On May 5, 2:19 pm, Mike Tomlinson <m...@jasper.org.uk> 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.
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 <m...@jasper.org.uk> 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" <mike.terr...@earthlink.net>
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 <dhky@shaw.ca> 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) |
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.
phil-news-nospam@ipal.net wrote:
> In alt.engineering.electrical Don Kelly <dhky@shaw.ca> 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 <fvn72o$rta$1@registered.motzarella.org>, noway@nohow.not 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!
? <spamfree@spam.heaven> ?????? ??? ??????
news:hkfu149a5vrit5hmv0diutsv7daiqor67i@4ax.com...
> On Mon, 5 May 2008 19:21:16 +0300, "Tzortzakakis Dimitrios"
> <noone@nospam.void> wrote:
>
>>
>>Ο "Tantalust" <Tantalust@paradise.net> έγραψε στο μήνυμα
>>news:RPidnaZzhcrV0oXVnZ2dnUVZ_hadnZ2d@comcast.co m...
>>> "NB" <nobuyout@gmail.com> wrote in message
>>> news:b53f2fef-00bd-40d0-9ac1-c69b3bcadf52@x41g2000hsb.googlegroups.com...
>>>> 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" <mike.terr...@earthlink.net>
> 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.
Jitt wrote:
>
> In article <fvn72o$rta$1@registered.motzarella.org>,
> noway@nohow.not 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.
Re: Surge / Ground / Lightning 
Linear Mode
