Which material has high enough ohmage to resist lightning?

[Radium]

Hi:

Is there any material that has enough electrical-resistance to block
off high-voltage such as that of lightning? Lightning is around a
million volts.

Another question. Which material has the strongest electrical
resistance of all?


Thanks,

Radium

 

[Sjouke Burry]

Hi:

Is there any material that has enough electrical-resistance to block
off high-voltage such as that of lightning? Lightning is around a
million volts.

Another question. Which material has the strongest electrical
resistance of all?


Thanks,

Radium

5000 meters or yards of air.

 

[Bob Myers]

Hi:

Is there any material that has enough electrical-resistance to block
off high-voltage such as that of lightning? Lightning is around a
million volts.

Another question. Which material has the strongest electrical
resistance of all?

I don't know why I'm bothering to respond to this troll, but....

It's not a question of simple resistance in ohms. Look
up "breakdown voltage" for further information.

Bob M.

 

[default]

Hi:

Is there any material that has enough electrical-resistance to block
off high-voltage such as that of lightning? Lightning is around a
million volts.

Around a million? Not several millions? Cloud to ground strikes can
be several miles long and range into the hundreds of millions and
billions of volts, and tens to hundreds of thousands of amps.

Another question. Which material has the strongest electrical
resistance of all?

Lots of electrical texts have charts for dielectric strength. I
doubt that one insulator will be right for all applications.
Dielectric strength is specified in volts per mil, so even poor
insulators, if thick enough, can stand off high voltages.

What was your idea? Surround something with an insulator to protect
it from lightning? Surround what?

Lightening is a fast rise time pulse(s). The insulator, even if it
withstands the strike, will likely couple enough energy to the
"protected" device to cause damage

Thanks,

Radium

All the practical systems of lightening protection I'm aware of, deal
with directing the strike away from something, or bleeding off the
space charge before a discharge can occur in that area.

 

[Eeyore]

Hi:

Is there any material that has enough electrical-resistance to block
off high-voltage such as that of lightning? Lightning is around a
million volts.

Another question. Which material has the strongest electrical
resistance of all?

Ohhhh ! Not you again you brain dead nitwit.

Just try *thinking* about the stupidity of your question will you ?

Graham

 

[chuck]

Hi:

Is there any material that has enough electrical-resistance to block
off high-voltage such as that of lightning? Lightning is around a
million volts.

Another question. Which material has the strongest electrical
resistance of all?


Thanks,

Radium

I would think a vacuum would do it.

Sometimes it's better to "go with the
flow" and "re-route" the lightning,
rather than attempt to block it.

Consider surrounding the device to be
protected with a grounded conductor and
forget about insulators.

Chuck

 

[Mark Fortune]

I would think a vacuum would do it.

I thought that a vacuum had relatively weak (electrical) insulating
properties, to say.. air for example?

Mark

 

[John Larkin]

I thought that a vacuum had relatively weak (electrical) insulating
properties, to say.. air for example?

Mark

A hard vacuum is very good. The lowest breakdown is at some low
pressure, a small fraction of atmospheric as I recall; after that
point, better vacs are better insulators. A perfect vacuum is a
perfect insulator, and the only limit is when the field strength gets
so high that ions are ripped out of any metal electrodes that are
present, at vaguely around 1e8 v/m. Tomographic atom probes use this
effect; see Imago.com.

An interesting effect is secondary emission in metallic surfaces,
which can become a positive feedback effect for AC. See "Farnsworth
multipactor."

John

 

[Radium]

Around a million? Not several millions? Cloud to ground strikes can
be several miles long and range into the hundreds of millions and
billions of volts, and tens to hundreds of thousands of amps.

Probably in the billions of volts. I was just guessing.

Lots of electrical texts have charts for dielectric strength. I
doubt that one insulator will be right for all applications.
Dielectric strength is specified in volts per mil, so even poor
insulators, if thick enough, can stand off high voltages.
Okay

What was your idea?

I was just curious

Surround something with an insulator to protect
it from lightning? Surround what?
Anything.

Lightening is a fast rise time pulse(s). The insulator, even if it
withstands the strike, will likely couple enough energy to the
"protected" device to cause damage

Are you referring to damage caused by the EM waves emitted by the
pulse?

 

[Radium]

I would think a vacuum would do it.

Doesn't a vacuum has very *low* resistance? Or are you referring to the
stuff around the vacuum? What is the insulation covering the vacuum
made of?

 

[John Fields]

chuck wrote:

Doesn't a vacuum has very *low* resistance?

 

[default]

Are you referring to damage caused by the EM waves emitted by the
pulse?

Insulators are dielectrics they will transfer energy just like a
capacitor charging. Fast rise time is similar to high frequency -
large high frequency component in the wave form. One plate is the
ionized gases surrounding the insulator, the other the protected
device.

And as you point out EMP

I was on a beach stringing a wire from my bike to a tent to run a
reading light. A strike that was easily 10 miles away induced enough
voltage in my wire to give me a shock.

 

[Mark Fortune]

An ohmeter I would expect to read infinate resistance, but at the
voltages we're talking about (ie involving lightning) isnt the breakdown
voltage much lower than air?

 

[John Fields]

An ohmeter I would expect to read infinate resistance, but at the
voltages we're talking about (ie involving lightning) isnt the breakdown
voltage much lower than air?

 

[Michael A. Terrell]

I thought that a vacuum had relatively weak (electrical) insulating
properties, to say.. air for example?

It would be damn hard to manufacture vacuum tubes and CRTs if you
were right.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Homer J Simpson]

5000 meters or yards of air.

8000 miles of earth.




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| | / _` | '_ ` _ \ | __ |/ _ \| '_ ` _ \ / _ \ '__|
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| (_) | | | |_) | (_) | | | (_| |_
\___/|_| |____/ \___/|_| \__, (_)
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[John Larkin]

An ohmeter I would expect to read infinate resistance, but at the
voltages we're talking about (ie involving lightning) isnt the breakdown
voltage much lower than air?

Vacuum can't break down; there's nothing to conduct with.

Electrodes in a vacuum can break down, namely emit electrons or ions
from their surfaces, but that's different.

John

 

[Bob Myers]

I thought that a vacuum had relatively weak (electrical) insulating
properties, to say.. air for example?

Once again, with feeling: do not confuse "insulating properties"
with resistance ALONE. Think "breakdown voltage," which
is something else altogether.

Bob M.

 

[Bob Myers]

Doesn't a vacuum has very *low* resistance? Or are you referring to the
stuff around the vacuum? What is the insulation covering the vacuum
made of?

A vacuum has an extremely HIGH resistance, as long as you
are talking about conduction in the normal sense. Again, go
look up "breakdown voltage" and learn something for a
change. Up to the breakdown point, I think you'll find that
the I vs. V curve for a reasonable amount of separation in a
vacuum is pretty damned flat...

Bob M.

 

[Bob Myers]

Electrodes in a vacuum can break down, namely emit electrons or ions
from their surfaces, but that's different.

Damn, John, now you're REALLY going to send Radium, et
al, down a rathole.....

I'll get the popcorn...

Bob M.