admitted by Michael is a reasons why so little lightning in
the UK creates so much damage. Master sockets are not even earthed as
the equivlant NID is, routinely, in all North America.

Responsible people who suffer surge damage immediately search for
the human failure that made damage possible. Search typically begins
by looking for defects in the single point earth ground system. Those
who promote magic box plug-in protectors would not do this and must
assume lightning damage cannot be avoided - a defeatist attitude.

On May 6, 3:08 pm, wrote:
W_ denies MOVs are commonly used in typical electonics or modern
appliances too. He had to, because he can't answer the obvious
question of how MOVs can be used effectively in these applications,
yet they can't work in plug-in protectors and the only way to get any
protection is to have a nearby direct earth ground. Faced with the
problem of MOVs providing protection in electronics/appliance without
an earthground, he simply denies MOVs are used in electronics and
appliances. ...

Using trader's reasoning, all appliances contain MOVs. Therefore
plug-in protectors need not be purchased AND all appliances never
suffer surge damage. Conclusions directly from trader's post.

Reality: all appliances contain protection using numerous techniques
such as galvanic isolation. Protection that means all but a rare and
typically destructive surge is made irrelevant. Internal appliance
protection is dependent on a properly earthed 'whole house'
protector. The typically destructive surge must be earthed to not
overwhelm protection inside all appliances.

On May 6, 10:22 am, Eric wrote:
I can attest to vhf/uhf content in lightning strikes. I worked for a
communications outfit. We owned and maintained a number of comm sites
with towers and antennas. One strike on an antenna destroyed the LDF rf
cable all the way to the polyphaser at the bottom of the tower.

Eric notes damage only up to the earthed Polyphaser protector.
Polyphaser is legendary among professionals who install effective
protection. Polyphaser is blunt about what provides protection - why
their products are so effective. Polyphaser protectors are earthed.
Polyphaser application notes repeatedly discuss what their products
must connect to; what provides protection: earth ground:
http://www.polyphaser.com/technical_notes.aspx

In article
..com, w_tom writes

[snip w_'s usual lies and bald statements with no citations or proof to
back them up and his boilerplate messianic statement of religious
belief]

Same technique used by Rush Limbaugh to prove Saddam
had WMDs.

ROTFL!! You've really lost it this time, w_****.
I hereby invoke Godwin's law.

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

On May 7, 12:36*am, Mike Tomlinson wrote:
In article
.com, w_tom writes

[snip w_'s usual lies and bald statements with no citations or proof to
back them up and his boilerplate messianic statement of religious
belief]

Same technique used by Rush Limbaugh to prove Saddam
had WMDs.

ROTFL!! *You've really lost it this time, w_****. *
I hereby invoke Godwin's law.

And as usual, W_'s statement taken at face value is wrong and/or
misleading. A simple check of history shows Saddam did in fact have
WMDs for years, because they were used in war and against his own
people. The UN weapons inspectors had spent a decade of hide and seek
locating and destroying most of them. Just prior to the start of
the Iraq war, not only did US intelligence believe he still had some
of them and was trying to reconstruct the weapons programs, but so did
British, Israeli and Russian intelligence.





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

w_tom wrote:

What will provide sufficient earthing?

A large series air-core copper toroid (eg 1' diam x 2' long with
a 3" wire spacing) followed by a small spark gap to a poor ground.

Nick

On May 6, 2:42*am, w_tom wrote:
* *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.

I'd love to see a reference for this. In that time frame, lightning
was already fairly well understood. I find it hard to believe any ham
would try to use a mason jar in this way. Sounds more like some urban
legend to me.



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.


And guess what component is used as part of that robust protection?
MOVs, which W_ denies are used in electronics/appliances. Once again,
I'll ask the same question W_ refuses to answer. How is it that MOVs
or any other component can offer protection when used in a PC power
supply, but are useless in a plug-in surge protector? According to
W_, surge protection is impossible unless there is a direct and short
connection to earth ground. Does the PC power supply come with a
built-in earth ground?

wrote:

wrote:

| I wonder if "ring mains" (an extra wire from the last outlet to make
| a loop back to the fusebox) are legal in the US. Seems like a nice way
| to improve voltage regulation with a little extra wire, and if the ring
| wire only breaks in one place, all the outlets keep working.

It is not legal in the US. It is also considered technically unsafe.

Lots of things are "technically unsafe" :-) Safety is often used as excuse
for people-control...

The safest case would be wiring both ends of the ring into the same breaker
rated for the current capacity of the wire as if used in a regular branch
circuit.

Sounds good to me.

... If the wire became loose at one point in the ring, it would still be
a potential hot spot

Maybe not too hot, if the rest of the wire is intact.

... a neutral would have to be wired in from both ends of the ring, and
each be wired in a separate hole (not doubled up) in the neutral bus bar.

The "separate hole problem" has lots of solutions.

... The issue of voltage stability is addressed by keeping branch circuits
short. It is my understanding that UK ring circuits tend to be longer and
run all around the portion of a house (often an entire floor).

Sounds more cost-effective to me. Why don't more people use large PEX pipe
"ring mains" with Ts, vs home runs with tiny pipe and expensive manifolds?

Nick

On May 6, 9:52*pm, w_tom wrote:
On May 6, 3:08 pm, wrote:

W_ *denies MOVs are commonly used in typical electonics or modern
appliances too. * He had to, because he can't answer the obvious
question of how MOVs can be used effectively in these applications,
yet they can't work in plug-in protectors and the only way to get any
protection is to have a nearby direct earth ground. * Faced with the
problem of MOVs providing protection in electronics/appliance without
an earthground, he simply denies MOVs are used in electronics and
appliances. *...

* Using trader's reasoning, all appliances contain MOVs. *Therefore
plug-in protectors need not be purchased AND all appliances never
suffer surge damage. Conclusions directly from trader's post.

LOL. You're a real riot. YOU are the one that in previous and
similar long threads has stated that manufacturers of appliances and
electronic equipment put surge protection in them and that it works,
and used that as an argument as to why a plug-in surge protector is
useless.

I never stated that all appliances contain MOVs. I only stated that
they frequently or commonly do. You, on the other hand, denied that
MOVs are used in that kind of application. At which point, I
provided you references to a couple of articles in Appliance Magazine
that discuss how MOV are in fact commonly used in those applications:
A poster just told you his microwave has them. Another told you the
phone system sitting in front of him has them.

So, once again, stop lying about what I stated and answer the simple
question:

How is it that MOVs can work as surge protection inside the appliance,
but not in a plug-in surge protector? Where is that essential direct
earth ground? Does that microwave come with a built-in earth
ground? If not, then just like the plug-in surge protector, there is
no direct earth ground, so how can the MOV be helping protect the
microwave?

And it would help if you just answer that question, not start with a
long rant.






* Reality: all appliances contain protection using numerous techniques
such as galvanic isolation. *Protection that means all but a rare and
typically destructive surge is made irrelevant. *Internal appliance
protection is dependent on a properly earthed 'whole house'
protector. *The typically destructive surge must be earthed to not
overwhelm protection inside all appliances.

On May 6, 3:29*am, wrote:
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.


I find Bud's use of actual references interesting and think they add
to his credibility. Trying to suggest that someone using references
such as the IEEE to support their position detracts from their
credibility is preposterous. And trying to impugn him in this fashion
only detracts from your credibility.





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.

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