I have recently learned, thanks to several of the folks here who took the
time to educate me, that earth ground is the most important thing in a
whole-house surge protector.
I was instructed on how to manually check it for any obvious problems.
However, the two pipes going from the ground into my electric meter are
plastic. Also I didn't mention that I am in a condo that's only open on one
side (sometimes called a row house, I think) with units attached to the back
and both sides. There are two end units, then eight row units, four facing
North and four facing South.
These condos are build for affordability, so I don't expect the contractor
did anything more than they had to by law. I'm in Minnesota (in case it
makes a difference for the codes.)
I am thinking about asking the electric company if they have an earth ground
testing service. No sense in installing a whole-house suppressor if there
isn't a good earth ground.
One more thing--are good surge suppressors able to accurately monitor their
condition and indicate when they need to be replaced?
What year was building constructed? What is soil? Nothing
(reasonable) will test for proper connection to and quality of earthing
for lightning protection. A utility typically will not even verify
earthing. First, earthing is onwer's problem and your electrical
inspector's concern. Second, a utility will only inspect for human
safety problems.
Even with plastic pipes, your building must still be earthed. That
means a bare copper wire out of breaker box AND means that wire is
obvious where it goes into earth. That wire located to inspect it.
Just one earth ground rod connected short to breaker box is a massive
earthing improvement. Posted previously were inspections to make
earthing even better. But again, there is no better solution than you
personally doing that inspection, or hiring an electrician to identify
the wires.
No reasonable testing exists for how that wire is routed. None.
Expensive testing equipment will typically only report earth
conductivity. But you have a ballpark grasp of conducitivity by
defining soil - a question asked above. Again, visual inspection as
defined earlier. No way around that requirement.
Does your AC electric conform to post 1990 code? Otherwise, hire
the electrician to upgrade earthing to post 1990 requirements and to
install a 'whole house' protector. Again, and this should be obvious
from previous posts - visual inspection. Defined was what you must
look for. No reasonable replacement for visual inspection exists.
There is no replacement for an earthing connection from each and every
incoming utility wire (and that also included satellite TV dish) to
that earth ground. But another part of the visual inspection that you
must perform. Testing will not replace a visual inspection.
A properly sized protector cannot "accurately monitor their condition
and indicate when they need to be replaced". A protector worse than
undersized - grossly undersized - will vaporize. A light would
indicate a failure that should not exist - if protector was properly
sized. Protectors degrade. Minimally sized protectors (as defined by
numbers previously) should be more than sufficient for 10 years. In MN
(except in neighborhoods that have frequent lightning damage), that
protector may be sufficient for your entire lifetime because it is
properly sized.
If earthing is not sufficient to make a 'whole house' protector
effective, then major code violations may exist. Just upgrading
earthing to post 1990 requirements means a 'whole house' protector
does something useful. Currently you are suffering damage because
essentially nothing useful exists. You have virtually no protection.
Either no protectors or plug-in protectors located too far from earth
and too close to appliances.. Or your utilities do not share a single
point earthing electrode.
Earthing electrode so important that, if necessary, hire an
electrician to teach you. That earthing is not just for appliance
protection. Utility inspectors have described homes even exploding, in
part, because that earthing was disconnected.
If I did not say it before, above is secondary protection. Also
inspect the utility's primary protection:
http://www.tvtower.com/fpl.html
Adam Corolla wrote:
2000
I looked at the breaker box and the meter box. The meter box has two
plasyic PVC pipes going into the ground and nothing else coming out of it.
The breaker box has one plastic pipe going into the garage floor (it is an
attached garage) and nothiong else going down. The ONLY copper I see coming
out of either box is two things that look like small copper pipes (not
cables) about 1/6th of an inch wide coming out of the breaker box, but they
go up through the ceiling! The garage is on ground level and there's no
basement.
I live in a townhouse/row house which is only open on one side, the other
three sides have adjascent (attached) units. There are ten units in the
structure. Is it possible the structure itself is grounded but not each
individual unit?
Oddly, my computer was undamaged even though it was on and not plugged into
a surge supressor. I guess I lucked out on that one. I got a surge strip
for it a few days ago.
That wire located to inspect it.
Be aware that there is a difference between lightning arrestors and
surge protectors. Generally (but not always) lightning arrestors are
provided on the utility side of the meter by the utilty. Whole house
surge protectors are installed after the meter demarcation point. A
direct lightning stoke is just as likely to blow apart your surge
protector as other parts of your wiring system. The currents can be
incredibly high. That's what lightning arrestors were invented for.
Lightning causes surges, but surges can be caused by many additonal
factors including routine utiltiy operations, overloaded lines, and
equipment that starts and stops frequently. For example, if you are
running a business office, you would not want your elevator circuits
directly connected to your server room.
The best whole-house surge protectors do work and generally have "OK"
and "Needs Service" illuminated indicators. Some have audible alarms.
Leviton is a good model. Here is one from Smarthome: (no
affiliation)
http://www.smarthome.com/4860.HTML
Note that these are not cheap. Outdoor models are also available.
Proper surge protection in the North American system requires 3 mode
protection. That is, the HOT to NEUTRAL, HOT TO GROUND, and NEUTRAL
TO GROUND. The HOT to NEUTRAL protection mode does not require a
ground.
Check with Underwriters Labs if you want to understand the difference
between a cheap outlet surge protection and a large capacity whole
house system. Surge protectors are rated in joules and generally the
higher, the better.
Beachcomber
Any surge protector that does not earth a direct lightning strike and
does not remain functional was a waste of money. Many other transients
listed are made irrelevant by protection already inside appliances.
How do we know? Everyone is not trooping daily to hardware stores to
replace appliances damaged by switching transients. "Equipment that
starts and stops frequently" would be destroying appliances everywhere
every day if appliances already did not contain effective internal
protection.
Effective 'whole house' protector is about earthing a transient -
lightning - so that protection already inside appliances is not
overwhelmed.
We install protectors for lightning - the typically most destructive
transient. Protector must earth a direct lightning strike AND remain
functional. Many of those plug-in type protectors with G-N, N-H, and
H-N connections are so grossly undersized as to be vaporized by a
potentially destructive transient. Some examples of ineffective
protectors:
http://www.ehs.washington.edu/LabSaf/surge.htm
http://www.westwhitelandfire.com/Articles/Surge%20Protectors.pdf
http://www.hanford.gov/rl/?pageU6&parentU4
Necessary is a protector that earths lightning and remains
functional. Minimally acceptable 'whole house' protectors for this
task are 1000 joules and 50,000 amps. What is a typical direct
lightning strike? 20,000 amps. Does all that current pass into the
home? Not if the utility primary protector is also properly earthed.
IOW 'whole house' protector - secondary protection - must be sufficient
to handle a direct lightning strike. Utility's primary protector also
makes that direct strike even less potentially destructive.
Just another reason why the primary protection system should be
inspected:
http://www.tvtower.com/fpl.html
A protector is installed for a most typically destructive event -
direct lightning strike. Protector must earth that strike and remain
functional. Other potentially destructive transients such as utility
switching transients are made irrelevant by that protector installed
for lightning protection.
I am wondering how direct. If a large bolt striked the lines right where
they enter the breaker box, that would obviously be very different than
striking the transformer down the block. Now, I barely understand the
basics (E=I/R) so if my line of questioning is off, please understand. But
it seems to me that a $200-300 whole house surge protector trying to shunt
between 25,000 and 45,000 amps (direct strike) to ground is sort of like a
traffic cop trying to keep a tsunami wave constricted to the main street,
blocking it from going down a side street. The cop can blow his whistle
until his face is red, the wave will just knock him down and go where it
wants. Plus, the core temperature of a lightning channel is approximately
50,000 degrees Fahrenheit, isn't that enough to vaporize metal inside the
surge supressor and turn it into plasma for a few microcesonds? I remember
when it struck my dad's home CB antenna, it melted the copper coil and
sprayed it out into the air, where it solidified as very small roughly
spherical copper balls, similar to BBs.
Adam:
You are correct.
As a former broadcast transmission engineer, believe me... I
experienced my share of lighting strikes at a transmitter facility.
If it were possible to just buy once piece of equipment such as an
oversize surge protector to solve all our lighting problems, then
that's what we would do. This has not been the case.
Unfortunately, defending against lightning is a complex and sometimes
expensive task. It requires a combination of good grounding,
shielding, bonding, and surge protection.
Start with good grounding. Current techniques in high-resistance
ground locations are starting to specify ground rods of 50 - 60 feet
long (at least in commercial and industrial installations). Most
studies indicate that such a ground will give a good, low resistance
value of under 5 ohms or so.
Also Google UFER ground for a good alternative to ground rods.
Any conductive path to your house, electric wires (buried or not),
cable tv, telephone lines, metallic piping, etc. is a potential
pathway for bringing lightning inside the house. Commercial
installations in high lightning areas will channel all of these
through one-location, more or less, and often through a flange
connected to a grounded copper bonding plate.
Your last defence is often the whole-house or whole-facility surge
protector, which, if sized properly, will protect against all but the
worst lightning strikes.
By the way, switching transients and other non-lightning related
surges do cause damage to unprotected systems. It might take years
before a failure mode manifests itself because it is a cumulative
process. Most circuits are clean and free from such unpleasentries,
but if you live downline from the local sawmill, you might have some
trouble with your computers and laser printers.
Beachcomber
Thank you, I appreciate the info on real-world experiences. Valuable
information for me.
Thanks to you and others, I feel I know enough to put in my own earth ground
setup. Unfortunately, I can't do this right now because I live in a
townhouse, but it will be useful information especially if I ever move to a
regular house. I guess I would need to hire an electrician to install a
good ground rod in order to get the association's approval. Besides, the
"yards" (tiny patches of grass) here are so small and crammed with electric,
gas, cable and other utility lines and pipes, it's probably illegal for me
to dig anywhere.
Interesting concept!! Grounding with rebar in concrete as part of the earth
ground.
It sounds like the only setup that would be completely lightning-proof (or
as close as possible) would be to have all internal-external connections
(phone, internet, etc) completely wireless, and use an independent generator
for the power supply, surrounded by an extremely well-grounded cage of very
conductive material capable of handling a large, direct strike without
seriously compromising the cage structure (like thick steel girders), as
well as good EMF shielding. Any plumbing facilities would have to be
located outside the cage. Any spikes or surges coming from equipment inside
the cage I'm not considering in this little mental exercise.
Of course, I would never need a setup like this, everything I have can be
replaced. I'm just wondering if I've covered all the bases here to the
point where if a very large bolt struck directly at the power lines
connecting the supply and equipment inside the cage would be diverted by the
cage and completely shunted off to ground? Because I feel that part of
understanding how to protect reasonably well from surges is to understand
what the perfect (or as close to it as can be) setup is, then I will be a
step closer to grasping the whole picture here if how to get the most
protection for my investment.
By the way, is it possible to shield from EMF pulses? I think it must be
possible at least to some extent, but I'm not sure how. I remember hearing
that a large nuclear warhead exploded too far above a city to cause much
damage would, as a result of the EMF pulse, fry pretty much every electronic
device in the city.
What are switching transients? From the context I'm thinking machinery or
equipment that uses a lot of juice switching on and off relatively near my
location and on the same grid?
The guy who fixed my furnace (I kept the circuit board he replaced and you
can see the little burn mark) said that he had a nearby strike that fried
some stuff in his house but apparently left the big-screen TV unharmed.
However for six months after that, they kept having appliances fail for no
apparent reason, and it was driving him nuts. Then one night he heard a
noise from the TV (I think he might have said it was OFF at the time?) and
saw smoke come out of it. The TV was fine, but a couple more appliances
went belly-up after that. He figured out that the TV was periodically
sending relatively large surges out even though it worked fine.
Weird, eh?
You are probably thinking of the Faraday Cage, which is to completely
surround the protected room with conductive metal including the
smallest openings. Theoretically, the inside of the cage will not be
affected by external fields. If the conductor is thick enough (copper
plate), the inside of the structure will be completely protected from
lightning. Of course provisions must be made for entry of power, RF
connectors, and other signal circuits. These will require further
protection. Needless to say, this is usually impractical and
expensive.
This is why people driving around in cars are generally protected from
lightning strikes as they are at least partially surrounded by
conductive metal. Any direct strike on the car would be conducted by
the frame and through the tires to ground.
People who work in metal skyscrapers are generally protected from
lightning. It is said the Empire State Building takes dozens of
lightning hits each year.
Shielding for electric fields is easy. All one needs is a thin layer
of metal.
Shielding for magnetic fields is a bit more difficult. It can be done
with something called high mu metal, which for all practical purposes
is a sheet of heavy cast iron metal.
Beachcomber
Read numbers yourself rather than posting speculations. Why would a
responsible manufacturer spec 50,000 amps if it could not shunt 50,000
amps? Why are you making speculations while ignoring other parameters
such as time and voltage? Direct strikes routinely hit telephone
poles often without damage. Look at that earthing connection. If all
earthing must be rods 60 feet deep, then everything struck is destroyed
- a 'woe is me' mentality for failure.
Put too much impedance in a path to earth, such as via a CB coil,
then energy content increases massively. So of course a CB coil melted.
It tried to stop the entire lightning bolt. Just another example of
why protectors that try to stop surges fail. Why are plug-in
protectors so ineffective? That CB coil demonstrates that protection
by stopping or blocking lightning - high impedance - means failure.
Put lightning into perspective. As the US Forestry Service
demonstrated, more than 95% of trees suffer a direct strike without
appreciable damage. Many who see a rare, destructive strike falsely
assume that all lightning strikes are that destructive. Earthing a
direct strike with no appreciable damage is easy. Swallow those wild
speculations. Take what was posted here - provided with professional
citations - and confirm it yourself. You have numbers from
responsible manufacturers. 50,000 amps. Which one is false? Them or
your speculations?
Lightning strikes a Franklin rod using equivalent earthing. Direct
strike leaves no damage. Ground rod is not blown from the earth. When
will you go to Home Depot or Lowes to confirm numbers? What tells us
you have done nothing? You are still posting a protector price of
$200-$300. You are speculating rather than getting fingers dirty.
Get out and learn reality.
Is lightning a high energy transient at its strike location? Not if
lightning is properly earthed. One of the most respected professionals
in this industry says:
A direct strike to a transformer was a direct strike to household
appliances if incoming wires were not earthed (ie through a 'whole
house' protector). So why did damaged electronics not explode inside
the house? Based upon what you have posted, wires should have been
blown from inside walls. Earthing a direct strike without damage is
easy as even demonstrated by studies from the US Forestry Service. Are
those numbers from GE, et al lies? That is what you have posted with
speculation about a traffic cop directing a tsunami. You have numbers
and solutions. At this point, you should be posting what that
electrician found. You should already know if earthing meets post 1990
NEC requirements. Time for speculation is over. Posts should now
contain facts of what actually exists?
BTW, why does a commercial broadcaster earth 60 feet deep? Once in
everyone's lifetime, a 200,000 amp lightning strike may occur. That
commercial broadcasting station must even earth a rare 200,000 amp
lightning seeking a 1000 foot tower and never cause damage. You
don't have a 1000 foot tower. You protect from lightning that does
not even leave appreciable damage to trees. Currently that trivial
strike can cause appliance damage before you don't have a properly
earthed 'whole house' protector.
Adam Corolla wrote:
I would, but I don't know what numbers to read. I thought I had made it
clear that my level of understanding on this subject was virtually nil, but
apparently not.
Learning reality is exactly what I am trying to do, and I am learning a few
things in spite of your posts. I would love to go to Lowes or Home Depot
and learn more, but I am not ready to because I don't understand the forces
involved well enough yet to ask intelligent questions about it. In case it
isn't obvious, I don't even really understand how a surge protector works.
That's why I came here first.
A number of times, you went out of your way to point out the fact that I was
making wild speculations and to sarcastically and snidely point out how
wrong I was.
I was just trying to frame a question, Did you miss my statement:
"Now, I barely understand the basics (E=I/R) so if my line of questioning is
off, please understand."
Do you follow? Can you comprehend what it means when someone says " I
barely understand the basics... so if my line of questioning is off, please
understand"?
Apparently not. But thanks anyway for ramming it down my throat repeatedly
that I am an idiot. It really helps me understand electrical principles
much more clearly.
Minimum for a protector is 1000 joules and 50,000 amps. Multiple
times posts - that was the numbers you read in Lowes two days ago on
boxes. Typical lightning strike averages 20,000 amps. Therefore a
protector that is double or more is sufficient. Again, you have known
what numbers to read so many posts ago. (BTW, as joules increase, a
protector's life expectancy increases exponentially. I was wating
for you to go to Lowes so that that sentence could be appreciated.)
Those numbers are printed on each protector's box. No insult. Either
do that or learn little useful from this thread.
How does a Franklin lightning rod work? Lightning seeks earth
ground. Either lightning finds earth ground through things you
treasure, or lightning finds earth via a non-destructive path.
Lightning rod connects a direct lightning strike to earth, shunts
lightning to an earth ground, and leaves no damage. All effective
lightning protection systems only do that - as posted repeatedly. That
is it. Notice that E=IR appears nowhere - is irrelevant. This
paragraph says, but again, everything that an effective protector does.
It's that complex.
Lightning strikes a utility pole down the street. That is a direct
strike not to a roof. That is a direct strike to household appliances.
Same concept. Either lightning finds earth ground destructively via
appliances OR lightning finds earth at the service entrance - via a
'whole house' protector thereby causing no damage.
Earthing is what effective protector does. If we attempt to stop or
block lightning, then damage results. Stopping or blocking lightning
created a melted CB antenna coil.
Testing earth ground reports little useful information. Inspect
earthing and wire connections to earthing. If not, then hire
assistance - the electrician. That earthing must meet post 1990 code.
That ground rod must be as long as one sold in Home Depot. IOW that
rod must be solidly in earth; not move horizontally or vertically as
would be obvious once you hold that rod in Lowes. Earthing should
exceed code by requirements defined previously: 'less than 10
feet', separated from other non-earthing wires, no sharp bends or
splices, etc. Conditions that exceed code - make earthing even
better - were listed previously. But again, these numbers mean
nothing until your hands get dirty in that store.
Is that sufficient for earthing a commercial radio station? No. Not
even close. But then you are not earthing every lightning strike that
can ever exist. If earthing is upgraded to post 1990 electrical code,
then major protection exists. If someone installs a 'whole house',
then that is a massive protection improvement.
Why is a Ben Franklin lightning rod complex? A concept so simple as
to be taught in 2nd grade science. 'Whole house' protector does same.
Other simple requirements exist such as post 1990 code requirements,
routing wire as short as possible, etc. But a protector is nothing
more than a connection to earth - as Ben Franklin demonstrated in 1752.
A shunt mode protector is nothing more than a connection to earth -
just like Franklin's lightning rod.
We could do additional things - more rods, a halo ground, Ufer ground
etc - to make the system more effective. In fact, every new building
should have an Ufer ground standard. We still don't build as if
transistors exists. So we install an earthing electrode. We can do
more - a protector of more joules - to expand protector's life
expectancy.
You suffered surge damage and need effective protection. You
currently don't even know if the building has an earth ground.
Therefore anything done, as defined in above posts, is a massive
protection improvement. Even that utility earth ground - inspecting
the primary protection system - may result in major lightning
protection. As soon as you saw pictures from www.tvtower.com , then
you were outside looking? Why not? Dirty feet are required to
comprehend what was posted.
There is nothing to test. We install what is necessary. If damage
occurs later, we enhance an earthing system or we locate an incoming
conductor that entered building without being earthed. IOW we learn
from mistake. Lightning damage is failure directly traceable to a
human. Humans only learn from mistakes. Unfortunately, only useful
testing is lightning - destructive testing. So we do the best we can.
If that is not sufficient, then we learn from a mistake and make that
system better. But in most cases, a 'whole house' protector and
earthing to conductive soil makes surge damage irrelevant. A solution
that costs so little and yet is a massive improvement.
I am honest - not politically correct. You will never understand
what was posted without visiting Home Depot. All necessary numbers
have been posted repeatedly: joules, amps, 8 foot rod, 'less than 10
foot' connection, and post 1990 code. E=IR reports nothing useful.
If you did not hold that ground rod in your hands, then you are not yet
ready to reread everything posted. Where is that paper with every
number from every protector's box? What did that wire clamp feel
like? What does a 6 AWG wire look like? What were prices? Without
dirty hands, then information posted here will remain confusing.
If you think for one minute that posts were sarcastic or insulting,
then you completely missed a logical fact. You should have been in
Lowes days ago just holding things. Damage may be days away and you
still don't have dirty hands. Get into that store yesterday.
Everything - all necessary numbers - have been posted here at least
twice. You probably know more about protection than every person in
your neighborhood. But without multiple visits to Home Depot, you
don't yet know what you know. That's not an insult. That is what
your best friend would say. Get off your ass and read those boxes.
What day did you call an electrician? Nothing useful is posted here if
you have not yet done these things. Then you are ready to reread
previous posts for a third and fourth time. Then suddenly those
previous posts have information you never saw.
Adam Corolla wrote:
As a source of information I really recommend
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
published by the Institute of Electrical and Electronic Engineers.
Another good source is
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf
published by the US government - National Institute of Standards and
Technology.
Both guides were intended for wide distribution to the general public to
explain where surges come from (lightning and switching) and how to
protect against them. The IEEE was targeted at people who have some (not
much) technical background.
--------------
Nuclear bombs produce EMP - electromagnetic pulse. The military protects
against it, but it is not practical for anyone else. The military uses
screen rooms - Faraday cages or special protection for field equipment.
EMP is very high energy which is picked up by wiring over a very wide
area. The EMP produces a high voltage pulse on wiring which is
particularly hazardous to transistors. The wiring can be inside
computers and under the hood of cars (surge protectors won't help). Old
cars with ignition points and vacuum tube radios may survive.
(Lightning also produces EMP but the energy is far lower and range very
limited. It is particularly an issue for an equipment room next to a
tower antenna.)
bud--
The above is utter rubbish. Impedance is not a source
of energy - it won't increase the energy content by
the smallest fraction, let alone massively. Either
the statement does not convey what you have in mind,
or what you have in mind is horribly wrong.
Ed
What happens when a constant current source feeds increasing
impedance? Increased energy builds in that high impedance device.
What happens when lightning is blocked by larger impedance such as a CB
coil? CB coil melted. Melting occurred because impedance in a
constant current was excessive.
Basic electrical concepts demonstrate that lightning surges are not
stopped, blocked, or absorbed. Basic electrical concepts demonstrate
why Franklin's lightning rods - a low impedance path to earth - shunt
lightning without damage. Protection is about a low impedance path to
earth. No way around a principle demonstrated even 100 years ago.
Yes impedance is not a source of energy. But then no such claim was
posted. Increased impedance means massive energy in that high
impedance device during a lightning strike. How do we prevent damage?
Provide lightning with a lowest impedance path to earth.
ehsjr wrote:
Given that the neutral and ground are bonded at the panel within inches of
there the surge handling gadget is, so long as all metal in the house in
bonded to that point, it doesn't really make much difference how "good" you
ground is.
Basically, it "sh*t" happens, your wiring system voltages might bounce about
"true" ground but the voltages between conductor pairs would still be
limited.
In another cited URL (from Bud), two TVs plugged into a power strip
protector are at 8000 volts when the other end of that same safety
ground wire in breaker box is only at zero volts. Why? Because wire
has impedance. TV end of that wire is at 8000 volts whereas breaker
box end is at near zero volts. Wire is not a perfect conductor.
Electricity at both ends of a wire is not same because wire is not a
perfect conductor. How do we get that 8000 volts on TV reduced? That
plug-in protector must be near zero feet to breaker box and earth
ground. Makes no difference here that neutral and safety ground wires
are bonded in breaker box. Distance of wire determines impedance.
Meanwhile those two TVs at 8000 volts find other destructive paths to
earth because plug-in protector was too far (8000+ volts) from earth
ground.
Neutral and safety ground bonded together in breaker box tells us
nothing. That junction must make a 'less than 10 foot' connection to
earth. What makes a breaker box 'whole house' protector so effective?
Because it connects where neutral, safety ground, and earthing ground
all connect AND because that earthing meets post 1990 code
requirements, AND because that earthing wire connection is low
impedance - short - 'less than 10 feet'.
Sh*t happens because a human failed to properly install earthing -
failed to learn what was well understood even 50+ years ago. No damage
from direct lightning strikes is routine if lightning is properly
earthed before entering a building.
Is all metal properly grounded short to that AC electrical box?
Don't forgot other conductors to earth such as wall paint, linoleum
tile, concrete floors, baseboard heat pipes, etc. Those too must be
bonded short to that breaker box. If not, then 8000 volts on those two
TVs have other and destructive paths to earth. Just another reason why
earthing is the most critical component in any protection system. No
earth ground means no effective protection.
John Gilmer wrote:
The link at
http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
which is a guide published by the IEEE, and is a link posted by you,
plainly describes the operation of a multiport plug-in surge suppressor
as clamping all power and signal wires for a device to a common ground
at the surte suppressor. That protects the TV. Other TVs may need their
own multiport surge suppressor. They work primarily by clamping, not
earthing. The IEEE says plug-in surge suppressors are effective.
The NIST at
http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf
also says plug-in surge suppressors are effective. You have still not
provided a link to a reputable source that says plug-in surge
supppressors are not effecive.
Citation describes various protectors in Category A, B , and C. It
repeatedly demonstrates numerous weaknesses with Category A (plug-in)
protectors. For example, why are two TVs sitting at 8000 volts somehow
protected from surges? You call TVs charged to 8000 volts effective
protection? Yes Bud does. If that protector was moved to and earthed
at the service entrance, then two TVs would not be sitting at 8000
volts. But again, that is why 'whole house' protectors are so
effective.
How does that 8000 volts not conduct current? Of course it conducts
current through other paths found inside all homes. Some of those
paths are destructive.
http://www.eeel.nist.gov/817/817g/spd-anthology/files/SRE%20link.pdf
Repeatedly Bud ignores quotes from his own citations to post half
truths. At least he stopped falsely claiming that IEEE recommends
plug-in protectors. They don't. Those IEEE papers only define
different types of protectors. Each paper has some little paragraph
that notes either how plug-in protectors can contribute to appliance
damage or that a 'whole house' protector is the superior solution.
Plug-in protetors are shunt mode devices. Without that low impedance
connection to earth, then what do they do? Shunts 8000 volts into
those two TVs? What kind of protection is that? One that assumes the
entire room has been reconstructed as a Faraday cage. Meanwhile
effective protection earths before destructive surges get into that
room and appliances - which is why those professional papers repeatedly
note a superior 'whole house' protection method.
Bud, acting as troll is sophmoric. And being an employee of a surge
protector manufacturer does not help your credibility. Repeatedly
demonstrated is why plug-in protectors can even contribute to damage of
adjacent appliances. Somehow you call that effective protection? This
from your own previous citation:
Damage occurs "even when or perhaps because" plug-in protectors are
present at "the point of connection of appliances". IOW plug-in
protectors may even contribute to damage of the adjacent appliance.
You would call them effective? Maybe to test a household insurance
policy.
Bud-- wrote:
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