Lightning Strike and surge

[spodosaurus]

I hate it when college kids post here, so, let me repeat it, the computer,
no damage, operated normally, no glitches, no slowdowns, no changes . . .

Got it?

Apparently you've got no clue how a computer works, nor where faults may
occur after power spikes, nor how to go about testing for them. Does
your car have a leaking sump gasket, bald tires, and one too few
functioning spark plugs? I guess by your reasoning it's still fine,
nothing wrong, as long as you can still drive it down the road to buy
your smokes and lottery tickets. I hope you've got up to date backups of
important data.

Cheers,

Ari

--
spammage trappage: remove the underscores to reply
Many people around the world are waiting for a marrow transplant. Please
volunteer to be a marrow donor and literally save someone's life:
http://www.abmdr.org.au/
http://www.marrow.org/

 

[Charlie]

Assume a destructive type surge entered memory on a signal or
voltage pin. Ok. That would be the incoming path. Where is the
outgoing path?

The ground (often called Vss) pins.
http://pinouts.ru/Memory/dimm_184p_pinout.shtml

This type surge cannot be outgoing on ground...

Why Not?

Charlie

 

[geoff]

Apparently you've got no clue how a computer works, nor where faults may

occur after power spikes, nor how to go about testing for them.

Ok, lets try it again, the strike happened almost 2 years ago, no problems,
no issues, no glitches, no errors, no slowdowns, no problems at all, none,
zero, nothing, nada, zilch, zippo . . . all works normally, same as before
the strike, as if there was no strike.

Got it now?

--g

 

[Matt]

Assume a destructive type surge entered memory on a signal or
voltage pin. Ok. That would be the incoming path. Where is the
outgoing path? This type surge cannot be outgoing on ground or
another signal line. Those lines are also charged near or up to the
same potential as that incoming pin. However, if you touch memory
when a surge occurs; now memory has an outgoing path to earth ground -
via you. Now damage may occur.

Surges that typically do damage are on some or all signal and power
lines. Not seeking a path to some other line. Any potential
difference between these pins is trivial. Surge seeks a connection to
earth. For memory, no such path exists.

Would the same argument apply to a PS/2 keyboard?

 

[david]

shunting electricity is not
really what protects the circuit.

Incorrect. The surge energy is dissipated in the MOV.

http://en.wikipedia.org/wiki/Varistor

Since the circuit input and output

voltages are the same thanks to the MOV becoming a short-circuit,
destructive current flow through the protected device is (ideally)
prevented.

Incorrect again. The MOV has a low, but non-zero, resistance once its
threshold voltage has been exceeded.

 

[John Doe]

Incorrect. The surge energy is dissipated in the MOV.

http://en.wikipedia.org/wiki/Varistor

Don't believe everything you read on Wikipedia.

Incorrect again. The MOV has a low, but non-zero, resistance once
its threshold voltage has been exceeded.

Doesn't have to be zero, it just has to be low enough to limit
voltage at the circuit inputs, and that's how it protects the
circuit.

 

[spodosaurus]

Ok, lets try it again, the strike happened almost 2 years ago, no problems,
no issues, no glitches, no errors, no slowdowns, no problems at all, none,
zero, nothing, nada, zilch, zippo . . . all works normally, same as before
the strike, as if there was no strike.

Got it now?

--g

And therefore? One of two possibilities. The strike's power dissipated
to the extent that when it burnt the UPS insufficient power made it to
the PC to damage it. Or two, components of the PC have been damaged but
insufficiently to fail or affect performance under the conditions you
use it. Either way, the original poster has had significant system
damage and if he wants a reliable system and uncorreupted data he needs
to replace his PC.

Ari

--
spammage trappage: remove the underscores to reply
Many people around the world are waiting for a marrow transplant. Please
volunteer to be a marrow donor and literally save someone's life:
http://www.abmdr.org.au/
http://www.marrow.org/

 

[david]

Don't believe everything you read on Wikipedia.

I don't, but this article happens to be correct. You can search for
yourself if you don't believe it.

Doesn't have to be zero, it just has to be low enough to limit voltage
at the circuit inputs, and that's how it protects the circuit.

The MOV clamps the voltage across its terminals at its turn-on threshold,
which could be more than 400 volts, depending on the breakdown voltage of
the particular device. It is not a short circuit.

 

[Ed Cregger]

If a billion volts hits your house or near you, forget any protection
devices. Lightening don't give a good god damn about anything and WILL go
where it wants.

-----------

Many folks aren't aware of the fact that simply removing the power cord from
the wall (along with disconnecting ether net or outboard devices) is not
enough. If you really want to keep your PC's protected, you have to unplug
the power cord from the PC power supply, along with any other cable that is
connected to the PC.

Wires of any sort can act as antennas and can pick up enough induced voltage
from a nearby strike to damage computer components. Yes, it's a PITA, but
it's the truth.

Another good thing is to have insurance (home/apartment) with the lowest
possible deductible. Insurance companies are used to EMP damage claims for
PC's/consumer electronics and usually do not bat an eye at fulfilling their
end of the bargain.

Ed Cregger

 

[Ed Cregger]

I don't, but this article happens to be correct. You can search for
yourself if you don't believe it.


The MOV clamps the voltage across its terminals at its turn-on threshold,
which could be more than 400 volts, depending on the breakdown voltage of
the particular device. It is not a short circuit.

-------------

Problem is, sometimes it can be difficult to identify a consumed MOV.
Constant replacement is mandatory in most cases to ensure proper
functioning.

Ed Cregger

 

[John Doe]

I don't, but this article happens to be correct. You can search
for yourself if you don't believe it.

I have. A MOV regulates the voltage at the circuit's terminals.
Apparently shunting current allows it to do that, but shunting
current is not what protects the device. What protects the device is
regulating voltage at the circuit's terminals.

The MOV clamps the voltage across its terminals at its turn-on
threshold,

The resistance drops dramatically, so it becomes like a closed
switch, a short-circuit, or whatever you want to call it.

threshold which could be more than 400 volts, depending on the
breakdown voltage of the particular device. It is not a short
circuit.

Use whatever terminology you feel like using.

 

[w_tom]

If a billion volts hits your house or near you, forget any protection
devices. Lightening don't give a good god damn about anything and
WILL go where it wants.

If one is foolish as to try to stop or absorb a surge, that current
will create something less than 1 billion volts. Then surge energy
causes massive damage.

Those who learned how electricity work also know a shunted surge has
near zero volts. That is what effective protection does. Tens of
thousands of amps get conducted elsewhere. Near zero voltage. Energy
dissipated harmlessly in earth.

So Ben Franklin's lighting rods did not work? Direct strike to
lightning rods created billion of volts on that lightning rod -
destroyed every church steeple? Of course not. A lightning rod
reduced thousands of volts to near zero volts. That assumed 'billion
volts' instead was dissipated harmlessly in earth. How curious. What
Franklin demonstrated in 1752 is how effective protectors make direct
lightning strikes irrelevant. Effective protection means that
'billion volts' is harmlessly dissipated in earth.

What does a plug-in protector or UPS do to surges? It cannot make
that energy dissappear. So it must stop or absorb that energy.
Trying to stop or absorb that current will only created a 'less than
a billion' volts. Will those silly little MOVs absorb that 'billion
volts'? Of course not. Effective protectors do what Franklin
lightning rods also do. A surge shunted short (ie 'less than 10
feet') into earth creates near zero voltage inside a building (or
church steeple) and dissipates that 'billion volts' harmlessly in
earth - no damage.

 

[w_tom]

Incorrect.  The surge energy is dissipated in the MOV.
http://en.wikipedia.org/wiki/Varistor

Wikipedia says where surge energy gets dissipated:

Varistors can absorb part of a surge. How much effect
this has on risk to connected equipment depends on
the equipment and details of the selected varistor.
Varistors do not absorb a significant percentage of a
lightning strike as energy that must be conducted
elsewhere is many orders of magnitude greater than
what is absorbed by the small device.

Where does surge energy get dissipated? Not in the MOV. If a shunt
is adjacent to an appliance, then a surge voltage is too high due to a
high impedance connection to earth - wire too long, too many sharp
bends, etc. 8000 volts shunted destructively through an adjacent
appliance - Page 42 (of 61) Figure 8. A protector without a short
connection to earth simply connected that surge energy 8000 volts
destructively to earth via an adjacent TV. Effective MOVs divert
(shunt, connect) surge energy on a low impedance connection into
earth.

Effective MOVs require an earthing wire that is typically 'less than
10 feet'. What increases impedance and therefore the surge voltage?
Not wire diameter or gauge. Critical to low impedance - to make that
connection to earth more conductive - is a shorter wire, no sharp
bends, not inside metallic conduit, separated from other wires, etc.

 

[w_tom]

The ground (often called Vss) pins.

http://pinouts.ru/Memory/dimm_184p_pinout.shtml

Digital ground on a memory SIMM is different from chassis ground is
different from AC equipment ground which is different from circuit
breaker box ground which is different from earth ground which is
different from ground inside a car which is different from the safety
ground attached to water pipes which is different than another ground
found on PC boards (analog ground), etc. All may be interconnected.
But every ground is electrically different. This should be obvious to
everyone.

Those who use word association to know something would connect a
rooftop lightning rod to the ground pin of a memory board? Charlies
post demonstrates how others just know only because they read some
words.

Vss is a digital ground. Lightning and surges are not earthed to or
by a digital ground. Even a long (ie 50 foot) electric wire inside
walls is too long - excessive impedance. That same wire is a safety
ground or equipoment ground. But length is signficantly too long to
be an earth ground for surges.

Anyone with basic electrical knowledge would understand the
difference between wire resistance and wire impedance. That also
makes it obvious why a memory SIMM digital ground does not provide
earth ground.

 

[Charlie]

http://pinouts.ru/Memory/dimm_184p_pinout.shtml

Digital ground on a memory SIMM is different from chassis ground is
different from AC equipment ground...

Some digital circuits do use a completely different ground plane for digital
current but it is also common for the two grounds to be tied together at one
point. The reason for this is to eliminate the possibility of different
potentials existing between the planes.

Even if there were totally different planes (the memory chip pinout above
suggests there are not) the chip would still have to be powered (non-digital
DC) and the pinout clearly shows that power on several pins. The power
suppy current has to have a ground (I hope you are not suggesting that the
power supply current enters the chip and never leaves) and that would be a
path for your current surge.

which is different from circuit
breaker box ground which is different from earth ground which is
different from ground inside a car which is different from the safety
ground attached to water pipes which is different than another ground
found on PC boards (analog ground), etc. All may be interconnected.
But every ground is electrically different. This should be obvious to
everyone.

No not every ground is electrically different and even where there is
differences in potential that is irrelevant to the question of a surge since
there is still a path to earth.

It was you who stated (and snipped when I commented on it) and I
quote:

"Assume a destructive type surge entered memory on a signal or
voltage pin. Ok. That would be the incoming path. Where is the
outgoing path? "

unquote.

A surge of current cannot enter memory on any pin and not leave. That is
electrically impossible.

Your talk of the ground inside a car has nothing to do with this discussion.
I wonder why you brought that up. Your statement that breaker box ground is
different from earth ground is true in that they are physically different
but (at least where I live) they are required to be tied together
electrically (bonded).

Those who use word association to know something would connect a
rooftop lightning rod to the ground pin of a memory board?

I have no idea how you arrived at that.

Charlies
post demonstrates how others just know only because they read some
words.

What others?

Vss is a digital ground.

Since Vss is the only ground I see, so then the power to the chip must also
be using that ground. Even if it wasn't using Vss as a ground, then it
(power) has to have a ground ( to complete the circuit) which the surge
current would follow.

Lightning and surges are not earthed to or
by a digital ground.

Well, I believe you are wrong on that but I welcome any information that you
can point me to on the internet, specifically stating that a current surge
cannot flow to earth on any home computer digital ground.

Even a long (ie 50 foot) electric wire inside
walls is too long - excessive impedance. That same wire is a safety
ground or equipoment ground. But length is signficantly too long to
be an earth ground for surges.

This too is irrelevant. Why did you include it?

Anyone with basic electrical knowledge would understand the
difference between wire resistance and wire impedance.

Of course.

That also
makes it obvious why a memory SIMM digital ground does not provide
earth ground.

Again it was you that stated the stated:

"Assume a destructive type surge entered memory on a signal or
voltage pin."

The signal pin is digital and the voltage pin is power. If the surge can
come in on the digital pin as you state then it can leave on the digital
ground; in fact it has to.
A surge on the power pin must leave as well.

Charlie

 

[Charlie]

If a billion volts hits your house or near you, forget any protection
devices. Lightening don't give a good god damn about anything and
WILL go where it wants.

If one is foolish as to try to stop or absorb a surge, that current
will create something less than 1 billion volts. Then surge energy
causes massive damage.

Those who learned how electricity work also know a shunted surge has
near zero volts. That is what effective protection does. Tens of
thousands of amps get conducted elsewhere. Near zero voltage. Energy
dissipated harmlessly in earth.

So Ben Franklin's lighting rods did not work? Direct strike to
lightning rods created billion of volts on that lightning rod -
destroyed every church steeple? Of course not. A lightning rod
reduced thousands of volts to near zero volts. That assumed 'billion
volts' instead was dissipated harmlessly in earth. How curious.

Not curious at all since voltage is not what causes harm. It is the current
that does that.
The 'billion volts' could have (and often does have) low amperage.

What
Franklin demonstrated in 1752 is how effective protectors make direct
lightning strikes irrelevant. Effective protection means that
'billion volts' is harmlessly dissipated in earth.

Using Franklin's lightning rods as an argument in this context is not really
a good one since no on and that includes you and me completely understands
how lightning rods work. In fact Franklin didn't either. To this day there
is argument among the 'experts'. Franklin originally felt that his rods
dissipated the charge between the earth and clouds slowly so that the rods
(and therefore the buildings they protect) were not struck as often. Indeed
his own observations seemed to conclude that buildings with lightning rods
were struck much less often that those without rods.
Later he changed his mind. I'm unsure why. In the years that followed his
original theory gained ground (no pun intended) until about 50 years ago.
Now most believe the lightning rods work because they are a better path to
ground. This modern belief (in my opinion) ignores
the easily demonstrated fact that current flows through the lightening rod
system when a storm charged cloud moves close above it (without lightning
hitting the rod). Without strong evidence to the contrary I'll stick with
Franklin's original 'slow charge dissipation theory'.

the rest snipped <

Charlie

 

[geoff]

The OP asked why his computer is starting slow.

He did not ask for your opinion on how MOV regulation works.

Read your own post on thread purity. and go start a separate thread.

--g

 

[bud--]

Wikipedia says where surge energy gets dissipated:

..
I agree that with both service panel and plug-in suppressors very little
of the energy in a surge is dissipated in the MOVs.
..

8000 volts shunted destructively through an adjacent
appliance - Page 42 (of 61) Figure 8.

..
If poor w_ could only read and think he could discover what the IEEE
guide says in this example:

- A plug-in suppressor protects the TV connected to it.
- "To protect TV2, a second multiport protector located at TV2 is required."
- In the IEEE example, a surge comes in on a cable service with the
ground wire from cable entry ground block to the power service ground
that is far too long. In that case the IEEE guide says "the only
effective way of protecting the equipment is to use a multiport protector."
- w_'s favored power service suppressor would provide absolutely NO
protection.


Never seen - a source that agrees with w_ that plug-in suppressors are
NOT effective.

Never answers to simple questions:
- Why do the only 2 examples of protection in the IEEE guide use plug-in
suppressors?
- Why does the NIST guide says plug-in suppressors are "the easiest
solution"?
- How would a service panel suppressor provide any protection in the
IEEE example, pdf page 42?
- Why does the IEEE guide say "the only effective way of protecting the
equipment is to use a multiport protector"?

For real science read the IEEE and NIST guides. Both say plug-in
suppressors are effective.

 

[bud--]

What does a plug-in protector or UPS do to surges? It cannot make
that energy dissappear. So it must stop or absorb that energy.

..
Poor w_ can’t understand how plug-in suppressors work. It is explained
in the IEEE guide (starting pdf page 40) if poor w_ could only read.
Plug-in suppressors work primarily by clamping the voltage on all wires
to the common ground at the suppressor. The guide says they do not work
primarily by earthing. And nobody but w_ says they work by stopping or
absorbing. The guide explains that earthing occurs, just not primarily
through the plug-in suppressor.


Never seen - a source that agrees with w_ that plug-in suppressors are
NOT effective.

Never answers to simple questions:
- Why do the only 2 examples of protection in the IEEE guide use plug-in
suppressors?
- Why does the NIST guide says plug-in suppressors are "the easiest
solution"?

For real science read the IEEE and NIST guides. Both say plug-in
suppressors are effective.

 

[w_tom]

Not curious at all since voltage is not what causes harm.  It is the
current that does that. The 'billion volts' could have (and often does
have) low amperage.
...
Using Franklin's lightning rods as an argument in this context is not
really a good one since no on and that includes you and me
completely understands how lightning rods work.  In fact Franklin
didn't either.  To this day there is argument among
the 'experts'.  Franklin originally felt that his rods dissipated the
charge between the earth and clouds slowly so that the rods
(and therefore the buildings they protect) were not struck as
often.  

Correct is that surges are current. That voltage only increases if
the current is obstructed, absorbed, or blocked. We routinely earth
surges without damage all over the world and for 100 years because the
concepts are that well understood and proven. Protectors without
earth ground violate these well proven concepts - are installed only
for a type of surge that is typically not destructive.

How lightning rods work is well understood. However, like plug-in
protectors, myths also promote ESE devices. Charlie is posting myths
from the ESE industry that have been roundly discredited in NFPA
reviews and IEEE papers. No lightning rod discharges the air to make
lightning less likely. Will that ESE type lightning rod (some with
radioactive materials) somehow stop charges three miles up from
building a path to earth? That is what ESE proponents claim.

Lightning rods are diverting devices. Lightning rod is only as
effective as its earth ground. Lightning rod - like a 'wjhole house'
protector - are only as effective as its earth ground. There is no
confusion about how lighting rods work. There still are many deceived
by ESE myths. Myths promoted using the same half truths that promote
plug-in protectors.

Protection is about connecting (diverting, clamping, shunting) the
energy to where that energy gets dissipated harmlessly - earth
ground. That is what properly earthed protectors do. That is what
spark gaps do on every broadcast tower. That is what lightning rods
do.

Where is the IEEE paper that promotes ESE (discharge the air)
protection? Does not exist. That was the point make by the NFPA.
NFPA complaint was very specific about that. ESE promoters have done
no research - done nothing to prove - that discharging the air
protects from lightning. In fact, these ESE promoters spend massive
sums suing the NFPA in a legal threat to force the NFPA to accept ESE
protectors. NFPA still refused because no responsible source says
lightning rods discharge the air. That 'discharging' is a popular
myth promoted to those who *know* without first learning the science.

Am I blunt about this? Yes, Charlie. You posted junk science. You
did not first learn the technology. Lightning rods obviously do not
work by discharging the air. It would have to discharge miles of
air. It cannot and does not do that. You should have known how often
ESE technology is rejected by responsible sources. You are invited to
learn how Hearly Bros tried to force the world to accept ESE devices -
using the same logic you have posted.