lightning protection

[Halfgaar]

Hi list,

Is there a way to reasonably reliably protect electronic equipment from
indirect lightning hits? I have an extensioncord (well, not really an
extensioncord, I just don't know what else to call it) with
surgeprotection. It says: "max clamping voltage: 750V with standing surge
current 1250A". Can this do the trick, or is it only to protect the
equipment from a faulty powergrid?

TIA

Halfgaar
--
To send email, change nospam.com into yahoo.com.

 

[CWatters]

An FAQ here..
..
http://www.penlight.org/FAQ/faq_surge.html

Don't neglect the modem - my mothers was trashed in a T-Storm only last
month.



"Halfgaar" <voor_achter@nospam.com> wrote in message
news:3f22432b$0$140$edd6591c@news.versatel.net...

Hi list,

Is there a way to reasonably reliably protect electronic equipment from
indirect lightning hits? I have an extensioncord (well, not really an
extensioncord, I just don't know what else to call it) with
surgeprotection. It says: "max clamping voltage: 750V with standing surge
current 1250A". Can this do the trick, or is it only to protect the
equipment from a faulty powergrid?

TIA

Halfgaar
--
To send email, change nospam.com into yahoo.com.

 

[w_tom]

Ben Franklin demonstrated the concept in 1752. Lightning
traveled miles through non-conductive air to obtain earth
ground. Is some silly opto-isolator or point of use surge
protector going to stop, block, or absorb lightning? Of
course not. But effective protection has been demonstrated
repeatedly since before WWII. Effective protection does what
Franklin did in 1752.

Lightning seeks earth ground. Divert lightning to earth
before it can strike the church steeple. Well proven by
centuries of experience.

Electronics has the same problem. If lightning finds a
circuit path to earth via household electronics, then surge
damage result. Again well proven is to earth the surge, at
service entrance, before surge can enter a building.

It's called 'whole house' surge protectors. But surge
protectors are not surge protection. A surge protector is
only as effective as its connection to surge protection -
earth ground. No short connection to earth ground (which is
the problem with plug-in or point of use surge protectors)
means no effective connection.

A surge protector is only as effective as its earth ground.
Surge protectors are simple science - often hyped into myth.
The art of protection is earthing - not a surge protector.
Which again demonstrates why 'point of use' protectors are so
ineffective. Since they don't provide effective protection,
then there is no dedicated (less than 10 foot) connection to
earth AND those ineffective protectors avoid all discussion
about earthing.

Just as Franklin demonstrated. Surge protection is about
earthing a surge. That is what a surge protectors does.
Connect all wires to earth ground only during the surge (which
is why a surge protector must have a less than 10 foot
connection to earth).

The most common source of destructive surges (even to
modems) is AC electric. Surge enters on the one utility that
typically has no protection. Telephone line has and CATV
should have 'whole house' protection. But AC electric - the
utility highest on pole and most struck - makes a direct
hardwire connection even to modem ICs.

What does a surge seek? Earth ground. Any appliance that
makes a connection from AC electric to earth ground becomes a
complete surge circuit. Modems and portable phone base
stations are easily destroyed. Incoming on AC electric.
Outgoing to earth ground on phone line (because telco already
installs 'whole house' protector on phone line).

Two minimally sized 'whole house' protectors are sold in
Home Depot - Intermatic EG240RC or IG1240RC, and Siemens
QSA2020. Never seen any effective surge protectors sold in
Sears, Walmart, Lowes, Kmart, Staples, or Office Max.
Obviously. They don't have a dedicated connection to earth
ground AND avoid all earthing discussions. They don't even
claim to protect from the typically destructive type of surge.

Just a few introductory concept about protection. Will not
even discuss so many erroneous facts posted in the
www.penlight.org FAQ. Discussion for another post. But this
is the fundamental fact. A surge protector is only as
effective as its earth ground. Surge protectors don't stop,
block, or absorb surges. They only shunt - connect all wires
together - during the surge. That shunting is protection only
if connected less than 10 feet to earth ground.


Halfgaar wrote:

Hi list,

Is there a way to reasonably reliably protect electronic equipment
from indirect lightning hits? I have an extensioncord (well, not
really an extensioncord, I just don't know what else to call it)
with surgeprotection. It says: "max clamping voltage: 750V with
standing surge current 1250A". Can this do the trick, or is it
only to protect the equipment from a faulty powergrid?

 

[Halfgaar]

w_tom wrote:

Ben Franklin demonstrated the concept in 1752. Lightning
traveled miles through non-conductive air to obtain earth
ground. Is some silly opto-isolator or point of use surge
protector going to stop, block, or absorb lightning? Of
course not. But effective protection has been demonstrated
repeatedly since before WWII. Effective protection does what
Franklin did in 1752.

Lightning seeks earth ground. Divert lightning to earth
before it can strike the church steeple. Well proven by
centuries of experience.

Electronics has the same problem. If lightning finds a
circuit path to earth via household electronics, then surge
damage result. Again well proven is to earth the surge, at
service entrance, before surge can enter a building.

It's called 'whole house' surge protectors. But surge
protectors are not surge protection. A surge protector is
only as effective as its connection to surge protection -
earth ground. No short connection to earth ground (which is
the problem with plug-in or point of use surge protectors)
means no effective connection.

A surge protector is only as effective as its earth ground.
Surge protectors are simple science - often hyped into myth.
The art of protection is earthing - not a surge protector.
Which again demonstrates why 'point of use' protectors are so
ineffective. Since they don't provide effective protection,
then there is no dedicated (less than 10 foot) connection to
earth AND those ineffective protectors avoid all discussion
about earthing.

Just as Franklin demonstrated. Surge protection is about
earthing a surge. That is what a surge protectors does.
Connect all wires to earth ground only during the surge (which
is why a surge protector must have a less than 10 foot
connection to earth).

The most common source of destructive surges (even to
modems) is AC electric. Surge enters on the one utility that
typically has no protection. Telephone line has and CATV
should have 'whole house' protection. But AC electric - the
utility highest on pole and most struck - makes a direct
hardwire connection even to modem ICs.

What does a surge seek? Earth ground. Any appliance that
makes a connection from AC electric to earth ground becomes a
complete surge circuit. Modems and portable phone base
stations are easily destroyed. Incoming on AC electric.
Outgoing to earth ground on phone line (because telco already
installs 'whole house' protector on phone line).

Two minimally sized 'whole house' protectors are sold in
Home Depot - Intermatic EG240RC or IG1240RC, and Siemens
QSA2020. Never seen any effective surge protectors sold in
Sears, Walmart, Lowes, Kmart, Staples, or Office Max.
Obviously. They don't have a dedicated connection to earth
ground AND avoid all earthing discussions. They don't even
claim to protect from the typically destructive type of surge.

Just a few introductory concept about protection. Will not
even discuss so many erroneous facts posted in the
www.penlight.org FAQ. Discussion for another post. But this
is the fundamental fact. A surge protector is only as
effective as its earth ground. Surge protectors don't stop,
block, or absorb surges. They only shunt - connect all wires
together - during the surge. That shunting is protection only
if connected less than 10 feet to earth ground.

Is it also impossible to protect against indirect hits? I know that direct
hits are fatal, but a few days ago, I saw an add in the paper from a
company which sells protectors for indirect hits. You don't just buy the
device, but also an insurrance. If anything is damaged, they'll pay the
damages. Is this possible, or just a trick to get people to buy those
things? After all, not everyone who buys such a thing gets hit by lightning
(well, their equipment...), so maybe the devices are fake and they just
make money on the insurances.

Halfgaar
--
To send email, change nospam.com into yahoo.com.

 

[Halfgaar]

I have read the faq at penlight. A few more question have come up.

I have this "extensioncord" with, I quote, "full three line surge
protection" and "overload protection" and as I said it says "max clamping
voltage: 750V with standing surge current 1250A". It has a button which
says "press to reset" and a device with an indication light. Is the latter
the surge protection and the former the overload protector?

I have an amplifier connected to it which outputs clicks in the speakers
when lights and the like are turned off/on. It used to do that before I had
the surge protector, and it still does. Isn't it suposed to suppress that?
I do have it connected to the ground.

And finally, how can I check if the surgeprotection actually works?

Halfgaar
--
To send email, change nospam.com into yahoo.com.

 

[w_tom]

I am confused as to what that disconnect protector would
be. However it appears to disconnect all wires - a relay
function. Relays, like circuit breakers, take tens of
milliseconds to respond. Well over 400 consecutive and
destructive surges could pass through in that forever 10+
milliseconds. Clearly a disconnecting device cannot respond
fast enough for the typically destructive surge.

I guess that protector will disconnect UP to 750 volts and
up to 1250 amp currents. But a problem. Lighting is current
source meaning that it will increase voltage, if necessary, to
maintain that fixed flow of current. If something disconnects
(or blocks) such surges, then surge voltage increases to
overwhelm the isolation. Voltage would increase beyond 750
volts, form a plasma path across the contacts, and maintain
that surge current flow.

No way to simple test that a surge protector is working.
You could hit it with a surge or conduct the 1 milliamps
test. But most people don't have the equipment and knowledge
(including component data sheets) to perform that test.

Surge protector have an "OK" lamp. But that lamp can only
report if the surge protector is non-functional. It cannot
report that the surge protector is good or OK.

The most important component of a surge protection
'system'. What is the quality of earth ground? How to test
that surge protection component. Earthing is the art of
protection. Basically we install what experience says was a
sufficient earth ground or better - then wait (on average once
every 8 years) to see if the system works. Repair or enhance
an earthing system if anything inside the building was
damaged.

Its not all that difficult. Installing a sufficient earth
ground is simple. Least expensive if don't when the concrete
footing are poured. But rare geological anomalies and other
unknown conditions can undermine what would normally be an
excellent earth ground 'system'.

Appliances have internal protection. Effects of a nearby
strike are really quite small, easily handled by appliance
internal protection, and also made redundant by the 'system'
designed for direct strike protection. If nearby strikes were
so destructive, then all car radios and portable transceivers
would also be damaged with every nearby strike.

Another problem is called induced surges. These occur when
a direct strike is being earthed. Any wire bundled with that
earthing wire would have a transient induced on it. Important
that all earthing wires be run separate from other wires to
avoid induced surge problems. Many confuse induced surges
with electromagnetic fields from a nearby lightning strike.

Induced surge is but another reason why plug-in surge
protectors are not effective. They would try to earth the
surge down a ground wire bundled with all other wires.
Induced transients to other household appliances would result
because the surge protector was not connected 'less than 10
feet' to earth ground.

One type of (most interesting) 'disconnecting for
protection' device. A radio receiver is placed on the roof
listening for radio signals during the formation of a
lightning bolt. The receiver sends a message to a disconnect
relay in the basement to disconnect phone service AND ground
those phone wires. Since lightning formation takes a long
time, then the device has time to disconnect AND earth the
incoming phone line. This occurs for about 400 milliseconds.
Long enough for any incoming surge to be earthed AND not too
long to disconnect the incoming phone call. After 400
milliseconds, the phone line is restored; the parties only
heard a short conversation interruption.

However the telco provided surge protector basically does
same thing at less cost.

Here is the point. Disconnecting does not provide
protection. Protection is provided by earthing the incoming
phone line for 400 milliseconds. If device only disconnected
phone line, then the incoming surge would arc across those
open contacts - restoring a surge circuit. For all surge
protection, the most critical part is the earthing component.
Earthing is an art form. There is no simple testing for
earthing. Quality is defined by how ground is installed, up
front. A surge protector is only as effective as its earth
ground.

Halfgaar wrote:

I have read the faq at penlight. A few more question have come up.

I have this "extensioncord" with, I quote, "full three line surge
protection" and "overload protection" and as I said it says "max clamping
voltage: 750V with standing surge current 1250A". It has a button which
says "press to reset" and a device with an indication light. Is the latter
the surge protection and the former the overload protector?

I have an amplifier connected to it which outputs clicks in the speakers
when lights and the like are turned off/on. It used to do that before I had
the surge protector, and it still does. Isn't it suposed to suppress that?
I do have it connected to the ground.

And finally, how can I check if the surgeprotection actually works?

Halfgaar
--
To send email, change nospam.com into yahoo.com.

 

[w_tom]

White pine is said to be an excellent lighting protector.
Observations also suggest there is a difference between trees
with straight verses circular twisted grain in protection
effectiveness.

What affects where lightning may strike is the ground. For
example, on FL couple had repeated strikes to a bathroom
wall. They installed lightning rods connected to 8 foot
copper ground rods. But lightning struck that bathroom wall
again. Why? Bathroom plumbing probably made a better
connection to more conductive earth. Lightning rod grounds
were only driven into low conductive sand. Lightning did the
predictable thing. It went for the better earth ground.

Fred Abse wrote:

A lightning bolt can carry as much as 30,000 amps. One tenth of an ohm
will drop 3000 volts. What is the resistance to ground of the usual type
of lightning rod?

ISTR a guy down at Langmuir Lab being interviewed. He was researching the
effectiveness of different types of lightning conductor, all the way from
soimple blunt ones to the "sophisticated" types using radioactive sources
to ionize the surrounding air. His comments were something on the lines
of: "We can't really get meaningful results, because the lightning seems
to prefer to strike the trees."

--
Then there's duct tape ...
(Garrison Keillor)
nofr@sbhevre.pbzchyvax.pb.hx

 

[Fred Abse]

On Sun, 27 Jul 2003 03:28:30 +0100, w_tom wrote:

Lightning seeks earth ground. Divert lightning to earth before it can
strike the church steeple. Well proven by centuries of experience.

A lightning bolt can carry as much as 30,000 amps. One tenth of an ohm
will drop 3000 volts. What is the resistance to ground of the usual type
of lightning rod?

ISTR a guy down at Langmuir Lab being interviewed. He was researching the
effectiveness of different types of lightning conductor, all the way from
soimple blunt ones to the "sophisticated" types using radioactive sources
to ionize the surrounding air. His comments were something on the lines
of: "We can't really get meaningful results, because the lightning seems
to prefer to strike the trees."

--
Then there's duct tape ...
(Garrison Keillor)
nofr@sbhevre.pbzchyvax.pb.hx

 

[Fred Abse]

On Sat, 26 Jul 2003 19:59:27 +0100, Andre wrote:

The ony thing that works is to optically isolate the phone line .
Trouble is that the telco doesen't like that !

Reminds them that they're going to have to dig up all that copper and put
fiber in sometime soon

--
Then there's duct tape ...
(Garrison Keillor)
nofr@sbhevre.pbzchyvax.pb.hx

 

[tube2ic]

I have an amplifier connected to it which outputs clicks in the speakers
when lights and the like are turned off/on. It used to do that before I had
the surge protector, and it still does. Isn't it suposed to suppress that?
I do have it connected to the ground.

Your surge protector will not suppress clicks from low amplitude spike
in the AC mains due to noisy fluorescents or other loads.

 

[Fred Abse]

On Sun, 27 Jul 2003 17:20:54 +0100, w_tom wrote:

It went for the better earth ground.

What's the proper name for those glassy tube things that lighning strikes
make in sandy soil? I forget.

--
Then there's duct tape ...
(Garrison Keillor)
nofr@sbhevre.pbzchyvax.pb.hx

 

[Sir Charles W. Shults III]

"Fred Abse" <excretatauris@cerebrumconfus.it> wrote in message
newsan.2003.07.28.18.22.26.68271.964@cerebrumconfus.it...

On Sun, 27 Jul 2003 17:20:54 +0100, w_tom wrote:

It went for the better earth ground.

What's the proper name for those glassy tube things that lighning strikes
make in sandy soil? I forget.

Fulgurites.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip

 

[Halfgaar]

tube2ic wrote:

I have an amplifier connected to it which outputs clicks in the speakers
when lights and the like are turned off/on. It used to do that before I
had the surge protector, and it still does. Isn't it suposed to suppress
that? I do have it connected to the ground.

Your surge protector will not suppress clicks from low amplitude spike
in the AC mains due to noisy fluorescents or other loads.

You're saying that the flourescents don't produce a high amplitude spike?
But will the surgeprotector probably still protect my equipment from those
high amplitude surges?

Halfgaar
--
To send email, change nospam.com into yahoo.com.

 

[w_tom]

Spike from a power line that do not appear with lightning's
intensity is noise. Typically so small that surge protectors
ignore those transients. Typically so small that internal
protection in appliances are more than sufficient.

If suffering frequent power line transients, then you are
frequently replacing things far more susceptible to damage
such as dimmer switches, cheap radios, and GFCI outlets.
Plug-in surge protectors are typically so undersized that
frequent transients would degrade a plug-in protector in
months. Joules determines how long a protector lasts.
Plug-in protectors are typically undersized - often grossly
undersized.

Meanwhile, those power line transients would occur too
quickly for an electromechanical device, such as that
overcurrent protector, to be effective.

Provided previously was one example of why outlet safety
ground wire is not effective earth ground - induced
transients. Another major reason: wire has impedance. Low
wire resistance is why that outlet safety ground is effective
for human safety. But wire impedance is why that same outlet
safety ground is not an earth ground.

Numbers: that 50 foot of 20 amp wire may measure 0.2 ohms
resistance. But same wire might measure 130 ohms impedance to
a surge. Suppose an adjacent, plug-in protector is trying to
earth a trivial 100 amp surge. 100 amps times 130 ohms means
adjacent computer and surge protector would be something less
than 13,000 volts relative to earth ground. A surge shunted
by adjacent surge protector will seek other destructive paths
to earth such as through computer modem.

Now put a surge protector in AC breaker box - a 'whole
house' surge protector. Same trivial 100 amp surge would be
something less than 400 volts relative to earth. That 50 foot
of wire between 'whole house' protector and computer now
contributes to computer protection! Protector at wrong end of
50 foot wire could only contributed to adjacent appliance
damage.

Bottom line - outlet safety ground is not earth ground
because 'a too long' wire has excessive impedance. Because
ground wire is bundled with other wires. Because the
connection to earth has too many splices and sharp bends. Too
many fundamental electrical reasons why outlet safety ground
is not earth ground. Too many reasons that say a plug-in
surge protector has all but no earth ground. No earth ground
means no effective surge protection.

Plug-in protectors avoid all discussion about earthing since
effective protection is not even claimed. Why raise an issue
that would hurt their grossly excessive profit margin?
Currently, many use junk science reasoning - that a surge
protector and surge protection are one in the same. Surge
protector is simply a shunting device - nothing more. It does
not and cannot stop, block, or absorb a surge. Surge
protection is earth ground. Surge protector is ineffective
without a 'less than 10 foot' connection to the 'system's most
critical protection component - single point earth ground.


For reasons of human safety, even ineffective plug-in
protectors must meet UL1449 2nd Edition. For reasons of
transistor safety, a surge protector must complete a less than
10 foot connection from AC mains to single point earth ground.

Single point earth ground is typically the earth ground rod
that breaker box connects. That rod is required by post 1990
NEC requirements. However many older homes don't have an
earth ground let alone on necessary for surge protection.
Single point earth ground is the point where all incoming
utilities connect to the same earth ground rod, ring, plate,
or whatever is installed.

Where does a 'whole house' protector connect to AC main.
Measure distance from that connection, through surge
protector, to single point earth ground. Less than 10 feet.
Shorter means even better protection.

BTW, that penlight.org FAQ contained many fundamental
technical errors. It was not written by an engineer with
technical experience on the subject.


Halfgaar wrote:

Well, I think that disconnect protector is an overload protector like
a breakerbox. I think it just shuts off when you overload it (past
the 3500W it allows).

I use the ground inside the wallsocket. Can that generally be
considered well enough?
BTW, how do you define the "10 feet to the earth"? Where does the
earth begin?

You know, the thing is, I bought this extensioncord with
surgeprotector to protect my equipment from spikes on the powergrid,
not even specificly from lightening. But as an "ignorant consumer" I
really don't know if it actually works or if I've just been had (or
screwed, which ever you prefer ). A friend of mine bought a
surgeprotecting extensioncord, but when he opened it, he noticed
there were no special parts inside. Mine has some parts, I just
don't know if it works. It also doesn't have any certificate,
not even the ones the penlight faq says to avoid.

Halfgaar

 

[tube2ic]

Halfgaar <voor_achter@nospam.com> wrote in message news:<3f2578e7$0$149$edd6591c@news.versatel.net>...

tube2ic wrote:

I have an amplifier connected to it which outputs clicks in the speakers
when lights and the like are turned off/on. It used to do that before I
had the surge protector, and it still does. Isn't it suposed to suppress
that? I do have it connected to the ground.

Your surge protector will not suppress clicks from low amplitude spike
in the AC mains due to noisy fluorescents or other loads.

You're saying that the flourescents don't produce a high amplitude spike?
But will the surgeprotector probably still protect my equipment from those
high amplitude surges?

Halfgaar

Relative to lightning, a fluorescent will not produce a high enough
pulse to fire your surge protector. If your fluorescent is ignited
using a Ballast and starter instead of the newer electronic ballast,
then if your mains is 220V, the ballast produces a surge of about
600-700V to ignite the tube. Once the tube is ignited, the tube itself
acts like a regulator and maintains the voltage at around 110V with
the ballast dropping the rest.
It is the 600-700V spikes produced when your tube ignites that you
hear on your stereo. However by the time it reaches your surge
protector, the energy is already dissipated and will not be strong
enough to fire the suppressor.
It should still protect you against a lethal surge such as an indirect
hit from lightning.

 

[w_tom]

Now provide the inductance of that choke - the numbers.
Ironically, an electronic appliance must already have a
superior in-line choke filter. In other threads, some bought
cheap power supplies that did not have that required filter.
The resulting radio interference was completely unaffected by
a surge protector with filter choke - because that surge
protector filter choke is simply too small.

Surge protectors do not stop, block, or absorb surges. They
are called shunt mode devices for good reason. Their job is
to simply shunt (connect, distribute, short) a surge from one
wire to all others. No short, dedicated, and independent
connection to earth ground means the plug-in surge protector
only provides a destructive surge with more paths to find
earth ground - destructively through adjacent appliances.

A good quality surge supressor notes the critical importance
of earthing. Benchmarks in surge protection, such as
Polyphaser, don't discuss their product line in application
notes. Polyphaser discusses the most critical component in
any surge protection 'system' - central earth ground:
http://www.polyphaser.com/ppc_pen_home.asp

How important is earthing to Polyphaser? A product does not
even have a connection to earth ground. Distance to earth
must be so short that the Polyphaser product mounts directly
ON earth ground. But then those who know surge protector know
that Polyphaser is an industry benchmark. Therefore
Polyphaser discusses earthing - extensively.

No earth ground means no effective surge protection. So
plug-in protectors lie by telling half truths. They avoid all
discussion about earthing since they have none. A surge
protector is only as effective as its earth ground.

tube2ic wrote:

A good quality surge supressor, would have at least one common mode
choke (A black ferrite ring) with thick wire wound on it with 4 wires
connected across the input. At least 2 high voltage capacitors and a
fairly big (the size of a dime) thing that looks like a capacitor
(which is probably an MOV-Metal Oxide Varistor). Also it should have a
three pin plug. No doubt there are other designs as well.
While a good ground is a good thing, it is not necessary to get too
paranoid about it. Just make sure that it is connected to the socket
that you are using. You can check by connecting a meter between phase
and ground and between phase and neutral. If the difference is no more
than 2 Volts, your ground is adequate.

 

[Halfgaar]

w_tom wrote:

Spike from a power line that do not appear with lightning's
intensity is noise. Typically so small that surge protectors
ignore those transients. Typically so small that internal
protection in appliances are more than sufficient.

If suffering frequent power line transients, then you are
frequently replacing things far more susceptible to damage
such as dimmer switches, cheap radios, and GFCI outlets.
Plug-in surge protectors are typically so undersized that
frequent transients would degrade a plug-in protector in
months. Joules determines how long a protector lasts.
Plug-in protectors are typically undersized - often grossly
undersized.

Meanwhile, those power line transients would occur too
quickly for an electromechanical device, such as that
overcurrent protector, to be effective.

Provided previously was one example of why outlet safety
ground wire is not effective earth ground - induced
transients. Another major reason: wire has impedance. Low
wire resistance is why that outlet safety ground is effective
for human safety. But wire impedance is why that same outlet
safety ground is not an earth ground.

Numbers: that 50 foot of 20 amp wire may measure 0.2 ohms
resistance. But same wire might measure 130 ohms impedance to
a surge. Suppose an adjacent, plug-in protector is trying to
earth a trivial 100 amp surge. 100 amps times 130 ohms means
adjacent computer and surge protector would be something less
than 13,000 volts relative to earth ground. A surge shunted
by adjacent surge protector will seek other destructive paths
to earth such as through computer modem.

Now put a surge protector in AC breaker box - a 'whole
house' surge protector. Same trivial 100 amp surge would be
something less than 400 volts relative to earth. That 50 foot
of wire between 'whole house' protector and computer now
contributes to computer protection! Protector at wrong end of
50 foot wire could only contributed to adjacent appliance
damage.

Bottom line - outlet safety ground is not earth ground
because 'a too long' wire has excessive impedance. Because
ground wire is bundled with other wires. Because the
connection to earth has too many splices and sharp bends. Too
many fundamental electrical reasons why outlet safety ground
is not earth ground. Too many reasons that say a plug-in
surge protector has all but no earth ground. No earth ground
means no effective surge protection.

Plug-in protectors avoid all discussion about earthing since
effective protection is not even claimed. Why raise an issue
that would hurt their grossly excessive profit margin?
Currently, many use junk science reasoning - that a surge
protector and surge protection are one in the same. Surge
protector is simply a shunting device - nothing more. It does
not and cannot stop, block, or absorb a surge. Surge
protection is earth ground. Surge protector is ineffective
without a 'less than 10 foot' connection to the 'system's most
critical protection component - single point earth ground.


For reasons of human safety, even ineffective plug-in
protectors must meet UL1449 2nd Edition. For reasons of
transistor safety, a surge protector must complete a less than
10 foot connection from AC mains to single point earth ground.

Single point earth ground is typically the earth ground rod
that breaker box connects. That rod is required by post 1990
NEC requirements. However many older homes don't have an
earth ground let alone on necessary for surge protection.
Single point earth ground is the point where all incoming
utilities connect to the same earth ground rod, ring, plate,
or whatever is installed.

Where does a 'whole house' protector connect to AC main.
Measure distance from that connection, through surge
protector, to single point earth ground. Less than 10 feet.
Shorter means even better protection.

BTW, that penlight.org FAQ contained many fundamental
technical errors. It was not written by an engineer with
technical experience on the subject.

This is complicated matter. A short answer please : Does a point of use
surgeprotector has any use when you connect it to the safety ground (as the
one I have is designed to)?

And you say that with many power transients, the protector breaks down fast.
But in the penlight faq, it says that surges happen all the time. If the
protector nullifies all the surges, then it must be dead very soon, right?
And if it is a shunting device, shoudn't I notice power cutt-offs all the
time?

Something else I thought of: Some devices say something about FCC rules,
that it doesn't create harmfull interference and that it must accept any
harmfull interference received. I'm not sure if this is just for radio
equipment. Is it? Or does it have anything to do with surges?

Halfgaar
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[Halfgaar]

tube2ic wrote:

A good quality surge supressor, would have at least one common mode
choke (A black ferrite ring) with thick wire wound on it with 4 wires
connected across the input. At least 2 high voltage capacitors and a
fairly big (the size of a dime) thing that looks like a capacitor
(which is probably an MOV-Metal Oxide Varistor). Also it should have a
three pin plug. No doubt there are other designs as well.
While a good ground is a good thing, it is not necessary to get too
paranoid about it. Just make sure that it is connected to the socket
that you are using. You can check by connecting a meter between phase
and ground and between phase and neutral. If the difference is no more
than 2 Volts, your ground is adequate.

I'll check the parts sometime.

Won't measuring the phase and the ground create a leakage so that the "earth
leakage breaker" (I don't know what it's called in English) will disconnect
power?

Halfgaar
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[w_tom]

To be earth grounded, that surge protector must make a less
than ten foot connection from incoming utility wire to earth
ground. Surge protector is a switch - that closes only during
the surge. During a surge, the protector must make a less
than ten foot connection from the utility wire to earth
ground. But, again, wire impedance means a fifty plus foot
wire connection to earth ground is all but no earth ground.
That ten foot is essential to minimize impedance. Not only
short - less than ten feet. Other requirements. The
connection must have no sharp bends, no splices, not inside
metallic conduit, not bundled with other non-grounding wires,
etc. This is explained in greater detail in the newsgroup
misc.rural in two threads among engineers:
Storm and Lightning damage in the country 28 Jul 2002
Lightning Nightmares!! 10 Aug 2002
http://tinyurl.com/ghgv or http://tinyurl.com/ghgm

Outlet safety ground typically is not earth ground - from
the perspective of a surge. Wire is too long - and other
problems.

A plug-in surge protector may be effective if plugged into
the receptacle attached to breaker box and if the protector
power cord is cut short. Then it might make the less than 10
foot connection.


As noted previously, that penlight.org FAQ has many gross
errors. First one I remember was that nonsense about many
daily surges. First, if you are suffering daily surges, then
you visiting your local hardware store to replace dimmer
switches, electronic timer switches, touch on-off lamps, GFCI
human protection electronics, etc.

If you are suffering such daily surges, your utility must be
confronted. But then if you are suffering such surges, the
same 'whole house' protector is properly located and properly
sized to also address those problems.

Even a computer power supply is an RF transmitter. It
typically transmits a 20 Khz voltage through a smaller
transformer. All electronics must not radiate radio
frequencies. Power supplies, for example, (are suppose to)
have in-line filters to keep noise from interfering with AM
radios. That inline filter also is part of the power supply's
ability to withstand surges.

UL is concerned only with human safety. NEC is about human
safety. FCC is concerned with radio frequency interference
and communication standard. None make standards for surge
protection. However some things they require are also provide
surge protection.

Don't waste big bucks on typically undersized 'point of use'
(plug-in) surge protectors. Money is often better spend
improving, enhancing, or creating a single point earth
ground. Then have all incoming utilities connect less than 10
feet to this earth ground - either by direct hardwire
connection (CATV, Satellite dish) or via a surge protector (AC
electric, telephone). The most critical component of a surge
protection system is earth ground. Surge protectors are
simple components, sometimes required (sometimes not), to make
the earth ground surge protection system effective.

Halfgaar wrote:

This is complicated matter. A short answer please : Does a point
of use surgeprotector has any use when you connect it to the safety
ground (as the one I have is designed to)?

And you say that with many power transients, the protector breaks
down fast. But in the penlight faq, it says that surges happen all
the time. If the protector nullifies all the surges, then it must
be dead very soon, right? And if it is a shunting device, shoudn't
I notice power cutt-offs all the time?

Something else I thought of: Some devices say something about FCC
rules, that it doesn't create harmfull interference and that it
must accept any harmfull interference received. I'm not sure if
this is just for radio equipment. Is it? Or does it have anything
to do with surges?

 

[w_tom]

Classic surges are 8/20 microsecond events. Ground Fault
Circuit Interrupters (GFCI) (called RCD in UK if correct)
typically take milliseconds to respond.

GFCI (RCD) are but another household electronic device that
must be protected from surges. Where is the plug-in protector
for that electronic device - the GFCI? Just another reason
why homes require 'whole house' protectors connected short to
a single point earth ground.

Halfgaar wrote:

I'll check the parts sometime.

Won't measuring the phase and the ground create a leakage so that
the "earth leakage breaker" (I don't know what it's called in
English) will disconnect power?

Halfgaar
--
To send email, change nospam.com into yahoo.com.