T
Tom MacIntyre
Guest
On Mon, 12 Jul 2004 00:07:12 GMT, "sparky" <sparky@world.net> wrote:
mainboard in the shop PC (8 or so feet away), and temporarily
scrambled the LED display on the Sencore oscilloscope nearby,
requiring it to be reset. A lightning strike would have much more
energy than that.
Tom
I have seen a horizontal yoke on a 27" TV arcing, which took out the"w_tom" <w_tom1@hotmail.com> wrote in message
news:40EF1EA0.268A87E7@hotmail.com...
Chris has misrepresented what was posted. Anything else
installed as part of the protection system is, at best,
supplementary. Until the 'whole house' protector and single
point earth ground is installed, then nothing else can be
effective. Supplementary devices are all but useless without
first earthing the incoming transient. Furthermore, those
supplementary devices that can work adjacent to a computer are
already inside that computer.
Take, for example, series mode protectors from Zerosurge,
Brickwall, and Surgex. Good piece of design. However notice
the soft underbelly. There is this little thing called a
safety ground that completely bypasses a series mode
protector. If the building is not 'shunt mode' protected
right at the single point earth ground as described
previously, then a series mode protector is easily bypassed -
ineffective. Series mode protector is only supplementary and
can be ineffective without the 'whole house' earthed
protection system.
There is no more superior protection than single point earth
ground and 'whole house' protector. Furthermore, the cost of
enhancing that single point earth ground is significantly less
expensive and more effective than plug-in protectors on every
appliance. Provided is the most cost effective and overall
effective solution to hardware transient protection.
The silly suggestion is that lightning hitting a nearby tree
will create some kind of monster electromagnetic field that
will destroy electronics.
You are providing a great deal of misinformation to this
group, intentionally or not. A close lightning strike can
and WILL cause a large transient that can damage
electronic components. Please refrain from posting
until you have researched the subject thoroughly.
mainboard in the shop PC (8 or so feet away), and temporarily
scrambled the LED display on the Sencore oscilloscope nearby,
requiring it to be reset. A lightning strike would have much more
energy than that.
Tom
I am still waiting for anyone to
provide those numbers. Lightning striking a tree and causing
internal appliance damage is more often a direct strike to the
appliance. Often associated with not using the single point
earth ground.
An example demostrates how a nearby tree can actually
channel a surge into and out of household appliances. 6
campers were sleeping beneath a tree that was struck. 4 were
sleeping perpendicular to the tree and therefore remained
healthy. Two were sleeping pointed towards that tree. They
were seriously hurt because lightning left earth, traveled
down each body, then reentered earth. Those two suffered a
direct strike because they were a path from cloud to earth
borne charges located elsewhere.
Same concept applies to building protection. That lightning
that struck a tree could have found a conductive path through
appliances because house did not use a single point earth
ground. Notice the most important component in a surge
protection 'system'? Single point earth ground.
How do campers avoid a direct strike from the ground?
Again, single point earth ground which means both feet
together - the only point where a human body touched earth.
Is the 'whole house' solution as proposed perfect? Of
course not. Someone here may suffer a rare strike that even
overwhelms that 'whole house' protection. But then we are not
installing perfect protection. We are upgrading near zero
protection to protection that is well over 95% effective - at
very little cost. To have well over 95% effectiveness does
not require zero resistance grounding. Ufer grounding even
enhances that 95+% effective protection. Somehow Chris has
invented values (such as resistance for Ufer grounding - but
he does not even provide the number) that I did not provide
and that does not adversely effect that far more superior
solution. Near zero resistance in an Ufer ground is so
effective that the method is used to keep ammunition from
exploding due to a direct lightning strike.
Telco stations and cell towers, on the other hand, must
never suffer damage even from that most rare and powerful
strike. Therefore they install massive amounts more earthing
just to improve that less than 5%. The bottom line remains.
They too use the 'whole house' protectors with a massive
single point earth ground. They also don't use useless and
grossly overpriced plug-in protectors. The do use a UPS that
also contributes to protection because that UPS is also
properly earthed; not a plug-in type.
The point here being that one can spend tens of times more
money per protected appliance and get virtually no effective
protection from plug-in protectors.
Unfortunately Chris Lewis has mischaracterized my posts. He
still thinks a protector adjacent to the computer and
essentially unearthed will provide some type of protection.
That can only be true in a DC world. Due to wire impedance
and the RF nature of destructive surges, then adjacent plug-in
protectors have no earth grounding. IOW plug-in protectors are
ineffective. Apparently Chris doesn't understand about RF,
rapid transients and slew rates which is why he thinks a
plug-in protector is earthed.
In learning about lightning strikes by actually replacing
the damaged ICs, multiple computers were damaged because a
powered off computer was adjacent to a plug-in surge
protector. That's right. An adjacent surge protector even
contributed to damage of that powered off computer and spread
through the network to damage other computer network cards.
Damage created by a plug-in protector that was too close to
transistors and too far from earth ground.
Any protection that can work adjacent to the computer is
inside the computer. Any surge protector without a less than
10 foot connection to earth ground, well, its manufacturer
does not even claim to protect from that typically destructive
type of surge.
Provided was both the theory AND experimental evidence of
effective protection. Chris Lewis is invited to provide
theory and experimental evidence that explains how a plug-in
protector could possibly protect an adjacent computer. Chris
will have to provide the evidence because that surge protector
manufacturer will not even make that claim. That manufacturer
so fears we might learn about earthing that he does not even
mention earthing. That manufacturer knows this basic fact: a
surge protector is only as effective as its earth ground.
Better to avoid the topic to not harm sales.
Supplementary protectors remain largely ineffective if the
essential 'whole house' and single point earth ground is not
installed.
Chris Lewis wrote:
Don't get me wrong, there's nothing whatsoever wrong with a
whole house surge suppressor. It'll usually do most of the
job just fine on a _line_ strike. Which is probably the
most common.
On the other hand, a lightning strike hitting a tree a few
hundred feet away on the other side of the house from the
panel is not all that uncommon, and a whole-house suppressor
will be much less help. Surge suppression (even with
relatively remote/poor grounding) _local_ to the device
helps more.
tom_w's obsession is that _only_ whole house surge
suppressers work, _only_ whole house surge suppressors
_can_ work, (and dare I say it), work _perfectly_ all
the time, and all other devices are all-out fraud and
completely useless.
He doesn't understand that earth grounds (even UFERs
spec'd well beyond code req'ts) aren't (and often not
even close to) zero resistance.
He doesn't understand about RF (lightning strikes have
LOTs of RF in them), rapid transients and slew rates.
He's living in a DC world.
The real world just isn't quite like that.