ground rod at parking lot luminare pole base (again)

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concrete

concrete

When considering concrete as a over all conductor you must use all the variables reactance, impedance, Resistance and inductance.
Also a ratio of time as well as potential must be entered.
Frankly lightning delivers a very large load in a very short time span the goal is to deliver it to were it wants to go as quickly as possible.
(a) How does it react
(b) How much impedance does it encounter
(c) what posses a resistive factor
(d) does it encounter an inductive situation
 
Dennis
Think of the contact resistance comparison between the ground rod and the concrete pier.

The rod has less surface area.
The rod does not have the weight of the fixture and the concrete base to push against the earth, as does the pier.

If there is poor soil conditions, this will most likely affect the ground rod much more than the pier.


I am not saying not to add the rod, just that it is not very effective and I believe that it will not help the fixture during a lightning event anyway.
The lamp head gets hit by lightning it is goodbye electronics.

The lighting will travel down the pole, into the base and disperse into the earth. Most likely it will not follow the supply conductors due to the very fast/high frequency developed by the lightning stroke.
 
concrete VS rod

concrete VS rod

I understand your position. I can add little more with these exceptions.
A) Equip-potential plane: A grid,sheet,mass, or masses of conducting material which, when bonded together offers a negligible impedance to current flow.
(B) skin effect limits current flow to the extreme outer surfaces of conductors

Concrete can offer a very high impedance particularly through its mass, although as I stated earlier lightning travels as a skin effect over the outside surfaces of a true conductor.
Although the concrete has a greater over all mass, one must determine the ability for it to conduct over that surface. considering that a magnetic field forms around a conductor and hence is instrumental in the delivery of current I can not say with any certainty what if any kind of magnetic wave form or vector would be formed over concrete my gut feeling is do to the lack of uniform magnetic lines of flux as encountered in a conductor some off the lightning will be conducted although I believe do to its overall impedance numerous streamers will result
 
Concrete can offer a very high impedance particularly through its mass,
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I would bet that the concrete in the earth will almost always be a better conductor than the earth around the concrete.
Don
 
the earth

the earth

The earth is the ultimate negative charge and it has been prov en that it acts as an almost perfect conductor at certain frequency's
 
dennis schaffert said:
The earth is the ultimate negative charge and it has been prov en that it acts as an almost perfect conductor at certain frequency's
Click to expand...

Can you provide some data for that?

Roger
 
negitive

negitive

I would suggest reading the combined works of Nikola Tesla to start ,if you are not familiar with his research in the early 1900s you will find that most of our power distribution system , lighting and three phase power is attributed to his work. from his work was developed our communication system to submarines around the world
Also research of the x ray and its effects this will lead you to more modern day information on the subject.
Lightning is the equivalent to the discharge of a highly charged capacitor only on a global scale theoretically the concept is the same regardless of the size or amount of voltage the discharge occurs equalizing the unbalance potential that exists .
It is estimated that the sun delivers 216,000.000.000 VA continually to the earth and it sucks it right up ,thats one heck of a conductor!
 
The earth is the ultimate negative charge and it has been prov en that it acts as an almost perfect conductor at certain frequency's
Click to expand...

I'll ask again, can you provide some data to your statement?

Roger
 
??

??

So correct me if I am wrong but the strike creates voltage with a higher frequency? The higher frequency travels on the outside skin of the conductors? Is there any information on what kind of frequency the energy is delivered at?
 
Dennis
You have pointed out some areas of research that can be very convincing, especially whenever we discuss Tesla.
However...
There are modern day facts of which we are discussing.
You will see that most info espousing the benefits of ground rods comes from manufacturers of ground rods.

I am not too sure if you understand current flow principles when the current has very quick rise and high frequency. The lightning will not really see the longer conductors from the light pole supply that goes back into the building, because it will see the concrete pier as a much "better" path to the earth.
The same will be for the relatively small conductor that connects the pole to the ground rod.

I would also suggest that instead of just fighting the trend you see here from some very, very talented people of our great industry, that maybe you reach out and see if maybe your trend of thought may no longer be the accepted method(s) today.
Pay particular attention to Don and Dereck, as both have many years of very pertinent education to help us all here.
 
dennis schaffert said:
The earth is the ultimate negative charge and it has been prov en that it acts as an almost perfect conductor at certain frequency's
Click to expand...

Very true when you take the planet as a whole. However when taken by the dump truck full it is a very poor conductor.
 
"from his work was developed our communication system to submarines around the world"

Whaaat? Where do you get this from? Again please provide some background data.

EM1(SS) Zog
 
Back ground

Back ground

You might start by going to Jim Bieberich's Complete Nikola Tesla U.S. patent collection. As you begin to search you will be amazed. You will find that he was one of the first presidents of the now IEEE.
Secondly I would suggest that you review telluric current and a brief explanation can be found on wikipedia.
To your amazement you will also find that a judgment was made in his favor by the united states supreme court between Tesla and Marconi as to who built the first true wireless , as you progress into electrical history you will find very familiar names such as one of his key financiers George Westinghouse and also JP Morgan and of course J Edgar Hoover. the list goes on.
Recently some guys at MIT just duplicated one of his feats 100 years latter. and if you really get into it all ,you will figure out why he was written out of the history books .
Anyway the list of advances he contributed to electrical theory is vast
 
dennis schaffert said:
...Secondly I would suggest that you review telluric current and a brief explanation can be found on wikipedia.
Click to expand...
I would not consider this a peer reviewed source of information - certainly nothing I would cite for a paper.

Your conversations are very interesting, but contain little I would consider authoritative. I know that sounds harsh, but unless you have peer reviewed sources, the rest is just gossip.

carl
 
I'm still waiting for your backup. Telling us to read the history of Tesla, Westinghouse, Faraday, etc... is not substantiation to your staterment.

Okay, it's time to come clean, you really don't have any white papers or documentation to back up your claim do you? :grin:

Roger
 
I agree

I agree

I apologize for my rambling on and much of it bears little on code review. And I will not begin to attempt to see my self as a peer of any of the names mentioned
This started out with a question regarding lightning and there are differences of opinion I understand that much is still to be learned regarding the subject. although much has already been learned as well .

What we all must remember is that if questions and answers are not derived progress will never be achieved and many times these questions refer us back to basic fundamentals and theory and the review of past work. scientific fact only remains fact until a new discovery modifies it or changes it, this is true of the codes as well and future changes that will occur

Concerning some sort of back up or paper I did a quick look at my files and I will ask you to go to The United States Patent Office , you will have to down load there browser and do a search for patent No 787,412 April 18 1905. I believe you will find it interesting.
In ending this conversation I personally believe that the individual as mentioned earlier, and still today is the greatest authority concerning lightning and believe that his work is timeless and priceless at least what records still exist
Dennis
 
Dennis I am not sure where to begin, so I will just be blunt and throw it out there. To my knowledge Telsa, Edison, and Westinghouse have nothing to with any of the modern lightning protection schemes used today. It goes back a lot further to 1765 and good ole Ben Franklin, plain and simple. His practices are the foundation of all lightning protection used today endorsed by just about every electrical authority you can name.

The two bibles in use today are mirror images of each other. NFPA 780 and UL Black Label Program. 780 is the design and installation paperwork and UL Black Label is the certification organization, both endorsed by the NLSI. Of the 460,000 Master Label certified sites issued less than 1/10th of 1 percent of the sites employing Franklin techniques have experienced any damage from a lightning occurrence. Of those it was found either improper maintenance or modifications were made that compromised the system.

NFPA 780 is the bible of all Telephone and technical companies lightning protection standards and one I have followed for at least 30 years, and based all engineering standards I have had the pleasure to be part of.

Actual ground impedance is of little importance, it is the proper bonding of all metallic objects and there connection to the earth terminal that is important. When it gets right down to it the best electrode for lightning protection is a ring, followed by CCE, and at the bottom of preference is a rod because a rod has the highest AC impedance of all the electrodes. Basically a rod is a DC and power frequency device and not of much use in high frequencies.

If you really want to know where, when, and how of lightning protection systems here is your document which will back up everything I have said here.

http://www.lightningsafety.com/nlsi_lhm/conventionalLPT.pdf
 
dereckbc said:
Dennis I am not sure where to begin, so I will just be blunt and throw it out there. To my knowledge Telsa, Edison, and Westinghouse have nothing to with any of the modern lightning protection schemes used today. It goes back a lot further to 1765 and good ole Ben Franklin, plain and simple. His practices are the foundation of all lightning protection used today endorsed by just about every electrical authority you can name.

The two bibles in use today are mirror images of each other. NFPA 780 and UL Black Label Program. 780 is the design and installation paperwork and UL Black Label is the certification organization, both endorsed by the NLSI. Of the 460,000 Master Label certified sites issued less than 1/10th of 1 percent of the sites employing Franklin techniques have experienced any damage from a lightning occurrence. Of those it was found either improper maintenance or modifications were made that compromised the system.

NFPA 780 is the bible of all Telephone and technical companies lightning protection standards and one I have followed for at least 30 years, and based all engineering standards I have had the pleasure to be part of.

Actual ground impedance is of little importance, it is the proper bonding of all metallic objects and there connection to the earth terminal that is important. When it gets right down to it the best electrode for lightning protection is a ring, followed by CCE, and at the bottom of preference is a rod because a rod has the highest AC impedance of all the electrodes. Basically a rod is a DC and power frequency device and not of much use in high frequencies.

If you really want to know where, when, and how of lightning protection systems here is your document which will back up everything I have said here.

http://www.lightningsafety.com/nlsi_lhm/conventionalLPT.pdf
Click to expand...
Well said sir
Dennis
 
I understand concrete encased steel rebar is a great electrode as required by the NFPA 70 N.E.C., but is it permitted by NFPA 780 L.P.C. to be used as the lightning protection electrode?? or would it be connected to an earthing system ? I am not well educated on this subject but have enjoyed this thread ,... It has me thinking and that is a good thing!:smile:

I think what is being installed in the O.P. is a supplementary grounding electrode and as such , it is not required to be incorporated into the grounding electrode system???
 
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