A lot of older houses had lightning rods on their roofs. Particularly
farm houses. They would have a thick braided cable that went to ground
rods. Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. Anything that is a high point in an area attracts
it, such as large trees. Of course metal attracts, so putting a metal
rod on a roof is an attractant. In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

On Jan 23, 5:54 am, wrote:
A lot of older houses had lightning rods on their roofs. Particularly
farm houses. They would have a thick braided cable that went to ground
rods. Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. Anything that is a high point in an area attracts
it, such as large trees. Of course metal attracts, so putting a metal
rod on a roof is an attractant. In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

They do not "attract" lightning unless the charged area is within
a few feet of them already, solely because they provide a slightly
shorter path than the surrounding protrusions.
Electric fields appear randomly, and move across the terrain.
When the jump path is less than required for the discharge voltage,
it flashes over. If the field moves over a house, the lightning rod
defines the jump path, and discharge thru the house is avoided.

The glass ball is decoration. Makes it look like the customer
is paying for more than a thick piece of metal. The metal needs
to be set above the roof with an insulator, until it terminates in
the ground.

Telephone poles usually have a piece of copper wire running
down them to the ground, for the same reason.

This technique is also used in some types of aircraft and in
missles, which are often struck by lightning. The metal strips
act as a guide to channel the bolt in a particular path, and
prevent it from jumping willy-nilly into anything that may be
around, which could cause damage. A metal fuselage will
take care of itself, but a composite fuselage , or long
radome, needs "channels" for this.

Lightning is very dangerous for flagpole sitters.

"Robert" wrote in message
...
On Jan 23, 5:54 am, wrote:
A lot of older houses had lightning rods on their roofs. Particularly
farm houses. They would have a thick braided cable that went to ground
rods. Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. Anything that is a high point in an area attracts
it, such as large trees. Of course metal attracts, so putting a metal
rod on a roof is an attractant. In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

They do not "attract" lightning unless the charged area is within
a few feet of them already, solely because they provide a slightly
shorter path than the surrounding protrusions.
Electric fields appear randomly, and move across the terrain.
When the jump path is less than required for the discharge voltage,
it flashes over. If the field moves over a house, the lightning rod
defines the jump path, and discharge thru the house is avoided.

The glass ball is decoration. Makes it look like the customer
is paying for more than a thick piece of metal. The metal needs
to be set above the roof with an insulator, until it terminates in
the ground.

Telephone poles usually have a piece of copper wire running
down them to the ground, for the same reason.

This technique is also used in some types of aircraft and in
missles, which are often struck by lightning. The metal strips
act as a guide to channel the bolt in a particular path, and
prevent it from jumping willy-nilly into anything that may be
around, which could cause damage. A metal fuselage will
take care of itself, but a composite fuselage , or long
radome, needs "channels" for this.

Lightning is very dangerous for flagpole sitters.

Because the flow of the electric fields during a thunderstorm is so
unpredictable, the best that lightning rods can do is reduce the chances of
a damaging strike. That they do. What lightning rods also do, and not
mentioned above, is to bleed the ground charge into the air harmlessly
through the needle-sharp tip of the rod. That reduces the voltage between
the ground and the cloud overhead and so further reduces the chances of a
lightning strike.

My own experience is that I've never had damage to a barn or house that had
lightning rods. On houses without rods, I've had several damage incidents.
I can also say that the "cone-of-protection" provided by higher structures
and trees does work. I've lived in a couple of houses surrounded by tall
trees and had those trees stripped of bark by lightning with no damage to
the houses.

Tomsic

On Jan 23, 8:07*am, "Tomsic" wrote:
"Robert" wrote in message

...





On Jan 23, 5:54 am, wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod..

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

They do not "attract" lightning unless the charged area is within
a few feet of them already, solely because they provide a slightly
shorter path than the surrounding protrusions.
* *Electric fields appear randomly, and move across the terrain.
When the jump path is less than required for the discharge voltage,
it flashes over. *If the field moves over a house, the lightning rod
defines the jump path, and discharge thru the house is avoided.

* The glass ball is decoration. *Makes it look like the customer
is paying for more than a thick piece of metal. *The metal needs
to be set above the roof with an insulator, until it terminates in
the ground.

* Telephone poles usually have a piece of copper wire running
down them to the ground, for the same reason.

* *This technique is also used in some types of aircraft and in
missles, which are often struck by lightning. *The metal strips
act as a guide to channel the bolt in a particular path, and
prevent it from jumping willy-nilly into anything that may be
around, which could cause damage. A metal fuselage will
take care of itself, but a composite fuselage , or long
radome, needs "channels" for this.

* Lightning is very dangerous for flagpole sitters.

Because the flow of the electric fields during a thunderstorm is so
unpredictable, the best that lightning rods can do is reduce the chances of
a damaging strike. *That they do. *What lightning rods also do, and not
mentioned above, is to bleed the ground charge into the air harmlessly
through the needle-sharp tip of the rod. *That reduces the voltage between
the ground and the cloud overhead and so further reduces the chances of a
lightning strike.

My recollection is that the above has been disproven. For
one thing, given the huge distance between the cloud and
the air terminal, the fact that air is a decent insulator, and
the huge amount of energy involved, the amount of bleed-off
that could occur is negligible.

On Jan 23, 11:54*am, wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Lightning conductors are necessary particularly on buildings that are
a high local point and are hence more likely to be struck. They need
to be checked regularly that the ground point is good ie low
resistance.
The lightning conductor provides a low resistance path to earth.
The energy released by a strike is simple (I squared R) So the low
resistance path provided by the lightning conductor means most of the
energy is dissipated in the ground, not on the building.
High commercial buildings are frequently struck and no-one even
notices.

The problem is the copper gets stolen theses days.

On 1/23/2013 7:07 AM, Tomsic wrote:
wrote in message
...
On Jan 23, 5:54 am, wrote:
A lot of older houses had lightning rods on their roofs. Particularly
farm houses. They would have a thick braided cable that went to ground
rods. Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. Anything that is a high point in an area attracts
it, such as large trees. Of course metal attracts, so putting a metal
rod on a roof is an attractant. In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

They do not "attract" lightning unless the charged area is within
a few feet of them already, solely because they provide a slightly
shorter path than the surrounding protrusions.
Electric fields appear randomly, and move across the terrain.
When the jump path is less than required for the discharge voltage,
it flashes over. If the field moves over a house, the lightning rod
defines the jump path, and discharge thru the house is avoided.

The glass ball is decoration. Makes it look like the customer
is paying for more than a thick piece of metal. The metal needs
to be set above the roof with an insulator, until it terminates in
the ground.

Telephone poles usually have a piece of copper wire running
down them to the ground, for the same reason.

This technique is also used in some types of aircraft and in
missles, which are often struck by lightning. The metal strips
act as a guide to channel the bolt in a particular path, and
prevent it from jumping willy-nilly into anything that may be
around, which could cause damage. A metal fuselage will
take care of itself, but a composite fuselage , or long
radome, needs "channels" for this.

Lightning is very dangerous for flagpole sitters.

Because the flow of the electric fields during a thunderstorm is so
unpredictable, the best that lightning rods can do is reduce the chances of
a damaging strike. That they do. What lightning rods also do, and not
mentioned above, is to bleed the ground charge into the air harmlessly
through the needle-sharp tip of the rod. That reduces the voltage between
the ground and the cloud overhead and so further reduces the chances of a
lightning strike.


A properly installed lightning rod (now called "air terminal") system
provides very good protection to a building. They provide a safe "point
of attachment" for lightning that will hit the building anyway. The do
not attract lighting and "metal" does not attract.

As electrical charge descends in a "stepped leader" lightning will hit
what is nearest to the leader when the leader is close enough to the
ground. The rod system is designed so the rods are nearer than the building.

They do not "bleed the charge", and points are not necessarily
needle-sharp. The rather limited research that has been done shows a
rounded tip is more likely to be hit than a sharp one at the same
location. A sharp one will be hit if there is no rounded one.

The rod system is not insulated from the building. It may have to be
bonded to metal within 6 feet of the rods and down conductors. If not
bonded, the rod system can be at high enough potential with respect to
other building parts there can be a side flash during a lightning strike.

A properly installed system also includes other protection, including
surge protection at the power service panel.

wrote:
A lot of older houses had lightning rods on their roofs. Particularly
farm houses. They would have a thick braided cable that went to
ground rods. Many of them had a glass ball in the center of the
copper rod.

I'm wondering of they really did any good. Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. Anything that is a high point in an area attracts
it, such as large trees. Of course metal attracts, so putting a metal
rod on a roof is an attractant. In a direct strike, I doubt they
would do anything, in fact they might get hot enough to start a fire.
But a discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Early on, there was a fierce debate among various religions. Since churches
in small towns, with their elevated bell towers and steeples were commonly
hit, lightning rods seemed a good idea. There were those, however, who said
even if they work, lightning rods would be interfering with God's will.

The debate eventually subsided as this group continued to get burnt out
while the other denominations flourished.

On Wed, 23 Jan 2013 08:07:03 -0500, "Tomsic" wrote:


"Robert" wrote in message
...
On Jan 23, 5:54 am, wrote:
A lot of older houses had lightning rods on their roofs. Particularly
farm houses. They would have a thick braided cable that went to ground
rods. Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. Anything that is a high point in an area attracts
it, such as large trees. Of course metal attracts, so putting a metal
rod on a roof is an attractant. In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

They do not "attract" lightning unless the charged area is within
a few feet of them already, solely because they provide a slightly
shorter path than the surrounding protrusions.
Electric fields appear randomly, and move across the terrain.
When the jump path is less than required for the discharge voltage,
it flashes over. If the field moves over a house, the lightning rod
defines the jump path, and discharge thru the house is avoided.

The glass ball is decoration. Makes it look like the customer
is paying for more than a thick piece of metal. The metal needs
to be set above the roof with an insulator, until it terminates in
the ground.

Telephone poles usually have a piece of copper wire running
down them to the ground, for the same reason.

This technique is also used in some types of aircraft and in
missles, which are often struck by lightning. The metal strips
act as a guide to channel the bolt in a particular path, and
prevent it from jumping willy-nilly into anything that may be
around, which could cause damage. A metal fuselage will
take care of itself, but a composite fuselage , or long
radome, needs "channels" for this.

Lightning is very dangerous for flagpole sitters.

Because the flow of the electric fields during a thunderstorm is so
unpredictable, the best that lightning rods can do is reduce the chances of
a damaging strike. That they do. What lightning rods also do, and not
mentioned above, is to bleed the ground charge into the air harmlessly
through the needle-sharp tip of the rod. That reduces the voltage between
the ground and the cloud overhead and so further reduces the chances of a
lightning strike.

My own experience is that I've never had damage to a barn or house that had
lightning rods. On houses without rods, I've had several damage incidents.
I can also say that the "cone-of-protection" provided by higher structures
and trees does work. I've lived in a couple of houses surrounded by tall
trees and had those trees stripped of bark by lightning with no damage to
the houses.

Tomsic

The house and barn on the farm my mother grew up on were on top of a
hill - with a huge oak tree. Both had lightning rods. Bothe were
struch MANY times - and no damage except when lightong struck the
cistern pump, jumped to the house, through the back door to the
aluminum strip on the edge of the counter - across the woodstove,
through the water dipper, to the well pump at the wash-sink. It blew
the enamel off the dipper about the size of a silver dollar. The oak
was struck several times as well.

I think that if there was good evidence that lightening rods DIDN'T work, we would have heard about the controversy by now. If tall building are all equipped with lightening rods, that's good enough evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to transfer all of that current around the house and into the ground. But, I'd rather fry a $300 cable than have lightening set my house on fire.

I'd put one in if it wuz my house.

On Jan 24, 2:05 am, nestork wrote:
I think that if there was good evidence that lightening rods DIDN'T
work, we would have heard about the controversy by now. If tall
building are all equipped with lightening rods, that's good enough
evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to
transfer all of that current around the house and into the ground. But,
I'd rather fry a $300 cable than have lightening set my house on fire.

I'd put one in if it wuz my house.

--
nestork

The current may be many thousands of amps, but it only lasts
for a few thousandths of a second. Consequently, the conductor
doesn't have to be massive since the short conduction time
means shorter heating time. Something like #6 wire is usually
enough, even tho it may carry an instantaneous 50,000 amps
or so. This can be confirmed by checking the size of the
grounding wire at your service entrance. Local codes and the NEC call
out the required size.
As far as a previous poster commenting on "bonding to the
structure", keep in mind that most houses have wood, non-conducting
construction, and that doesn't apply..... If the structure has steel
girders, it is another matter.

On Thursday 24 January 2013 08:05 nestork wrote in alt.home.repair:


I think that if there was good evidence that lightening rods DIDN'T
work, we would have heard about the controversy by now. If tall
building are all equipped with lightening rods, that's good enough
evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to
transfer all of that current around the house and into the ground. But,
I'd rather fry a $300 cable than have lightening set my house on fire.

I'd put one in if it wuz my house.


Cable?? The rods I've seen all use 1" x 1/4" (or roundabouts) solid copper
bar.

--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"History will be kind to me for I intend to write it."

On Jan 24, 5:07*am, Tim Watts wrote:
On Thursday 24 January 2013 08:05 nestork wrote in alt.home.repair:



I think that if there was good evidence that lightening rods DIDN'T
work, we would have heard about the controversy by now. *If tall
building are all equipped with lightening rods, that's good enough
evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to
transfer all of that current around the house and into the ground. *But,
I'd rather fry a $300 cable than have lightening set my house on fire.

I'd put one in if it wuz my house.

Cable?? The rods I've seen all use 1" x 1/4" (or roundabouts) solid copper
bar.


That sure must be an expensive and very labor intensive installation.
Here in the USA I've never seen such a thing. All the ones I've seen
use cable, it's accepted practice and it works.

On Jan 24, 3:07*am, Tim Watts wrote:
On Thursday 24 January 2013 08:05 nestork wrote in alt.home.repair:



I think that if there was good evidence that lightening rods DIDN'T
work, we would have heard about the controversy by now. *If tall
building are all equipped with lightening rods, that's good enough
evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to
transfer all of that current around the house and into the ground. *But,
I'd rather fry a $300 cable than have lightening set my house on fire.

I'd put one in if it wuz my house.

Cable?? The rods I've seen all use 1" x 1/4" (or roundabouts) solid copper
bar.

--
Tim Watts * * * * * * * * Personal Blog:http://www.dionic..net/tim/

"History will be kind to me for I intend to write it."

Thickness of the conductor is NOT to survive heating, but to maintain
LOW impedance during a strike. The sharp impulse of current is limited
by the self inductance [relating to diameter and shape of the
conductor] and the impedance [related to the cross sectional area]

Although a bar shape is probably the only available shape one can
easily get for the conductor, a round cross sectional area is the
best.

On Thursday 24 January 2013 13:00 wrote in
alt.home.repair:

On Jan 24, 5:07 am, Tim Watts wrote:
On Thursday 24 January 2013 08:05 nestork wrote in alt.home.repair:



I think that if there was good evidence that lightening rods DIDN'T
work, we would have heard about the controversy by now. If tall
building are all equipped with lightening rods, that's good enough
evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to
transfer all of that current around the house and into the ground.
But, I'd rather fry a $300 cable than have lightening set my house on
fire.

I'd put one in if it wuz my house.

Cable?? The rods I've seen all use 1" x 1/4" (or roundabouts) solid
copper bar.


That sure must be an expensive and very labor intensive installation.
Here in the USA I've never seen such a thing. All the ones I've seen
use cable, it's accepted practice and it works.

Seems to be the standard here (and the whole thing of lightning rods has a
complete set of standards all to itself).

OTOH, apart from pikeys nicking the copper, it doesn;t need re-doing very
often (ever??).

Before Fred Dibnah took to knocking down loads of victorian chimneys, one of
his more called upon jobs was installing lightning rods on them.
--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"History will be kind to me for I intend to write it."

On Thursday 24 January 2013 14:23 Robert Macy wrote in alt.home.repair:

On Jan 24, 3:07 am, Tim Watts wrote:
On Thursday 24 January 2013 08:05 nestork wrote in alt.home.repair:



I think that if there was good evidence that lightening rods DIDN'T
work, we would have heard about the controversy by now. If tall
building are all equipped with lightening rods, that's good enough
evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to
transfer all of that current around the house and into the ground.
But, I'd rather fry a $300 cable than have lightening set my house on
fire.

I'd put one in if it wuz my house.

Cable?? The rods I've seen all use 1" x 1/4" (or roundabouts) solid
copper bar.

--
Tim Watts Personal Blog:http://www.dionic.net/tim/

"History will be kind to me for I intend to write it."

Thickness of the conductor is NOT to survive heating, but to maintain
LOW impedance during a strike. The sharp impulse of current is limited
by the self inductance [relating to diameter and shape of the
conductor] and the impedance [related to the cross sectional area]

Although a bar shape is probably the only available shape one can
easily get for the conductor, a round cross sectional area is the
best.

Good point - hadn't thought of that.

Just thinking about it, our flat roof at work in central London has not only
rods, but a load of the same copper bar running all over the roof cross
bonding bits of metal handrail (those roofs are a fire escape route
sometimes) and other misc bits of metal and ventilation ducts.

They are not leaving anything to chance - and this building is 4 floors
high!
--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"A fanatic is one who can't change his mind and won't change the subject."

On Jan 24, 9:23*am, Robert Macy wrote:
On Jan 24, 3:07*am, Tim Watts wrote:





On Thursday 24 January 2013 08:05 nestork wrote in alt.home.repair:

I think that if there was good evidence that lightening rods DIDN'T
work, we would have heard about the controversy by now. *If tall
building are all equipped with lightening rods, that's good enough
evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to
transfer all of that current around the house and into the ground. *But,
I'd rather fry a $300 cable than have lightening set my house on fire..

I'd put one in if it wuz my house.

Cable?? The rods I've seen all use 1" x 1/4" (or roundabouts) solid copper
bar.

--
Tim Watts * * * * * * * * Personal Blog:http://www.dionic.net/tim/

"History will be kind to me for I intend to write it."

Thickness of the conductor is NOT to survive heating, but to maintain
LOW impedance during a strike.

The too are kind of one and the same....



The sharp impulse of current is limited
by the self inductance [relating to diameter and shape of the
conductor] and the impedance [related to the cross sectional area]

Although a bar shape is probably the only available shape one can
easily get for the conductor,

Say what?


a round cross sectional area is the
best.- Hide quoted text -

- Show quoted text -

On 1/24/2013 3:35 AM, Robert wrote:
On Jan 24, 2:05 am, wrote:
I think that if there was good evidence that lightening rods DIDN'T
work, we would have heard about the controversy by now. If tall
building are all equipped with lightening rods, that's good enough
evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to
transfer all of that current around the house and into the ground. But,
I'd rather fry a $300 cable than have lightening set my house on fire.

I'd put one in if it wuz my house.

--
nestork

The current may be many thousands of amps, but it only lasts
for a few thousandths of a second. Consequently, the conductor
doesn't have to be massive since the short conduction time
means shorter heating time. Something like #6 wire is usually
enough, even tho it may carry an instantaneous 50,000 amps
or so. This can be confirmed by checking the size of the
grounding wire at your service entrance. Local codes and the NEC call
out the required size.

Your comments on short duration are entirely right. But the NEC applies
to power systems, not lightning rod systems. (NFPA780 is the
installation standard for lighting rods.)

The average lighting strike is about 20,000A. About 5% are over
100,000A. Some are over 200,000A.

The numbers I have seen for down conductors are a little over #3 for
class 1 systems and over 1/0 for class 2. (I have no idea what the
difference between class 1 and 2 is.)

As far as a previous poster commenting on "bonding to the
structure", keep in mind that most houses have wood, non-conducting
construction, and that doesn't apply..... If the structure has steel
girders, it is another matter.

More than just structural steel. For commercial/industrial a rooftop
HVAC unit may have to be bonded if it is within 6 feet of the system
conductors. Cast iron plumbing stack? Service entrance riser? The point
was you can't effectively insulate the rod system from the building.

On Jan 23, 5:24*am, "
wrote:
On Jan 23, 8:07*am, "Tomsic" wrote:





"Robert" wrote in message

...

On Jan 23, 5:54 am, wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

They do not "attract" lightning unless the charged area is within
a few feet of them already, solely because they provide a slightly
shorter path than the surrounding protrusions.
* *Electric fields appear randomly, and move across the terrain.
When the jump path is less than required for the discharge voltage,
it flashes over. *If the field moves over a house, the lightning rod
defines the jump path, and discharge thru the house is avoided.

* The glass ball is decoration. *Makes it look like the customer
is paying for more than a thick piece of metal. *The metal needs
to be set above the roof with an insulator, until it terminates in
the ground.

* Telephone poles usually have a piece of copper wire running
down them to the ground, for the same reason.

* *This technique is also used in some types of aircraft and in
missles, which are often struck by lightning. *The metal strips
act as a guide to channel the bolt in a particular path, and
prevent it from jumping willy-nilly into anything that may be
around, which could cause damage. A metal fuselage will
take care of itself, but a composite fuselage , or long
radome, needs "channels" for this.

* Lightning is very dangerous for flagpole sitters.

Because the flow of the electric fields during a thunderstorm is so
unpredictable, the best that lightning rods can do is reduce the chances of
a damaging strike. *That they do. *What lightning rods also do, and not
mentioned above, is to bleed the ground charge into the air harmlessly
through the needle-sharp tip of the rod. *That reduces the voltage between
the ground and the cloud overhead and so further reduces the chances of a
lightning strike.

My recollection is that the above has been disproven. *For
one thing, given the huge distance between the cloud and
the air terminal, the fact that air is a decent insulator, and
the huge amount of energy involved, the amount of bleed-off
that could occur is negligible.

Personal experience says they do work. Back in the 30s and 40s
lightning rod salesmen were common out in the farming country. Lots
of people bought them. I never heard of a house with them being
hit...but then I never heard of a house without them being hit
either .

We had horrendous thunderstorms every summer back on the Camas Prarie
in
Central Idaho.

Harry K

On Thu, 24 Jan 2013 01:35:34 -0800 (PST), Robert
wrote:

On Jan 24, 2:05 am, nestork wrote:
I think that if there was good evidence that lightening rods DIDN'T
work, we would have heard about the controversy by now. If tall
building are all equipped with lightening rods, that's good enough
evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to
transfer all of that current around the house and into the ground. But,
I'd rather fry a $300 cable than have lightening set my house on fire.

I'd put one in if it wuz my house.

--
nestork

The current may be many thousands of amps, but it only lasts
for a few thousandths of a second. Consequently, the conductor
doesn't have to be massive since the short conduction time
means shorter heating time. Something like #6 wire is usually
enough, even tho it may carry an instantaneous 50,000 amps
or so. This can be confirmed by checking the size of the
grounding wire at your service entrance. Local codes and the NEC call
out the required size.
As far as a previous poster commenting on "bonding to the
structure", keep in mind that most houses have wood, non-conducting
construction, and that doesn't apply..... If the structure has steel
girders, it is another matter.
The cables on the old farm house were braided copper as thick as my
thumb -but loosely braded of roughly 16 guage wire with an open core
to allow good air cooling. After a heavy strike there was obvious
signs of heating (the oxide coating changed colour, and in some places
cracked)

On Jan 24, 2:05*am, nestork wrote:
I think that if there was good evidence that lightening rods DIDN'T
work, we would have heard about the controversy by now. *If tall
building are all equipped with lightening rods, that's good enough
evidence for me to believe they do work.

Obviously, you want to ensure that you have a pretty massive cable to
transfer all of that current around the house and into the ground. *But,
I'd rather fry a $300 cable than have lightening set my house on fire.

I'd put one in if it wuz my house.

--
nestork

Mr/Ms nestork,

Lightening is what Michael Jackson did to his skin, What comes outof
the sky with a flash of light and loud noises is lightning.

In article ,
wrote:

A lot of older houses had lightning rods on their roofs. Particularly
farm houses. They would have a thick braided cable that went to ground
rods. Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. Anything that is a high point in an area attracts
it, such as large trees. Of course metal attracts, so putting a metal
rod on a roof is an attractant. In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?


Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft static
discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a local
strike in the first place.

Erik

On Jan 24, 10:00 am, bud-- wrote:


Your comments on short duration are entirely right. But the NEC applies
to power systems, not lightning rod systems. (NFPA780 is the
installation standard for lighting rods.)

The average lighting strike is about 20,000A. About 5% are over
100,000A. Some are over 200,000A.

The numbers I have seen for down conductors are a little over #3 for
class 1 systems and over 1/0 for class 2. (I have no idea what the
difference between class 1 and 2 is.)

As far as a previous poster commenting on "bonding to the
structure", keep in mind that most houses have wood, non-conducting
construction, and that doesn't apply..... If the structure has steel
girders, it is another matter.

More than just structural steel. For commercial/industrial a rooftop
HVAC unit may have to be bonded if it is within 6 feet of the system
conductors. Cast iron plumbing stack? Service entrance riser? The point
was you can't effectively insulate the rod system from the building.

You're 100% right. Thanks for posting the NFPA780 reference,
which can be googled for some good information. I was thinking
of the grounding conductor at the service entrance panel, and
just guessed that it would be sufficient for a lighning strike....
I wuz wro..wrr.. wrooo...... mistaken......

On Jan 24, 5:02*pm, Erik wrote:
In article ,

wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft static
discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a local
strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. Conceptually it doesn't make
sense to me. Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. You put some
metal points about a foot higher on two spots on the
bottom plate. Now you start applying a charge to the
two plates. Are those two points going to do anything
to lessen the charge in any material way? Air is a pretty
good insulator, until it becomes ionized. And once that
occurs, we know what's going to happen.....

On Jan 24, 6:38*pm, "
wrote:
On Jan 24, 5:02*pm, Erik wrote:





In article ,

wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft static
discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a local
strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. *Conceptually it doesn't make
sense to me. *Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. *You put some
metal points about a foot higher on two spots on the
bottom plate. * Now you start applying a charge to the
two plates. *Are those two points going to do anything
to lessen the charge in any material way? *Air is a pretty
good insulator, until it becomes ionized. *And once that
occurs, we know what's going to happen.....- Hide quoted text -

- Show quoted text -

Something else to consider: There's cloud-to-ground discharges and
ground-to-cloud discharges. On a ground-to-cloud would the discharge
be from the roof rods? I've felt a ground vibration build up to where
it rattled dishes before the discharge happened. Thats a definite
ground to cloud discharge!

Another point though is discussion of the charge conductor - solid or
cable. Electrical charges travel on the surface of the conductor, not
through the center. A cable has multiple strands, each strand with
it's own surface. So a stranded cable provides more surface area &
more electrical discharge than a solid copper wire.

Another point is the roof lightning rods. The protection provided is
a 45 degree downward cone from each rod. So height of the rods above
the roof is important - short ones give very little surface area
protection whereas multiple higher ones can protect most of the roof.

On Friday 25 January 2013 02:50 Red wrote in alt.home.repair:

On Jan 24, 6:38 pm, "
wrote:
On Jan 24, 5:02 pm, Erik wrote:





In article ,

wrote:
A lot of older houses had lightning rods on their roofs.
Particularly farm houses. They would have a thick braided cable that
went to ground rods. Many of them had a glass ball in the center of
the copper rod.

I'm wondering of they really did any good. Sure, you want to ground
a strike, but on some ways, it would seem to me that they also could
attract lightning. Anything that is a high point in an area attracts
it, such as large trees. Of course metal attracts, so putting a
metal rod on a roof is an attractant. In a direct strike, I doubt
they would do anything, in fact they might get hot enough to start a
fire. But a discharge nearby could be sent to ground via the
lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft
static discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a
local strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. Conceptually it doesn't make
sense to me. Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. You put some
metal points about a foot higher on two spots on the
bottom plate. Now you start applying a charge to the
two plates. Are those two points going to do anything
to lessen the charge in any material way? Air is a pretty
good insulator, until it becomes ionized. And once that
occurs, we know what's going to happen.....- Hide quoted text -

- Show quoted text -

Something else to consider: There's cloud-to-ground discharges and
ground-to-cloud discharges. On a ground-to-cloud would the discharge
be from the roof rods? I've felt a ground vibration build up to where
it rattled dishes before the discharge happened. Thats a definite
ground to cloud discharge!

Another point though is discussion of the charge conductor - solid or
cable. Electrical charges travel on the surface of the conductor, not
through the center. A cable has multiple strands, each strand with
it's own surface. So a stranded cable provides more surface area &
more electrical discharge than a solid copper wire.

Isn't that applicable for high frequency AC (the skin effect)? For DC, bulk
matters.

Now, I agree that the duration of a lightning strike is short so the skin
effect may be relevant - but just for the sake of being precise...

However, bulk does provide thermal mass to prevent overheating for a given
I^2.t



Another point is the roof lightning rods. The protection provided is
a 45 degree downward cone from each rod. So height of the rods above
the roof is important - short ones give very little surface area
protection whereas multiple higher ones can protect most of the roof.
--
Tim Watts Personal Blog: http://www.dionic.net/tim/

"A fanatic is one who can't change his mind and won't change the subject."

On Jan 24, 9:50*pm, Red wrote:
On Jan 24, 6:38*pm, "
wrote:





On Jan 24, 5:02*pm, Erik wrote:

In article ,

wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft static
discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a local
strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. *Conceptually it doesn't make
sense to me. *Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. *You put some
metal points about a foot higher on two spots on the
bottom plate. * Now you start applying a charge to the
two plates. *Are those two points going to do anything
to lessen the charge in any material way? *Air is a pretty
good insulator, until it becomes ionized. *And once that
occurs, we know what's going to happen.....- Hide quoted text -

- Show quoted text -

Something else to consider: There's cloud-to-ground discharges and
ground-to-cloud discharges. *On a ground-to-cloud would the discharge
be from the roof rods? *I've felt a ground vibration build up to where
it rattled dishes before the discharge happened. *Thats a definite
ground to cloud discharge!

Another point though is discussion of the charge conductor - solid or
cable. *Electrical charges travel on the surface of the conductor, not
through the center.

That is true for high frequencies, not DC. The depth the
current penetrates below the surface of a conductor
decreases as the frequency increases. At say 60hz,
the penetration is deep enough that it's not a factor in the conductor
gauges used for typical wiring and the current
can be assumed to be carried throughout the entire
conductor.

I don't know what the frequency profile of a lightning
strike looks like, but would suspect it has a broad range
of frequency components to it, so there likely is some
skin effect involved, but I doubt anywhere near all the
current travels only close to the surface.






*A cable has multiple strands, each strand with
it's own surface. *So a stranded cable provides more surface area &
more electrical discharge than a solid copper wire.

Another point is the roof lightning rods. *The protection provided is
a 45 degree downward cone from each rod. *So height of the rods above
the roof is important - short ones give very little surface area
protection whereas multiple higher ones can protect most of the roof.- Hide quoted text -

- Show quoted text -

On Fri, 25 Jan 2013 06:11:39 -0800 (PST), "
wrote:

On Jan 24, 9:50*pm, Red wrote:
On Jan 24, 6:38*pm, "
wrote:





On Jan 24, 5:02*pm, Erik wrote:

In article ,

wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft static
discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a local
strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. *Conceptually it doesn't make
sense to me. *Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. *You put some
metal points about a foot higher on two spots on the
bottom plate. * Now you start applying a charge to the
two plates. *Are those two points going to do anything
to lessen the charge in any material way? *Air is a pretty
good insulator, until it becomes ionized. *And once that
occurs, we know what's going to happen.....- Hide quoted text -

- Show quoted text -

Something else to consider: There's cloud-to-ground discharges and
ground-to-cloud discharges. *On a ground-to-cloud would the discharge
be from the roof rods? *I've felt a ground vibration build up to where
it rattled dishes before the discharge happened. *Thats a definite
ground to cloud discharge!

Another point though is discussion of the charge conductor - solid or
cable. *Electrical charges travel on the surface of the conductor, not
through the center.

That is true for high frequencies, not DC. The depth the
current penetrates below the surface of a conductor
decreases as the frequency increases. At say 60hz,
the penetration is deep enough that it's not a factor in the conductor
gauges used for typical wiring and the current
can be assumed to be carried throughout the entire
conductor.

I don't know what the frequency profile of a lightning
strike looks like, but would suspect it has a broad range
of frequency components to it, so there likely is some
skin effect involved, but I doubt anywhere near all the
current travels only close to the surface.

OTOH, like charges repell. At these current densities it does matter.

On Jan 24, 7:50*pm, Red wrote:
...snip....
Another point though is discussion of the charge conductor - solid or
cable. *Electrical charges travel on the surface of the conductor, not
through the center. *A cable has multiple strands, each strand with
it's own surface. *So a stranded cable provides more surface area &
more electrical discharge than a solid copper wire.

...snip....

Not true. Purge that thought from your memory. If the stranded cable
is made of uninsulated conductors, the electromagnetic forces will
successfully move all the conduction to the outside of the cable.
Thus, the conductor areas on the inside will still carry almost no
current, similar to what happens in the solid conductor. If the
'wires' all all insulated, wrapped in a simple twist pattern, and
connected in parallel at their ends; the impedance is NOT as low as
your thought process would expect. The impedance IS a bit lower with
insulated conductors placed randomly into a bundle, called Litz wire.
However, if the goal is to connect two points together with the lowest
impedance possible; make certain the connection is wider than long.
Then you have a chance at low impedance between the two points.

If you want to explore for yourself and not suffer through all the
equations, download a free copy of a finite element analysis program
called femm 4.2 Any trouble trying to use the program, the user group
is extremely knowledgeable, fast, and helpful.

On Jan 25, 8:27*am, Robert Macy wrote:

Not true. Purge that thought from your memory. If the stranded cable
is made of uninsulated conductors, the electromagnetic forces will
successfully move all the conduction to the outside of the cable.
Thus, the conductor areas on the inside will still carry almost no
current, similar to what happens in the solid conductor. If the
'wires' all all insulated, wrapped in a simple twist pattern, and
connected in parallel at their ends; the impedance is NOT as low as
your thought process would expect.

It's not my thought process, it's the knowledge I was taught when I
installed lightning protection systems. And the cable wasn't just a
standard twisted strand, it was more of a woven type which might have
had some different characteristics. I would assume the thought
process came from engineers who designed the materials used in
lightning protection.

On Jan 25, 9:21*am, wrote:
On Fri, 25 Jan 2013 06:11:39 -0800 (PST), "





wrote:
On Jan 24, 9:50*pm, Red wrote:
On Jan 24, 6:38*pm, "
wrote:

On Jan 24, 5:02*pm, Erik wrote:

In article ,

wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft static
discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a local
strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. *Conceptually it doesn't make
sense to me. *Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. *You put some
metal points about a foot higher on two spots on the
bottom plate. * Now you start applying a charge to the
two plates. *Are those two points going to do anything
to lessen the charge in any material way? *Air is a pretty
good insulator, until it becomes ionized. *And once that
occurs, we know what's going to happen.....- Hide quoted text -

- Show quoted text -

Something else to consider: There's cloud-to-ground discharges and
ground-to-cloud discharges. *On a ground-to-cloud would the discharge
be from the roof rods? *I've felt a ground vibration build up to where
it rattled dishes before the discharge happened. *Thats a definite
ground to cloud discharge!

Another point though is discussion of the charge conductor - solid or
cable. *Electrical charges travel on the surface of the conductor, not
through the center.

That is true for high frequencies, not DC. *The depth the
current penetrates below the surface of a conductor
decreases as the frequency increases. *At say 60hz,
the penetration is deep enough that it's not a factor in the conductor
gauges used for typical wiring and the current
can be assumed to be carried throughout the entire
conductor.

I don't know what the frequency profile of a lightning
strike looks like, but would suspect it has a broad range
of frequency components to it, so there likely is some
skin effect involved, but I doubt anywhere near all the
current travels only close to the surface.

OTOH, like charges repell. *At these current densities it does matter.- Hide quoted text -

- Show quoted text -

Then kindly provide us a formula that shows that skin
effect applies to DC moving through a conductor at high
currents. Or a reference that shows that this phenomena
exists. FYI, high current does not imply a build-up of charge
within a conductor. It's just the faster movement of
electrons that are already there.

On 1/24/2013 8:50 PM, Red wrote:

Another point though is discussion of the charge conductor - solid or
cable. Electrical charges travel on the surface of the conductor, not
through the center. A cable has multiple strands, each strand with
it's own surface. So a stranded cable provides more surface area&
more electrical discharge than a solid copper wire.

I agree with Robert Macy.

I believe hams like flat braid (like a flat stranded wire) for
conductors that may carry high lighting currents.


Another point is the roof lightning rods. The protection provided is
a 45 degree downward cone from each rod. So height of the rods above
the roof is important - short ones give very little surface area
protection whereas multiple higher ones can protect most of the roof.


Far as I know, the current design technique is to roll a sphere with a
radius of 30m over the building and surroundings. The sphere stays on
top of the rods. If the sphere touches the building, lightning can
strike there.

You likely need fewer rods with the sphere design than the cone design.
But if you transport the Empire State building to the middle of
Nebraska, with no surrounding buildings, lightning can hit the side of
the building. Sides of buildings may also need lighting protection.

On Fri, 25 Jan 2013 07:17:34 -0800 (PST), Red
wrote:

On Jan 25, 8:27*am, Robert Macy wrote:

Not true. Purge that thought from your memory. If the stranded cable
is made of uninsulated conductors, the electromagnetic forces will
successfully move all the conduction to the outside of the cable.
Thus, the conductor areas on the inside will still carry almost no
current, similar to what happens in the solid conductor. If the
'wires' all all insulated, wrapped in a simple twist pattern, and
connected in parallel at their ends; the impedance is NOT as low as
your thought process would expect.

It's not my thought process, it's the knowledge I was taught when I
installed lightning protection systems. And the cable wasn't just a
standard twisted strand, it was more of a woven type which might have
had some different characteristics. I would assume the thought
process came from engineers who designed the materials used in
lightning protection.
Correct, Red. Robert has obviously not installed them and likely has
neve seen an installation up close.

ALL of the farm lightning rod systems I've ever seen have used the
looase braid copper cable.(Class 1)

See: http://www.kuefler-lightning.com/ser...conductors.htm
OR:
http://www.tlpinc.com/products/condu...lass/506T.html

On Jan 25, 4:35*am, Tim Watts wrote:
On Friday 25 January 2013 02:50 Red wrote in alt.home.repair:





On Jan 24, 6:38 pm, "
wrote:
On Jan 24, 5:02 pm, Erik wrote:

In article ,

wrote:
A lot of older houses had lightning rods on their roofs.
Particularly farm houses. *They would have a thick braided cable that
went to ground rods. *Many of them had a glass ball in the center of
the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground
a strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a
metal rod on a roof is an attractant. *In a direct strike, I doubt
they would do anything, in fact they might get hot enough to start a
fire. *But a discharge nearby could be sent to ground via the
lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft
static discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a
local strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. *Conceptually it doesn't make
sense to me. *Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. *You put some
metal points about a foot higher on two spots on the
bottom plate. * Now you start applying a charge to the
two plates. *Are those two points going to do anything
to lessen the charge in any material way? *Air is a pretty
good insulator, until it becomes ionized. *And once that
occurs, we know what's going to happen.....- Hide quoted text -

- Show quoted text -

Something else to consider: There's cloud-to-ground discharges and
ground-to-cloud discharges. *On a ground-to-cloud would the discharge
be from the roof rods? *I've felt a ground vibration build up to where
it rattled dishes before the discharge happened. *Thats a definite
ground to cloud discharge!

Another point though is discussion of the charge conductor - solid or
cable. *Electrical charges travel on the surface of the conductor, not
through the center. *A cable has multiple strands, each strand with
it's own surface. *So a stranded cable provides more surface area &
more electrical discharge than a solid copper wire.

Isn't that applicable for high frequency AC (the skin effect)? For DC, bulk
matters.

Now, I agree that the duration of a lightning strike is short so the skin
effect may be relevant - but just for the sake of being precise...


I with you on the above. It's exactly what I said in
another post.

On Fri, 25 Jan 2013 07:19:46 -0800 (PST), "
wrote:

On Jan 25, 9:21*am, wrote:
On Fri, 25 Jan 2013 06:11:39 -0800 (PST), "





wrote:
On Jan 24, 9:50*pm, Red wrote:
On Jan 24, 6:38*pm, "
wrote:

On Jan 24, 5:02*pm, Erik wrote:

In article ,

wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft static
discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a local
strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. *Conceptually it doesn't make
sense to me. *Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. *You put some
metal points about a foot higher on two spots on the
bottom plate. * Now you start applying a charge to the
two plates. *Are those two points going to do anything
to lessen the charge in any material way? *Air is a pretty
good insulator, until it becomes ionized. *And once that
occurs, we know what's going to happen.....- Hide quoted text -

- Show quoted text -

Something else to consider: There's cloud-to-ground discharges and
ground-to-cloud discharges. *On a ground-to-cloud would the discharge
be from the roof rods? *I've felt a ground vibration build up to where
it rattled dishes before the discharge happened. *Thats a definite
ground to cloud discharge!

Another point though is discussion of the charge conductor - solid or
cable. *Electrical charges travel on the surface of the conductor, not
through the center.

That is true for high frequencies, not DC. *The depth the
current penetrates below the surface of a conductor
decreases as the frequency increases. *At say 60hz,
the penetration is deep enough that it's not a factor in the conductor
gauges used for typical wiring and the current
can be assumed to be carried throughout the entire
conductor.

I don't know what the frequency profile of a lightning
strike looks like, but would suspect it has a broad range
of frequency components to it, so there likely is some
skin effect involved, but I doubt anywhere near all the
current travels only close to the surface.

OTOH, like charges repell. *At these current densities it does matter.- Hide quoted text -

- Show quoted text -

Then kindly provide us a formula that shows that skin
effect applies to DC moving through a conductor at high
currents. Or a reference that shows that this phenomena
exists. FYI, high current does not imply a build-up of charge
within a conductor. It's just the faster movement of
electrons that are already there.

A lightning strike doesn't add electrons to the wire? Go figgr.

On Jan 25, 12:42*pm, wrote:
On Fri, 25 Jan 2013 07:19:46 -0800 (PST), "





wrote:
On Jan 25, 9:21*am, wrote:
On Fri, 25 Jan 2013 06:11:39 -0800 (PST), "

wrote:
On Jan 24, 9:50*pm, Red wrote:
On Jan 24, 6:38*pm, "
wrote:

On Jan 24, 5:02*pm, Erik wrote:

In article ,

wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft static
discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a local
strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. *Conceptually it doesn't make
sense to me. *Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. *You put some
metal points about a foot higher on two spots on the
bottom plate. * Now you start applying a charge to the
two plates. *Are those two points going to do anything
to lessen the charge in any material way? *Air is a pretty
good insulator, until it becomes ionized. *And once that
occurs, we know what's going to happen.....- Hide quoted text -

- Show quoted text -

Something else to consider: There's cloud-to-ground discharges and
ground-to-cloud discharges. *On a ground-to-cloud would the discharge
be from the roof rods? *I've felt a ground vibration build up to where
it rattled dishes before the discharge happened. *Thats a definite
ground to cloud discharge!

Another point though is discussion of the charge conductor - solid or
cable. *Electrical charges travel on the surface of the conductor, not
through the center.

That is true for high frequencies, not DC. *The depth the
current penetrates below the surface of a conductor
decreases as the frequency increases. *At say 60hz,
the penetration is deep enough that it's not a factor in the conductor
gauges used for typical wiring and the current
can be assumed to be carried throughout the entire
conductor.

I don't know what the frequency profile of a lightning
strike looks like, but would suspect it has a broad range
of frequency components to it, so there likely is some
skin effect involved, but I doubt anywhere near all the
current travels only close to the surface.

OTOH, like charges repell. *At these current densities it does matter.- Hide quoted text -

- Show quoted text -

Then kindly provide us a formula that shows that skin
effect applies to DC moving through a conductor at high
currents. *Or a reference that shows that this phenomena
exists. * FYI, high current does not imply a build-up of charge
within a conductor. * It's just the faster movement of
electrons that are already there.

A lightning strike doesn't add electrons to the wire? *Go figgr.- Hide quoted text -

- Show quoted text -

Not in any amounts that create the effect you're claiming.
Electrons moving through a wire are like water flowing
through a pipe. If you double the flow rate of the water,
do you increase the amount of water in the pipe? No you
still have the same amount of water in the pipe at any
point in time, it's just moving through it faster
Same thing with current through a wire. You're pushing
electrons in one end and some other electrons come
out the other end of the wire.

If you still believe you're correct, ie that skin effect exists
in a conductor for DC as current increases, it should be
easy to find the formula that expresses it. The only skin
effect I know of is always discussed as only applying to AC
because you need a changing field to create it. The
changing field doesn't exist with DC. And the skin depth
effect varies as a function of the frequency and can be
expressed in a formula. Put zero in for frequency
in the formula and you get infinite skin depth.

Disclaimer: I'm not saying skin effect isn't of importance
in a lightning strike. I said that I believe it is, because
lightning has a fast rise time, so clearly it has high freq
components to it. I'm only saying DC current in a
conductor is evenly distributed.

On Jan 25, 10:57*am, "
wrote:
On Jan 25, 12:42*pm, wrote:





On Fri, 25 Jan 2013 07:19:46 -0800 (PST), "

wrote:
On Jan 25, 9:21*am, wrote:
On Fri, 25 Jan 2013 06:11:39 -0800 (PST), "

wrote:
On Jan 24, 9:50*pm, Red wrote:
On Jan 24, 6:38*pm, "
wrote:

On Jan 24, 5:02*pm, Erik wrote:

In article ,

wrote:
A lot of older houses had lightning rods on their roofs. *Particularly
farm houses. *They would have a thick braided cable that went to ground
rods. *Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. *Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. *Anything that is a high point in an area attracts
it, such as large trees. *Of course metal attracts, so putting a metal
rod on a roof is an attractant. *In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. *But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft static
discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a local
strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. *Conceptually it doesn't make
sense to me. *Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. *You put some
metal points about a foot higher on two spots on the
bottom plate. * Now you start applying a charge to the
two plates. *Are those two points going to do anything
to lessen the charge in any material way? *Air is a pretty
good insulator, until it becomes ionized. *And once that
occurs, we know what's going to happen.....- Hide quoted text -

- Show quoted text -

Something else to consider: There's cloud-to-ground discharges and
ground-to-cloud discharges. *On a ground-to-cloud would the discharge
be from the roof rods? *I've felt a ground vibration build up to where
it rattled dishes before the discharge happened. *Thats a definite
ground to cloud discharge!

Another point though is discussion of the charge conductor - solid or
cable. *Electrical charges travel on the surface of the conductor, not
through the center.

That is true for high frequencies, not DC. *The depth the
current penetrates below the surface of a conductor
decreases as the frequency increases. *At say 60hz,
the penetration is deep enough that it's not a factor in the conductor
gauges used for typical wiring and the current
can be assumed to be carried throughout the entire
conductor.

I don't know what the frequency profile of a lightning
strike looks like, but would suspect it has a broad range
of frequency components to it, so there likely is some
skin effect involved, but I doubt anywhere near all the
current travels only close to the surface.

OTOH, like charges repell. *At these current densities it does matter.- Hide quoted text -

- Show quoted text -

Then kindly provide us a formula that shows that skin
effect applies to DC moving through a conductor at high
currents. *Or a reference that shows that this phenomena
exists. * FYI, high current does not imply a build-up of charge
within a conductor. * It's just the faster movement of
electrons that are already there.

A lightning strike doesn't add electrons to the wire? *Go figgr.- Hide quoted text -

- Show quoted text -

Not in any amounts that create the effect you're claiming.
Electrons moving through a wire are like water flowing
through a pipe. *If you double the flow rate of the water,
do you increase the amount of water in the pipe? *No you
still have the same amount of water in the pipe at any
point in time, *it's just moving through it faster
Same thing with current through a wire. *You're pushing
electrons in one end and some other electrons come
out the other end of the wire.

If you still believe you're correct, ie that skin effect exists
in a conductor for DC as current increases, it should be
easy to find the formula that expresses it. * The only skin
effect I know of is always discussed as only applying to AC
because you need a changing field to create it. *The
changing field doesn't exist with DC. *And the skin depth
effect varies as a function of the frequency and can be
expressed in a formula. * Put zero in for frequency
in the formula and you get infinite skin depth.

Disclaimer: *I'm not saying skin effect isn't of importance
in a lightning strike. *I said that I believe it is, because
lightning has a fast rise time, so clearly it has high freq
components to it. *I'm only saying DC current in a
conductor is evenly distributed.

You are absolutely correct. DC Current demonstrates NO skin effect.
The conductance carriers are distributed uniformly across the profile
of the conductor. of course, uniform in the absence of an external
field. The earth's field at 50uT is too small to notice much.

However, it is worth noting that DC current is an approximation.
Cannot truly exist because it was not always flowing. Actually, every
current is AC, just a matter of the degree of how slow you want to
consider the frequency to be.

On Jan 25, 10:00*am, wrote:
On Fri, 25 Jan 2013 07:17:34 -0800 (PST), Red
wrote:





On Jan 25, 8:27*am, Robert Macy wrote:

Not true. Purge that thought from your memory. If the stranded cable
is made of uninsulated conductors, the electromagnetic forces will
successfully move all the conduction to the outside of the cable.
Thus, the conductor areas on the inside will still carry almost no
current, similar to what happens in the solid conductor. If the
'wires' all all insulated, wrapped in a simple twist pattern, and
connected in parallel at their ends; the impedance is NOT as low as
your thought process would expect.

It's not my thought process, it's the knowledge I was taught when I
installed lightning protection systems. *And the cable wasn't just a
standard twisted strand, it was more of a woven type which might have
had some different characteristics. *I would assume the thought
process came from engineers who designed the materials used in
lightning protection.

*Correct, Red. Robert has obviously not installed them and likely has
neve seen an installation up close.

ALL of the farm lightning rod systems I've ever seen have used the
looase braid copper cable.(Class 1)

See:http://www.kuefler-lightning.com/ser...conductors.htm
OR:http://www.tlpinc.com/products/condu...tors/main-size....

Thank you for those two URL's

ALL the cables from these two sources appear to have bare, uninsulated
strands.

Near DC, these cables are probably only 40% higher impedance than
solid cable of the same diameter. Being a bundle of uninsulated
strands, they will still have high impedance caused by skin effect. At
initial inrush, during the fast transient of a strike, the conducting
carriers will still move to the outside of the stranded bundle and be
restricted to a small region around the outside edges. Picture a
'tube' of current going along the cable.

There will NOT be an overall lowering of impedance at higher frequency
because the cable has 17 strands in it.

The main advantage of stranded cable? Easily made, easily bent. As in
good luck working with a cable that is that large in diameter and is
therefore a solid rod.

The large diameter has an advantage of strength. Its strength will
help during a discharge to prevent the cabling from launching itself
off the building as it tries to straighten out.

An example of wire straightening out during high current flow of a
discharge was very noticeable in a piece of test equipment I once
built for testing telecom equipment. Telecom equipment usually takes
-48Vdc. Four 12 V batteries. To test telecom equipment against surges
in their power supply, simulating the event of someone dropping a
wrench across the bare distribution cables, I put a 50 foot length of
0000 cable loosely coiled on the floor between the batteries and the
telecom equipment. Then in parallel to the equipment I placed a
starter solenoid in series with a 3AG 1A FB fuse [small glass tube
with a tiny wire in it] Activating the solenoid put all 48 volts
across the little fuse [no pun intended] and it quickly blew out,
going off much like a flash bulb. The momentary short would draw up to
500 Amps that after the fuse had blown would then try to go through
the telecom equipment attached next to it. If the current couldn't go
through, the voltage would quickly climb to over 300 to 500 volts and
literally blast its way in trying to supply 500A. The extremely heavy
cable would jump up off the floor as it tried to straighten out. Now
that was only 500A. Imagine the 'straightening' power of 20,000 Amps!

On Jan 25, 8:17*am, Red wrote:
On Jan 25, 8:27*am, Robert Macy wrote:



Not true. Purge that thought from your memory. If the stranded cable
is made of uninsulated conductors, the electromagnetic forces will
successfully move all the conduction to the outside of the cable.
Thus, the conductor areas on the inside will still carry almost no
current, similar to what happens in the solid conductor. If the
'wires' all all insulated, wrapped in a simple twist pattern, and
connected in parallel at their ends; the impedance is NOT as low as
your thought process would expect.

It's not my thought process, it's the knowledge I was taught when I
installed lightning protection systems. *And the cable wasn't just a
standard twisted strand, it was more of a woven type which might have
had some different characteristics. *I would assume the thought
process came from engineers who designed the materials used in
lightning protection.

I understand. But remember that *if* you take 17 strands of a small
diameter wire, combine them into a bundle, near DC the overall cable
will act like 17 wires in parallel and have lowered impedance, but at
high frequency the new bundle of 17 wires will not act like 17 wires
in parallel, but rather act much like a large diameter, somewhat solid
cable.

The only way to connect two points with a really low impedance is to
make the connection WIDER than LONG. Then you have a shot at lowered
impedance. And, that even means making the connection wider than you
think necessary, like 2X wider. Then your connection becomes very low
impedance acting much like a ground plane, very low impedance. Else,
if connection is longer than wide, you have an inductor. And as you
know, for an inductor it will not pass any appreciable current for a
short bit of time, no matter how large a voltage you slap across it.

You can kind of cheat a bit and approximate a wide connection by using
several connectors. That is why a well bonded wire grid structure
protects buildings/structures so well. The connections, albeit not
solid over the whole width, help lower the impedance of the connection
by making it wider than long.

" wrote:
On Jan 25, 12:42 pm, wrote:
On Fri, 25 Jan 2013 07:19:46 -0800 (PST), "





wrote:
On Jan 25, 9:21 am, wrote:
On Fri, 25 Jan 2013 06:11:39 -0800 (PST), "

wrote:
On Jan 24, 9:50 pm, Red wrote:
On Jan 24, 6:38 pm, "
wrote:

On Jan 24, 5:02 pm, Erik wrote:

In article ,

wrote:
A lot of older houses had lightning rods on their roofs. Particularly
farm houses. They would have a thick braided cable that went to ground
rods. Many of them had a glass ball in the center of the copper rod.

I'm wondering of they really did any good. Sure, you want to ground a
strike, but on some ways, it would seem to me that they also could
attract lightning. Anything that is a high point in an area attracts
it, such as large trees. Of course metal attracts, so putting a metal
rod on a roof is an attractant. In a direct strike, I doubt they would
do anything, in fact they might get hot enough to start a fire. But a
discharge nearby could be sent to ground via the lightning rods.

One other thing, was there any usefulness to the glass balls in the
middle, or were they strictly decorations?

Years ago I recall watching a lightning study documentary... and IIRC,
they suggested that arrays of smaller sharp devices like aircraft static
discharge wicks might be superior.

Not that they dealt with strikes well, but were efficient at quickly
bleeding off local atmospheric electric charges, thus preventing a local
strike in the first place.

Erik

I think the idea that lightning rods bleed off atmospheric
charges has been disproven. Conceptually it doesn't make
sense to me. Consider two huge metal plates, say a city
block size in area, seperated by 2000 ft of air.. You put some
metal points about a foot higher on two spots on the
bottom plate. Now you start applying a charge to the
two plates. Are those two points going to do anything
to lessen the charge in any material way? Air is a pretty
good insulator, until it becomes ionized. And once that
occurs, we know what's going to happen.....- Hide quoted text -

- Show quoted text -

Something else to consider: There's cloud-to-ground discharges and
ground-to-cloud discharges. On a ground-to-cloud would the discharge
be from the roof rods? I've felt a ground vibration build up to where
it rattled dishes before the discharge happened. Thats a definite
ground to cloud discharge!

Another point though is discussion of the charge conductor - solid or
cable. Electrical charges travel on the surface of the conductor, not
through the center.

That is true for high frequencies, not DC. The depth the
current penetrates below the surface of a conductor
decreases as the frequency increases. At say 60hz,
the penetration is deep enough that it's not a factor in the conductor
gauges used for typical wiring and the current
can be assumed to be carried throughout the entire
conductor.

I don't know what the frequency profile of a lightning
strike looks like, but would suspect it has a broad range
of frequency components to it, so there likely is some
skin effect involved, but I doubt anywhere near all the
current travels only close to the surface.

OTOH, like charges repell. At these current densities it does
matter.- Hide quoted text -

- Show quoted text -

Then kindly provide us a formula that shows that skin
effect applies to DC moving through a conductor at high
currents. Or a reference that shows that this phenomena
exists. FYI, high current does not imply a build-up of charge
within a conductor. It's just the faster movement of
electrons that are already there.

A lightning strike doesn't add electrons to the wire? Go figgr.- Hide quoted text -

- Show quoted text -

Not in any amounts that create the effect you're claiming.
Electrons moving through a wire are like water flowing
through a pipe. If you double the flow rate of the water,
do you increase the amount of water in the pipe? No you
still have the same amount of water in the pipe at any
point in time, it's just moving through it faster
Same thing with current through a wire. You're pushing
electrons in one end and some other electrons come
out the other end of the wire.

If you still believe you're correct, ie that skin effect exists
in a conductor for DC as current increases, it should be
easy to find the formula that expresses it. The only skin
effect I know of is always discussed as only applying to AC
because you need a changing field to create it. The
changing field doesn't exist with DC. And the skin depth
effect varies as a function of the frequency and can be
expressed in a formula. Put zero in for frequency
in the formula and you get infinite skin depth.

Disclaimer: I'm not saying skin effect isn't of importance
in a lightning strike. I said that I believe it is, because
lightning has a fast rise time, so clearly it has high freq
components to it. I'm only saying DC current in a
conductor is evenly distributed.

I think the thing to remember, DC has no skin effect with a steady state or
slow rate changes. A spike has frequency content. Instantaneous changes
have frequency. Never thought about this before except in the case of
electronic filtering.

Greg

Robert Macy wrote:
On Jan 25, 8:17 am, Red wrote:
On Jan 25, 8:27 am, Robert Macy wrote:



Not true. Purge that thought from your memory. If the stranded cable
is made of uninsulated conductors, the electromagnetic forces will
successfully move all the conduction to the outside of the cable.
Thus, the conductor areas on the inside will still carry almost no
current, similar to what happens in the solid conductor. If the
'wires' all all insulated, wrapped in a simple twist pattern, and
connected in parallel at their ends; the impedance is NOT as low as
your thought process would expect.

It's not my thought process, it's the knowledge I was taught when I
installed lightning protection systems. And the cable wasn't just a
standard twisted strand, it was more of a woven type which might have
had some different characteristics. I would assume the thought
process came from engineers who designed the materials used in
lightning protection.

I understand. But remember that *if* you take 17 strands of a small
diameter wire, combine them into a bundle, near DC the overall cable
will act like 17 wires in parallel and have lowered impedance, but at
high frequency the new bundle of 17 wires will not act like 17 wires
in parallel, but rather act much like a large diameter, somewhat solid
cable.

The only way to connect two points with a really low impedance is to
make the connection WIDER than LONG. Then you have a shot at lowered
impedance. And, that even means making the connection wider than you
think necessary, like 2X wider. Then your connection becomes very low
impedance acting much like a ground plane, very low impedance. Else,
if connection is longer than wide, you have an inductor. And as you
know, for an inductor it will not pass any appreciable current for a
short bit of time, no matter how large a voltage you slap across it.

You can kind of cheat a bit and approximate a wide connection by using
several connectors. That is why a well bonded wire grid structure
protects buildings/structures so well. The connections, albeit not
solid over the whole width, help lower the impedance of the connection
by making it wider than long.

The only way to have a bunch of conductors bundled, is to insulate each to
prevent interaction. Except it must withstand, how many volts !!!! Even
insulated, stranding close to other strands will have interaction
nullifying what your trying to do.

The cables I have seen on buildings are stranded aluminum at least 3/4 inch
in diameter.

Greg