First a minor point: I did not says 'ten foot'. I said short and
"for example 'less than 10 feet'".
Moving on - wire resistance is not relevant. To mention a 'thick
wire' says Cinder Lane did not read the many professonal sources. For
example, a 50' 12 AWG wire may be less than 0.2 ohms. But that same
wire is maybe 120 ohms impedance. Impedance is different from
resistance. Wire thickness is not significant. Wire length, sharp
bends, splices, not inside metallic conduit etc - all there are
relevant parameters.
A trivial 100 amp surge would be maybe 200 volts to the breaker box
due to resistance; and something less than 12,000 volts due to
impedance. Same point is demonstrated on Page 42 Figure 8. A
protector too far from earth ground therefore earthed a surge, 8000
volts destructively, via TV2. Why 8000 volts if 12 AWG resistance is
so low? Because wire resistance is completely irrelevant. Wire
impedance is why a protector too far from earth ground (Page 42 Figure
8) has all but no earthing.
I am completely befuddled why you are making claims contrary to every
cited professional source including both front page EE Times
articles? I am complete befuddled why you don't understand the
difference between wire resistance and impedance. These concepts are
first year engineering concepts. These basic concepts that were
implemented even 100 years ago must be muddled by plug-in protector
promoters to protect obsece profits. You did not grasp what
professional say - you even don't understand the significant of wire
impedance and wire length.
Surge protectors do not absorb and slowly bleed off those surges.
You are confusing a series mode protector with what standard surge
protectors do - shunt mode. A surge protector connects appliances
directly to AC mains AND diverts only the destructive surge in another
path to earth ground. Surge protectors connect to AC mains just like
another light bulb - shunt mode. Surge protector does not sit between
a surge and the appliance. Review the circuit in those Zerosurge
pictures. Buy and break open a $7 grocery store protector to learn.
These are shunt mode devices using MOVs, spark gaps, gas discharge
tubes (GDT), avallanch diodes, thyristors, etc. None storge charges.
If I am wrong, then you will post numbers from the manufacturer
datasheet. Posted was a myth. Protectors do not absorb and then
release a surge. Please learn the engineering; stop listening to
propaganda written by a communication major.
If a tiny inductor can stop surges, then more robust fitlers inside
all electronics means no surges damage ever occurs. If you believe a
protector absorbs surges, then every power supply with fare more
robust compnents makes all surges completely irrelevant. No reason
for any surge protector because better circuits, required by industry
standards, means no surges ever cause damage. If a surge protector
works as Cinder Lane posted, then even FCC required circuits mean no
appliance is ever damaged.
All appliances already contain massive protection. We install a
shunt mode ('whole house')protector to "simply divert it to ground,
where it can do no harm" (quoted from NIST that says what a protector
does) so that protection already inside all appliances is not
overwhelmed. Reality: plug-in protector can even give surges new
destructive paths throught an appliance - Page 42 Figure 8. Same was
discovered over 20 years ago when a surge was earthed through all
networked and powered off computers by two plug-in protectors. Yes,
the plug-in protector earthed that lightning strike destructively via
each adjacent computer.
Cinder Lane - we learned this stuff from decades of design
experience and from reading numerous professional papers. We learned
from how protection was installed even 100 years ago. You don't know
how protectors work, clearly don't have technical experience, have
confused wire resistance with impedance, did not grasp the signifcance
of Page 42 Figure 8, confused wire thickness with wire length (and no
sharp bends, no splices, not inside metallic conduit, etc), have
confused safety ground with earth ground, failed to read or understand
both EE Times front page articles, did not read the long list of other
professional citations, assumed little components inside a Tripplite
will somehow absorb what three miles of sky could not stop, did not
understand that MOVs must never explode, and ... well, Cinder Lane,
your post is so chock full of technical errors and popular myths
that ... well, ...
Maybe this simile better demonstrates what you did not comprehend.
Dams do not stop floods. A flood simply overflows a dam. What stops
a town from being flooded? A larger downriver channel - equivalent to
an earthed, shunt mode, 'whole house' protector. When effective
protection is installed (larger downriver channel), then a town does
not even notice the flood. Properly earthed protectors means a
homeowner never even knows a surge exists.
A dam relocated as a dike can supplement protection. Series mode
protectors such as Brickwall, Surgex, or Zerosurge do same. Notice
how large and expensive these series mode devices must be to only
supplement protection. Neither the dike nor a series mode protector
is effective without that downriver channel ('whole house' protector
connected short to earth ground).
Where are surges from inside a building? If these surges existed,
then we are all trooping to hardware stores daily to replace dimmer
switches, clock radios, smoke detectors, and the dishwasher. Why does
the hardware store do so little business? Those 'surges' are only
noise; made completely irrelevant by protection inside all appliances.
Lets assume surges can be earthed by that 100' 12 AWG romex wire as
you have speculated. Then one 'whole house' protector makes all those
internal surges irrelevant. Again, the properly sized and properly
earthed 'whole house' protector even makes the mythical internal surge
irrelevant.
Two reasons why destructive internal surges are mythical. Oh. If
an appliance is createing those mythical internal surges, what is the
first thing destroyed? The surge source. So where is the protector
needed? On that surge creating appliance. Just two more reasons why
internal surges are classic myths.
A Tripplite plugged into an AC recepacle or still inside its box has
no earthing. Appreciate why a receptacle ground is not called 'earth
ground'. It is called a 'safety ground' or 'equipment ground'. Wire
impedance numbers (made obvious in both articles entitled "Protecting
Electrical Devices from Lightning Transients" and in above 50' 12 AWG
example) make it obvious. That Tripplite has all but no earth ground.
No earth ground means no effective protection.
If both articles were read to better appreciate what we learned
generations ago - why our designed protectors with a 2 feet connecton
to earth were even more effective. But again, do you know or do you
first learn by from professionals? Legendary are application notes
from Polyphaser. What does Polyphasaer routinely discuss for
protection? Single point earth ground, low impedance, and shorter
connections. Things completely ignored to sell a Triipplite. Learn
what professinals understand about surge protection. Please read
professional citations before posting so much junk science reasoning:
http://www.polyphaser.com/technical_notes.aspx
MOVs explode when grossly undersized. How does one MOV
manufacturer test MOVs?
> The change of Vb shall be measured after the impulse
> listed below is applied 10,000 times continuously with
> the interval of ten seconds at room temperature.
Why 10,000 surges without explosion. Why 10,000 surges with only
degradatioin? Protector must be properly sized to never explode. To
get the naive to recommend a protector, plug-in protectors
manufacturers will even grossly undersized the protector - and charge
more money. How to get a protetor to withstand 10,000 surges with
even less than ten seconds? Size it larger. MOVs explode when
undersized - a human failure or a plug-in manufacturer maximizing
profits rather than providing protection. So how often does lightning
strike 10,000 times - each strike in less than ten second?
Any protector that explodes (or its indicator light re****ts same
failure) is so pathetically designed that these scary pictures are
considered failure created by humans and why UL1449 was created in
1985:
http://www.hanford.gov/rl/?page=3D556&parent=3D554
http://www.westwhitelandfire.com/Articles/Surge%20Protectors.pdf
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html
http://tinyurl.com/3x73ol
http://www3.cw56.com/news/articles/local/BO63312/
To review the many myths and half truths. 1) A 100 foot 12 AWG wire
is too long - too much impedance - explains why the adjacent TV was
destroyed when a plug-in protector earthed a surge 8000 volts through
that TV - Page 42 Figure 8. It demonstrates why a Tripplite in or out
of the box still has no earth ground. Both front page EE Times
articles (that you did not read) explain this.
2) Protector does not work by absorbing surges. Absurd that a silly
little part will stop or absorb what three miles of sky could not
stop. NIST article even says protectors don't work as Cinder Lane has
assumed. A protector is only as effective as its earth ground - where
surge energy must be dissipated.
3) Destructive internal surges do not exist for maybe ten reasons -
four were provided above. But internal surges from vacuum cleaners
are myths promoted by promoters (not engineers) because profits are at
risk. Myths protect obscene profits. Appliance already contain
robust protection. Even one 'whole house' protector makes irrelevant
any internal surges.
4) MOVs must never explode. A protector must be properly sized so
that its light never indicates a failure. Protectors that are grossly
udersized (and obscenely profitable) will use MOV destruction or a
blown thermal fuse to promote more sales. Why does a telco suffer
maybe 100 surges during each thunderstorm without damage? Protectors
must routinely earth surges and remain functional. After every
thunderstorm, do telcos replace 100,000 protectors (two on each phone
line) in each CO? Of course not. Equivalent protector is also
installed where their wire enters your building. How often do you
replace that protector? Effective protectors are properly sized.
Ineffective protector explode and are recommended by myth purveyors.
5) How does a user know that a surge will occur? He does not and
should not. Effective protection means surges are dissipated in earth
AND a human never even knows a surge existed. How frequent are
surges? On average once every seven years - a number that can change
even within a town. A number learned by canvassing the neighborhood
for the rare surge damaged items over a past decade or generation.
Did your eyes glaze over/ Or did you realize how much knowledge
came from two generations of learning, experimenting, and direct
lightning strikes without damage? After so much experience, you would
tell me I am confused? You did not even read something so simple as
both articles from EE Times. One 'whole house' protector with proper
earthing makes surge damage irrelevant. Protection is only as
effective as the single point earth ground; not measured by dollars
spent on undersized and obscenely priced plug-in protectors. A
protector is only as effective as its earth ground.
On Apr 3, 10:00=A0pm, Cinderl...@[EMAIL PROTECTED]
(Cinder Lane) wrote:
> W_tom, I think that you are confused. =A0
>
> You stated that a surge protector is only as effective as its earth
> ground. =A0That is true. =A0You also stated that plug-in surge
protectors
> and wall outlets do not have earth grounds because their ground wires
> are longer than ten feet. =A0That is false.
>
> The "ten foot" requirement means that the electrode at the end of the
> ground wire must be embedded into the earth for a minimum of ten feet.
> It does not mean that ground wires greater than ten feet are not earth
> grounds.
>
> A 100-foot-long 12-gauge ground wire might have too much resistance to
> divert a lightning strike, but it is more than adequate to divert a
> power surge away from a plug-in surge protector. =A0Consider that the
> surge *entered* the protector through a 12-gauge wire. =A0The
requirements=
> for an earth ground for a surge protector are not as demanding as the
> requirements for an earth ground for a lightning rod.
>
> In the United States the ground wire and the neutral wire are bonded
> together at the service entrance. =A0That means that a surge protector
> does not even need a ground wire. =A0By diverting surges into the
NEUTRAL
> (normal mode), they go to earth ground.
>
> Surge protectors absorb surges and then "slowly" (relatively speaking)
> release them into the earth ground. =A0Because the earth ground does not
> have to dissipate the surges as quickly as they happen, a "short thick"
> ground wire is unnecessary.
>
> You mentioned that Tripplite does not have an earth ground. =A0Of course
> it doesn't as you take it out of the box, but it does once you plug it
> in.
>
> With respect to whole-house surge protectors -- they may suppress surges
> from the outside, but most surges originate from INSIDE -- from
> refrigerator motors, air conditioners, and vacuum cleaners. =A0And no,
UPS=
> units, muffin fans, and disk drives -- although it *might* be argued
> that they are the same technology as refrigerator motors -- do not
> produce surges when they power on.
>
> With respect to your remark that MOVs explode because they are
> underrated for their application (I paraphrase) -- =A0 They explode
> because they do not have a chance to cool off between surges. =A0How is
a
> user to know how frequently surges are going to occur?
|
