household ground system

[w_tom]

You are correct that lightning is a common mode transient -
not differential. If lightning were differential, then
earthing would be irrelevant. But every serious protector
manufacturer discusses earthing extensively.

Building is earthed for two reasons - human safety and
transistor safety. Codes require earthing so that electrical
faults will blow fuses before killing a human. Typically,
that is an earth ground rod that connects power board to earth
ground. One of two AC electric wires will always have a
connection to earth so that a dangerous short will blow a
fuse.

BTW, electricity into an appliance is differential mode -
relevance taken from perspective of the appliance. That means
current enters on one wire and leaves on the other wire.

For transient protection, the earthing requirements become
tighter. First building must have only one single point earth
ground. And every incoming wire must connect to that ground
before entering the building. For example, the CATV cable
uses a ground block to make a less than 3 meter connection to
that earth ground. Other wires, such as all telephone wires
and most AC electric wires, cannot be connected directly.
Therefore we make that earthing connection (again less than 3
meters) via surge protectors.

That is all an effective surge protector does - make a
temporary connection to earth during the transient. Why?
Destructive transients are common mode. That means current
enters on one or all AC electric wires and leaves by some
other means. For example computer modems are most often
damaged by a destructive transients entering one or all AC
electric wires and leaving via one or all phone line. That is
a common mode transient - the most common destructive
transient.

No you cannot put an earth ground rod outside your building
and be protected. That and other concepts explained in
legendary application notes from Polyphaser - some listed
here:
http://www.polyphaser.com/ppc_PEN1002.asp
http://www.polyphaser.com/ppc_PEN1014.asp
http://www.polyphaser.com/ppc_PEN1024.asp

Note what Polyphaser discusses as essential for protection
in virtually every application and engineering note - single
point earth ground.

Some diagrams demonstrate how earthing is accomplished - the
good and the bad:
http://www.cinergy.com/surge/ttip08.htm
http://www.xantrex.com/support/docserve.asp?id=337

http://www.erico.com/public/library/fep/technotes/tncr002.pdf

The last diagram demonstrates two separate structures, each
with its own earth ground. Any wire that enters that
structure must first connect to that structure's single point
earth ground. Notice even buried wires (ie phone line) can
carry transients into the building; must also be connected to
that single point ground before entering the building.

That plug-in UPS does not make any claims about common mode
protection for very obvious reason. Typically, it contains
exact same circuit found in power strip protectors. Since it
does not make a less than 3 meter connection to central earth
ground, then it does not provide effective protection. So it
avoids all mention of both common mode protection and
earthing. This in contrast to serious building wide UPS
systems that are properly earthed - that do provide effective
protection.

The most important feature in protection is the quality of
that central earth ground. Also all connections must be
short, direct, and independent - as defined in discussions
from misc.rural below. All electronics contains effective
protection that can be overwhelmed if incoming transients are
not earthed before entering the building. You apparently have
seen what can happen. Earthing those incoming utilities makes
internal appliance protection effective - more than sufficient
- for direct strike protection.

More detailed discussion about earthing was in two threads
in the newsgroup misc.rural including the concepts of short,
direct and independent. Quality of that single point ground
determines the effectiveness of any protector. Art of
earthing discussed by engineers in:
Storm and Lightning damage in the country 28 Jul 2002
Lightning Nightmares!! 10 Aug 2002
http://tinyurl.com/ghgv and http://tinyurl.com/ghgm

Arpit wrote:

hmm, ok. is lightning a differential mode spike? Id think not, but the
fact that neutral is connected to earth may change that? Its primarily
lighting I am concerned with, I lost a couple of hundred dollars of
equipment in the last storm.

 

[Richard Freeman]

"Arpit" <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in message
news:i7lt20502samtis7p08rfjrvmh6040f1l9@4ax.com...

On Sun, 15 Feb 2004 12:43:58 +1100, "Rod Speed" <rod_speed@yahoo.com
wrote:


Arpit <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in
message news:ktet20hcd9hp7cm8u53nn8ak12joo739fi@4ax.com...

I invested in a UPS system, primarily to filter surges and spikes.
However, I know for this to be useful I need a good ground.

You dont, actually. Thats always beena pig ignorant myth.

One largely propogated by an ignorant fool called w_tom who likes to
pontificate at length about Lightning protection but actually seems to know
very little about the subject (well certainly far less than me and I would
hardly consider myself an expert)

A decent UPS will get rid of differential mode spikes fine and
thats what the absolute vast bulk of spikes and surges are.


hmm, ok. is lightning a differential mode spike? Id think not, but the
fact that neutral is connected to earth may change that?

It is usually ends up being common mode in strikes to Power lines - in fact
it usually ends up heading for the Neutral/Earth and it is fairly uncommon
for Lightning hitting Power lines to cause damage and in the rare cases this
does happen all the surge supressors in the world would generally not
provide much protection (certainly not w_toms infamous 1KJ movs)

Its primarily
lighting I am concerned with, I lost a couple of hundred dollars of
equipment in the last storm.

Tell me what equipment did you lose and did you have your modem plugged into
the phone line at the time ?

The most common path for Lightning causing damage is in via Phone/Data Lines
or cable TV
The second most common path is in via TV/Radio Aerials
The third most common path is via building wiring (Alarms, Lans, Audio lines
etc) in near/direct strikes
After this lot comes Damage via Power Lines.

I think, but Im not sure, that the ground for my
house is a pipe at the side stuck into the earth,

Yes, thats the usual way its done.

and it looks a little dodgy.

In what way ?

the wire to it doesnt even have any insulation and looks tarnished,
THe join between the pipe and the wire looks crusty.

So I was thinking of instlaling my own ground outside my room,
in the form of 3 1.5 meter galvanised pipes in the ground.

Pointless, wont help.

Well actually even worse in the event of a lightning strike extra grounds
added at semi random will increase the chance of something being fried a
good Earth (around 0.5 ohm ) will typically achieve an EPR in excess of
50,000 Volts above Earth in the event of a direct strike.

If your Earth is dodgy it is also Backed up by your neighbours earth etc but
then again maybe you should get a sparky to re-run the earth while he
installs that new 30 A circuit you want

I'd then take a wire from each and connect each wire to
the ground pin of a standard plug. THen, I'd put the 3 plugs
into a 4 way power board, and plug the power board into a
wall outlet. the 4th socket would hold the plug for my UPS.

The Earth stakes need to be bonded directly to each other with substantial
braid and at least the length of the Earth stake apart (ie 6 Feet) or is
that twice the length of the earth stake apart ? - to keep them outside of
the 'zone of influence' of each other then bond the Earth system at the
switchboard with the Neutral from the Street.
Next enclose all your equipment in a metal box (Metal room etc) bonded to
this earth system -note when this earth system is implemented properly it
will cost a few $ in fact a decent earth system as used for Radio/TV
transmitters often covers 1000 square meters or more and even then the
Transmitters still suffer Lightning damage from time to time (I noticed
channel 7 went off the air the other night due to Lightning).

And that wont help either. The surge impedance will be much too high.

I'm not sure what exactly you mean by the surge impedance, but Im
assuming you mean the poor ability of the earth to take a large blast
of current sourced from elsewhere in the house, because of the thin
powerboard leads. Wouldnt the surge impedance be low on the actual
powerboard itself? THats really all Im concerned with.
If you do want to do something about common
mode surges, you need to put that in the meter
box and that has to be done by a licensed electrician.


It makes a lot more sense to just makes sure that the
house insurance covers that sort damage instead.

I'll look into that, thanks

Are there any problems with multiple grounds for a house system?

Nope, it just wont achieve anything useful.

POtential problems I can think of, would be

- galvanic corrosion of the ground electrodes

Sure, but galvanised pipe fixes that.

-ground loops

That wont happen in that situation.

- melting of the powerboard lead iin case of a lightning strike

Thats the main problem with doing it like that.

but I don't know enough aobut the above to come to a
conclusion. COuld anyone give me some advice please?

Check your house insurance cover Lightning damage

Unplug your Modem from the phone line when not in use,

Log off when Lightning is brewing and Unplug the phone line (computer etc)

Never use an internal modem (Once you have brought the Lightning into the PC
chassis it is all over at least an external modem keeps the Lightning at
arms length)

Back up all important data Regularly

Ignore advice offered by w_tom . ( in fact where is the fool maybe he
received such a bollocking last time he visited aus.electronics he ignores
it now)

 

[Bob M]

Hi there,

Sorry to hear about the problems you encountered because of the
lightening. The energy dissipated by a direct strike is HUGE. It is
pretty much financially impractical for a homeowner to install
something capable of handling this situation. The best investment is
an insurance policy that handles this type of event.

In the 70s, I worked at CNCP Telecommunications, here in Toronto
Canada, home of the worlds tallest free standing structure aka the
worlds tallest lightening rod! It gets directly struck many times a
year. I had a tour of the systems installed to handle this:

A copper alloy ground plain the size of a football field.

Huge copper buss bars connecting the antennae systems to the ground
plain (about 1 inch by 6 inches if I remember correctly).

A motor generator set installed on the equipment floor (just under the
restaurant) to isolate the power system from the grid.

All data/communication connections running vertically up the tower are
fibre optic.

There are many "rules" developed over the years about what and how
things can connect together to prevent any unwanted electrical paths.
These have been developed as a result of investigation of failures
after lightening strikes.

Here in Canada, each home owner is required to provide a ground
connection to the utility grid. Three ground rods, each 3.5 meters in
length must be pounded into the earth at least 3 meters apart from
each other. They must be connected with a minimum #8 gauge wire to the
neutral/grounding buss connection in the main power panel. In some
cities, you can use the incoming water pipe as a ground source, but
this is becoming less and less practical because the water
distribution systems are being upgraded to fibreglass/plastic pipes.

The best you can do is ensure your main panel grounding system is up
to code and install surge protected power sources to your equipment.
If you have the opportunity, shutdown and disconnect any electrical
equipment during storms.

The most important thing is to ensure your insurance premiums are
paid!

Cheers from Canada!

Bob M

"Richard Freeman" <deletethisrichard@atps.net> wrote in message news:<4031a4c6$1_1@news.iprimus.com.au>...

"Arpit" <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in message
news:i7lt20502samtis7p08rfjrvmh6040f1l9@4ax.com...
On Sun, 15 Feb 2004 12:43:58 +1100, "Rod Speed" <rod_speed@yahoo.com
wrote:


Arpit <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in
message news:ktet20hcd9hp7cm8u53nn8ak12joo739fi@4ax.com...

I invested in a UPS system, primarily to filter surges and spikes.
However, I know for this to be useful I need a good ground.

You dont, actually. Thats always beena pig ignorant myth.

One largely propogated by an ignorant fool called w_tom who likes to
pontificate at length about Lightning protection but actually seems to know
very little about the subject (well certainly far less than me and I would
hardly consider myself an expert)



A decent UPS will get rid of differential mode spikes fine and
thats what the absolute vast bulk of spikes and surges are.


hmm, ok. is lightning a differential mode spike? Id think not, but the
fact that neutral is connected to earth may change that?

It is usually ends up being common mode in strikes to Power lines - in fact
it usually ends up heading for the Neutral/Earth and it is fairly uncommon
for Lightning hitting Power lines to cause damage and in the rare cases this
does happen all the surge supressors in the world would generally not
provide much protection (certainly not w_toms infamous 1KJ movs)



Its primarily
lighting I am concerned with, I lost a couple of hundred dollars of
equipment in the last storm.

Tell me what equipment did you lose and did you have your modem plugged into
the phone line at the time ?

The most common path for Lightning causing damage is in via Phone/Data Lines
or cable TV
The second most common path is in via TV/Radio Aerials
The third most common path is via building wiring (Alarms, Lans, Audio lines
etc) in near/direct strikes
After this lot comes Damage via Power Lines.



I think, but Im not sure, that the ground for my
house is a pipe at the side stuck into the earth,

Yes, thats the usual way its done.

and it looks a little dodgy.

In what way ?

the wire to it doesnt even have any insulation and looks tarnished,
THe join between the pipe and the wire looks crusty.

So I was thinking of instlaling my own ground outside my room,
in the form of 3 1.5 meter galvanised pipes in the ground.

Pointless, wont help.

Well actually even worse in the event of a lightning strike extra grounds
added at semi random will increase the chance of something being fried a
good Earth (around 0.5 ohm ) will typically achieve an EPR in excess of
50,000 Volts above Earth in the event of a direct strike.

If your Earth is dodgy it is also Backed up by your neighbours earth etc but
then again maybe you should get a sparky to re-run the earth while he
installs that new 30 A circuit you want



I'd then take a wire from each and connect each wire to
the ground pin of a standard plug. THen, I'd put the 3 plugs
into a 4 way power board, and plug the power board into a
wall outlet. the 4th socket would hold the plug for my UPS.

The Earth stakes need to be bonded directly to each other with substantial
braid and at least the length of the Earth stake apart (ie 6 Feet) or is
that twice the length of the earth stake apart ? - to keep them outside of
the 'zone of influence' of each other then bond the Earth system at the
switchboard with the Neutral from the Street.
Next enclose all your equipment in a metal box (Metal room etc) bonded to
this earth system -note when this earth system is implemented properly it
will cost a few $ in fact a decent earth system as used for Radio/TV
transmitters often covers 1000 square meters or more and even then the
Transmitters still suffer Lightning damage from time to time (I noticed
channel 7 went off the air the other night due to Lightning).




And that wont help either. The surge impedance will be much too high.

I'm not sure what exactly you mean by the surge impedance, but Im
assuming you mean the poor ability of the earth to take a large blast
of current sourced from elsewhere in the house, because of the thin
powerboard leads. Wouldnt the surge impedance be low on the actual
powerboard itself? THats really all Im concerned with.
If you do want to do something about common
mode surges, you need to put that in the meter
box and that has to be done by a licensed electrician.


It makes a lot more sense to just makes sure that the
house insurance covers that sort damage instead.

I'll look into that, thanks

Are there any problems with multiple grounds for a house system?

Nope, it just wont achieve anything useful.

POtential problems I can think of, would be

- galvanic corrosion of the ground electrodes

Sure, but galvanised pipe fixes that.

-ground loops

That wont happen in that situation.

- melting of the powerboard lead iin case of a lightning strike

Thats the main problem with doing it like that.

but I don't know enough aobut the above to come to a
conclusion. COuld anyone give me some advice please?


Check your house insurance cover Lightning damage

Unplug your Modem from the phone line when not in use,

Log off when Lightning is brewing and Unplug the phone line (computer etc)

Never use an internal modem (Once you have brought the Lightning into the PC
chassis it is all over at least an external modem keeps the Lightning at
arms length)

Back up all important data Regularly

Ignore advice offered by w_tom . ( in fact where is the fool maybe he
received such a bollocking last time he visited aus.electronics he ignores
it now)

 

[Rod Speed]

w_tom <w_tom1@hotmail.com> wrote in message
news:403188CA.7E069C91@hotmail.com...

You are correct that lightning is a
common mode transient - not differential.

Wrong. As always. Most of the spikes and surges
on the mains due to lightning are in fact differential.

Its only very close lightning strikes that are common
mode. And it aint economically feasible to attempt to
eliminate those in a residential situation. The only thing
that makes any sense in a residential situation is to
ensure that the insurance covers those rare events.

That doesnt necessarily even cost anything, you just
need to make sure that the insurance you buy covers it.

If lightning were differential, then earthing
would be irrelevant. But every serious protector
manufacturer discusses earthing extensively.

Not for residential housing they dont.

Thats for situations where the cost of outages is very high,
and where the risk of a direct lightning strike is high too.

Building is earthed for two reasons
- human safety and transistor safety.

Not a clue, as always. ALL transistorised equipment
that is powered from the mains has differential
protection built in, because the cost of warranty
claims would be unsustainable without that.

Codes require earthing so that electrical
faults will blow fuses before killing a human.

Utterly mangled all over again with the ground stake.
Its just a fundamental part of the MEN system design.

In fact the modern trend is double insulated appliances
where thats practical with no earthing at all.

Typically, that is an earth ground rod that
connects power board to earth ground.

Not for safety.

One of two AC electric wires will always have a connection
to earth so that a dangerous short will blow a fuse.

Separate issue entirely to the ground rod.

BTW, electricity into an appliance is differential mode -
relevance taken from perspective of the appliance. That
means current enters on one wire and leaves on the other wire.

For transient protection, the earthing requirements become tighter.

And cant be justified for houses unless they
are in a particularly lightning prone area.

First building must have only one single point earth ground.

Soorree, not even possible with MEN.

You keep mindlessly rabitting on about what is
feasible when MEN isnt used and havent even
noticed that it aint even possible with MEN systems.

And every incoming wire must connect to
that ground before entering the building.

Just not feasible with residential housing.

For example, the CATV cable uses
a ground block to make a less than 3
meter connection to that earth ground.

Not even feasible in this country you pig ignorant fool.

Other wires, such as all telephone wires and most
AC electric wires, cannot be connected directly.
Therefore we make that earthing connection
(again less than 3 meters) via surge protectors.

Again, not economically feasible with domestic housing.

That is all an effective surge protector does - make
a temporary connection to earth during the transient.

Not a fucking clue, as always.

Why? Destructive transients are common mode.

Not a fucking clue, as always.

That means current enters on one or all AC
electric wires and leaves by some other means.

Not a fucking clue, as always.

For example computer modems are most often
damaged by a destructive transients entering one or
all AC electric wires and leaving via one or all phone line.

Wrong. As always. Thats by far the least common cause of damage.

That is a common mode transient -
the most common destructive transient.

Not a fucking clue, as always.

No you cannot put an earth ground rod outside
your building and be protected. That and other
concepts explained in legendary application
notes from Polyphaser - some listed here:
http://www.polyphaser.com/ppc_PEN1002.asp
http://www.polyphaser.com/ppc_PEN1014.asp
http://www.polyphaser.com/ppc_PEN1024.asp

None of which has any relevance to
whats practical with domestic housing.

Note what Polyphaser discusses as essential
for protection in virtually every application and
engineering note - single point earth ground.

Not even possible with the MEN system, you pig ignorant clown.

Some diagrams demonstrate how earthing
is accomplished - the good and the bad:
http://www.cinergy.com/surge/ttip08.htm
http://www.xantrex.com/support/docserve.asp?id=337
http://www.erico.com/public/library/fep/technotes/tncr002.pdf

None of which are even using the MEN system, clown.

The last diagram demonstrates two separate structures,
each with its own earth ground. Any wire that enters that
structure must first connect to that structure's single point
earth ground. Notice even buried wires (ie phone line) can
carry transients into the building; must also be connected to
that single point ground before entering the building.

Not even possible with the MEN system, you pig ignorant clown.

That plug-in UPS does not make any claims about
common mode protection for very obvious reason.

Nope, because they realise that its differential mode that matters.

Typically, it contains exact same
circuit found in power strip protectors.

Which is what works with differential
mode spikes and surges, fuckwit.

Since it does not make a less than 3 meter
connection to central earth ground, then it
does not provide effective protection.

Not a fucking clue, as always.

So it avoids all mention of both common mode
protection and earthing. This in contrast to serious
building wide UPS systems that are properly earthed
- that do provide effective protection.

Never economically feasible with houses, fuckwit.

The most important feature in protection
is the quality of that central earth ground.

Not even possible with the MEN system, fuckwit.

Also all connections must be short, direct, and independent
- as defined in discussions from misc.rural below.

Not even possible with the MEN system, fuckwit.

All electronics contains effective protection
that can be overwhelmed if incoming transients
are not earthed before entering the building.

Not even possible with the MEN system, fuckwit.

You apparently have seen what can happen. Earthing
those incoming utilities makes internal appliance protection
effective - more than sufficient - for direct strike protection.

Not a fucking clue, as always.

More detailed discussion about earthing was in
two threads in the newsgroup misc.rural including
the concepts of short, direct and independent.

Not even possible with the MEN system, fuckwit.

Quality of that single point ground determines
the effectiveness of any protector.

Not even possible with the MEN system, fuckwit.

Art of earthing discussed by engineers in:
Storm and Lightning damage in the country 28 Jul 2002
Lightning Nightmares!! 10 Aug 2002
http://tinyurl.com/ghgv and http://tinyurl.com/ghgm

Not even the MEN system, cretin.

Arpit wrote:

hmm, ok. is lightning a differential mode spike? Id think not, but the
fact that neutral is connected to earth may change that? Its primarily
lighting I am concerned with, I lost a couple of hundred dollars of
equipment in the last storm.

 

[Joe Van]

"w_tom" <w_tom1@hotmail.com> wrote in message
news:403188CA.7E069C91@hotmail.com...

You are correct that lightning is a common mode transient -
not differential.

Ahh that is a relief then that means equipment is safe from Lightning
strikes to AC Mains!

If lightning were differential, then
earthing would be irrelevant. But every serious protector
manufacturer discusses earthing extensively.

Well actually if Lightning were differential it would damage equipment
connected to AC Mains much more often than it does in reality

Building is earthed for two reasons - human safety and
transistor safety. Codes require earthing so that electrical
faults will blow fuses before killing a human. Typically,
that is an earth ground rod that connects power board to earth
ground. One of two AC electric wires will always have a
connection to earth so that a dangerous short will blow a
fuse.

BTW, electricity into an appliance is differential mode -
relevance taken from perspective of the appliance. That means
current enters on one wire and leaves on the other wire.

For transient protection, the earthing requirements become
tighter. First building must have only one single point earth
ground.

well this is a load of crap to start with a single Earth stake will suffer
an EPR well in excess of 50,000V in the event of a Lightning Strike
rendering it ineffective This is actually one of the Reasons that the MEN
Earth system is so effective. But then admitting this fact would show that
most of w_toms other statements were crap also.

And every incoming wire must connect to that ground
before entering the building. For example, the CATV cable
uses a ground block to make a less than 3 meter connection to
that earth ground. Other wires, such as all telephone wires
and most AC electric wires, cannot be connected directly.
Therefore we make that earthing connection (again less than 3
meters) via surge protectors.

Unfortunately though Surge protectors are not worth a pinch of .... in a
Lightning strike. Fortunately though the MEN AC power distribution System
actually does a pretty good job of absorbing and riding out Lightning
Strikes.

That is all an effective surge protector does - make a
temporary connection to earth during the transient. Why?
Destructive transients are common mode. That means current
enters on one or all AC electric wires

One or All??? Is it common mode or differential ??? in one sentence you say
it is common mode in the next you suggest it could be either

and leaves by some
other means. For example computer modems are most often
damaged by a destructive transients entering one or all AC
electric wires and leaving via one or all phone line. That is
a common mode transient - the most common destructive
transient.

So this surge leaves on the phone line and goes where ???? Phone lines are
not earthed !! not any bloody where - yes they connect to earth via a feed
bridge at the exchange but this usually adds 1K ohm resistance to this path
to earth and as for surges arrestors in the event they are connected to the
phone line (not all that common in Australia - and this is aus.electronics )
they typically last about 20nS in a Lightning Strike lasting in excess of
100nS (often well in excess).

w_tom as per usual is completely wrong here the most common path for
Lightning damage is :

Lightning hits phone Line (yes even underground Cables) and heads for the
nearest low impedance path to earth - this is typically a modem or fax
Machine. Lightning may pause momentarily to blow the living shite out of any
surge protection connected to the Phone line but really the best earth
available is usually that provided by the MEN Earth via your Modem.

I have seen MDF's at buildings (which did have Surge arrestors installed)
following Lightning strikes where every single Surge arrestor (on a 200 pair
cable so 200 Surge arrestors ) was blown to kingdom come and Modems and Fax
machines in the Building were still fried.

No you cannot put an earth ground rod outside your building
and be protected. That and other concepts explained in
legendary application notes from Polyphaser - some listed
here:
http://www.polyphaser.com/ppc_PEN1002.asp
http://www.polyphaser.com/ppc_PEN1014.asp
http://www.polyphaser.com/ppc_PEN1024.asp

Note what Polyphaser discusses as essential for protection
in virtually every application and engineering note - single
point earth ground.

Some diagrams demonstrate how earthing is accomplished - the
good and the bad:
http://www.cinergy.com/surge/ttip08.htm
http://www.xantrex.com/support/docserve.asp?id=337

http://www.erico.com/public/library/fep/technotes/tncr002.pdf

The last diagram demonstrates two separate structures, each
with its own earth ground. Any wire that enters that
structure must first connect to that structure's single point
earth ground. Notice even buried wires (ie phone line) can
carry transients into the building; must also be connected to
that single point ground before entering the building.

That plug-in UPS does not make any claims about common mode
protection for very obvious reason. Typically, it contains
exact same circuit found in power strip protectors.

What? Does w_tom actually know the difference between a UPS and a surge
Protector ??? - yes UPS often contain spike suppression but they also often
(depending on the type of UPS) provide isolation which can and often does
provide better protection than a MOV (note that most of the cheaper UPS's do
not provide full isolation until/unless the Power Fails.

Since it
does not make a less than 3 meter connection to central earth
ground, then it does not provide effective protection. So it
avoids all mention of both common mode protection and
earthing. This in contrast to serious building wide UPS
systems that are properly earthed - that do provide effective
protection.

The most important feature in protection is the quality of
that central earth ground.

Well actually probably the single most important feature for effective
Lightning protection is installing all equipment in an Earthed Metal Box or
Rack and ensuring that all the equipment remains at the same potential.

Also all connections must be
short, direct, and independent - as defined in discussions
from misc.rural below. All electronics contains effective
protection that can be overwhelmed if incoming transients are
not earthed before entering the building. You apparently have
seen what can happen. Earthing those incoming utilities makes
internal appliance protection effective - more than sufficient
- for direct strike protection.

Bullshit !!! - there really is no other single term that describes this
statement and its inaccuracy adequately - this is a load of utter, utter
Crap - but then would we expect anything else from w_tom ? long and hard
experience by Telco's, and Transmitter owners proves time and time again
that even with the best Lightning protection regimes available Transmitters
and Telco installations can and Do Suffer Damage from Direct Lightning
Strikes.

More detailed discussion about earthing was in two threads
in the newsgroup misc.rural including the concepts of short,
direct and independent. Quality of that single point ground
determines the effectiveness of any protector. Art of
earthing discussed by engineers in:

Yes well I guess this sums up w_toms ideas on Lightning protection ...
Unfortunately though contrary to w_toms wild ideas Lightning follows fairly
simple rules of Physics - and therefore it is not a black art .

Storm and Lightning damage in the country 28 Jul 2002
Lightning Nightmares!! 10 Aug 2002
http://tinyurl.com/ghgv and http://tinyurl.com/ghgm

Engineers?? when you skim through the list they seem to be mostly Farmers
and even then there are a few who point out that the best (in fact the only)
sure protection is to unplug during a Thunderstorm. But then again that is
probably why w_tom holds these postings up as 'proof' of his fantasies -
there are no engineers on that N.G to argue with him and point out that he -
w_tom speaks utter crap.

In point of fact Rural Power can be quite a different Beastie to
Metropolitan Power with such things as earth return Power feeds and limited
numbers of Houses/Premises being feed by a single transformer (and hence
maybe only 1 or 2 Neutral- Earth connections)

Arpit wrote:
hmm, ok. is lightning a differential mode spike? Id think not, but the
fact that neutral is connected to earth may change that? Its primarily
lighting I am concerned with, I lost a couple of hundred dollars of
equipment in the last storm.

Regards
Joe Van (you work it out ;-)

 

[w_tom]

How does a Men system protect without earthing every
incoming wire? Any one wire on the Men system not earthed at
service entrance is a direct path from cloud, through
appliances, to earth ground - the destructive common mode
transient. So how does this Men system provide electricity
with all wires earthed?

That Men system is a perfect example of why common mode
transients are so destructive. Differential mode transients
are easily quashed. Common mode transients require short
connection to earth ground.

Earth can be 50,000 volts underneath a building AND building
therefore is 50,000 volts. That is zero volts difference -
perfect protection. A concept called equipotential. So what
is your point?

In the meantime those 50,000 volts were invented. You have
not a clue as to what is going where. But then 50,000 volts
is irrelevant. Current is the dominant factor - had you first
learned basic concepts of surge protection. But don't let
these little science facts stop you...

Curious that no responsible industry citation is ever
provided to support that Men system claim. In the meantime,
destructive transients are common mode which is why effective
protection has long (before WWII) been about earthing
transients before entering a building.

If you have problems with this, then post responsible
industry citations - for once provide some supporting evidence
- concerning your Men system protection.

Please feel free to show the world what the protection
industry failed to learn for 70 years now. Dirty little
secret - you can't cite such sources.

Joe Van wrote:

"w_tom" <w_tom1@hotmail.com> wrote in message
news:403188CA.7E069C91@hotmail.com...
You are correct that lightning is a common mode transient -
not differential.

Ahh that is a relief then that means equipment is safe from
Lightning strikes to AC Mains!

If lightning were differential, then
earthing would be irrelevant. But every serious protector
manufacturer discusses earthing extensively.

Well actually if Lightning were differential it would damage
equipment connected to AC Mains much more often than it does
in reality

Building is earthed for two reasons - human safety and
transistor safety. Codes require earthing so that electrical
faults will blow fuses before killing a human. Typically,
that is an earth ground rod that connects power board to earth
ground. One of two AC electric wires will always have a
connection to earth so that a dangerous short will blow a
fuse.

BTW, electricity into an appliance is differential mode -
relevance taken from perspective of the appliance. That means
current enters on one wire and leaves on the other wire.

For transient protection, the earthing requirements become
tighter. First building must have only one single point earth
ground.

well this is a load of crap to start with a single Earth stake
will suffer an EPR well in excess of 50,000V in the event of a
Lightning Strike rendering it ineffective This is actually one
of the Reasons that the MEN Earth system is so effective. But
then admitting this fact would show that most of w_toms other
statements were crap also.

And every incoming wire must connect to that ground
before entering the building. For example, the CATV cable
uses a ground block to make a less than 3 meter connection to
that earth ground. Other wires, such as all telephone wires
and most AC electric wires, cannot be connected directly.
Therefore we make that earthing connection (again less than 3
meters) via surge protectors.

Unfortunately though Surge protectors are not worth a pinch of
.... in a Lightning strike. Fortunately though the MEN AC power
distribution System actually does a pretty good job of absorbing
and riding out Lightning Strikes.

That is all an effective surge protector does - make a
temporary connection to earth during the transient. Why?
Destructive transients are common mode. That means current
enters on one or all AC electric wires
...

 

[Joe Van]

In a desperate attempt to misquote a post he is responding too "w_tom"
<w_tom1@hotmail.com> resorted to top posting in message
news:4032BE33.F1F08709@hotmail.com...

How does a Men system protect without earthing every
incoming wire? Any one wire on the Men system not earthed at
service entrance is a direct path from cloud, through
appliances, to earth ground - the destructive common mode
transient. So how does this Men system provide electricity
with all wires earthed?

hmm it is not immediatley clear what w_tom is misquoting here I suspect it
was :"Fortunately though the MEN AC power distribution System
actually does a pretty good job of absorbing and riding out Lightning
Strikes. "

Unfortunately for w_tom I did not say that all the wires were earthed merely
that MEN does a pretty good job of :
Absorbing Lightning strikes - well this is self apparent if you have a well
earthed Power distribution System (ie MEN) then Lightning is going to most
likely head for the Earth (Neutral) Wire or through all the (cumulatively)
low impedance paths (including the secondary winding in the distribution
Transformer) to MEN Earth

That Men system is a perfect example of why common mode
transients are so destructive. Differential mode transients
are easily quashed. Common mode transients require short
connection to earth ground.

where / how do these cause damage ?? as per usual with all of your claims
you are wrong !! explain using basic electrical Theory and physics how
common mode transients cause damage. But anyway it seems you do not
understand the MEN system - dont feel alarmed at your ignorance you show it
in regards to almost everything you choose to pontificate about - The
Queensland goverment have a good little series on MEN at :
http://www.eso.qld.gov.au/publicat/men/

Earth can be 50,000 volts underneath a building AND building
therefore is 50,000 volts. That is zero volts difference -
perfect protection. A concept called equipotential. So what
is your point?

Like many of your claims this contains a thread of truth but in the
application you have presented it is fundamentally flawed and in fact wrong
!! the earth stake is at 50,000Volts however unless the House is made
completely of metal then the house is Not ! neccasarily at 50,000V so that
the poor sod at the sink putting on a Kettle of water suddenly provides a
good path from the AC Mains Earth through to the water pipe connected to the
sink, connected to the

In the meantime those 50,000 volts were invented. You have
not a clue as to what is going where. But then 50,000 volts
is irrelevant. Current is the dominant factor - had you first
learned basic concepts of surge protection. But don't let
these little science facts stop you...

I see you must have a wee bit of trouble with basic Physics lets see now
.....
Yes you are right Current is a dominant Factor as is hmmm ..... thats It !
Earth Resistance ! ummm lets see now -
Typical Lightning Strike Current > 100,000 Amps
Good Earth stake = 0.5 Ohms
Now whats the name of that law Thingy well known by all first year
electrical/electronics Students .... hmmm that one that is so well known
that even Sparkies often know it ..... Something to do with Ohm Thingys
wasent it ??? ..... Ahh yes OHMS LAW !!!

E=IR
E=100,000*0.5
E=50,000 Volts !!!!

I knew I figured that one out somehow ;-) I guess w_tom doesnt know :
1) Facts about Lightning
2) Basic Physics
3) Basic electrical Theory

Curious that no responsible industry citation is ever
provided to support that Men system claim. In the meantime,
destructive transients are common mode which is why effective
protection has long (before WWII) been about earthing
transients before entering a building.

Remind me again when was your beloved MOV developed ???

If you have problems with this, then post responsible
industry citations - for once provide some supporting evidence
- concerning your Men system protection.

where are your esponsible citations talking about protection of domestic
premises ??
Your Main problem is that you have so little understanding of Lightning
protection, Physics and basic electrical Theory that you take examples of
Protection systems that do enjoy some (but not complete as you claim)
success against Lightning then assume that implementing half the system in
for e.g. a domestic premises is going to afford better protection than
offered by the system when fully implemented.

Please feel free to show the world what the protection
industry failed to learn for 70 years now. Dirty little
secret - you can't cite such sources.

It is actually a system employed by Electricity authorities around the world
Because it offers the best inherent protection and Safety of any
Distribution System. This information btw is available in most primers on
power distribution systems.

....Oh sorry the 'Protection Industry' arent interested in publishing the
fact that the millions of Surge arrestors etc in fact offer no extra
protection than that already offered by the MEN distribution System I wonder
why that would be ??? can you spell Vested Self Interest or hysteria ? The
fact is that Lightning damage from AC Mains on the MEN system is very
uncommon and in the cases where it has occoured most common Surge protection
(including a 1KJ mov in the switchboard) would have offered no further
protection anyway. The rael Dirty little secret is that AC mains surge
protection offer little if any extra protection than that offered by :
protection already provided by the equipment itself or Protection already
provided inherently by the MEN distribution system

how does MEN work ? simple, Basic physics and simple electrical Theory. It
is well known that a single Earth stake often has a resistance to earth in
excess of 1/2 an ohm - multiple earth stakes connected together by
relatively low impedance wiring offers a far better earth than a single
earth stake. In addition it offers redundancy of the Earth/Neutral return. a
win win situation all round.

But any way now I have answered your question you still have a number of
outsanding questions you have not answered starting with the ones you
squirmed out of answering in my last post by your usual habit of top posting
:

First in response to :

That is all an effective surge protector does - make a
temporary connection to earth during the transient. Why?
Destructive transients are common mode. That means current
enters on one or all AC electric wires

I asked :
* One or All??? Is it common mode or differential ??? in one sentence you
say
* it is common mode in the next you suggest it could be either

which really helped Highlight w_toms ignorance of simple electrical
terminology as he seems to have trouble understanding what 'common mode'
actually means

then in response to :

For example computer modems are most often
damaged by a destructive transients entering one or all AC
electric wires and leaving via one or all phone line. That is
a common mode transient - the most common destructive
transient.

I asked:

* So this surge leaves on the phone line and goes where ???? Phone lines are
* not earthed !! not any bloody where - yes they connect to earth via a feed
* bridge at the exchange but this usually adds 1K ohm resistance to this
path
* to earth and as for surges arrestors in the event they are connected to
the
* phone line (not all that common in Australia - and this is
aus.electronics )
* they typically last about 20nS in a Lightning Strike lasting in excess of
* 100nS (often well in excess).

then w_tom stated:

That plug-in UPS does not make any claims about common mode
protection for very obvious reason. Typically, it contains
exact same circuit found in power strip protectors.

to which I asked :

What? Does w_tom actually know the difference between a UPS and a surge
Protector ???

and then there are questions from the past that w_tom is still yet to answer
:


Have you found out what a thermal Fuse is ?

Tell me how Lightning is a low energy event.

where and what is the direct connection between AC Mains and the Integrated
Circuits in a modern modem ?

explain how 0.28mm^2 copper wire (phone line) povides a much lower impedance
path than 2.5mm^2 copper wire (Power cable) and hence a better path to a
nonexistant earth.

Tell me how long your much loved 1KJ mov lasts in a Direct Lightning strike
?

how long does a surge last ? - what is the definition of a surge ?

what do you do or did you do for a living w_tom ?


I am sure w_tom will squirm out by top posting in answer to this posting so
he can avoid answering the points raised but then that always was his style

Regards
Joe Van (Guess its still Me ;-) )

 

[Richard Freeman]

"Joe Van" <JoeVandeletethis@atps.net> wrote in message
news:4032effc_1@news.iprimus.com.au...

In a desperate attempt to misquote a post he is responding too "w_tom"
w_tom1@hotmail.com> resorted to top posting in message
news:4032BE33.F1F08709@hotmail.com...

Dont worry Joe that is a Classic w_tom Tactic he/It ( the moron incarnate )
will carefully avoid answering or quoting you directly that way he/it can
carefully misrepresent what you said and Lie blatently about you ( joke here
Q) how do you know when w_tom is writing crap ?
A) he is writing about anything to do with Lightning on a Newsgroup)

w_tom seems to use Google groups to find references to Lightning protection
so he can rush in and speak crap about Subjects he knows Little about ie
Lightning protection, Basic electrical theory and basic physics

How does a Men system protect without earthing every
incoming wire? Any one wire on the Men system not earthed at
service entrance is a direct path from cloud, through
appliances, to earth ground - the destructive common mode
transient. So how does this Men system provide electricity
with all wires earthed?

hmm it is not immediatley clear what w_tom is misquoting here I suspect it
was :"Fortunately though the MEN AC power distribution System
actually does a pretty good job of absorbing and riding out Lightning
Strikes. "

Unfortunately for w_tom I did not say that all the wires were earthed
merely
that MEN does a pretty good job of :
Absorbing Lightning strikes - well this is self apparent if you have a
well
earthed Power distribution System (ie MEN) then Lightning is going to most
likely head for the Earth (Neutral) Wire or through all the (cumulatively)
low impedance paths (including the secondary winding in the distribution
Transformer) to MEN Earth

That Men system is a perfect example of why common mode
transients are so destructive. Differential mode transients
are easily quashed. Common mode transients require short
connection to earth ground.

where / how do these cause damage ?? as per usual with all of your claims
you are wrong !! explain using basic electrical Theory and physics how
common mode transients cause damage. But anyway it seems you do not
understand the MEN system - dont feel alarmed at your ignorance you show
it
in regards to almost everything you choose to pontificate about - The
Queensland goverment have a good little series on MEN at :
http://www.eso.qld.gov.au/publicat/men/


Earth can be 50,000 volts underneath a building AND building
therefore is 50,000 volts. That is zero volts difference -
perfect protection. A concept called equipotential. So what
is your point?

Like many of your claims this contains a thread of truth but in the
application you have presented it is fundamentally flawed and in fact
wrong
!! the earth stake is at 50,000Volts however unless the House is made
completely of metal then the house is Not ! neccasarily at 50,000V so that
the poor sod at the sink putting on a Kettle of water suddenly provides a
good path from the AC Mains Earth through to the water pipe connected to
the
sink, connected to the



In the meantime those 50,000 volts were invented. You have
not a clue as to what is going where. But then 50,000 volts
is irrelevant. Current is the dominant factor - had you first
learned basic concepts of surge protection. But don't let
these little science facts stop you...

I see you must have a wee bit of trouble with basic Physics lets see now
....
Yes you are right Current is a dominant Factor as is hmmm ..... thats It
!
Earth Resistance ! ummm lets see now -
Typical Lightning Strike Current > 100,000 Amps
Good Earth stake = 0.5 Ohms

Well actually joe you are being conservative here 1/2 ohm to earth is a good
Earth stake - a damn good earth stake I am willing to bet they are not often
that good and 100,000 Amps is a smaller ground strike

Now whats the name of that law Thingy well known by all first year
electrical/electronics Students .... hmmm that one that is so well known
that even Sparkies often know it ..... Something to do with Ohm Thingys
wasent it ??? ..... Ahh yes OHMS LAW !!!

E=IR
E=100,000*0.5
E=50,000 Volts !!!!

I knew I figured that one out somehow ;-) I guess w_tom doesnt know :
1) Facts about Lightning
2) Basic Physics
3) Basic electrical Theory

I personally am astounded that w_tom is intelligent enough to know how to
breath without written instructions..

Curious that no responsible industry citation is ever
provided to support that Men system claim. In the meantime,
destructive transients are common mode which is why effective
protection has long (before WWII) been about earthing
transients before entering a building.

Remind me again when was your beloved MOV developed ???

Late 50,s early 60s I guess WWII was running late

If you have problems with this, then post responsible
industry citations - for once provide some supporting evidence
- concerning your Men system protection.

where are your esponsible citations talking about protection of domestic
premises ??
Your Main problem is that you have so little understanding of Lightning
protection, Physics and basic electrical Theory that you take examples of
Protection systems that do enjoy some (but not complete as you claim)
success against Lightning then assume that implementing half the system in
for e.g. a domestic premises is going to afford better protection than
offered by the system when fully implemented.

Please feel free to show the world what the protection
industry failed to learn for 70 years now. Dirty little
secret - you can't cite such sources.

I will let you into w_toms dirty little Secret - he actually knows
absolutely nothing about Electricity, Electronics or Lightning protection

It is actually a system employed by Electricity authorities around the
world
Because it offers the best inherent protection and Safety of any
Distribution System. This information btw is available in most primers on
power distribution systems.

...Oh sorry the 'Protection Industry' arent interested in publishing the
fact that the millions of Surge arrestors etc in fact offer no extra
protection than that already offered by the MEN distribution System I
wonder
why that would be ??? can you spell Vested Self Interest or hysteria ? The
fact is that Lightning damage from AC Mains on the MEN system is very
uncommon and in the cases where it has occoured most common Surge
protection
(including a 1KJ mov in the switchboard) would have offered no further
protection anyway. The rael Dirty little secret is that AC mains surge
protection offer little if any extra protection than that offered by :
protection already provided by the equipment itself or Protection already
provided inherently by the MEN distribution system

how does MEN work ? simple, Basic physics and simple electrical Theory. It
is well known that a single Earth stake often has a resistance to earth in
excess of 1/2 an ohm - multiple earth stakes connected together by
relatively low impedance wiring offers a far better earth than a single
earth stake. In addition it offers redundancy of the Earth/Neutral return.
a
win win situation all round.

But any way now I have answered your question you still have a number of
outsanding questions you have not answered starting with the ones you
squirmed out of answering in my last post by your usual habit of top
posting

well actually you forgot the fundamental question which gives the whole game
away : Why is the AC mains distribution system Earthed ? what does Earthing
it accomplish ? - if you followed the sort of logic w_tom uses floating the
AC Mains actually makes it safer - think about it you could hang on to an
Active quite safely and since you are not completing the circuit you should
be O.K - the real question is why is this untrue ?

First in response to :

That is all an effective surge protector does - make a
temporary connection to earth during the transient. Why?
Destructive transients are common mode. That means current
enters on one or all AC electric wires

I asked :
* One or All??? Is it common mode or differential ??? in one sentence you
say
* it is common mode in the next you suggest it could be either

which really helped Highlight w_toms ignorance of simple electrical
terminology as he seems to have trouble understanding what 'common mode'
actually means

then in response to :
For example computer modems are most often
damaged by a destructive transients entering one or all AC
electric wires and leaving via one or all phone line. That is
a common mode transient - the most common destructive
transient.

I asked:

* So this surge leaves on the phone line and goes where ???? Phone lines
are
* not earthed !! not any bloody where - yes they connect to earth via a
feed
* bridge at the exchange but this usually adds 1K ohm resistance to this
path
* to earth and as for surges arrestors in the event they are connected to
the
* phone line (not all that common in Australia - and this is
aus.electronics )
* they typically last about 20nS in a Lightning Strike lasting in excess
of
* 100nS (often well in excess).

then w_tom stated:

That plug-in UPS does not make any claims about common mode
protection for very obvious reason. Typically, it contains
exact same circuit found in power strip protectors.

to which I asked :

What? Does w_tom actually know the difference between a UPS and a surge
Protector ???

and then there are questions from the past that w_tom is still yet to
answer
:


Have you found out what a thermal Fuse is ?

Tell me how Lightning is a low energy event.

where and what is the direct connection between AC Mains and the
Integrated
Circuits in a modern modem ?

explain how 0.28mm^2 copper wire (phone line) povides a much lower
impedance
path than 2.5mm^2 copper wire (Power cable) and hence a better path to a
nonexistant earth.

Tell me how long your much loved 1KJ mov lasts in a Direct Lightning
strike
?

how long does a surge last ? - what is the definition of a surge ?

what do you do or did you do for a living w_tom ?


I am sure w_tom will squirm out by top posting in answer to this posting
so
he can avoid answering the points raised but then that always was his
style

Ahh you found my list on Google - w_tom must have me killfiled as he never
answered my posts asking these questions - I think he realised I knew a heck
of a lot more about Lightning damage and protection than he/it did. as he
stopped responding to my posts pointing out what a complete moron he/it was.
In fact you have kicked him/it so thouroghly in the goolies in this post he
has probably just added you to his Kill file too, Like me and probably Rod
speed. He he he he he

Good luck getting through to the Moron w_tom you will need it

Best Regards
Maintain the Rage
Richard Freeman

 

[w_tom]

Joe Van would have everyone believe that his Men system
somehow and magically earths every incoming utility line. Men
is simply a three phase Y system found in most every country.
A standard design taught to every 1st year engineering
student. Four incoming wire system has a neutral wire
connected to earth ground AND three hot wires (Phases A, B &
C) that are not earthed. Schematic found in his cited Section
One, figure 1.2:
http://www.eso.qld.gov.au/publicat/men/men1.pdf

A destructive transient enters on all wires. Neutral wire
is earthed meaning common mode transient terminates there.
But destructive transient continues on into building on other
three hot wires. Common mode transient on phase C, into
appliance, then out any and every destructive path such as
human, floor tiles, phone line, etc. (This outgoing path is
why modems, fax machines, and portable phone base stations are
so easily damaged). Outgoing path also not shown in Joe's
figure 1.2 because his MEN tutorial does not discuss nor even
claims to provide transient protection.

Still we await some proof from Joe Van that Men systems
provide protection. He still cannot cite a responsible
source; in part because no responsible source would make his
speculative claims.

Therein is the problem with Joe Van's repeated claims.
Again he cites no support for his speculation. No shunt to
earth ground on Phases A through C means no effective
protection.

For effective surge protection, all three hot wires (Phase
A, Phase B, and Phase C) must be earthed at building
entrance. How? When a phase connects to earth, then AC
electric is shorted out - fuse blows. A 'whole house'
protector shunts each hot wire (each Phase) to earth ground,
at the service entrance, during a destructive common mode
transient.

Destructive common mode transient is earthed. Fuse does
not blow. Human need not even know a destructive transient
existed. Effective protection.

Joe Van would have us believe all four wires in that three
phase system are earthed. Obviously not. Even figure 1.2
makes that obvious.

No earth ground means no effective protection. All three
phases are a direct and destructive path for common mode
transients into building appliances. Effective protection is
a 'whole house' protector from each Phase to earth ground;
shunts to earth. Of course a plug-in UPS in the original post
cannot accomplish this nor does it even claim to.

Joe Van wrote:

...
Unfortunately for w_tom I did not say that all the wires were
earthed merely that MEN does a pretty good job of :
Absorbing Lightning strikes - well this is self apparent if you
have a well earthed Power distribution System (ie MEN) then
Lightning is going to most likely head for the Earth (Neutral)
Wire or through all the (cumulatively) low impedance paths
(including the secondary winding in the distribution Transformer)
to MEN Earth

 

[Jim Jones]

w_tom <w_tom1@hotmail.com> wrote in message
news:40341949.F9554525@hotmail.com...

Joe Van would have everyone believe that his Men system
somehow and magically earths every incoming utility line. Men
is simply a three phase Y system found in most every country.

Not a fucking clue, as always.

Reams of pig ignorant shit flushed where it belongs.

 

[Joe Van]

Note how the Pathalogical BS artist w_tom" <w_tom1@hotmail.com> in an effort
to misrepresent what was written top posts in
news:40341949.F9554525@hotmail.com...

First of all w_tom how about some answers to those questions you keep
avoiding In fact just to show what a complete and utter Ignoramous w_tom is
I think I should provide google references for these questions :

Have you found out what a thermal Fuse is ?

how long does a surge last ? - what is the definition of a surge ?

both these come from one of w_toms Postings where he thinks a Thermal fuse
protects against Over current and where he claims a Surge is a Spike

http://groups.google.com/groups?q=w_tom+belkin&hl=en&lr=&ie=UTF-8&oe=UTF-8&s
elm=3FAB0E6D.F1E51914%40hotmail.com&rnum=8

Tell me how Lightning is a low energy event.

More fruit loop Ideas from the Moron w_tom which also displays more of his
ignorance - He claims that 1,000,000,000 - 10,000,000,000 Joule events are
low energy ? (yes yes I know 90% of that is turned into : Heat, Light and
Shock waves (Sound) enroute but given that the Heat and shock waves are what
causes Damage this is still relevant) :

http://groups.google.com/groups?q=g:thl2460924250d&dq=&hl=en&lr=&ie=UTF-8&oe
=UTF-8&selm=3F672099.8AF65807%40hotmail.com&rnum=26

where and what is the direct connection between AC Mains and the Integrated
Circuits in a modern modem ?

This highlights w_toms ignorance of modems, Telecommunications and even
sensible Electronics - Yes in a desperate attempt to explain the damage to
modems during Lightning strikes w_tom invented a direct connection between
AC Mains and the Integrated Circuits in a modem ;-)

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=dfee1359.03
04141805.6c8c0bb2%40posting.google.com

In fact on that I just found a classic illustration of w_toms ignorance in :

http://groups.google.com/groups?q=g:thl2197306145d&dq=&hl=en&lr=&ie=UTF-8&oe
=UTF-8&selm=3D6E93C3.225651F9%40usa.net

where he describes testing for continuity between a PC motherboard and the
earth pin on the AC Mains plug and then states that he is not sure how
Lightning would have found an Earth with the PC switched off ;-) no I have
to quote this stupidity directly :
Quote from w_tom ;-)

Use a multimeter in continuity mode. Check for a connection
from some motherboard IC pins to the center AC prong. Notice
a direct connection. How lightning found earth ground through
your machine is not entirely clear

explain how 0.28mm^2 copper wire (phone line) povides a much lower impedance
path than 2.5mm^2 copper wire (Power cable) and hence a better path to a
nonexistant earth.

well this keeps cropping up whenever w_tom talks about Lightning damaging
Modems - geez this guy is a fool ! he keeps claiming that Lightning leaves
the MEN earth alone and heads for a nonexsistant earth on a phone Line

Tell me how long your much loved 1KJ mov lasts in a Direct Lightning strike


what do you do or did you do for a living w_tom ?


Now on to my hobby of showing w_tom up for the fool he is ....;-)

Joe Van would have everyone believe that his Men system
somehow and magically earths every incoming utility line.

A classic case of misrepresentation by w_tom (please feel free to read the
Previous post to see what I did in fact claim) once again w_tom resorts to
top posting to avoid the Truth in fact this is actually true giving it
further consideration the AC Mains distribution System does effectively
provide a low impedance path to Earth from each Active wire.

Since w_tom does not understand Basic electrical Theory he will have a bit
of trouble understanding how this happens but to those who are curious may I
suggest this simple experiment :
get a Power Transformer and simply measure the resistance of the secondary
winding - pretty low isnt it ? The secondary side of a Power Distribution
Transformer built to deliver thousands of Amps is Much,much lower.

of course w_tom will claim that Lightning is a High Frequency Signal (- this
is actually a load of Crap Lightning is in fact Pulsed DC but then w_tom
completely fails to understand Basic Electrical Theory and I hardly expect
him to understand the ramifications of Fourier analysis) the High Frequency
component is actually not of too much concern to us as it is quickly
attenuated by the series Impedance of the Power distribution System it is
the Lower Frequency component that has the potential to cause more damage
and that is typically common mode to the Power system and easily absorbed
into the MEN Earth

Men
is simply a three phase Y system found in most every country.
A standard design taught to every 1st year engineering
student. Four incoming wire system has a neutral wire
connected to earth ground AND three hot wires (Phases A, B &
C) that are not earthed. Schematic found in his cited Section
One, figure 1.2:
http://www.eso.qld.gov.au/publicat/men/men1.pdf

Note how he carefully avoids the MAJOR point of MEN - The Earthing System
after which MEN is named. There are two possible reasons why w_tom has
avoided this :

1) Because he has no understanding of MEN this is likely as he has
demonstrated a complete lack of understanding of basic Earthing principles
and in Fact Basic electrical Theory.

2) he is desperately trying to avoid the earthing issue because he knows
that that supports most of my claims

A destructive transient enters on all wires. Neutral wire
is earthed meaning common mode transient terminates there.
But destructive transient continues on into building on other
three hot wires. Common mode transient on phase C, into
appliance, then out any and every destructive path such as
human, floor tiles, phone line, etc. (This outgoing path is
why modems, fax machines, and portable phone base stations are
so easily damaged). Outgoing path also not shown in Joe's
figure 1.2 because his MEN tutorial does not discuss nor even
claims to provide transient protection.

See what I mean w_tom calls the Transient Common mode and then describes a
differential Transient. Why ? because actually despite his pontifications he
actually has no idea what he is Talking about - note his claims that the
Transient goes from the AC mians to the Phone Line. We all know that
Lightning seeks Earth ground, We know (well w_tom pretends he does not )
that the MEN system provides one of the best Earth Systems available (which
is why w_tom carefully avoided talking about MEN Earth above) and we also
know that Telephone Lines : 1) Have no direct connection to Earth 2) use
relatively High impedance wiring. Simple Physics tells us that the Lightning
strike lets say it is to Active is going to see a very Low impedance to
Earth via the Distribution Transformer, Flashovers and the total Load on the
Circuit and will become Common mode to the AC Mains. The same basic Physics
tells us that this strike will also be shunted to Earth via the MEN System.

So what about the most common forms of damage from Lightning ? Faxes,
Answering Machines and Modems do these support w_toms claims ?
Not really as anyone who has worked in the Telco Industry can tell you
actually by far the most common path for Lightning damage is from the Phone
Line through the Fax, Answering Machine or Modem usually leaving other
equipment that was plugged into AC Mains still working this suggests that
any surge via AC Mains is therefore Common mode ( the claim that even w_tom
makes while missing the point that the Common mode surge is going to be
grounded out by the MEN Earth system) or the real explanation that is since
the Telephone system has no effective Earth it merely carries the Lightning
surge to the Nearest convenient Earth that of the MEN Power system via the
Modem, Fax machine etc.

Still we await some proof from Joe Van that Men systems
provide protection. He still cannot cite a responsible
source; in part because no responsible source would make his
speculative claims.

Therein is the problem with Joe Van's repeated claims.
Again he cites no support for his speculation. No shunt to
earth ground on Phases A through C means no effective
protection.

I Have cited the reasons why MEN provides effective Lightning Protection
however w_tom desperately Top posted in an effort to avoid it he has also
avoided answering any of the questions I have asked him please feel free to
refer to my previous posts.

For effective surge protection, all three hot wires (Phase
A, Phase B, and Phase C) must be earthed at building
entrance. How? When a phase connects to earth, then AC
electric is shorted out - fuse blows. A 'whole house'
protector shunts each hot wire (each Phase) to earth ground,
at the service entrance, during a destructive common mode
transient.

This merely shows w_toms lack of understanding of basic Electrical
Principles the AC Mains system. But then also note that w_tom never explains
who he is or how he makes a living (except deying that he sold protection
systems - it is odd he was so specific about that)

Destructive common mode transient is earthed. Fuse does
not blow.

dunno why he bothered mentioning the Fuse - actually usually when MOVs cop a
near or direct strike they do Blow themselves to Bits - and no they dont
last long enough to offer any real protection but then when you read the
spec they are typically only rated for 20nS whereas a Lightning strike
usually lasts in excess of 100nS

Human need not even know a destructive transient
existed. Effective protection.

Joe Van would have us believe all four wires in that three
phase system are earthed. Obviously not. Even figure 1.2
makes that obvious.

w_tom lacks sufficent understanding to realise how a Low impedance path
exsists to earth from the Three active Lines - something that is even Taught
to electrical Fitters in TAFE - but w_tom is ignorant of it ??? even
Audiophiles understand this principle (known in audiophile circles as
Amplifier 'Damping' which is really basically the same principle) and they
tend to be a pretty ignorant lot.

No earth ground means no effective protection.

Yep occasionally w_tom throws out a true statement but unfortunately he does
not understand the Basic principles involved so he then goes on to make some
really inaccurate and way out claims

All three
phases are a direct and destructive path for common mode
transients into building appliances.

Here he goes again - he has obviously heard the term 'common mode' but since
he has no understanding of what it actually means he describes a
differential Transient then calls it Common mode. In fact this is really the
whole secret of MEN protection that Transients are Common mode but w_tom
does not have the basic understanding to see that.

Effective protection is
a 'whole house' protector from each Phase to earth ground;
shunts to earth.

w_toms 'Whole house protectors provide no extra protection from Lightning
than already exsists and are largely a Con.

Of course a plug-in UPS in the original post
cannot accomplish this nor does it even claim to.

I would describe w_tom as a Moron but that would probably offend Honest Hard
working Morons

Regards
Joe Van

 

[Vermin]

On Fri, 20 Feb 2004 11:49:56 +1100, "Joe Van"
<JoeVandeletethis@atps.net> slandered:

First of all w_tom how about some answers to those questions you keep
avoiding In fact just to show what a complete and utter Ignoramous w_tom is
I think I should provide google references for these questions :

Have you found out what a thermal Fuse is ?

Actually that was me not this tosser (though from checking the header
it appears he has been conned into using bigpond broadband too,
however he is posting from another state, look up the servers).

And if you are still missing the point of that old argument;

1) Thermal fusing is recommended by MOV manufacturers to prevent fire
risk due to current limited sustained over voltage faults. Check the
literature I can't be fucked finding it for a wanker like you.

2) Thermal fuses such as the THF-184 shown here;
http://www.allelectronics.com/cgi-bin/category.cgi?category=765
fail short circuit and will not go open circuit due to over
temperature after being subject to just one 3kA 8/20ľs surge.

I have tested this. I do not care if you do not believe me. as I
wouldn't piss on you if you were on fire anyway. Burn.

Get your facts straight, and don't bother replying because I wont.

V.
Formerly Tom L, and Bender *NOT* tom_w

 

[Phil Allison]

"Vermin" <Vermin@nowhere.com> wrote in message
"Joe Van" <JoeVandeletethis@atps.net> slandered:

Have you found out what a thermal Fuse is ?

Actually that was me not this tosser ...

** Nice to see at least one tosser admit it.

And if you are still missing the point of that old argument;

1) Thermal fusing is recommended by MOV manufacturers to prevent fire
risk due to current limited sustained over voltage faults. Check the
literature I can't be fucked finding it for a wanker like you.

2) Thermal fuses such as the THF-184 shown here;
http://www.allelectronics.com/cgi-bin/category.cgi?category=765
fail short circuit and will not go open circuit due to over
temperature after being subject to just one 3kA 8/20ľs surge.

** I dunno what bizarre from of English is used where Vermin hails from
( Tasmania ? ) but a fuse always fails open.

You see, a fuse that is not open still lets current through - ergo, it
has not failed.

How can this possibly be misconstrued ?????

Vermin has managed it with ease.

I have tested this.

** I just have to know the test that demonstrates a thermal fuse failing
short - that must be a real beaut.

I do not care if you do not believe me.

** Vermin does not care if he makes any sense - he answers no questions
except to make less sense than the first time.

as I wouldn't piss on you if you were on fire anyway.

** Vermin lives up to his adopted handle.

Get your facts straight, and don't bother replying because I wont.

** I like to see a man who stands behind his words - while others piss
on them.

V.
Formerly Tom L, and Bender

** Ah !! - now I get it.

Vermin is what Tom L transforms into when he goes on a Bender !!!

Simple.




.............. Phil

 

[Arpit]

Hi, thanks to everyone who replied. I've learnt quite a bit from this
thread. I've decided that installing a separate earth on the
powerobard like I was thinking of doing would be silly. I do seem to
live in a lighting prone area though, so in the future a surge
protector which mounts in the fusebox may be an idea. Ive enquired
with my mother, and yes household insurance does cover lightning
strikes,, but I think a surge protector in the fusebox still would be
nice as a protective measure, just as a thermal cutout for an oven
would still be useful even though you have fire insurance.
Putting less than 3 meters of heavy guage cable to the earth would not
be a problem. I also think I could install this myself, I know it's
illegal, but really its a simple job.
I'll just trust in my current earth for the moment. I gather from this
thread than the MEN system means that even if it is a little shoddy,
my neighbours excellent earth will make up for it.

So yeah, thanks everyone



On Sun, 15 Feb 2004 11:26:37 +1100, Arpit
<DONTSPAMMEF00Lneko4@dodo.com.au> wrote:

Hi, I invested in a UPS system, primarily to filter surges and spikes.
However, I know for this to be useful I need a good ground. I think,
but Im not sure, that the ground for my house is a pipe at the side
stuck into the earth, and it looks a little dodgy. So I was thinking
of instlaling my own ground outside my room, in the form of 3 1.5
meter galvanised pipes in the ground. I'd then take a wire from each
and connect each wire to the ground pin of a standard plug. THen, I'd
put the 3 plugs into a 4 way power board, and plug the power board
into a wall outlet. the 4th socket would hold the plug for my UPS.

Are there any problems with multiple grounds for a house system?
POtential problems I can think of, would be

- galvanic corrosion of the ground electrodes
-ground loops
- melting of the powerboard lead iin case of a lightning strike

but I don't know enough aobut the above to come to a conclusion. COuld
anyone give me some advice please?

Thanks,
Arpit THomas

 

[w_tom]

The Men system does not even claim to provide protection.
Your neighbors earthing does not compensate. In all AC
electric systems, one incoming wire to each building (the
neutral wire) must make a connection to earth ground. Earth
ground at another building still does not provide earthing for
your building. That Men system description (written for those
without electrical knowledge) demonstrates why your building
must be earthed for human safety reasons. Why even earthing
on neighbor's does not provide essential earthing even for
human safety.

Transistor safety is why a 'whole house' protectors with a
less than 3 meter connection to earth is installed. Whereas
wire *resistance* is important to human safety; wire
*impedance* is important to transistor safety.

An example that demonstrates the concept: Lets say a 100
amp transient must obtain earth ground (via receptacle safety
ground wire) on a 20 amp circuit that is 18 meters long. To
AC electric, that wire would be less than 0.2 ohms
'resistance'. But to a 100 amp common mode transient, that
same wire might be 120 ohms impedance. That 120 ohms
impedance could be even higher due to sharp bends and splices
in that 18 meter wire. Sharp bends and splices would not
affect resistance. But transient protection is about wire
impedance. Therefore sharp bends, etc creates even worse
earthing.

For human safety, wire length is irrelevant since resistance
is so low. However, for transistor safety, wire length
significantly increases impedance - makes all but no earth
ground. Again, why that connection from each Phase (A thru
C), via protector, must be less than 3 meters to earth ground.

Therein lies the advantage of a 'whole house' protector. It
makes a short (low impedance) connection to earth ground. If
same 'whole house' protector was connecting to earth via 20
meter wire, then protector is all but not grounded - too much
wire impedance.

A three phase (Men) system with earth ground does not makes
a 'whole house' protector so effective. 'Whole house'
protector that connects each phase to central earth ground
(less than 3 meters) makes that protection system effective.

Please do not confuse surge protector and surge protection.
They are different. Surge protector is effective when it
makes a connection (from each wire) less than 3 meters to
surge protection - single point earth ground. Your neighbors
earth ground is way too far - more than 3 meters. Wire is not
a conductor when discussion higher frequency, common mode
transients. Wire becomes another electronic component. Wire
length is critical. Other factors that also increase wire
impedance are sharp bends, routing wire inside a metallic
conduit, wire splices, and other joints. In fact joints as
such a problem for protection that CAD welding (low impedance
connection) is often used.

That three phase system as described in
http://www.eso.qld.gov.au/publicat/men does not discuss any
of this since that tutorial describes earthing only for human
safety. 'Whole house' protectors are installed for transistor
safety. That earth ground serves two purposes - human safety
and transistor safety.

To better appreciate the topic without so many uneducated
experts hyperventilating, please visit a summary discussion
in http://tinyurl.com/l3m9 or
http://tinyurl.com/p1rk
where concepts of resistance and impedance are actually
understood. Where posters were first trained in basic
electrical principles.

For those who need a sound byte: a surge protector is only
as effective as its earth ground.

Arpit wrote:

Hi, thanks to everyone who replied. I've learnt quite a bit from this
thread. I've decided that installing a separate earth on the
powerobard like I was thinking of doing would be silly. I do seem to
live in a lighting prone area though, so in the future a surge
protector which mounts in the fusebox may be an idea. Ive enquired
with my mother, and yes household insurance does cover lightning
strikes,, but I think a surge protector in the fusebox still would be
nice as a protective measure, just as a thermal cutout for an oven
would still be useful even though you have fire insurance.
Putting less than 3 meters of heavy guage cable to the earth would not
be a problem. I also think I could install this myself, I know it's
illegal, but really its a simple job.
I'll just trust in my current earth for the moment. I gather from this
thread than the MEN system means that even if it is a little shoddy,
my neighbours excellent earth will make up for it.

So yeah, thanks everyone

 

[Rod Speed]

Arpit <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in message news:t38d30p7s8ee35nhu7b468ddgmvmjca597@4ax.com...

Hi, thanks to everyone who replied. I've learnt quite a bit from this
thread. I've decided that installing a separate earth on the
powerobard like I was thinking of doing would be silly. I do seem to
live in a lighting prone area though, so in the future a surge
protector which mounts in the fusebox may be an idea. Ive enquired
with my mother, and yes household insurance does cover lightning
strikes,, but I think a surge protector in the fusebox still would be
nice as a protective measure, just as a thermal cutout for an oven
would still be useful even though you have fire insurance.

Trouble is that it doesnt help with direct lightning strikes and
may not help with that many surges and spikes in practice.

Putting less than 3 meters of heavy guage cable to the
earth would not be a problem. I also think I could install
this myself, I know it's illegal, but really its a simple job.

Installing a surge protector in the meter box isnt tho.

I'll just trust in my current earth for the moment. I gather from
this thread than the MEN system means that even if it is a little
shoddy, my neighbours excellent earth will make up for it.

So yeah, thanks everyone

On Sun, 15 Feb 2004 11:26:37 +1100, Arpit
DONTSPAMMEF00Lneko4@dodo.com.au> wrote:

Hi, I invested in a UPS system, primarily to filter surges and spikes.
However, I know for this to be useful I need a good ground. I think,
but Im not sure, that the ground for my house is a pipe at the side
stuck into the earth, and it looks a little dodgy. So I was thinking
of instlaling my own ground outside my room, in the form of 3 1.5
meter galvanised pipes in the ground. I'd then take a wire from each
and connect each wire to the ground pin of a standard plug. THen, I'd
put the 3 plugs into a 4 way power board, and plug the power board
into a wall outlet. the 4th socket would hold the plug for my UPS.

Are there any problems with multiple grounds for a house system?
POtential problems I can think of, would be

- galvanic corrosion of the ground electrodes
-ground loops
- melting of the powerboard lead iin case of a lightning strike

but I don't know enough aobut the above to come to a conclusion. COuld
anyone give me some advice please?

Thanks,
Arpit THomas

 

[Rod Speed]

w_tom <w_tom1@hotmail.com> wrote in message
news:4036AE95.C0E26928@hotmail.com...

The Men system does not even claim to provide protection.

Wrong. As always.

Reams of pig ignorant shit flushed where it belongs.

 

[Richard Freeman]

"Arpit" <DONTSPAMMEF00Lneko4@dodo.com.au> wrote in message
news:t38d30p7s8ee35nhu7b468ddgmvmjca597@4ax.com...

Hi, thanks to everyone who replied. I've learnt quite a bit from this
thread. I've decided that installing a separate earth on the
powerobard like I was thinking of doing would be silly. I do seem to
live in a lighting prone area though, so in the future a surge
protector which mounts in the fusebox may be an idea. Ive enquired
with my mother, and yes household insurance does cover lightning
strikes,, but I think a surge protector in the fusebox still would be
nice as a protective measure, just as a thermal cutout for an oven
would still be useful even though you have fire insurance.

Don't Bother Arpit unless you can get and install the Surge arrestor for
next to Nothing, as in Practice Surge arrestors across the Mains provide
very little extra Protection than already exists in the power distribution
System and the equipment already. The Power Distribution system is by its
very Nature a Low impedance System which means that in the event of a
Lightning strike to AC Mains the strike gets pretty well absorbed or really
..
two or Three months ago we had a Lightning strike to the 415V lines about 50
Metres down the road from my house - The body count from my street (checking
with my neighbours etc) was nil.

By Far the most common path for Lightning damage is in via the Phone Line.
The Second most common is via TV and Radio Aerials
The Third most common is via Near or direct Strikes being picked up by
Building wiring

and finally the least common Path for Lightning damage ........

AC Mains !!!!

Putting less than 3 meters of heavy guage cable to the earth would not
be a problem. I also think I could install this myself, I know it's
illegal, but really its a simple job.
I'll just trust in my current earth for the moment. I gather from this
thread than the MEN system means that even if it is a little shoddy,
my neighbours excellent earth will make up for it.

So yeah, thanks everyone

well in reality a Nice thick bit of cable to your Earth stake will probably
again make very little difference as from Memory when I used to service
Telex machines (yep I know showing my age !! ) an Earth of less than 10 Ohms
was considered a Good earth ( Telex machines used DC for signalling, DC =
Electrolysis (Corrosion) so Telex machines were not allowed to be earthed
Via AC Mains Earth) and in fact the 1/2 Ohm required for the quoted EPR on
an Earth stake is actually for a very Good Earth, in reality wether the
Bonding wire to the Earth stake is 0.001 Ohm or 0.004 Ohm will probably in
fact make little or no Difference in the scheme of things.

w_tom is very coy about what his Job actually is - He does not display
enough basic knowledge of Electrical theory to even equal most electricians
I have met (and believe me that is saying Something! ) note in his arguments
that whenever he makes a claim off his own Bat he is generally wrong and
whenever he quotes Websites he generally manages to completely misunderstand
the Context and even has trouble telling the difference between a Farmer and
an Engineer (on an Aside my Business card at my last job used to claim I was
a field engineer I never could figure out if that meant I was a Back hoe
operator or a Farmer )

Given his Pontifications I suspect he installs Surge arrestors for a Living
and therefore has a vested interest in selling them and I suspect an
Electrician of this sort of Level would barely need to know much more than
w_tom actually does.

Basically any Advice given by w_tom on the subject of Lightning protection
would be best ignored as he makes it obvious He does not have a clue about
Lightning protection, Basic Electrical Theory or Physics.

Regards
Richard Freeman

 

[James]

snip

Don't Bother Arpit unless you can get and install the Surge arrestor for
next to Nothing, as in Practice Surge arrestors across the Mains provide
very little extra Protection than already exists in the power distribution
System and the equipment already. The Power Distribution system is by its
very Nature a Low impedance System which means that in the event of a
Lightning strike to AC Mains the strike gets pretty well absorbed or really
.
two or Three months ago we had a Lightning strike to the 415V lines about 50
Metres down the road from my house - The body count from my street (checking
with my neighbours etc) was nil.

I think lightning arrestors have some value, and Ive seen plenty of

things damaged from surges on the mains. Saw a switchboard last year
damaged by lighting, looked like it had a bomb go off inside it. It
flashed over from blue phase to the steel case, vapourising part of
the bus bar and burning a large hole in the case. Looked quite
spectacular.

Around where I am the LV overhead lines have lightning arrestors on
them near the ends and at the transformer. There are lightning
arrestors on the 11 or 22kV side of the transformer also. The HV
lightning arrestors look like insulators mounted next to the
transformer bushings, the LV arrestors look like black blobs attached
to brackets welded to the pole cross arm.

Putting less than 3 meters of heavy guage cable to the earth would not
be a problem. I also think I could install this myself, I know it's
illegal, but really its a simple job.
I'll just trust in my current earth for the moment. I gather from this
thread than the MEN system means that even if it is a little shoddy,
my neighbours excellent earth will make up for it.

Idea of the MEN system is for the neutral to carry mains fault
current. An earth stake alone is unable to sink much fault current.
There have been a few cases of where the MEN link is missing or broken
and an earth fault occurring in a stove or something and the whole
earthing system in the house livening up. In a particular case I read
about the earthing system was bonded to the water pipes in the house
and these livened up also and someone reveived a severe shock from
touching a tap. The MEN system works well when installed properly but
can be very dangerous if not connected correctly or a main neutral is
damaged.

cheers
james

 

[Richard Freeman]

"James" <j.l@octa4.net.au> wrote in message
news:9c685cb8.0402240403.36b85208@posting.google.com...

snip
Don't Bother Arpit unless you can get and install the Surge arrestor for
next to Nothing, as in Practice Surge arrestors across the Mains provide
very little extra Protection than already exists in the power
distribution
System and the equipment already. The Power Distribution system is by
its
very Nature a Low impedance System which means that in the event of a
Lightning strike to AC Mains the strike gets pretty well absorbed or
really
.
two or Three months ago we had a Lightning strike to the 415V lines
about 50
Metres down the road from my house - The body count from my street
(checking
with my neighbours etc) was nil.

I think lightning arrestors have some value, and Ive seen plenty of
things damaged from surges on the mains. Saw a switchboard last year
damaged by lighting, looked like it had a bomb go off inside it. It
flashed over from blue phase to the steel case, vapourising part of
the bus bar and burning a large hole in the case. Looked quite
spectacular.

The real question is given the level of damage described in this Switchboard
how much damage do you think would have been avoided by a set of 1KJ Movs
(as recommended by the Moron w_tom) across the power Lines ???

I have seen plenty of MOVs across Phone Lines - they usually provide no
Protection in the event of a near or Direct Strike in fact I have seen Main
Distribution Frames where over 200 MOVs were Literally blown to pieces and
still Fax Machines, Modems and Answering Machines and Krone Modules had been
Destroyed .
I have in Fact seen a case where the MOVs were blown off the MDF and the
surge still travelled down the Telephone cable and destroyed a connector at
an exchange after over 4.5 Kms of cable.

My point is that for any distant or low Energy Strike where a MOV may
provide some degree of protection the MEN distribution System ( and the
equipment involved) already provides the Same Degree of protection as the
MOV.
Where the strike is of sufficent Magnitude to cause damage then the MOV is
going to fail in roughly the first 20nS (it is all they are typically rated
for) leaving in excess of 80nS for the Lightning to cause further
destruction.

The Danger of Morons like w_tom is that he is stupid enough to claim that
his 'whole house protection' provides 100% protection from Lightning. This
is contrary to what anyone who has seen the effects of Lightning first hand
would tell you. Unfortunately People on these Newsgroups like Arpit may not
have the experience or knowledge to assess w_toms Flawed advice and realise
that w_tom is in fact full of Crap and then fail to take reasonable
precautions as a result of the Very bad advice they have received.

Around where I am the LV overhead lines have lightning arrestors on
them near the ends and at the transformer. There are lightning
arrestors on the 11 or 22kV side of the transformer also. The HV
lightning arrestors look like insulators mounted next to the
transformer bushings, the LV arrestors look like black blobs attached
to brackets welded to the pole cross arm.



Putting less than 3 meters of heavy guage cable to the earth would not
be a problem. I also think I could install this myself, I know it's
illegal, but really its a simple job.
I'll just trust in my current earth for the moment. I gather from this
thread than the MEN system means that even if it is a little shoddy,
my neighbours excellent earth will make up for it.


Idea of the MEN system is for the neutral to carry mains fault
current. An earth stake alone is unable to sink much fault current.
There have been a few cases of where the MEN link is missing or broken
and an earth fault occurring in a stove or something and the whole
earthing system in the house livening up. In a particular case I read
about the earthing system was bonded to the water pipes in the house
and these livened up also and someone reveived a severe shock from
touching a tap. The MEN system works well when installed properly but
can be very dangerous if not connected correctly or a main neutral is
damaged.

Unfortunately like all power distribution Systems it works when it works and
can be very Nasty when it doesnt.

Regards
Richard Freeman