[BC] Lightning and grounding ... fun for all!

[Bruce Doerle]

Alan,
 
Good morning to you; it was interesting story you wrote.  I have had some too, but nothing as interesting or as extensive as yours.
 
Let's get back to CTS devices.
 
"So does it work?"  It does not work as claimed.  Uncle Sam does not knowingly allow the installation of these devices.  The  Federal Interagency Lightning Protection User Group consisting representatives from the Army, Navy, Air Force, NOAA, NASA, DOD Explosives Safety Board, National Nuclear Security Administration, and FAA submitted a finding in June 2001 that basically said that nothing has been found to improve upon the conventional lightning protection devices as defined in NFPA 780.  NFPA only recognizes lightning rods, not CTS or ESE devices.  Their report, "The Basis of Conventional Lightning Protection Technology - A review of the scientific development of conventional lightning protection technologies and standards", can be found on the internet.
 
In the old west, snake oil salesman played upon the desires and hopes of the unknowing.  If you are looking for an easy cure, you're a prime canidate for their product.
 
It seems to me that on that one facility that you mentioned, there may be more at play.  Certainly the upgraded ground system will do more to protect the systems than anything else by providing a means of discharging the strike.  If you had a good grounding system on the tower in your story, you probably would not have had much of story either.  In most sources discussing lightning system protection, a solid ground system is essential.
 
I am not saying don't use them, I am saying you to know what you are or are not getting.  Most of it is hollow promises and it is your money to waste.  You might want to read the following email concerning a discussion of the CTS devices installed at the Memphis FEDEX facility.    
 
http://bellsouthpwp.net/B/r/BroadCastDesign/lightning/CTS_Gadgets_at_FedEx.txt 
 
Have a nice day,
 
Bruce

>>> radiotech at bellsouth.net 05/19/05 7:26 AM >>>

Bruce,
I did read your post on radio tech, I have read the information you have 
provided below. I have also seen the number of strikes dramatically 
decrease when a static dissipation array was installed. So does it work?
I can't say it does or it doesn't, but it sure seems to help. In the 
poly phasor document you have provided, it indicates that a ground for 
the array may not have been provided. What I know of the dissipater 
systems they don't work without a very solid ground. Also if you 
properly install them you will have also provided a way to control a 
strike should it occur. So far none of my clients have decided to 
installed an array, so I've only played with them on others sites.
But I'm not as quick to dismiss their effectiveness since I have seen 
the lack of evidence that they don't work.
One facility I'm thinking of was getting serious damage at least twice a 
year. They installed a system, they haven't received any damage since 
that time (about 5 years now). So the question is are they just lucky, 
or did the array do something to help? Was it the additional grounding 
they did to install the system? I think only Mother nature knows for 
sure and she hasn't written a white paper on it yet.
It seems to me (humm I might have to jump on this) the ideal solution 
might be a Franklin rod incorporated into a dissipating device.

I have experienced up close and personal what I consider the strike of 
the century. It destroyed all conventional protection. Would a 
dissipater have prevented it? we'll never know.  This strike hit 1 tower 
in a 3 tower DA array. It came from an almost clear blue sky, one lonely 
cloud, that produced one single strike and no rain. It hit the beacon 
and demolished it (all glass blown out top blown off, to be later found 
500' from a 300' tower) at the base of the tower 2" solid arm ball gaps 
were bent backward around the base of the tower. 4 3" .032 copper straps 
feeding to the ground system were gone leaving only black stripes on the 
base where they had been. With ground gone the strike decided it would 
run the cables back to the transmitter shack some 1500' away. Once in 
the phasor it open arced 22' across the room to a 100 pr phone entry 
block. were it exited the building to run under the street and blow a 
5000 pr phone cable in half under the street. I was in the room but 
luckily not between the phasor and phone block when the strike hit. It 
was a few minutes before I could see again and my ears rang for 2 days.
there was quite a bit of other damage at the site. Radio station damages 
were about $25,000, and probably about $10,000 for ma Bell.  I'm not 
sure how much it costs to have 10 cable splcers working around the clock 
for 2 days. Ok so this story doesn't provide anything towards the 
discussion at hand, other than good conventional systems can fail too. 
But I do like telling this story. :)

-- 
Alan Alsobrook CSRE AMD CBNT
St. Augustine Fl. 32086 904-829-8885
aalso at Bellsouth.net