Lightning rods still needed?
Wubba
metal roof.
My question is this: We "currently" <G> have the original lightning rods up
on the roof peaks, and chimney (chembley if you're from Appalachian Ohio)...
Does today's technology suggest that they are still needed, or has it been
proven that they actually draw lightning strikes, or are useless?...
Roofer says they are "old technology"...and I assume he's right, but I
wanted to ask the sages here before we pitch em out...
TIA,
Wendy Hannum
JimMcCarty
I don't know about the "technology" of them, but I know people that have
them and swear by them. I know people that recommend them even though
they don't have them themselves. And I know you can still buy them as
opposed to some things that technology as made obsolete. Saw the for
sale at Rural King the other day.
If nothing else I'd put them back on to keep the house looking origianl
and for the nostalgia. Especially if it is a very tall two story farm
house.
--
Jim McCarty
Sent via Deja.com http://www.deja.com/
Before you buy.
Lou Boyd
>
> We are about to have our 50 yr old farm house re-roofed with another fine
> metal roof.
>
> My question is this: We "currently" <G> have the original lightning rods up
> on the roof peaks, and chimney (chembley if you're from Appalachian Ohio)...
> Does today's technology suggest that they are still needed, or has it been
> proven that they actually draw lightning strikes, or are useless?...
>
> Roofer says they are "old technology"...and I assume he's right, but I
> wanted to ask the sages here before we pitch em out...
I suppose 50 years is long enough to keep a house. Go ahead and remove
the lightning rods and let the house burn down if lightning hits it.
Does your roofer think that "new technology" is simply having fire
insurance? What is he recommending?
Lightning rods do not "draw lightning". What they do is provide a path
for the current to flow to ground through the wire instead of through
the wood in your house. The pointed spikes will only make a local
difference of a few feet in where the lightning strikes but they do help
some. Lightning rods make almost no difference in the number of times
your house will get hit. They make a big difference in how much damage
will be done when your house is hit.
A lot of houses don't have lightning rods. A lot of houses don't get
hit by lightning because of their location. Some don't have protection
and get hit but a lightning strike doesn't necessarily cause a fire.
And having lighting rods and ground wires doesn't even guarantee the
lighting will hit the wire instead of the flat shingled roof and still
start a fire. They do improve the probablility that your house won't be
damaged or distroyed if hit by lightning, probably by a factor of about
5 to ten times.
I don't have lightning rods on my house and it has frame
construction. It's at the base of a 300 foot hill and extremely
unlikely to be hit. My observatory gets hit a couple of times a year.
It's on a mountain peak. The buildings there don't have lightning rods
either but they are all metal construction with copper ring grounds
surrounding them and have transient suppressors on all wires ( power
feeds) which enter the building. Some damage to electronic equipment
can still occur because of induced voltages from the intense magnetic
field associated with the lightning strikes, but it's minimal.
I've designed lighting protection systems for a number of mountaintop
microwave repeater sites and astronmical observatories where lightning
strikes happen several time per year. The objective is to minimize the
overall cost. Spending more on a protection system than will be
damaged over a 30 year period makes no sense. Metal buildings provide
protection without special protection other than grounding. But on a
frame farmhouse in an exposed location having lighting rods and their
associated ground wires is inexpensive insurance. Don't remove your
lighting rods. Do inspect them and make certain that the bonding wire
is intact, that it runs continuously along the peak of your roof, and
that it is properly grounded, preferably to a driven ground rod at each
end of your house. The ground wire should be straight and vertical with
no loops or severe kinks. Without the ground wire(s) the lighting rods
give no protection.
--
Lou Boyd
Fairborn Observatory
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Dmdolrodeo
>on the roof peaks, and chimney (chembley if you're from Appalachian Ohio)...
That reminds me of being corrected as a kid:
Chim-NEE is on the house
Chim-LEE does the laundry!
See you in the short go!
dmdol...@aol.com
(It's that damned ol' rodeo!)
Shawn Turner
Wubba wrote in message ...
>My question is this: We "currently" <G> have the original lightning rods up
>on the roof peaks, and chimney (chembley if you're from Appalachian Ohio)...
>proven that they actually draw lightning strikes, or are useless?...
My opinion is probably. If your house is the highest point for miles around
yes. If your house is in the shadow of the Eiffel Tower, no-the tower is a far
better l.r. than you can pay for.
There's this famous old tree somewhere that has a lightning rod on it, I was
surprised by how many hits the news story said it took per year, none of which
blow the tree to splinters because of the lightning rod. (I'm thinking a "tree"
and "Whitehouse"?)
That lightning is going to take the easiest way it can to ground itself, and
what that is varies as the storm moves, if there will not _always_ be a path
that is better than through your house yes, you need.
My brother told me that the wire leading from the quite nice looking lightning
rod we put back up after we re-roofed turn white hot after a lightning strike.-
I can verify that the flash and boom were simultaneous and scared the crap
out of me because it sounded like the end of the world was starting six feet
above me but I don't know what he was doing outside.
>Roofer says they are "old technology"...and I assume he's right, but I
>wanted to ask the sages here before we pitch em out...
<Shrug>, so are drinking glasses. And knives. And flintlocks muskets.
Me, make him put them back. Historical, decorative.
If he doesn't say "[Sure, your dime]" get a weather vane, make him put that
up, and during the first heavy rain you have after he says he's done shine a
bright flashlight around your attic, special attention to were the weathervane,
lightning rod, possibly vents and chimneys are. Shiny spots means leak
means dude's crew does not know how to flash uhm, I mean know how to
apply flashing around *.* to keep the rain out and you will need to improve
his business by making him learn/teach them. (Brick chimbley where the
roof rafters are totally independent of the chembley are real tough, but can
be done-two mating parts, inside one seals to the roof, outside one seals
to the chimney).
Repeat that attic check about monthly for the next year (weather changes
can be a prob-a few inches of snow can rip the tar seam open) and it's
been a few years since I have (I gotta start a to do list.), and we all do need
to do this every couple years.
Shawn T
Spamblock: My e-mail address is not a barnyard.
Larry Caldwell
> We are about to have our 50 yr old farm house re-roofed with another fine
> metal roof.
> on the roof peaks, and chimney (chembley if you're from Appalachian Ohio)...
> Does today's technology suggest that they are still needed, or has it been
> proven that they actually draw lightning strikes, or are useless?...
> wanted to ask the sages here before we pitch em out...
Lightning rods don't draw lightning, they bleed off the charge before
lightning can strike. The sharp point of a lighning rod causes
electrolyte breakdown of the air, and the rod bleeds electrons into the
atmosphere. From time to time you can actually see corona discharge
around the points of lightning rods.
Far from being old technology, they are still the most effective way of
protecting homes and electronic equipment from lightning strikes.
However, weathering can dull the point on the rod. Take a close look at
the point, and if it is dull you can sharpen it and re-tin it, or just
clamp a sharpened piece of copper, stainless steel, or other conductive
metal onto the existing rod so there is good contact.
Also check the ground wire and ground rods. Lightning rods need good
direct contact to ground if they are going to work right.
-- Larry
Chuck Dunn
impressive array of lightening rods. I think they are charming as well
as protective.
Chuck
wmbjk
"Wubba" <we...@SPAMFOOLERcountrytraditions.com> wrote in message
news:KcGC5.1896$Z75....@newsfeed.slurp.net...
> We are about to have our 50 yr old farm house re-roofed with another fine
> metal roof.
>
> My question is this: We "currently" <G> have the original lightning rods
up
> on the roof peaks, and chimney (chembley if you're from Appalachian
Ohio)...
> Does today's technology suggest that they are still needed, or has it been
> proven that they actually draw lightning strikes, or are useless?...
>
> Roofer says they are "old technology"...and I assume he's right, but I
> wanted to ask the sages here before we pitch em out...
>
> Wendy Hannum
>
There is a wealth of info about this subject on the web. Here's a link to
the place where we bought our gear. http://www.lightningrod.com/index.html
There are still a lot of old wive's tales about lightning rods floating
around, so check your sources. A good book is "Lightening Protection For
People and Property" by Marvin M Frydenlund.
I'll summarize the usual home protection setup. Rods on the roof, usually on
the ridge every 25 feet or so, connected to a large braided copper wire
running the length of the ridge, terminating at two or more ground rods,
wires, or plates. There are specific rules about wire size and bend radius
etc, but it's easy enough for most do-it-yourselfers.
If you live in a lightening prone area, and have poor fire protection
services (most rural areas), then lightning protection is a good investment.
We have a very long ridge line and difficult soil, so we needed seven rods,
three down lines, and trenched ground connections. Materials cost was about
$500.
Wayne
isg...@my-deja.com
hose. Lighting hits wherever it wants and not simple rod is going to
stop it. What a lighting rod does is 24x7x365 provide a path for static
engergy in the air to flow to ground. By doing this you reduce the
electrical potential between the house and the air and reduce the chance
of lighting finding that differanl between air and ground.
Why dont they put them up on homes now where they did 50 years ago?
Biggest reason has nothing to do with the rod, but has to do with how
close and how quick a fire truck can get to your house to put out the
fire. I am betting that 50 years ago your farm house didnt have any
neighbors close by and the fire dept (if any) was not fulltime staffed.
A fire would most likley destroy the entire home and farmers may not
have insurance. The only insurance they had was the lighting rod.
My 100year old farm house and barns have them and plan to keep them.
In article <KcGC5.1896$Z75....@newsfeed.slurp.net>,
"Wubba" <we...@SPAMFOOLERcountrytraditions.com> wrote:
> We are about to have our 50 yr old farm house re-roofed with another
fine
> metal roof.
>
> My question is this: We "currently" <G> have the original lightning
rods up
> on the roof peaks, and chimney (chembley if you're from Appalachian
Ohio)...
> Does today's technology suggest that they are still needed, or has it
been
> proven that they actually draw lightning strikes, or are useless?...
>
> Roofer says they are "old technology"...and I assume he's right, but I
> wanted to ask the sages here before we pitch em out...
>
> TIA,
> Wendy Hannum
>
>
Lou Boyd
> Lightning rods don't draw lightning, they bleed off the charge before
> lightning can strike. The sharp point of a lighning rod causes
> electrolyte breakdown of the air, and the rod bleeds electrons into the
> atmosphere. From time to time you can actually see corona discharge
> around the points of lightning rods.
It's true that the sharp point bleeds some current and produce a brush
discharge but it's a myth that this has a significant effect on
preventing (or attracting) lightning strikes. It will help make the
lightning hit the conductor rather than some other part of the roof, but
the distance over which that effect takes place is only a few feet. A
large array of pointed wires arranged over a wide area (acres) has been
shown to reduce the frequency of lightning strikes, but it's not very
practial to place enough points on and around a farmhouse to get that
effect. Still the rods and ground are effective in preventing fires
when the lightining does strike.
> Far from being old technology, they are still the most effective way of
> protecting homes and electronic equipment from lightning strikes.
> However, weathering can dull the point on the rod. Take a close look at
> the point, and if it is dull you can sharpen it and re-tin it, or just
> clamp a sharpened piece of copper, stainless steel, or other conductive
> metal onto the existing rod so there is good contact.
Keeping the entire system in good repair is important. Having the
lightning rods and bond wires without proper ground wires and grounds
can cause more damage than having no lightning rods at all. Because of
induced voltage from the magnetic fields which surround the ground wires
when lightning strikes lightning damage can still occur in electronic
equipment. Most lightning damage to electronics equipment comes through
transients on the power and phone lines since they are far more often
hit that the house directly. Its simply a matter of how large of area
they're exposed to. Lightning rods are generally designed to prevent
fires and electrocutions. If you want to have full protection of
electronic equipment you really need an all metal building with
protectors on all wires entering the building. Even with lightning rods
properly connnected transient suppressors are required. They should be
place at least at the power entrance box and near modems and fax
machines, any devices which uses both phone and AC.
> Also check the ground wire and ground rods. Lightning rods need good
> direct contact to ground if they are going to work right.
That's the most important part.
--
Lou Boyd
tgb
> There is a wealth of info about this subject on the web....
Oh, that's great. We got one poster essentially saying "lightning rods
are not to conduct strikes safely into the ground, they are intended to
dissipate the buildup of ground charge and so make strikes less likely,"
and then we've got another guy essentially saying "that's crap," and
wmbjk says "there's a wealth of info on the web" but ... doesn't tell us
who is right.
So, anyone with the time to spare want to surf a bit and tell us what
they think the most authoritative sources on "the web" (or otherwise)
really say?
tgb
cj
>
<SNIP>
>
> I'll summarize the usual home protection setup. Rods on the roof, usually on
> the ridge every 25 feet or so, connected to a large braided copper wire
> running the length of the ridge, terminating at two or more ground rods,
> wires, or plates. There are specific rules about wire size and bend radius
> etc, but it's easy enough for most do-it-yourselfers.
Braided copper wire works, but since lightning is an RF (radio
frequency) discharge, wide flat copper straps actually work better.
This is due to their lower impedance (kinda like resistance, but
includes capacitive and inductive effects) at radio frequencies.
Another (and probably even more important) thing to think about is
the actual connection to ground. Here again, you need a low impedance
connection, not just a low resistance connection. This usually equates
to greater surface area in contact with the ground. So, instead of a
single ground rod, an array is much more effective.
If you are having a concrete slab poured, consider using steel
reinforcing rods and using the slab itself as a groung contact (this
is known as a Ufer ground, concrete is generally more conductive than
soil and can make a very good ground see:
http://www.scott-inc.com/html/ufer.htm
for some good info, or search for "ufer ground"). As shown on this
page, you can do it with non-slab foundations too.
Protection for your electronics, etc. in the house requires that if
lightning does hit (your house, the wires, etc.) that everything
rises to the same potential. In other words, you don't want a huge
voltage at one side of the room, and zero at the other. This can be
accomplished by making sure that all wires, etc enter through one
point, called a ground window, and that everything is suppressed to
that ground window with *good* suppressors. The ground window is
essentially a well grounded metal plate where all wires come through.
Wires should feed through the plate via gas discharge suppressors
(see http://www.polyphaser.com ).
For another great (but long) discussion on lightning supression, by
a guy who really knows his stuff, Gary Coffman, see:
http://www.harvardrepeater.org/news/lightning.htm
There's even a discussion specifically about lightning rods about
half way down the page. Most of the info is directed specifically to
antennas and towers, but it all applies to general lightning
protection.
-cj
KD6AEG
-------------------------------------------------------------
|Remove the 'X' from my address to reply... |
|===========================================================|
|Out ranchin' | |
|in the Wild, Wild | Froghorn Ranch |
|West, of Idaho... | Registered Missouri Foxtrotters |
| | http://www.froghorn.com |
-------------------------------------------------------------
cj
on lightning suppression, it should be:
http://www.harvardrepeater.org/news/lightning.html
Sorry about that...
-cj
Wubba
Why dont they put them up on homes now where they did 50 years ago?
Biggest reason has nothing to do with the rod, but has to do with how
close and how quick a fire truck can get to your house to put out the
fire. I am betting that 50 years ago your farm house didnt have any
neighbors close by and the fire dept (if any) was not fulltime staffed.
A fire would most likley destroy the entire home and farmers may not
have insurance. The only insurance they had was the lighting rod.
My 100year old farm house and barns have them and plan to keep them.
~~~~~~~~~~~~
<Snort>...
Our Fire Dept. is still volunteer (and I ~am~ thankful to them...!) and are
about 6 miles away...but only have rather small pump trucks....
We get lightning hits all around the house all the time (you should see
all the fried pines up in my woods!)...
Hmmm, I DO believe the lightning rods will continue to grace the roof.. :o)
Wendy Hannum
Chris
Wubba <we...@SPAMFOOLERcountrytraditions.com> wrote in message
news:KcGC5.1896$Z75....@newsfeed.slurp.net...
> metal roof.
>
> My question is this: We "currently" <G> have the original lightning rods
up
> on the roof peaks, and chimney (chembley if you're from Appalachian
Ohio)...
> Does today's technology suggest that they are still needed, or has it been
> proven that they actually draw lightning strikes, or are useless?...
>
> Roofer says they are "old technology"...and I assume he's right, but I
> wanted to ask the sages here before we pitch em out...
>
> TIA,
> Wendy Hannum
>
are old and probably have old fashioned values do you throw them out too?!
Just kidding. I really think they add a lot of character to an older house.
Chris.
Lou Boyd
Sorting the wheat from the chaff on the web requires thought, not just
reverence for authority. Read a lot and sort out what makes sense.
You don't have to know how a TV or a computer work internally to use
them. Same for lightning rods. It's a fact that they reduce lightning
caused fires and making the desision to have them put on your house does
not require detailed knowledge of electromagnetic theory or plasma
physics. Following approved guidelines will prevent you from wasting a
lot of money or installing an ineffective system.
Here are a few web sites (selected out of about ten times this many I
checked.) which explain the general principles and explore some of the
peripheral issues of lightning protection. Some of them are companies
trying to make sales but that's free enterprise:
http://www.lightningrod.com/index.html#manual Typical installation
hardware and diagrams of how it's put together. Most homes would be
simpler than what they show. Their diagrams look reasonable to me
though maybe not optimum. There are tradoffs of performance and a
"pretty" installation. I don't know anything about their prices or
company reliability.
http://www.mikeholt.com/Newsletters/Lightningsuit.htm A typical
response to lightning damage and the response from several
"authorities". Some reasonable information, some BS. See if you can
tell which is which. In my opinion it only says that lightning
protection systems only improve the odds. None are absolute guarantees
aginst damage though salesmen might claim that.
http://www.lightningsafety.com/contents.html Probably as close to an
"authority" as you will find in the U.S. Sometimes I think they try too
hard to treat everyone with odd ideas "fairly".
http://www.rbs2.com/blitz.htm Brief discussion of both lighting rods
and suppression of transients.
http://www.gov.ns.ca/just/regulations/regs/lr1352.htm Canadian
government rules & regs on lightning protection. Lots of detail.
(unlike US laws). You could do worse than following this.
http://www.robbinslightning.thomasregister.com/olc/robbinslightning/home.htm
A manufacture with lots of lightning protection parts and pictures of
them. Not much "how to" information.
Lou Boyd
premiums than pay for copper and ground rods up front. Keep in mind
the story of the old farmer who went to buy fire insurance for his
barn. "Do you want tornado insurance too?" asked the agent. "Naw" said
the farmer, "I have no idea how to start a tornado."
Lightning is only one of many causes of fire and while frequent is isn't
a primary cause. Fire insurance covers many more of them than lightning
rods.
Lou Boyd
--
Lou Boyd
Fairborn Observatory
wmbjk
"tgb" <t...@execpc.com> wrote in message
news:39dd00bd$0$62629$726...@news.execpc.com...
>
> Oh, that's great. We got one poster essentially saying "lightning rods
> are not to conduct strikes safely into the ground, they are intended to
> dissipate the buildup of ground charge and so make strikes less likely,"
> and then we've got another guy essentially saying "that's crap," and
> wmbjk says "there's a wealth of info on the web" but ... doesn't tell us
> who is right.
> So, anyone with the time to spare want to surf a bit and tell us what
> they think the most authoritative sources on "the web" (or otherwise)
> really say?
>
If I was going to start making pronouncements about whose opinion is right
on lightning protection theory, then I might as well do the same with
religion while I'm at it. :-)
Unless you're interested in the theory for its own sake, you can just skip
that part anyway. Get a copy of "NFPA 780, Standard for the Installation of
Lightning Protection Systems" for the specs if you want an official
publication. Or just get your how-to advice from the web site I mentioned.
Wayne
lehu...@my-deja.com
t...@execpc.com wrote:
> wmbjk wrote:
>
> > There is a wealth of info about this subject on the web....
>
> are not to conduct strikes safely into the ground, they are intended to
> dissipate the buildup of ground charge and so make strikes less likely,"
> and then we've got another guy essentially saying "that's crap," and
> wmbjk says "there's a wealth of info on the web" but ... doesn't tell us
> who is right.
> So, anyone with the time to spare want to surf a bit and tell us what
> they think the most authoritative sources on "the web" (or otherwise)
> really say?
>
> tgb
>
The tree was out on the middle of a pasture, this surrounded by
cultivated land in northern Illinois.....slightly rolling plains. The
tree literally exploded from the top downward, to perhaps ten feet above
the ground. Bark and wood were strewn about the pasture, and large
splinters were driven into the ground. The upper part of the tree was
scorched.
If damage to a house resembles the damage to the cottonwood tree in any
way, it would seem to be a "no-brainer" to put lightning rods on a house
in a susceptible area!!!!!!!
And, yes, my uncle had lightning rods on his two story farmhouse.
Lou Boyd
> Years ago, my great uncle had a cottonwood tree struck by lightning.
> The tree was out on the middle of a pasture, this surrounded by
> cultivated land in northern Illinois.....slightly rolling plains. The
> tree literally exploded from the top downward, to perhaps ten feet above
> the ground. Bark and wood were strewn about the pasture, and large
> splinters were driven into the ground. The upper part of the tree was
> scorched.
>
> If damage to a house resembles the damage to the cottonwood tree in any
> way, it would seem to be a "no-brainer" to put lightning rods on a house
> in a susceptible area!!!!!!!
>
> And, yes, my uncle had lightning rods on his two story farmhouse.
If you have a tree you particularly value you can add an inconspicuous
lightning conductor to protect it too. A single wire won't guarantee
absolute protection but it will certainly improve the odds.
Lightning stokes have a wide range of intensity. A number 6 wire is
unlikly to be damaged, but even if the wire vaporizes the tree will
receive much less damage than if the lightning goes through the tree and
explodes it from steam pressure. You can leave the insulation on the
wire and hold it in place with a single slow helix up the tree,
attaching it firmly only to a high branch. Then run three radial wires
buried a few inches deep away from the tree at 120 degree angles about
ten feet to ground rods. Avoid sharp bends anywhere in the wires. Any
electrical supply house can provide the wire, ground rods, and clamps.
The cost should be around $50.
Your tree will appreciate it :-)
--
Lou Boyd
Mike Marshall
> So, anyone with the time to spare want to surf a bit and tell us what
>they think the most authoritative sources on "the web" (or otherwise)
>really say?
There used-to-be/maybe-still-is-I-can't-find-it-now such a site,
either a .gov or a .edu site. Maybe someone else remembers it...
The gist is: rods don't have anything to do with whether or
not lighting will hit your house, but if it does, you'll be glad
if you have proper rods.
"Proper" includes rods along the ridge and flat braided wires. If your
house has a more complex shape than "rectangular box with gable
roof", then there's possibly some complexity as to where the
right places are to put the rods.
When I was looking (I haven't installed lighting protection yet,
but am going to) it was easy for me to find companies who would
come do the work, but hard for me to find a company that would
just sell me the stuff, so I could do it myself.
I just bookmarked http://www.lightningrod.com/index.html, they'll
see you the stuff. They use round-profile cables though...
-Mike
Mike Marshall
>http://www.robbinslightning.thomasregister.com/olc/robbinslightning/home.htm
>A manufacture with lots of lightning protection parts and pictures of
>them. Not much "how to" information.
Cool. They sell round-profile *and* flat conductors. As I said before,
I can't locate the information to back it up, but it is my
belief that flag conductors are the right stuff...
-Mike
Lou Boyd
Electrically a flat conductor is better but they aren't common because
of cost and installation problems. Flat copper strips will be more
expensive since they aren't as commonly manufactured as wire. The
ultimate flat conductor for lighting protection is an all metal roof and
walls with proper bonding and grounding.
Mike Marshall
>The
>ultimate flat conductor for lighting protection is an all metal roof and
>walls with proper bonding and grounding.
So... I have an all metal standing seam roof. Where can I find out more
about what you are saying...?
-Mike
Olddog1
Lou Boyd wrote in message <39E5E051...@fairborn.dakotacom.net>...
>Mike Marshall wrote:
>>
>
>Electrically a flat conductor is better but they aren't common because
>of cost and installation problems. Flat copper strips will be more
>expensive since they aren't as commonly manufactured as wire. The
>ultimate flat conductor for lighting protection is an all metal roof and
>walls with proper bonding and grounding.
>
>--
>Lou Boyd
What do you guys think about those of us who are down towards the bottom
of a canyon? Would you say that it would be a good investment in safety or
would the likelihood of a strike be so reduced due to the location that it
might just be a waste of money?
Rigth now I'm inclined to go ahead and spend the money but input would
be appreciated.
Lou Boyd
> >of cost and installation problems. Flat copper strips will be more
> >expensive since they aren't as commonly manufactured as wire. The
> >ultimate flat conductor for lighting protection is an all metal roof and
> >walls with proper bonding and grounding.
> What do you guys think about those of us who are down towards the bottom
> of a canyon? Would you say that it would be a good investment in safety or
> would the likelihood of a strike be so reduced due to the location that it
> might just be a waste of money?
>
> Rigth now I'm inclined to go ahead and spend the money but input would
> be appreciated.
My home is near the base of a 300' hill and it's a wood frame building.
There are a number of surrounding trees and power poles higher than the
house. I have antennas on the roof which are more likely to be hit than
the house itself. Their coax cables go through grounding blocks.
They've never been hit but if they were the grounding blocks would
probably not protect the attached receivers. They would prevent fire.
I don't consider it worth the expense to add lightning rods or a ridge
wire. There are sufficient paths for lightning already. I have surge
protectors on the power and phone entrances and they are bonded to
metallic water and gas pipes. I still occasionally get damage to modems
from lightning strikes to the power system. Lightning rods would not
help that.
My observatory is on another hill about 1/4 mile away which is the
highest point for over a mile. All of the buildings there are steel
frame construction with steel roofs and walls and have copper ring
grounds buried outside of the concrete foundations. All of the
buildings are bonded together with 4-0 cables. Lighting hits
occasionally but damage has been limited to weather sensors which have
to be outside of the buildings. The buildings don't have (or need)
lightning rods. The power is well protected and all communication is by
microwave radio. I consider lightning protection very important but I
don't have lightning rod anywhere. That's not to say they aren't
useful in some situations.
If you're at the bottom of a canyon you might be better off spending
your money to protect against flooding or brush fires which could travel
to your home. Evaluate your overall situation and direct your effort
to the problems which present the most probable threat whether that's
lightning, flooding, fire, wind, earthquake, civil disorder, or nuclear
war. All protection schemes are a matter of trying to predict what is
most likely to happen. Your house could be destroyed by a hundred pound
meteor but the probability is too low to worry about.
--
Lou Boyd
Fairborn Observatory
Olddog1
Lou Boyd wrote in message <39E73148...@fairborn.dakotacom.net>...
>If you're at the bottom of a canyon you might be better off spending
>your money to protect against flooding or brush fires which could travel
>to your home.
Would that we had enough water to flood around here occasionally
(chuckle) , and I hear you on the " brush factor" , I'm sort of a bug
about keeping the brush down around the house and outbuildings.
There were a lot of folks who learned that lesson the hard way when
the last big fire came through here a few years back.
All protection schemes are a matter of trying to predict what is
>most likely to happen. Your house could be destroyed by a hundred pound
>meteor but the probability is too low to worry about.
I hear you on that one , it's all a matter of odds and rainstorms
accompanied by thunder and lightning are infrequent here but
spectacular when they do come.
By the way what's the altitude on your observatory? I don't know
anything of value about astronomy but do find the subject interesting
enough to have bought a cheap telescope.
isg...@my-deja.com
object that has the best path to ground. Often its a tree. A treee is
largely water and make a good conductor to ground. This does not
guarantee it will always be hit.
In article <39E73148...@fairborn.dakotacom.net>,
Lou Boyd <bo...@fairborn.dakotacom.net> wrote:
> Olddog1 wrote:
> >
> > Lou Boyd wrote in message
> If you're at the bottom of a canyon you might be better off spending
> your money to protect against flooding or brush fires which could
travel
> to your home. Evaluate your overall situation and direct your effort
> to the problems which present the most probable threat whether that's
> lightning, flooding, fire, wind, earthquake, civil disorder, or
nuclear
> war. All protection schemes are a matter of trying to predict what
is
> most likely to happen. Your house could be destroyed by a hundred
pound
> meteor but the probability is too low to worry about.
> --
> Lou Boyd
> Fairborn Observatory
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
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>
Lou Boyd
>
> lIGHTING DOES NOT JUST STIKE THE HIGHEST OBJECT...... It will strike the
> object that has the best path to ground. Often its a tree. A treee is
> largely water and make a good conductor to ground. This does not
> guarantee it will always be hit.
Your certainly right that lightning doesn't just strike the highest
object, but it doesn't necessarily strike an object with the "best path
to ground" either. It follows a path determined by the voltage gradient
and the ease of ionization of the air as the end of the arc channel as
it forms. This can vary wildly as a function of local moisture,
turbulance, and partical conditions in the air. That's why lightning
sometimes makes crazy loops and branches. Lightning has been known to
go right past a large metallic structure and hit a partially insulating
material near it's base. That's rare though. Except for completely
surrounding an object with metal there are few guarantees related to
lightning protection.
Steven Jones
>
> > Your certainly right that lightning doesn't just strike the highest
> object, but it doesn't necessarily strike an object with the "best path
> to ground" either. It follows a path determined by the voltage gradient
> and the ease of ionization of the air as the end of the arc channel as
> it forms. This can vary wildly as a function of local moisture,
> turbulance, and partical conditions in the air. That's why lightning
> sometimes makes crazy loops and branches. Lightning has been known to
> go right past a large metallic structure and hit a partially insulating
> material near it's base. That's rare though. Except for completely
> surrounding an object with metal there are few guarantees related to
> lightning protection.
> --
> Lou Boyd
> Fairborn Observatory
>
many times seen lightning hit houses, power poles, antennas, etc. and
trees. And yet I have never seen anything but trees be damaged by
lightning. Also, even in the high lightning areas, no one has lightning
rods because they believe there is no need for them. Obviously the
danger from lightning varies from place to place. Why is this so?
Thanks for any answers in advance.
Steven Jones
wmbjk
"Steven Jones" <rmo...@mcn.org> wrote in message
news:39E7F52A...@mcn.org...
> >
> I have a question about lightning, In California and Arizona, I have
> many times seen lightning hit houses, power poles, antennas, etc. and
> trees. And yet I have never seen anything but trees be damaged by
> lightning. Also, even in the high lightning areas, no one has lightning
> rods because they believe there is no need for them. Obviously the
> danger from lightning varies from place to place. Why is this so?
>
> Thanks for any answers in advance.
>
> Steven Jones
If some in lightning prone areas believe that they don't need protection,
then they are likely betting that insurance or a fire truck can be counted
on instead. Protection is required by code in places like Phoenix I think.
While major damage caused by lightning in our area is fairly rare, we spent
the money on protection anyway since the fire trucks would take about an
hour to get here. And rebuilding a house after a fire would be miserable
even with insurance benefits.
Check that web site mentioned in my previous post for photos of lightning
damage. Now consider that lightning protection would probably add about $300
to the cost of an average home. It's really no different than things like
foundation bolts or rafter tie downs. Paying for any of them seems like
wasted money unless an earth quake slides your house over a few feet, or a
big wind sails your roof over to the next block. :-)
Wayne
Steven Jones
>
> "Steven Jones" <rmo...@mcn.org> wrote in message
> news:39E7F52A...@mcn.org...
> > >
> > I have a question about lightning, In California and Arizona, I have
> > many times seen lightning hit houses, power poles, antennas, etc. and
> > trees. And yet I have never seen anything but trees be damaged by
> > lightning. Also, even in the high lightning areas, no one has lightning
> > rods because they believe there is no need for them. Obviously the
> > danger from lightning varies from place to place. Why is this so?
> >
> > Thanks for any answers in advance.
> >
> > Steven Jones
>
> If some in lightning prone areas believe that they don't need protection,
> then they are likely betting that insurance or a fire truck can be counted
> on instead. Protection is required by code in places like Phoenix I think.
>
> While major damage caused by lightning in our area is fairly rare, we spent
> the money on protection anyway since the fire trucks would take about an
> hour to get here. And rebuilding a house after a fire would be miserable
> even with insurance benefits.
>
I'm not really arguing about lightning rods, I'm a belt and suspender
guy and would put one up if it was needed where I live. I lived in Rio
Rico AZ for a few months and saw lightning strike houses several times,
and yet, when I asked a volunteer fireman about the danger from
lightning, he said that he had never heard of a house catching fire from
a lightning strike and that the worst thing that ever happened was cable
TV going out.
I also just got through calling my local volunteer fire department here
in Mendocino Country CA and was told much the same thing. I have never
read a news story about lightning starting a fire in Northern CA (don't
know about the high mountains - except to note that I've never noticed a
lightning rod).
And yet, three times I have seen trees hit by lightning and be severely
damaged. One at Lake Tahoe, one in Arizona and one on the Mendocino
coast (about 50' from me).
I have never knows anyone from CA to have suffered damage from Lightning
(other than electrical surge) and yet I know two people from the Midwest
who have, one was struck from lightning and the other lost a house to
fire.
The fact that I am asking why this might be, indicates that I don't know
why this is true and I would be curious if anyone knows.
Steven Jones
wmbjk
>
> I'm not really arguing about lightning rods, I'm a belt and suspender
> guy and would put one up if it was needed where I live. I lived in Rio
> Rico AZ for a few months and saw lightning strike houses several times,
> and yet, when I asked a volunteer fireman about the danger from
> lightning, he said that he had never heard of a house catching fire from
> a lightning strike and that the worst thing that ever happened was cable
> TV going out.
>
> I also just got through calling my local volunteer fire department here
> in Mendocino Country CA and was told much the same thing. I have never
> read a news story about lightning starting a fire in Northern CA (don't
> know about the high mountains - except to note that I've never noticed a
> lightning rod).
>
> And yet, three times I have seen trees hit by lightning and be severely
> damaged. One at Lake Tahoe, one in Arizona and one on the Mendocino
> coast (about 50' from me).
>
> I have never knows anyone from CA to have suffered damage from Lightning
> (other than electrical surge) and yet I know two people from the Midwest
> who have, one was struck from lightning and the other lost a house to
> fire.
>
> The fact that I am asking why this might be, indicates that I don't know
> why this is true and I would be curious if anyone knows.
>
> Steven Jones
One element is probably that major lightning damage isn't limited to fires.
If a lightning strike blasts the roof off a house, does the owner even call
the fire dept.? We had major damage here (while we were still in the
trailer) from a strike nearby, several thousand dollars worth to electronic
equipment, TV, VCR, computer, etc. Definitely didn't call the fire dept. Not
saying that rods would have made any difference in that case though.
One humorous note, a year or so ago I called the fire dept. to report a car
fire which we could see some six miles below us in the valley (turned out
to be flatlanders with a huge bonfire in the middle of the desert). I gave
the volunteer the name of the road, and the distance up from the highway. He
asked how to find the road. I said "it's the road your firehouse is on". He
said he hadn't lived here too long. LOL So, info from fire department people
might not be your best source. I can't think who else to ask though, perhaps
try to find some insurance data? Even some local insurance agencies might
have some useful anecdotal stories.
Or, just install a system and consider it a small investment for additional
peace of mind. Some homes I can think of would only need about $200 in
materials and an afternoon's work to do the job.
Also consider the answers you might get if you asked around about who had
suffered damage because of lack of rafter ties etc. It could take quite a
few calls to find some specific examples. Yet ties are required by code, and
I don't know anyone who would question whether they're worth the trouble.
Perhaps not because they will always pay off, but because they're so cheap
when compared to the potential damage caused by leaving them out.
Hey, don't you get about 100 inches of rain up there a year? Maybe those
deluges put out all the lightning fires. :-)
Wayne
Wes Wilson
Lightning rods are needed in my part of the country - the Missouri Ozarks -
because we get such seriously bad electrical storms here quite often. We moved
to this farm over twenty years ago from California and during that time my hay
barn has been hit twice. Once when lots of hay bales were stacked up in
there. First time it came through the tin roof and blew a newly installed
light apart and splintered pretty good a 2x10 vertical oak wall post upon which
I had installed the light with metal conduit around its feed wire which was
also grounded - a mistake - as I later found out. However, luckily no fire
resulted even though the light fixture pieces were widely scattered over very
dry hay bales - and I counted myself very lucky. Second time it went in at
about the same place and found what was left of the original conduit still left
at a lower elevation - still no fire resulted but we had still more damage to
the roof and wall. After that we decided to install four 11' tall home made
tapered copper rods welded onto steel bases whcih we bolted onto the ridge of
the roof (metal roof) and then connected them all in series via several twisted
copper wires which I had laying around from an old electric fencing system -
and these I pounded into the ground about 7' deep at opposite diagonal points
of the building. Since then - about three years ago - I've had no more
lighning strikes there yet - that I'm aware of (but I'm keeping my fingers
crossed of course) - but I do feel that this effort was worthwhile since I feel
much better now knowing that those tall rods are in place.
The theory for the lightning rod as I understand it is that the ground charge
build-up is dissipated through the thin tapers at the top of the roof rods
before enough of a charge can gather to cause the "bolt" of lightning to
occur. This is a post and beam loft barn - 40' wide by 60' long and about 35'
high at the ridge line.
Wes Wilson
Lou Boyd
That theory isn't very solid. The four points on your barn won't have a
significant effect on determining whether lightning hits or not. They
could even increase the number of hits. They will however tend to make
the lightning hit them (the rods) instead of other parts of the barn and
the ground conductors will prevent damage if they do. Sounds like a
good system to me.
--
Lou Boyd
Dave Hinz
(snip)
: and yet, when I asked a volunteer fireman about the danger from
: lightning, he said that he had never heard of a house catching fire from
: a lightning strike and that the worst thing that ever happened was cable
: TV going out.
As a volunteer firefighter (assistant Chief, actually), I'd like to say
that that guy was uninformed. I've been to two housefires which were
started by lightning, and neither had lightning rods.
We don't get called for the houses that have lightning rods; they don't
catch fire when lightning hits them, in my experience.
: I also just got through calling my local volunteer fire department here
: in Mendocino Country CA and was told much the same thing. I have never
: read a news story about lightning starting a fire in Northern CA (don't
: know about the high mountains - except to note that I've never noticed a
: lightning rod).
So, on a sample of two random volunteer firefighters, you are making your
decision? In our state (Wisconsin), if you're grandfathered in, you don't
need to have taken the state certification classes, and their opinion may
be no more informed than your "man on the street". Perhaps the level of
training of the 2 individuals you spoke with is similar.
: And yet, three times I have seen trees hit by lightning and be severely
: damaged. One at Lake Tahoe, one in Arizona and one on the Mendocino
: coast (about 50' from me).
The water in the tree boils, and the bark & wood can't stretch that far,
that fast. Lots of heat in that transaction; current with resistance
makes heat. Decrease the resistance (with, say, a well-grounded lightning
rod), and you get less heat.
: I have never knows anyone from CA to have suffered damage from Lightning
: (other than electrical surge) and yet I know two people from the Midwest
: who have, one was struck from lightning and the other lost a house to
: fire.
Well, I don't think that the lightning knows it's in the Midwest, but
it may have to do with atmospheric conditions and such. The guy from
the observatory (sorry; can't think of your name) knows more about that
sort of thing than I do, so I'll defer on that.
: The fact that I am asking why this might be, indicates that I don't know
: why this is true and I would be curious if anyone knows.
: Steven Jones
I guess it comes down to this - do you have a spare tire in your car?
Why? I know 3 guys with Chevy's, and they have *never* had a flat.
The lightning rod has scientific basis for why it can reduce damage in
the event of a direct lightning strike. It comes down to this - do you
want to spend a few hundred bucks to maybe keep your house from catching
fire as a result of a lightning strike? My decision was to put them on.
...if you're in *my* fire district, though, kindly make sure you
have batteries in your smoke detector, because I'd prefer that you
get out when your house catches fire.
Dave Hinz