Talk:Lightning rod/Archive 1
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 |
Asia
the Sri Lankan section needs further details; a copper tip on a building does not constitute a lightning conductor, or a protection against lightning. A path of conduction to the ground is also required. —Preceding unsigned comment added by 142.167.104.50 (talk) 21:06, 26 February 2011 (UTC)
Lightning boils water? Eh?
The article at the moment states "the huge currents involved can heat materials, and especially water to high temperatures causing fire" -- not only is that wordy, it is confusingly wordy. Is there some comma (common) sense missing? Can lightning really cause water to heat to such a temperature that it literally catches fire? Methinks not, but the current wording appears to say that.
Yes How-To Article
There is nothing wrong with encylcopedic explanations about how something is done or made. Rather than trying to remove 'how-to' information, it would be better to expand another aspect of the article to satisfy any complaints.
Not a How-To Article
This article needs to be reworded so it does not sound like a primitive how-to article on building lightning rods. It should describe lightning rod techniques, not what 'should' be done. Also, we need to verify the accuracy of these statements -- references would be helpful.
Help. I have discussed this issue with many people but I'm never satisfied with the answer/explaination.
I understand that a lightning rod neutralizes the static charge that is carried in by clouds in a storm.
It is my understanding that if everything is working right, the static charge is neutralized slow enough that there is no bright flash and thunder.
By everything working I mean:
1: The charge does not move in to quickly (nature cooperates). 2: The lightning rod is in good condition (resistence to ground is low, the rod is high enough, nothing is damaged, etc.)
I'm not sure if this controled discharge is not also refered to as a "strike" by many of the articles.
I understand the lightning (the flash and crash) do occur sometimes and the rod is struck, but isn't that a worse case/not supposed to happen event?
In other words, I understand that a lightning rod function is more to prevent a strike (the flash and crash)by premitting a controlled discharge of current the attractting the high voltage/high current flash.
The original idea by Franklin was that the lightning rod would indeed discharge the thundercloud and there would not accure lightning. In one of his first experiments, the lightning rod was struck by lightning. This experiments, and many experiment later, proves that you can not prevent lightning by a lightning rod, you can only make a safe path for it to the ground: the path from the lightning rod to the ground.
Because Franklin first thought that lightning could be prevented, he claimed that you should always use a lightning rod with a sharp point. It's strange that he kept convincing people that sharp point were the best, because his own experiment showed that lightning cannot be prevented, so there's no direct reason why pointed lightning rods would be better. In fact, they're less effective in attracting the lightning as blunt ones, because they weaken the electrical field at the tip.
The idea of a lightning rod is twofold - to reduce the probability of a strike and to reduce the damage caused by a strike when it happens.
The reduction of the chance of a strike occurs due to electrostatic induction and charge bleed-off. When a charged cloud passes over the landscape, the cloud's charge induces an opposing charge in the ground - so if the cloud is positively charged, the ground develops a negative charge. This increases the electrostatic field between the cloud and the ground. When the E-field exceeds the ionisation breakdown threshold of the air, you get a lightning strike.
The sharp tip of a lightning rod will concentrate the E-field in the region of the tip past the breakdown threshold of the air, without allowing the breakdown to occur all the way to the cloud. The result will be a localize bleed-off of the induced charge on the ground, reducing the overall E-field of the area (and reducing the chances of a strike).
The linked article in USA Today is correct but misleading - the idea of a lightning rod is NOT to "attract" lightning, but to discourage it. *IF* your goal is to make lightning strike - e.g. you are doing lightning research - then yes, use a blunt rod. If if your goal is to protect equipment from a strike - use a sharp rod.
The ARRL has a good link on lightning protection: http://www.arrl.org/tis/info/lightning.html - and they have been dealing with lightning for decades. N0YKG 17:02, 11 July 2005 (UTC)
The confusion here is understandable, because the state of the art of lightning protection is not tremendously advanced over that of theology. We have no way of doing a controlled experiment with natural lightning, and so just about everything we say here is either anecdotal or based on theory that we cannot verify with field data. The 'experts' know no more than we do about the phenomenon. Things are improving; it's possible that we'll get real data with improved triangulation of lightning strike antennas, but right now lightning protection involves as much prayer as mathematics. Kinsler33 06:11, 2 October 2007 (UTC)
- Oh, please!
- "[L]ightning protection is not tremendously advanced over that of theology ... lightning protection involves as much prayer as mathematics."
- Gimme a break. Understanding of lightning, and therefore of lightning protection, has advanced enormously over the years, and especially the last few decades. Praying to the gods isn't going to help anybody one wit. Cheers, Rico402 (talk) 11:52, 1 February 2009 (UTC)
Why rounded ends?
It says in the article that rounded ends are better, but doesn't explain why. It would seem that pointed ends are better because they would create a slow discharge before the actual strike. - Omegatron 16:13, Jun 19, 2004 (UTC)
- It seems no one has enough interest to answer the question. If we have no sources at all for the assertion (see the preceding section; neither the granting of a patent nor the say-so of Tesla is really conclusive), then we need to hedge this non-authoritative information. One could start with some "According to Tesla" wording; but first, maybe someone can come up with some solid information. Dandrake 19:59, Aug 8, 2004 (UTC)
- And by the way, the sentence just before this section asserts that pointed rods work less well because they weaken the electrical field around the tip. This needs explanation. The strong field around a sharp point produces ionization, which ought to make a locally lower resistance between cloud and ground. Intuitively, this would seem to promote discharge (whether gradual or violent) through this path. Why is this argument wrong? If no one can or will explain this, see the preceding. Dandrake 17:28, Aug 24, 2004 (UTC)
- There are sources for the assertion ... inparticular the patent or associated research on such topics. Hedge this authoritative information? "According to field research" wording could be good.
- As to pointed rods work less well because they weaken the electrical field around the tip? This link may help.
- As to the whole "strong field around a sharp point produces ionization" Why is this argument wrong? See the previous link. Other info is available.
- I'm gonna add this link to the article. JDR
- I doubt that the sharp tip makes the rods work less well than rounded-tip rods. Instead, the ionization would tend to make the sharp-tip rods BEHAVE AS round-tip rods. (But maybe the gas cloud makes the sharp-tip rod behave as a taller rod than it actually is, or maybe it gives the rod a random and changing electrical shape.) Why would sharp tips and ionization tend to weaken the field at the tip? It's because ionized air sent out by the sharp metal tip is a conductive gas, and this gas becomes electrically part of the lightning rod. With this extra region of "fluid conductor" present, the sharp metal tip of the rod is electrically no longer the "tip" of the rod instead the top of the conductive gas cloud acts as the "tip." In other words, the conductive gas cloud acts as a Faraday cage which shields the metal tip. The outside of this "Faraday cage" then becomes the lightning rod. Electrically the rod acts as if it has a conductive fuzzy shape enclosing the tip. Another issue: if the wind is blowing, the conductive gas cloud would be removed. All the above discussion applies only to still air. --Wjbeaty 19:16, Mar 2, 2005 (UTC)
- See [1]. Lightning protection is an area scholarly study with many books and articles in journals, but I hesitate to add info to such a liability-prone article, since someone's structure will inevitably be damaged by lightning and they will look for someone to blame. Edison 19:03, 25 April 2007 (UTC)
- I doubt that the sharp tip makes the rods work less well than rounded-tip rods. Instead, the ionization would tend to make the sharp-tip rods BEHAVE AS round-tip rods. (But maybe the gas cloud makes the sharp-tip rod behave as a taller rod than it actually is, or maybe it gives the rod a random and changing electrical shape.) Why would sharp tips and ionization tend to weaken the field at the tip? It's because ionized air sent out by the sharp metal tip is a conductive gas, and this gas becomes electrically part of the lightning rod. With this extra region of "fluid conductor" present, the sharp metal tip of the rod is electrically no longer the "tip" of the rod instead the top of the conductive gas cloud acts as the "tip." In other words, the conductive gas cloud acts as a Faraday cage which shields the metal tip. The outside of this "Faraday cage" then becomes the lightning rod. Electrically the rod acts as if it has a conductive fuzzy shape enclosing the tip. Another issue: if the wind is blowing, the conductive gas cloud would be removed. All the above discussion applies only to still air. --Wjbeaty 19:16, Mar 2, 2005 (UTC)
I've added a bit of material about points vs blunt rods. What I didn't mention is that Moore's paper is a study in the frustration of lightning studies: they put up several tall towers, watched them for something like seven years, and got twelve, count 'em, twelve, strikes. This in an area that sees lightning throughout the year. If that's not enough to keep you out of lightning research, nothing will.
I thought the orb was the best lightning arrestor. Actually you get MORE lighting strikes with the globe or that spider top. It de energizes the static environment and thus protects against the damaging high energy strikes. Too bad, using them is not promoted by insurance companies and taking about Tesla seems to be at odds with official science. A test was given and results published that the Tesla lightning design had more strikes. The globe or spider gives static charge more area to accumulate and discharge. The Globe is also in the text books for statics in physics. Teslafieldmachine 15:01, 5 August 2007 (UTC)
While we're considering the minutae of the end of the lightning rod, it's worth thinking about what a thundercloud sees when it's up there. It's ten miles long and maybe ten miles high, and all it sees when it looks down is flat fields of green with little dots of houses. It ain't gonna care about pointy vs. blunt vs. polished. The earth next to tall trees is struck. The sides of buildings are struck. Places on roofs next to lightning rods are struck.
You can't judge whether you get more lightning strikes with one or another sort of rod because the stuff is so random. Some researchers will contend that the best way to protect a structure from lightning is to install lightning instrumentation on it. It'll never get hit.
Poor Tesla. He may have had an insight or two on lightning protection, but he didn't have access to anything we don't. Because of the charlatans who adopted his name even before his death, his name has become something of a label for pseudoscience these days. Kinsler33 06:20, 2 October 2007 (UTC)
"Non-functional" glass balls
I notice in this article that it mentions lightning rods with a "non-functional" glass ball on it meant only as an ornament. However, living in storm-active "tornado alley" farmland I have heard that the glass balls actually do serve a function other than just being ornamental.
Supposedly, when the lightning strikes one of these glass-ball lightning rods, it heats up the glass ball so rapidly that it shatters, falling off the rod and serving as visual sign of a strike. This then allows the owner to see which rod took the strike without having to climb onto the roof, and also alerts the owner that they should check the building and lightning protection system for damage. Apparently this is a relatively unknown lightning rod tidbit, so I added it to the article. Torin Darkflight 06:11, Oct 30, 2004 (UTC)
They are not for the purpose described
They are not there for lightning to hit them; they serve a greater purpose. It is true that smaller objects hold less charge - therefore, the tip of a lightning rod is sharpened to a point. This makes it so that lightning will not hit the building which it is attached to because all the charge induced in the building will leak out through the rod. However, lightning DOES hit the rod sometimes but its main purpose is to prevent a strike.
--Nivedh, March 29, 2005
- According to the National Ag safety database (NASD) article on Boating-Lightning protection (which I assume to be public domain),
- "Lightning protection systems do not prevent lightning strikes. They may, in fact, increase the possibilities of the boat being struck. The purpose of lightning protection is to reduce the damage to the boat and the possibility of injuries or death to the passengers from a lightning strike."
- This seems to be the consensus, at least based upon the results of a Google search using the terms "lightning rod" "prevent lightning". I would agree that a lightning protection system is meant to protect, not to prevent, lightning. There is no way to equalize the massive difference in potential between a cloud, miles up in the sky, and the ground. The only thing you can do is hope to intercept it with an air terminal and send it to your grounding system. --Dual Freq 16:16, 10 December 2005 (UTC)
Inefficiency of the sharp tip
My understanding was that the sharp tip causes a significant increase of the electrical field directly around the tip. This induces early ionisation that partly and locally discharges the gradually increasing electric field caused by an approaching stepped leader. This reduces the chance of the ligtning rod being the source of the upward leader that makes the (safe) connection leading to the lightning strike.
Eric, June 6, 2005
- The article conflicts on this point.
- In the modern research section, it says that a correctly blunted lightning rod is better at conducting current to the ground since the field strength is stronger above it. This would mean that the blunt lightning rod is better because it attracts more lightning. This makes sense to me.
- In the Ben Franklin section, it says that a pointed lightning rod is worse for the exact same reason; that it has a greater field strength and so attracts more lightning.
- So from what I understand, Franklin knew about the ability of sharp objects to attract arcs (since the field strength is stronger around them), and he thought that sharp poles would dissipate the clouds' charge continuously through a corona discharge, preventing any lightning from striking the area. Instead, I suppose (original research time) the corona region just ends up looking like a very tall conductor that the lightning is much more prone to striking, making the rods attract lightning instead of preventing it. - Omegatron 01:09, August 8, 2005 (UTC)
As was explained in my US Navy electronics "A" (providing entry level knowledge & skills) school, since a (round) basketball, after being immersed in water, takes longer to shed water than a pointed object of an equivalent area, a pointed object is more efficient for dissipating an electrical charge. As I have observed, US military ordnance storage bunkers (conventional and nuclear), and US Embassies (at least the new one in Phnom Penh, Cambodia) utilize this design, as depicted on the top of the "Article" page for this topic.- Perry, APR 16, 2007(CDT)
- NFPA 780 (Standard for the Installation of Lightning Protection Systems} 2000 edition says the air terminal can be sharp or blunt. According to the references listed on the main page, tests of lightning rods indicate that blunt is more efficient at intercepting a lightning strike. Since the point of a lightning protection system is to prevent lightning from striking a protected structure, you want the rod to be as attractive as possible to the lightning. (Read some of my other refs on this page if you doubt this). It is a common misconception that lightning rods prevent lightning strikes. --Dual Freq 15:49, 21 January 2006 (UTC)
Lightning is not DC
Maybe I'm mistaken, but DC does not create a changing waveform, a requirement to producing a radio signal. It is well documented that lightning does produce a radio frequency signal, hence lightning must be an alternating current and not DC. User:66.222.126.249 02:29, 26 September 2005
You are ineducated moron. DC and AC are only very special case. Lightning is a very brief current spike and thereof in it's fouries (frequency) decomposition, very wide range of frequencies are present, basically whole radio frequency spectrum. If it lasted very long time and started/ended only very slowly, much less significant radio radiation would be emitted —Preceding unsigned comment added by 82.119.242.94 (talk) 19:20, 21 August 2008 (UTC)
Please sign your posts with 4 tildes (˜˜˜˜). As for lightning being "AC" because it is not DC - there are more types of current than "DC" and "AC". Alternating current specifically means a current in which the direction of flow reverses. Lightning does not have a current flow reversal. Yes, it IS a changing current, but then again, ALL currents are changing - there are no currents that started at time=0, and will continue until time=&infinity; without change. All DC means is that the current flows in the same direction for some subset of time that "makes sense" for the current in question. N0YKG 13:43, 26 September 2005 (UTC) (← that is what 4 tildes looks like, BTW).
DC current through a light filament (or electric arc, for that matter) produces light - a form of high frequency radio. Yet the current involved is indeed DC. On the other hand, are the different directions of the strike due to changes in the polarity of the charge (there are certainly positive and negative clouds) or merely in the direction of the plasma construction? njh 00:22, 27 September 2005 (UTC)
Lightning stikes both ways. Ground to cloud and cloud to ground. The ground usually seen as - and the cloud is seen as usually +, but I thinnk there are virations (and anomolies). The overall system is AC, an individual strike could be seen as DC. I believe it's the "direction of the plasma construction" (unless there is something that you mean that I am missing there). The system exchanges energy from the atmosphere to the earth and from the earth to the atmosphere all the time, but a lightning strike is the "dielectric breakdown" of the insulative medium ... causing the "boom". JDR 00:30, 27 September 2005 (UTC)
If it is the direction of formation then that is no proof that the current direction alternates. For it to alternate, a strike would have to carry more charge than required to neutralise the cloud. Now it is quite plausible that this happens, as it appears to be an LC circuit, but to prove the case I think we should find a reference that this happens. (So I don't consider this case closed just yet :) njh 00:44, 27 September 2005 (UTC)
According to Vince Calder at the DOEs ask a scientist web site (which I assume to be public domain):
"Question - Is lightning stroke DC current or AC current?"
- Answer - Lightning is DC -- well almost. ... Usually the charge carrier is negative (presumably electrons) but apparently some discharges appear to be positive! Often there is a "leader" stroke that on high speed photos approach the surface of the Earth, but "do not quite make it" and then there is a Earth -- Cloud return stroke (presumably the path is "set up" by the leader stroke. So this would be AC but with a single cycle."
That seems to be a vote for DC current. As for the radio frequency component, I think that is part of the Electromagnetic pulse related to the high levels of current involved with a lightning strike. If you looked at this pulse it would probably cover a large chunk of RF spectrum from DC up to VHF. See also Page 4 of Electromagnetic pulse and the radio amateur --Dual Freq 16:16, 10 December 2005 (UTC)
We design lightning protection systems on the assumption that lightning currents act like AC of high frequency. That's why we don't allow any sharp bends in the downconductor: the added inductance can create enough reactance in the line so that the lightning current will jump over it. And once the current leaves the downconductor, it's an arc, and things catch fire.
Lightning is typically unipolar in voltage, but the waveform contains high-frequency components. The IEEE standard 4 lightning stroke (there are others) jumps to a peak in 1.2 microseconds and then drops off exponentially such that the voltage is halved every fifty microseconds. This is called a 1.2 x 50 us stroke, which we use in electric power work. I don't understand the four tildes, but here they are Kinsler33 06:42, 2 May 2007 (UTC).
Lightning as AC
This is something to ponder ... found this "Lightning cannot be classified as either direct current or alternating current." Lightning Injuries from MA Cooper and CJ Andrews in Wilderness Medicine (2002). J. D. Redding
Repeated in MA Cooper, SV Cantrill, Electrical and lightning injuries. Patient Care, 1992 ... they say it's classed as a current thing rather than a voltage thing .. J. D. Redding 19:16, 2 May 2007 (UTC)
I personally fall into the camp that lightning is AC and not DC, because AC is more elegant ... J. D. Redding (PS., is there a strike and a return stroke after the strike anyways? ...)
One last thing ... looking at the stages of lightning came across this ... "Upward Moving Charges, Return Stroke (visible stroke) from the Earth to the sky, and Dart Leader" in a couple of place ...
related articles ... Stepped leader ... Return stroke ... Dart leader ...
- http://amsglossary.allenpress.com/glossary/search?id=dart-leader1
- http://amsglossary.allenpress.com/glossary/search?id=stepped-leader1
- http://amsglossary.allenpress.com/glossary/search?id=return-stroke1
http://amsglossary.allenpress.com/glossary/search?id=lightning-stroke1
lightning stroke : In a cloud-to-ground discharge, a leader plus its subsequent return stroke. In a typical case, a cloud-to-ground discharge is made up of three or four successive lightning strokes, most following the same lightning channel.
alternating current : an electrical current whose magnitude and direction vary cyclically ...
Disputed
This statement seems ridiculous to me and it should be removed from the page:
- Lightning rod dissipaters make a structure less attractive by which charges can flow to the air around it. This then reduces the voltage between the point and the storm cloud, making a strike less likely. The most common charge dissipaters appear as slightly-blunted metal spikes sticking out in all directions from a metal ball. These are mounted on short metal arms at the very top of a radio antenna or tower, the area by far most likely to be struck. These devices reduce, but do not eliminate, the risk of lightning strikes.
The whole purpose of an air terminal and associated lightning protection system, is to give lightning something to hit that is not important and direct it to the grounding system. It's meant to intercept the lightning and stop it from hitting a protected structure like a tower or building. You could look at it this way, but maybe it's an over simplification: Lightning originates from miles up in the atmosphere, where a difference in potential exists. This difference is so large that it jumps thousands of feet to ground. If someone were to tell me that I could stick a ball with metal spikes 10 feet above my house and that would safely equalize the potential difference between the ground and the sky 20,000 feet above it, thus preventing lightning, I would say that I have a bridge to sell them. I need to see a credible source that says this, and not some company web site that sells these things or some snake oil patent. You will not find any dissipater in a UL standard or NFPA document because they are not certified to prevent lightning. They may be approved as air terminals (for lightning to strike instead of a protected structure), but not as lightning prevention. They may reduce static and might lower noise levels on an antenna structure vs a pointed air terminal, but they will not prevent or stop lightning. See also: [2] and [3] --Dual Freq 17:15, 10 December 2005 (UTC)
- Yep, I agree, this is a weak line and I was tempted to remove it when I rewrote this article - Be Bold and delete it, someone can always add it again when they've got some good references. It sounds to me a lot like one of those things that gets passed around as fact without any good basis (like the common explanation of lift). njh 10:33, 11 December 2005 (UTC)
- I reworded and moved the section to a separate part at the bottom of the article. I attempted to cite my edits appropriately. If anyone feels they have better information, please cite your sources and make the appropriate changes. I'm only trying to help dispel a common misconception about lightning rods. I also think we need a picture of a 'real' lightning rod / air terminal, not one of these misleading lightning-protectors. I think a nice close up of a blunt-tipped air terminal would be best since that seems to be the standard one currently backed by NFPA, FAA (See page 31 of 100) etc. --Dual Freq 23:42, 11 December 2005 (UTC)
- Thanks for this! If you feel like cleaning up the rest of the article we may be able to remove the refs contention. njh 10:14, 12 December 2005 (UTC)
- Added image of a pointed-tip air terminal and relocated fictional "protector". --Dual Freq 23:50, 7 March 2006 (UTC)
Do you really think the 1/2 inch cable connecting lightning rods to earth could carry the temendous current from a lightning strike? Not likely. Immediate vaporization would eliminate the wire, and the strike would then travel through the structure causing damage.
....
It is completely counterintuitive, but it turns out that even the thinnest wires can handle most lightning strikes. In artificial lightning lab at Mississippi State University (a big one) we used solid #20 wire. That's not a misprint: the stuff was almost invisible, as you find out immediately when you're carrying a ladder through the lab and get tangled in it.
The reason is that while lightning currents are indeed in the thousands of amperes, they don't last long enough to heat anything much up--that is, there's not enough time to transfer substantial heat energy to the wire or, often enough, to whatever has been struck. This sort of thing can drive you nuts when you're trying to determine whether a structure or system has sustained a lightning strike.
There are, of course, long-duration, high-current strikes that transfer vast amounts of energy to the lucky target, like ship anchors that get bent into knots. They also create fulgurites when lightning hits sandy beaches. The problem is that we don't have much field data on such strokes, only that they seem to be rare.
(My apologies if this is an unacceptable way of inserting a comment; I'm new at this.)
.........
The "lightning preventer" idea has more credibility than this. You are right that it cannot completely neutralize the charge difference, but that is not necessary. As long as the lightning rod makes the structure a less attractive target than other nearby objects, it has done its job.63.85.214.60 14:49, 20 January 2006 (UTC)
- Yes, I really think that the NFPA 780 recommended down conductor can and does carry the current to ground, but it doesn't really matter what I think, check the sources I cited. Those sources are the organizations that keep homes, business and government safe from fires caused by lightning and other lightning damage, groups like UL, NFPA, NLSI and Lightning Protection Institute. No one certifies that any equipment will prevent a strike from occurring. All the articles cited above on this page should answer this question. If you disagree, please cite a source. If Daktronics or somebody else up there in Brookings, South Dakota sells something that prevents lightning, please post the website location I'd love to read about it, but I couldn't find any information on your company's website pertaining to lightning protection or prevention. I suspect that you do have lightning protection equipment installed with your signs, so I'm a bit surprised that you would make this kind of statement. Lightning rod types has some photos of rods that were struck by lightning. The 19mm diameter blunt tip lightning rods have small pits on them but they did not melt or 'vaporize'. --Dual Freq 20:31, 20 January 2006 (UTC)
- The lightning page states that each discharge produces 30kA. The conductor proposed (.25inch*.25inch*pi = 126mm^2) has a resistance of 1.6mR cm * 1m/126mm^2 = 0.13mR/m, each m weighs 126*9g = 1.14kg giving a heat capacity of 438 J/K per metre. Each m will drop 3V, i.e. 90kW of power. The flash lasts about 100ms so each meter of the bar has to dissipate 9kJ by heating by 20K. I think the mistake is to assume that because there is a lot of power dissipated in a strike, the conductor must dissipate a lot. In fact, as the conductor is probably 1 thousandth the total resistance of the strike it gets only 1 thousandth the power. njh 02:29, 21 January 2006 (UTC)
- To follow up on this (from a discussion on slashdot). Some people have proposed that a lightning rod is just an initiator rather than the sole conductor of the discharge. A parallel path ionisation seems very unlikely considering the available conductor density. If there were a parallel discharge one would expect melting or charring around conductors, either of which I've not seen.
- The resistance of the lightning rod might be 1000th the resistance of the whole strike (from cloud to ground), so although a lightning bolt has a high power, most of that power is being dissipated elsewhere. Lets work it out:
- From Lightning: An average bolt of negative lightning carries a current of 30 kiloamperes, transfers a charge of 5 coulombs, has a potential difference of about 100 megavolts and dissipates 500 megajoules (enough to light a 100 watt lightbulb for 2 months).
- 100MV/30kA = 3.3 kohm
- So a lightning discharge has a total resistance of 3K3 over say a distance of 3.3km, for a plasma resistance of 1ohm/m, nearly ten thousand times greater than that of the lightning rod, so it is unlikely that the lightning would choose to make its own path, and if it did, we would expect only 1/10000th the current to flow (a measly 3A).--njh 06:13, 4 March 2006 (UTC)
- I don't think it is disputed that lightning rods work, but how they work is quite a matter of contention. The organizations cited could very well have the effect desired (that is, protection of structures) while having the reasoning wrong. As industry organizations, the effect of their rules is what is important to them, not the scientific basis for those rules.205.241.238.3 22:28, 9 March 2006 (UTC)
Oops, I edited the article quite a bit without looking here first. Anyway, I came here to say that I removed the latter part of "Lightning rod dissipaters (known as Early Streamer Emission, Dissipation Array Systems, and Charge Transfer Systems) claim to make a structure less attractive by which charges can flow to the Earth's atmosphere around it.", replacing it with "attractive to lightning." I don't understand what the original is trying to say, I don't even think it's grammatical. I'm pasting it here in case something was lost in doing this. -- Coffee2theorems | Talk 16:11, 18 September 2006 (UTC)
...........
Again, a comment and a caution. There is very little science to support most of what we think we know about lightning protection. That is because it has proven impossible to conduct controlled experiments, which are at the base of any scientific evaluation. The reason for this is that natural lightning simply does not cooperate: it never strikes where and when we need it to, and it'll keep this game up for years. For a good example, read Dr Moore's laboriously-researched paper on blunt-vs-pointed lightning rods. I'm sorry to say that it is based on a grand total of twelve (12) strikes, this in a section of New Mexico that's treated to day after day of spectacular lightning displays, almost year round. It's enough to drive you nuts.
..........
I am curious as to when the discussions and information about DAS type solutions has been updated and by whom, particularly as to whether the individuals are promoting competing and traditional methods. I find it disengenuous to state that because something has been done one way for over 200 years that it is the only solution. If we took that attitude with most technology, there would be no Google, no iPhone, No PCs and no Internet. DAS technology has been actively in use for over 30 years, with hundreds, if not thousands of successful installations. Before launching into a full edit of the article, I want to understand the process and what the discussion/push back will be. Alan (talk) 18:00, 21 September 2010 (UTC)
Single greatest philanthropist?
I think that calling Franklin the single greatest philanthropist ever not only a big POV but alot people help without expecting reward 70.36.255.222 12:31, 6 January 2006 (UTC)
Planes and boats?
Anyone have any information on lightning protection devices for aeroplanes and watercraft? J. D. Redding 01:58, 19 April 2007 (UTC)
This'll add fuel to the fire: last time I looked in a catalog for boat lightning rods, there was a swell collection of thingies that looked like brushes. Yep: dissipators. Apparently a good many yachtssmen believe in them.
As for airplanes, it's worthwhile observing that nobody adds anything to an aircraft unless it, and they, have FAA approval, and that includes the paint. Thus you don't see too much lightning-rod gimcrackery on airplanes. The assumption made by the designers is that (1) the plane will probably get hit and (2) planes are perfectly capable of generating their own lightning when they travel through a thundercloud. Apparently it goes right up those contrails.
And so all we can do is to make a Faraday cage out of the airplane, and that's just what they do. Wiring is all in metal conduit (more for rf isolation than anything else) and there's electrical continuity everywhere. This is not so simple to do on the new plastic airplanes, but Boeing and them didn't fool around. Kinsler33 06:01, 2 October 2007 (UTC)
List of patents
This is not the place to list every single patent for lighting rods. --Dual Freq 01:06, 20 April 2007 (UTC)
- Nope it not every patent on lightning rods. Just applicable ones. AND, the last few I added are applicable ot aircraft lightning protection. J. D. Redding
There is no justification for listing 40+ patents in any wikipedia article. I'd suggest moving them to user space or a list article, but they can't all remain here. --Dual Freq 02:07, 20 April 2007 (UTC)
Moved the items to a List of lightning rod patents, part of the Category:Lists of patents. J. D. Redding 03:52, 20 April 2007 (UTC)
US bias?
This article is very US centric. For a start, in the UK, they are called lightning conductors. Also, I'm sure they have been used on churches in the UK for many years. The Victorians had a facination with electricity and stuck conductors on all tall buildings. I believe that today there is doubt as to their effectiveness.. Philsy 11:41, 13 May 2007 (UTC)
Please add UK info in history section. Please add the Victorian stuff to the history section. Lightning conductors are noted in intro. Scientifically the are lightning protectors. J. D. Redding 12:05, 13 May 2007 (UTC)
I disagree and feel that your revision has simply reverted to the US bias I was trying to address. In the UK they are called lightning conductors and, scientifically, that term is correct - they 'conduct' the lightning to ground. I don't see how the term 'lightning protector' (which means nothing to UK readers) is any more scientifically correct. Perhaps you could explain. Philsy 08:32, 15 May 2007 (UTC)
In the absence of any objection, I've put 'lightning conductor' at the start of the article, to reflect the terminology used in the UK. Ideally, the article's heading should be adapted accordingly, too. Philsy 16:57, 23 May 2007 (UTC)
- WP:ENGVAR has some guidance on this issue. Before you claim bias in the naming of this article, perhaps you could look at how the Flashlight and Torch articles address this. --Dual Freq 23:50, 23 May 2007 (UTC)
OK, let's leave the headinig as it is but we should also keep the term 'lightning conductor' in the first paragraph, just like 'torch' appears after 'flashlight'. :-) Philsy 07:58, 24 May 2007 (UTC)
GA delisted
In order to uphold the quality of Wikipedia:Good articles, all articles listed as Good articles are being reviewed against the GA criteria as part of the GA project quality task force. While all the hard work that has gone into this article is appreciated, unfortunately, as of May 31, 2008, this article fails to satisfy the criteria, as detailed below. For that reason, the article has been delisted from WP:GA. However, if improvements are made bringing the article up to standards, the article may be nominated at WP:GAN. If you feel this decision has been made in error, you may seek remediation at WP:GAR.
Please see the review at Talk:Lightning rod/GA1. --Malleus Fatuorum (talk) 00:35, 31 May 2008 (UTC)
Why don't new suburban homes have lightning rods?
For some reason most newer houses built in the United States do not seem to have lightning rod systems. This is particularly apparent in suburban areas with homes built from 1970 forward. Meanwhile older structures usually have the rods. What is the reason for the lack of interest in them? Were they required at one time by code, but now are not?
Also most manufactured homes almost never have lightning rods. Why is that? DMahalko (talk) 23:36, 24 February 2009 (UTC)
- I was wondering the same thing. My guess is that the material costs are too high. 192.91.171.42 (talk) 16:54, 11 June 2009 (UTC)
- I believe most homes these days use a lightning protection system that is mostly hidden. There are likely to be numerous, small projections on the roof, about a foot high, that serve the function. Additionally, weather vanes are usually tied in to the system. ~ Amory (user • talk • contribs) 14:42, 24 June 2009 (UTC)
Inhibitor
The chapter Inibitor de Raios/Blitzinhibitor/Lightning Inhibitor.... was placed by a spanish IP on all wikis in the middle September 2009 for making promotion of this physical not working part. --Schmendrik881 (talk) 00:04, 12 December 2009 (UTC)
Russian claim
The claim that Russia invented the lightning rod is doubtful for two reasons. First, it is unverifiable that Nevyansk tower, built between 1725 and 1732 was intended for the specific purpose of being utilized a lightning rod. Whather it was used as a lightning rod, it remains unverifiable. Secondly, I probably would believe such a claim if there was a in fact citation referenced in this article that is written in the English language. All we are given is an inappropriate and unacceptable reference in the form of a web page written in Russian that to English speakers, is totally useless to verify such a claim. This is English Wikipedia, not Russian Wikipedia. And thirdly, by conducting my own research, there is a vast consensus by doing a search engine which shows that by far and large, Benjamin Franklin is attributed to inventing the lightning rod, regardless if others may have built a rod that was unintended for such a purpose. Because of this, I have added a tag to the "Russia" section of this article.Yoganate79 (talk) 22:05, 22 July 2010 (UTC)
- The article's cited reference Офис первого русского олигарха (Office of the first Russian oligarch) is a rather clumsy extract from Невьянская башня (Neviansk tower). The applicable paragraphs of the latter are (according to Google translate):
- Study of the tower showed that at its construction of the most advanced technology of the time. Start with the fact that the tent of the tower was crowned, in addition to six-foot weather vane, lightning rod in the form of metallic gold-plated ball with spikes-rays. In the history of the tower it had never been struck by lightning. If we consider that Neviansk tower was built about 1732, it appears that the Ural masters built a lightning rod for about a quarter of a century before the invention shown contemporaries American Benjamin Franklin.
- It is worth remembering, and one more features. The metal frame of the tower, in fact, was grounded for the world's first lightning rod. The fact that the tower is crowned by six-foot flag weathervane with expanded metal ornament. On it - a coat of arms Demidovs: knight's helmet with a visor and shield with a hammer (we recall that Nikita Demidov was granted a title of nobility), and above it a ball, symbolizing the sun. The diameter of a sphere about 30 inches, the thickness of the metal one millimeter, and on its surface - about two dozen hollow triangular pointed spines-rays up to 40 centimeters long. Shar-rays attracts lightning, and then charge the rod, which he fastened on frame tent, on metal strips within the brickwork of the tower into the ground. Is it only for the sake of beauty tower crowned with a metallic sun, especially when you consider that all the surrounding buildings were made of wood? (Today, a new tent over the ball-sun: the former, Demidov times, horribly burned from lightning, is stored in the factory museum.) Or design has developed the lightning rod accident? It is believed that the lightning rod was invented in 1752 by the American scientist Benjamin Franklin. But it happened a quarter century after the construction Nevyansk tower. And in Russia the first lightning rod was officially established in 1786 by a special government order on Peter and Paul Cathedral in St. Petersburg. But nevyantsy know something, who first began to catch lightning!
- On the fourth floor - a large bright room. Museum. Behind the Glass - weathervane of a thick sheet iron, weighs 25 kg. This is the same vane, with a pierced arms Demidov, original. Instead, now the tower is crowned with its exact copy. Shar-sun, too, replaced by - its rays over 300 years have been repeatedly damaged by lightning.
- Terminate the tower roof with a metal spike, which, as mentioned above, is supplied with grounding. Thus, the tower was equipped with lightning rods for a quarter century before it was made and Benjamin Franklin.
- Myth number 4. At Nevyansk tower installed the first lightning rod in the world.
At the top is indeed installed grounded steeple as "the sun with spikes", who acted as a lightning rod (lightning rod), and protect from direct lightning strike, and, accordingly, the destruction Nevyansk inclined tower. It is interesting that the invention and installation of a lightning rod for attractions Neviansk occurred in a quarter century before the discovery was officially made by Benjamin Franklin. Now from lightning is little left - no thorns, and in the "ball" can be seen fused edges of the holes from the lightning, so recently the original was replaced with its exact copy.
- Myth number 4. At Nevyansk tower installed the first lightning rod in the world.
- This is marred by a contradiction: The first paragraph claims "it had never been struck by lightning", but a later paragraph states "Shar-sun, too, replaced by - its rays over 300 years have been repeatedly damaged by lightning." These contradicting phrases must have been written by different people. "Myth number 4" is immediately stated to be true, hence calling it a myth is a contradiction. Nevertheless, the translated paragraphs support the claim of a Russian lightning rod before Franklin's, however unlikely. — Joe Kress (talk) 08:22, 25 July 2010 (UTC)
- Here is the problem that I have with this. They built a structure before Benjamin Franklin. Nowhere in my own indepdnent research is there any substantiative proof that contends that when this tower was built in Russia, it was specificially intended to strike lightning. They might have built a lightning rod. However, that very well was not their intention, thus not realizing what they accomplished.
- In order to claim an "invention", one has to conceive of the initial and original idea. And that is exactly what Benjamin Franklin did in 1749 with his kite experiments and work in electricity.
- Also, I stand by my point that the citation/reference being used is quite unacceptable. This is English Wikipedia and not Russian Wikipedia. A reader of this pae should not have to have the text translated thereby setting themselves up for misinterpretation of what is being claimed. Until this Russian claim can be defended, which it is not, it is dubious due to the points I have made up above.Yoganate79 (talk) 15:04, 26 July 2010 (UTC)
- Although English sources are preferred, sources in other languages are permitted if they are the best available sources. -FisherQueen (talk · contribs) 15:20, 26 July 2010 (UTC)
- Also, I stand by my point that the citation/reference being used is quite unacceptable. This is English Wikipedia and not Russian Wikipedia. A reader of this pae should not have to have the text translated thereby setting themselves up for misinterpretation of what is being claimed. Until this Russian claim can be defended, which it is not, it is dubious due to the points I have made up above.Yoganate79 (talk) 15:04, 26 July 2010 (UTC)
Why the major edit?
Can someone explain this edit. Wtshymanski? Anyone?
http://en.wikipedia.org/w/index.php?title=Lightning_rod&diff=402388946&oldid=400257523
--J. D. Redding 07:49, 15 December 2010 (UTC)
- Oh, let's see...Electricity travels mostly along the path of least resistance, so an object outside the critical distance is unlikely to be struck by the leader if there is a grounded object solidly OR within the critical distance. is word soup and doesn't parse. Long paragraphs. Usual irrelevant Wikidribble where we flag especially golden lines of prose with "It is worth noting...". And so forth. You don't like it, change it. --Wtshymanski (talk) 14:16, 15 December 2010 (UTC)
Biased article, attempts to protray an object as a system.
This article, beyond the obvious bias inherent in it, attempts to cover too much subject matter, i.e., a lightning rod is not a lightning protection system, which has its own page... http://en.wikipedia.org/wiki/Lightning-protection_system Sadly, this page is extremely biased as well.
A lightning rod, is exactly that a "rod" or a piece of metal. It is also a subcategory of a more general specification, Air Terminals. Discussions of whether it should be pointy or blunt are relevant to this article. Discussions of down conductors, grounding rods, lightning arrestors, Charge Transfer, etc., are not.
The following sections have serious flaws
- 2 Structure protectors
* 2.1 Lightning diversion <-- attempts at discussing a system, not object o 2.1.1 Lightning arrester <-- a completely different object * 2.2 Electric power system lightning protection <-- a system * 2.3 Lightning protection of mast radiators <-- something not a LR * 2.4 Lightning conductors and grounding precautions <-- systems, not LR * 2.5 Lightning protection system design <-- should be in LPS article * 2.6 Should a lightning rod have a point? <-- relevant to a LR * 2.7 Lightning dissipation <-- biased & not a LR * 2.8 Evaluations and analysis <-- should be in LPS section
In this topic realm, there should be the following, whereby Lightning Rods are a subcategory... this is not an all inclusive list
Lightning Protection Systems
- Traditional, aka Franklin - Description - History - Design - Rolling Sphere Model (could have its own page0 - Components - Lightning Rods (Air Terminals) - Conductors - Grounding Terminals
Lightning "Prevention" Systems
- Charge Transfer or Dissipation Systems
The actual article on Lightning, http://en.wikipedia.org/wiki/Lightning is in need of a discussion on the characteristics of cloud to ground discharges, such as generation: step leaders, upward streamers, voltages/currents/ wave properties, etc.
I'm more than happy to work with anyone on an unbiased, scientifically based rewrite/overhaul on the topics of lightning protection systems, etc., as there is very little credible information contained in these discussions at present.