Installing Lightning Protection

CONTACT THE TELECOMMUNICATION TOWER COMPANY, EXPLAIN TO THEM WHAT IS HAPPENING AND TELL THEM THEY NEED TO FIX THE PROBLEM. NO COMPANY IS ALLOWED TO DO HARM TO YOUR PROPERTY EITHER PHYSICALLY OR ELECTRICALLY.

I HAVE FOUND WITH THE RIGHT APPROACH MOST COMPANIES WILL HELP TO FIX THE PROBLEM RATHER THAN GO THROUGH A LAW SUIT OR REPRESENT THEMSELVES AS BAD NEIGHBORS.

ALSO IF THEY ARE AN EXPERIENCED COMPANY, IT IS PROBABLE THAT THEY HAVE HAD SIMILAR PROBLEMS LIKE THIS AND KNOW WHAT TO DO.

Power generation grounding standards change from location to location depending on the local geology. The telecom tower grounding system can easily be a red herring in your thought process. Contact your local zoning control to identify your local grounding standards. Some suggestions on grounding configuration criteria are how deep your plate has to be, must the plate be salted to improve conduction during a storm, do you require a ring grounding system. Once you are certain that you meet local codes for power generation (this is frequently different from domicile requirements) investigate what, if any, surge suppresion your generator comes with. Your typical local weather may just normally exceed the number of joules your suppressor can safely handle.

Remember, lighting strikes are very powerful and unpredictable. The EMP field generated by them can produce enormous current loops in unexpectid circuits. Finding what configuration of parts produce a robust, reliable and cost effective system can be an iterative process.

Good Luck

I agree that the tower might be a red herring but in this case there seems to be good correlation between installation of the tower at 8 months ago and two damaging lightning strikes in the last six months. Assuming this hasn't happened before.

Are the grounding rods in wet soil or are they in an area where the soil is dry because of proximity to a foundation? That will affect your ground connection.

On the other hand it is correct that the tower owner is probably responsible for a fix. They seem to have created the problem and are usually responsible for fixing it. Unless you have a contract with them that says you have assumed this responsibility because they have leased the land from you.

Going to need a lot more detail beyond this.

There is a very good chance that the lightening strikes on the tower ground are momentarily raising the voltage potential of the ground itself to the point of damaging back

feeding currents to sensitive micro-electronic circuits that would definitely not be expecting significant potentials on either their circuit or safety ground connections.

Winding a clam shell choke for these connections could/should help trim transients.

The use of the plate rather than a rod could be a source of problems which could possibly be fixed by adding a rod to the ground circuit.

Surge arrestors fast and strong enough to stop lightening are problematic as the lightening usually wins the race.

Look into a Franklin Lightning Rod system, its old school, but in some applications, very effective.

You could have received an EMP due to a nearby strike.The magnetic field accompanying a strike is enormous, and can induce very high voltages.Make certain that all grounds are connected to a single grounding point.This will help prevent spurious currents in the conduits,metal framing, etc.Make sure all metal parts of the building are bonded together.The idea is to give the current only on path to ground. MOV's(metal oxide varistors) are a solid state device that responds very quickly to any voltage above it's rating, and has a "crow bar" effect.To choose the proper voltage breakdown,determine the working voltage of the affected circuit boards, and place MOV's in all three modes(hot to ground,,neutral to ground,, and hot to neutral).Select a MOV slightly above your working voltage.Electronic Parts books, such as Newark's have a good selection to choose from.The MOV's should be placed in series with a fuse; this tells you when they have been activated and need replacing.These are one-shot devices,and should be replaced after one use. I have used MOV's to great success in remote monitoring equipment to protect sensitive electronics from lightning and utility spikes. If you need specific part numbers, please provide the working voltages of the electronic equipment you wish to protect and I can help you choose the right component.

Hi, warrior!

Welcome to the CR4 crowd! I hope you thoroughly enjoy your participation in here.

Since the tower is attracting the major strikes, the generator is probably being harmed by the tentative pre-lightening strikes surrounding the tower. This means that the direction of the lightening through it is up through the earth, and not down from the clouds as the final portion of a lightening strike on the tower would be. Your lightening arrestors might be working against you by transferring this energy directly to the generator rather than grounding it.

There are two possible solutions. Insulate the bottom of the generator from the earth using e.g. old automobile tires, and/or bring it inside; and/or install separate lightening rods at a distance of 2-3 meters around the generator that are not connected to it in any way to attract the pre-lightening fields, or (preferably) both.

Mark

Do not: Repeat: Do not install separate ground rods unless they are all bonded together to a common point.Do not insulate the generator from ground.Handyman's advice goes against the National Electrical code, and sound electrical engineering practices as well.Multiple unbonded grounding points can create hazardous voltages. I suggest referring to the 2008 NEC handbook for further instruction on reducing lightning damage. I welcome input from any other QUALIFIED ELECTRICAL ENGINEER on this matter. ............................................................................................................... My grandfather had good advice:>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Never approach a horse from the rear, a bull from the front, or a fool from any direction. "nuff said.

Hi, Guest!

It is an unfortunate fact for the OP that every lightening strike is composed of two parts. The major strike comes from the clouds as they try to neutralize a strong positive load build up in their lower portion. That's the part that hits the tower.

Prior to that, there is a response to the cloud's charge from the earth, which forms the track for the major strike. That part travels from the earth to the cloud, and is characterized by smaller sparking in the area around the major strike as the cloud passes over nearby potential conduits (including, because of its construction and location, the generator).

The "juiciest" of those pre-strike charge pathways (tower) is the one that the major strike normally follows as it goes to ground.

Because the tower is in the vicinity of the generator, as the loaded cloud passes over, the feelers from the earth spark nearby it. The generator, being located near enough to the tower to provide a conduit for those feelers, is suffering from the result of being a simple conductor. Grounding the generator while it is exposed to the air is only going to assist it in this destructive function, whereas insulating it from the ground will prevent that eventuality.

Whether separate lightening arrestors or a 'chained series' is used around the generator, the idea is to channel the feelers through more attractive conduits than the generator, whose location is obviously attractive to lightening. No one is being urged to stand around them to personally check the voltages of the lightening strikes. And multiple lightening arrestors have been used on large roofs ever since Ben Franklin invented them.

Of course, the most useful response to this phenomenon would be to move the generator indoors in some fashion, even if it would be to mount it on a floor with a roof over it. The floor and roof would insulate the generator from the ground, and could be supplied with lightening arrestors.

In writing about insulating the generator from the ground, I was not referring to any sort of negative DC 'grounding' transmission lines, which could be located at some distance from the generator anyway. Generators per se do not have to be mounted on open ground. I don't think you'll find that requirement in the NEC.

And, apparently, some 'qualified electrical engineers' are not particularly well-versed regarding a phenomon normally associated with meteorology, which, unfortunately is the area in which the problem dwells.

In my own particular case, the subject of lightening strikes was part of a developmental study on transforming exhaust fumes into a plasmic state. This was accomplished via inducing an ionic avalanche to imitate nature by using a manufactured electrical "storm" in our product's pre-catalytic converter phase, so I learned a little about the topic.

I respect the urgency with which you urged caution in the methods used when undertaking the preventative measures, however, and second the motion.

Mark

Mark & All,

Referring back to my original reply suggestions, solving the problem of inferred or induced lightning strike damage is an iterative process for many different studies. Each of these disciplines should be ranked in their importance toward solving this perplexing problem.

1. Electrical Engineering (my own discipline that originally included work designing satellite communication ground stations) is the dominant engineering focus. One must know how the desired energy (whether produced by the backup facility or the local grid) gets distributed to the loads. Next the EE must guess how the undesired damaging energy enters the system and either prevent the energy from entering the system (i.e. ground rods, magnetic shielding) and/or dissipate the remainder of this energy in a safe manor (i.e. MOV varistors, spark gaps, surge suppressors.) Through out these attempts the EE must still permit the primary function of power distribution to succeed.
2. Geology and the local conditions comes second in my list of disciplines to consider. Identifying local grounding techniques and if all parties have adhered to them. A single ground plate or rod driven into a clay bank will not be an effective ground system. But a simple wire bolted to the pipe of an abandoned well might meet local code. A buried ground loop around the generator building with multiple rods will mean the ground around the building will have the same voltage potential during a strike.
3. Legally it appears that at a minimum the new communication tower has changed the local grounding conditions. Part of this change in local grounding is absolutely unavoidable, for now a big grounded metal structure must project up into the sky. Apparently, the communication tower's lightning grounding system works for the communication protection. But local conditions have changed. (This happens far more often than a lot of people realize.) Frequently part of the standard budget for a new commercial tower is a fund to improve local, off site grounding conditions.
4. Meteorology in my opinion ranks at the bottom of this list. Knowing the conditions that produce a lightning strike and the mechanism of lightening itself certainly is a fascinating topic and surely required to attempt reproduction. I do not intend to belittle anyone investigating this confusing field. But surviving a force of nature is the questioner's goal, not preventing or fabricating it. (yes, I do realize knowing how any phenomena happens can lead to mitigation.)

So to sum up, lightning and lightning protection involves multiple uncontrollable unknowns. Which "fix" will now make the energy released by a typical local lightning strike survivable can only be found by trying different approaches. As one responder emphasised, the owners of the tower likely expect to be required to modify neighbor's grounding system.

Redfred

A little knowledge is very dangerous.The generator MUST BE GROUNDED, not insulated.Inside a building or not, makes no difference. I once visited a village in Africa where the people put old car tires on their roof in the belief that it would prevent lightning strikes.To them it made more sense than a grounded lightning rod.Are you from that village, by chance? Please do not dispense dangerous ignorance as qualified advice. I have over 30 years experience in this field, so I have more than a little knowledge of the matter. I hope the original poster does not buy into your "logic" Caveat Emptor

Great comment. I find the "1/2 bucket of knowledge" syndrome to be a great hindrance to service, technology & engineering-although it is very profitable for a good tech!

Hi, DRFREON!

Good point. But nobody is, hopefully, slurring the pot here, in the very arena (CR4) that invites cross-disciplinary discussion on any topic.

To quote a previous blog of your own, "Troubleshooting ANYTHING requires attention to detail."

The answer to this lightening conundrum will lie in the details. When it has been solved, we'll have our answer... and we'll know which details are relevant. Let's not be caught dismissing any potentially relevant research or evidence out of hand before the mystery has been solved. [ ↔, if you get my drift.]

About 14 years back, I took a shore leave at Thunder Bay to visit an old buddy one year. We drove through a lightening storm and were privileged to have seen the lightening feelers licking skyward prior to a strike with our own eyes. It was a very memorable event; although at the time, I hadn't any information about what it was we were witnessing. (I thought it was a bunch of little strikes building up before a big one, so I wasn't too far off.)

Pre-lightening strikes are relevant to this discussion because

• they are ground-to-sky
• the actual strike can be at a considerable distance from any of the preliminary activity, since clouds drag over the ground at a good height and cover a large portion of the sky during a storm, and
• the generator keeps on getting fried by lightening despite having a roof over its head and a tall tower nearby.

Although redfred ranks meteorology as a cause at the bottom of his preferred list of suspects, he has admitted that is his opinion, and that he would rather explain the phenomenon in other terms. I guess my own preference is fairly obvious.

You have some electrical background, I suspect, from reading your past posts. What do you think is happening with this generator/tower interaction? [Prior to these posts, had you any direct knowledge of the lightening strike process?]

_{(And remember to mind your spelling & English, DRFREON! My old man was an English teacher, so you can't put anything over on me! )}

Mark

Mark,

I do not list meterology last as the cause of a lightning strike. I list it last as the solution to warrior's lightning related problem. This comes back to the distinction between an engineer and a scientist. Both noble disciplines deal with the universe. But while the scientist observes with the tools built by an engineer, the engineer builds from the observation of a scientist.

Hi, redfred!

We agree on this, then. In my blog, I wrote, "The answer to this lightening conundrum will lie in the details. When it has been solved, we'll have our answer... and we'll know which details are relevant. Let's not be caught dismissing any potentially relevant research or evidence out of hand before the mystery has been solved. [ ↔, if you get my drift.]"

And that's fine. I misunderstood you when you wrote, "Meteorology in my opinion ranks at the bottom of this list" to be indicating that it was not as worthy an area in which to look for a cause of the strikes as for example; and instead we should be looking at the protective arrangements around the generator as both cause and solution.

Certainly the cause is located somewhere in some body of basic knowledge; and a long-lasting solution must eventually be found in the field of protections summoned through the discipline of electrical engineering. An understanding of the (potential) meteorological causes for the problem will assist that search greatly; possibly because it is the science base from which the engineer will note the fix.

In your #1 area of EE research, you stated, "Next the EE must guess how the undesired damaging energy enters the system and either prevent the energy from entering the system (i.e. ground rods, magnetic shielding) and/or dissipate the remainder of this energy in a safe manor (i.e. MOV varistors, spark gaps, surge suppressors.)" My blogs have been about how that energy enters the system. The why of the problem: geological formations, proximity to the tower that gets the major strikes, improper installation, are all potentially going to lead to the fix, based upon avoiding or preventing the how. Meteorology (the science) has taken the guess work out of the equation.

The two possible simple fixes I suggested in my first blog #6 arise from the observations that very few cars ever get struck by lightening since they are separated from the road by rubber tires, which even when wet make poor buses; and that roof rod protection all over the world is designed specifically to give lightening of both types --up and down-- an alternative route to riding through valuable property.

That electrical engineering has developed all kinds of lightening arrestors and is capable of coming up with well-secured solutions to the problem by investigating preventative measures such as geological formation transmission tendencies is bonus. What I had noticed when I was privileged to have seen the pre-strikes (from the 'safety' of a travelling automobile...although not knowing what was going on, we hauled ass out of the area as quickly as we could) was that although they were coming from conductive points --hydro wires and guys stretched over the road, nearby roofs, and tall bushes-- none of those conductors was very massive in nature. At the time, I wondered whether they would have supported a full lightening surge without melting, burning, etc.

In retrospect, I wonder how the size of the available bus as compared to the nearness of its top to the cloud base rates in terms of resistance as a determinant for both the eventual strike area consideration and its voltage transmission.

Obviously, in Warrior's case, the tower wins on both counts (size & height); but suppose a small slim tower posed a slightly greater resistance than a chunky short generator due to size of the bus, and both tower and generator were exposed side-by side to the sky...which do you think lightening would choose for a major strike? Are the sizes of the available buses the cause of multiple lightening strikes during flash lightening storms? Interestingly, the CN tower here in Toronto is the highest most conductive lightening rod in the city, and not only attracts (when the cloud formations are high) but probably prevents (when the rainclouds are low) nearly all the lightening in the downtown core.

This leads me to think that in addition to installing Warrior's generator protection systems, perhaps the tower owners' increasing the lightening rod(s) on the tower near the generator in dimension & height may offer a more direct and/or attractive circuitry for the cloud currents as an additional protective measure for otherwise attractive nearby structures enough to avoid the pre-strike situation.

And maybe not, as despite their releative sizes and heights the generator is already providing pre-strike conductivity.

Mark

I have been aware of the multi-path strike of lightning(tracer and main charge) for over 30 years.It makes no difference which direction it travels. your knowledge of practical electrical theory is lacking severely. The tower should have been provided with a circular grounding array, with at least 5 legs leading out from the circle.The single point ground of the generator equipment should be connected to this grounding "ring". By the way, what do you suppose kept you safe in your car during the thunderstorm? Just curious on your opinion

Hi, Guest!

Despite the mocking tenor of your comments, it is evident that you have something of value to provide in here as a contributing member. Why not sign up and be identifiable as who you are professionally?

There are a few corrections I would like to offer to what I think you are trying to say, however, in this and the two previous blogs I am inclined to link you with because of the way they are phrased.

First, the lightening's strike direction of travel and timing of same (when up and when down: i.e. where they occur on the curve of the strike) are relevant to the discussion, which is about a fried generator control system and how to prevent it in future.

Second, technicians (and technologists) are not dull-witted unschooled jokers in an electrical or any other area of practice. They are experts, versed in the practicalities as well as the theory of any of their engineering or other disciplines, and are to be given the respect due to knowledgeable colleagues in the engineering or other fields they represent. They only differ from the professional engineer or other professional in the depth of theoretical knowledge we work with for producing new advances and solutions.

Third, the tower was erected well after the generator had already been in place. I and you have no idea of how competent their installers were or whether the grounding for either was incorrect or could have been better.

Fourth, linking the one ground of the generator to the lightening grounding ring from the tower is not a good idea.

Fifth, I have twice mentioned the size of the bus vis-a-vis the size of the voltage in a strike, and once with regard to the tires on the car. We both (I hope) know what happens with large voltages withinin large buses (allowing them to be e.g. liquid cooled). If you have a point to make, please feel free to be straighforward about it, such as in this case. I got your indirectly made point about my incorrectly written statement re the tires. Thanks.

And lastly, thanks for telling me that my electrical engineering knowledge ("practical theory" sounds like an oxymoron) is lacking, but I know that. However, it isn't lacking in any of the topics I have chosen to tackle in CR4. I admit to having forgotten quite a bit over the years as I have been about a dozen or so years out of practice. [Electrical (and electronic) theory, and trigonometric vector analyses in both those areas was, coincidentally, my favourite subject in skule, and I have had very little opportunity to exercise any theoretical knowledge since retiring, so it hurts to be out of touch.] But I have other important interests in my retirement years that (while not compensating for the fun of skule, hundreds of formulae to memorize and theory derivations) keep me busy. Fortunately, I keep most of my skule notes in my personal library (a 14-foot section of stuff I only rarely need to look into), so when I need a formula or explanation I can look it up in there or on the net.

Mark

WOW! Educated far beyond your intelligence!

When you get time to research and study the proper recognised grounding methods for towers and electrical equipment, you will blush when you realize how ignorant you were.

You will discover that I was being very kind with my criticism.

Till then, I wish you a very happy and productive education.

Via con Dios,compadre.

Here is a link that may help enrich your knowledge of tower and nearby equipment grounding.

http://www.copper.org/applications/electrical/pq/casestudy/mtwashington.html

Also reference the NEC for equipment bonding requirements.

Hi, Guest!

Thanks for the link. I read the info, and it explained that towers need to have adequate grounds and how some were installed in a hostile environment. Good innovative technique. No new information.

The situation in your referred article dealt with frying communications equipment connected to the towers, and no indication of protection was mentioned in the article for the communications equipment other than more adequate grounding on the towers.

Here's a reference link for the communications equipment protection that would have had to be installed in addition to the more effective grounding solution (which, you may have noticed, did not mention a ring ground being used below the cold layer in the Precambrian rock substrata because it would have been expensive and impractical as a fix):

http://www2.electronicproducts.com/Overvoltage_protection_technologies-article-farr_littelfuse_jun2008-html.aspx. Take your pick of the goodies presented for various communications equipment overload eventualities.

Perhaps my knowledge of ("tower and nearby equipment") grounding is a tiny bit more enriched than you suspected, though I thank you for the thought that prompted you to send the link. Certainly I appreciate any learning curve assistance --which is plentiful, believe me-- I receive from CR4 reading. As an example, I frequently subscribe to blogs about all manner of subjects without writing in to them just to enjoy the learning experience they offer.

Please feel free to debate me on any of my points rather than resorting to ad hominems all the time. I am a member of this valuable resource not only to provide my own thoughts an experience to others, but equally to keep learning, and would appreciate valid input.

I'll reserve the blush for juicier moments of real chagrin, though. (And I've had my share of those in here, as well...don't mind admitting it --all part of the learning curve.)

Mark

You will notice in reply # 5 I mentioned MOV's for internal protection of electronic equipment.The situation on Washinton mountain was an extreme example, because of the 600o feet of granite it was composed of.I used this to illustrate the value of proper grounding.Such extreme measures are not required or practical everywhere.

The value of a ground ring around the tower, and the necessity of bonding all grounds to a single point cannot be overstressed.Preventing lightning is impossible, one can merely try to control it's path by giving it a very good ground, and putting all metal at the same potential.

Look at the results achieved on washington mountain:

"Results

GTI's experience paid off. The new system exceeded everyone's expectations. Resistance to ground was between eight and nine ohms, well within specification and orders of magnitude lower than the earlier system.

The Mt. Washington communications facility has NEVER seen a major equipment loss or power outage due to lightning or any other discharge-induced cause in the FIVE YEARS since the new grounding system was installed. As an important added benefit, power quality at the site has improved measurably due to a much-reduced ground potential.

The new ground rods have maintained their low impedance. And, despite adverse weather and multiple freeze-thaw cycles, all of the copper connections have remained sound, with no evidence of loosening or corrosion.

Finally, the new protection system makes economic sense to the tower's tenants. Its installed cost was lower by far than the yearly cost to replace lightning-damaged equipment, let alone the loss of revenue due to power outages and signal interruptions. Without a doubt, Mt. Washington's investment in two boreholes, a pair of correctly installed copper-clad grounding electrodes and a few hundred meters of 500 kcmil copper cable has paid for itself many times over. Even more important, of course, is the improved reliability New England's communications customers now enjoy."

I will not waste any more time discussing this with a philosophunculist with NPD.

Good'ay

What is NPD? And what is a philosophunculist?

Hi, Guest!

Thanks. I had already read the article. In my opinion, not actually knowing what's in place around Warrior's nearby tower by way of lightening protection and whether it is a ringed ground or not, I think that connecting the generator's one ground line to conductors specifically intended to ground lightening is inadvisable.

Nothing to be gained in replying to the rest of your entry in this one.

Mark

I am not attacking you personally to deflect from the meat of the discussion, but all I know of you is presented to me by your unsubstantiated opinion.I have presented facts to try to show you the fallacy of your argument, but you turn it inward as a personal criticism.That is not the case.I would not expect a medical doctor to give advice on electrical matters,nor would I expect an electrical engineer to advise a doctor on a medical procedure.Each is competent in his own field, but totally lost when out of their element.It is apparent that you are out of your field, or depth, as the case may be. No reflection on you or your intelligence;simply because your statements argue against properly designed and engineered equipment standards. Please back up your claim of putting the generator on a stack of tires, or perhaps you were making a joke and I failed to see the humor, and saw it as ignorance of the highest order? Forgive me if this is the case, and I will have a hearty laugh at myself for being so obtuse. Where has this ever been done?Has it proved effective?Please present evidence to prove your point.I have presented mine. Your turn.

Hi, Guest!

"Please back up your claim of putting the generator on a stack of tires... Where has this ever been done? Has it proved effective?"

You may recall that my contention is the variety of energy frying Warrior's generator controls is not a lightening strike, but pre-lightening snaking up from the ground through available conduits in the general vicinity of the eventual strike.

I don't know whether placing insulators on the ground so as to eliminate a potential conductor from becoming part of the transient path has ever been utilized to prevent pre-strikes. There is a good depth of experience that illustrates the wisdom of removing items one does not want struck by lightening from the vicinity of grounded conductors. And I am aware that pre-lightening chooses well-grounded paths.

I am not limited, as a scientific investigator and innovator, to what has already been done. If it has not been done before, the very reason it may not have been tried is that folks reasoned, like yourself, that since the immense potential of lightening is able to penetrate through the resistance levels of normal dielectric barriers, therefore that must apply to pre-lightening strikes as well. This ignores two givens: first, that the pre-lightening strike, while possessing a strong enough voltage to enable it to penetrate the distance of air it does, is only a very small fraction of the voltage of a major strike; and second that the pre-lightening strike is the negative charge from earth seeking an upward path to neutralize with the positive charge in the cloud base.

The effectiveness of an isolation barrier to assist in preventing pre-strikes by shielding the isolated conductor is common sense; and can only be shown through observation. But it does not prevent pre-strikes from being able to penetrate the dielectric presented by the tires, should that eventuality occur. In conjunction with the nearby rods I had also suggested as alternate routes for the pre-strikes and the roof which would limit the passage of potential through the generator's own ground, I presented a package of plausible prevention through the presentation of a more attractive route. The idea, again, is not that the voltage of the pre-strikes could not penetrate the isolation barrier of tires, but rather that the isolation barrier could eliminate the generator as a potential choice of conduit with better ones nearby.

My 'field' as an engineer is to note the technical difficulties and, where the remedy has not yet been found, use my education to determine a plausible and hopefully useful response together with what's available as tools and materials; and to boldly explore innovation when the answer is not yet crystal clear.

I do not doubt that you are well-steeped in your field of knowledge, which is why I had suggested that your joining CR4 as a bona-fide member would be a great idea. However, if you do, may I suggest you leave your proclivity for ad hominem and mockery outside your discussions. They don't mitigate in your favour, and you have enough background to not need them anyway. I tried to give you some in return in order to have you experience what it feels like to be assaulted in that fashion, and I apologize for what I wrote of a sarcastic and ironic nature in some of my responses to it.

Mark

If someone brings a package to you, and you refuse it, to whom does it belong? I did not accept your comments as criticism of a personal level, but if you insist on going to that level,I can accommodate,although I prefer to be civil. The fact of lightning going both ways has been known for many decades, and I have argued the point to others in the field.The last discussion I had about this was 1971, so it is not a recent discovery.Perhaps to you, but not to the industry. Utility engineers and electrical companies have been aware of it for a long time. The first charge to leave the cloud is a tracer charge,"looking" for the best ground.It ionizes the air along it's path.When the circuit is complete, the main current carrying charge follows the path blazed by the "tracer" strike. The point is, the main current carrying charge follows the exact same path as the "feeler".Once it establishes a path, the main charge is committed to that path, because the air is ionized and has less resistance.The ionized particles may be blown out of line by the wind if it is severe, but the main current carrying strikes will not vary much from the original tracer path.There may be several back and forth, very rapid strikes along this path before the cloud is equalized. Taking all of this into consideration, the utilities are constructed as they are because it is the most effective means to guide lightning.Form follows function.No system is perfect, of course,but look at where the utilities place their ground wire for MGN: ABOVE THE CONDUCTORS!What? Won't this attract the lightning from below and strike the conductors along the way? No it will not.I will leave the rest up to you to research for yourself.When you are sufficiently educated as to understand why not, I will revisit this site.Perhaps in a year or two will suffice.I hate to leave it hanging like this, but I have never encountered such a stubborn case of Narcissistic Personality Disorder.(NPD) or a greater PHILOSOPHUNCULIST (Google it). Now you can properly accuse me of ad hominem. Goodbye and good hunting

I have been a fly on the wall of this forum,hoping to glean some information from you two guys butting heads,but so far nothing has fallen out except dandruff. Both of you have my sympathy. As for who is right or wrong:It really does not matter.Lightning goes where it pleases, and breaks all the rules as it sees fit.Aircraft get struck by lightning,cloud to cloud lightning is also common.A ground is not required,only a difference in potential. Oh, and a side note: The tires on a vehicle do not protect from lightning.It is the Faraday shield effect of the metal surrounding the occupants that directs the damage away form inside.Likewise in a plane.A quonset hut that is grounded properly is a nearly perfect shield from lightning damage inside, unless it is brought in by ungrounded conductors from outside. Anyway, I leave this forum no wiser, but a little sadder for the experience to see engineering disciples engaging in petty bickering. ----------------------The FLY-----------------------------------------------------

Hi, Guest!

Quite right. The Faraday shield effect is indeed similar in its protective results to what happens when people are in a car during a lightening storm. Since the lightening strike works initially from the ground up and then from the sky down, it is treated as an AC current; while that outside of the Faraday cage is supposed to be from a static DC source. With the lightening, one is dealing with almost unimaginable voltages and amperages; and, like all very major AC electrical paths, the current path tends toward the exterior of the conducting bus bar (saving, in the case of a car, those folks trapped in the center).

The normal dielectric value of the tires, while it may very well have protective value against, say, a downed power line (which is what foolish me had in mind when I made the incorrect statement about the insulative value of tires on a car...It was a rapid typing moment, not a thinking moment...), has no ability to stop lightening (which has the energy to jump kilometers through the air) from passing through the car's tires and body. Perhaps there are rare instances of isolation, but I doubt they're real.

In either case (DC or AC), outside of the conducting surface is a good place not to be, while inside is safe. And in the case of either one, any kind of contact with the exterior conducting surface is a really bad idea .

The 'other' point of view in the discussion held that it makes no difference whether the strike is up or down, since both follow the same path; and the best technology for protection is a separator to break the circuit during overload combined with adequately low grounding resistance.

I have been attempting to point out that the strike path (down) does not always follow the upward path of the feelers (circled on the photo below), and hence that it may be possible to prevent the feeler from occurring on an otherwise potential target to begin with by employing methods of isolation and redirection. Note as an example the difference between the locations of various feelers and the final strike in this classic photo I took from Google:

The difference between our two views --ignoring the unfortunate nonsense that accompanied them-- is that mine is more preventative and innovative, and his is more alleviative and traditional.

Both are directed at the problem originally presented by Warrior, which was that his generator hardware is getting fried by lightening despite (or possibly because of) a new communications tower erected nearby.

Speaking for myself, I did not think that the other view's suggested

• employment of MOVs or
• connection of the generator ground to the lightening rod ground on the tower

were useful or correct methods of alleviating Warrior's problems even through traditional means. I think that the latter might have been a hastily drawn conclusion from the normal concept of grounding all members of a system together into one ground. Putting aside the possibility for the connected lightening strike to travel through the generator in either direction before an intervening MOV might have tripped, they are not parts of the same system, and are at some distance apart besides.

During the interchange, it crossed my mind that his real depth of knowledge was not quite what he presented it to be, since the main force of his arguments was based in ad hominem (about my purported lack of depth of knowledge in the subject area), much sarcasm and large quotes from websites that were not exactly on point. But I could be as wrong about that as I was to allow myself to get sucked in to the kind of discussion this turned out to be in the first place. We are all fallible in that regard.

Thanks for being a fly on the wall during this interchange. Is your name "Buzz"?

I promise to use a dandruff shampoo next hair-wash .

Mark

A lightning strike is actually a series of pulses with an almost infinitely short rise time, making it behave the same as RF.There are multiple strikes within each strike, and it is truly AC,because the direction of travel reverses frequently. RF analysis of strikes reveals the true nature of lightning.There are also effects in the upper atmosphere called Sprites, that have not totally been explained, that accompany a strike.It is possible that the ionosphere influences the path of the strike as much as the source and target.After all these years, still a mystery. I have seen ball lightning,where glowing balls of current roll across the ground and go separate directions.Really weird looking.How does the ball maintain it's integrity? No one knows at this point. No wonder the ancient peoples were terrified.

Hi, Guest!

That's interesting information, and seems fit well with the vibrational "flashing" appearance of a lightening strike. Is there a scientific paper or report that I can read on the subject to learn more about the RF research, and view the recorded sine wave life of a strike?

Do you think this occurrence is the same as the Sprite lightning, only by a different name?

Mark

Nothing is as irritating to a know it all as someone who thinks they do, hence the mutual irritation between you and Guest. ------------------------------ Fried Freud-----------------------------------

Sorry my response is slow on this one, but thanks for your comments. I have had some direct experience: dad studied, researched and consulted on lightning strike avoidance, mostly in FL. I learned some of the business with him, but am far from an expert. I do know the pre-pathway explanation is an observed (as you experienced) phenomenon and its dissipation is key. My solution would involve getting as much strike info. as possible for the local area (I know FL keeps track) and to contact the tower people. We can't assume it's the tower only. Mark, what mistake did I make?

Hi, Warrior (and Hi, DRFREON)!

Not having a definitive answer for your OP myself, and leaning towards the idea of removing the generator from harm's way, I emailed the "ask the experts" electrical section with this question:

-----Original Message-----

Sent: Sunday, December 28, 2008 10:25 AM

To: William Little

Cc: James Rickloff

Subject: Ask The Experts

* * * * * Ask The Experts * * * * *

Name: Mark

Question: If a generator is placed outdoors, what kind of equipment/materials/flooring/base can be used to effectively isolate the body of the generator from the earth so that its only contact with the ground is through its ground line?

The requester has asked for a response within 3 days

-----Original Message-----

From: James Rickloff [mailto:james_rickloff@advancedbarrier.com]

Sent: Friday, January 02, 2009 10:08 AM

Cc: Klostermyer, John

Subject: RE: Ask The Experts

Hi Mark,

I would not recommend placing the unit outdoors at all. The RTD's don't work below a certain temperature so you will get an alarm upon power up.

The generator should not come in contact with water. I would recommend that you contact STERIS for their input (John Klostermyer is copied on this e-mail).

Regards,

Jim Rickloff

Partner / Scientific Director

Advanced Barrier Concepts, Inc.

From: Klostermyer, John [John_Klostermyer@steris.com]

To: James Rickloff; Mark

Mark,

Jim is correct. The potential issues associated with placing a unit outdoors in an uncontrolled environment would outweigh any potential benefits.

John

Well, DRFREON, I have seen dozens of outdoor installations of generators with no more protection than a mounting slab (and the idea of freezing weather hadn't occurred to me in those instances since I was usually standing in bright sunshine at the time) --sometimes apparently exposed (although encased), and sometimes in big ventillated metal boxes, and I have seen dozens of generators located indoors on everything from ships to apartment building basements exhausting to the out-of-doors. Ordinarily, I'd be torn about what kind of advice to offer you. However, your difficulty presents as a generator that gets hit by lightening. So, for whatever reason that is occurring, and despite the fact that there are lots of lightening protection systems you could otherwise employ to protect it, your best bet seems probably to be: bring it indoors (or construct a separate building to house it)... and protect its building with appropriate strike interception equipment. Then the entire idea of its being struck with lightening will no longer be an issue for you. I hope you find this to be a useful set of ideas for your situation.

Best of luck. What did the tower guys advise, Warrior?

DRFREON, please remain the exemplar of sound engineering knowledge, good judgement and grammatical correctness that you have already set out to be. I didn't notice any particular 'mistakes' from you. Should I have?

Mark

None I could find, Mark, but I beat my brains out looking! Thanks for the clever info. search approach!

thank you all 4 the incoming suggestions..

i have arranged a talk with the telecom people and they agreed to look in to the issue..

A crow's feet earthing is recommended for generator earthing..

i find CR4 very useful.. thank you again..