Hello everyone,
I'm searching for information regarding lightning protection standards, requirements and testing procedures.
So far I have found numerous sources mentioning indirect lightning standards like EN61000-4-5 which deals with the induced surge in the system.
Not a lot of sources discuss about direct lightning protection testing. So far I have found that DO 160 section 23 specializes on that aspect but can't find a lot of information regarding the test procedure, even the type of testing equipment to use (compared to a lot of surge generators used for the EN61000-4-5 test).
Anyone has experience on this issue? Is this much more common to use indirect lightning tests than the direct one?
The object to be tested here is outdoor communication equipment.
Thank you all in advance.

 

I know that military contractors do lightning testing. I personally didn't do the testing but was directly involved with the aftermath and design changes after the testing. A quick search of NASA documents I came up with https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20000004589.pdf and Mil Spec search http://everyspec.com/MIL-HDBK/MIL-HDBK-1000-1299/MIL-HDBK-1004-1_NOTICE-1_24175/

 

I suspect the main reasons for the lack of standards covering protection from direct lighting strikes is the random characteristics of such real world events, and the cost of equipment capable of generating such high voltage/current events.

I believe that the standards you cite in relation to indirect strikes use a 1.2/50us test waveform – even so, such equipment capable of generating this waveform with a peak voltage of 10kV costs many thousands.

In the real world, radio transmitter masts are fitted with voltage surge arrestors together with voltage detection circuits that disconnect the signal feed in the event of a strike. Even with such protection, direct strikes may result in considerable damage to the transmitting equipment.

 

The best idea is for testing the house hw much it is fire-proof, try to burn this house. Isnt the thunder-strike test sth similar??
But to more serious note, there at ebay exists a cheap tester for atmospheric charge measurement. I use it for cleanroom ion count balancing. Ther must be negative charge for air by aeroionizer, but not too high. I imagine that Your case if You measure under around the house, You positively will see how far the earth potential is being seeded by Your grounded `sword`.

 

There are no standards, because all you need is an iron rod connected to ground.

 

There are no standards, because all you need is an iron rod connected to ground.

How does your system test the effect of lightning on an aircraft in flight? I am having a hard time visualizing how you connect that aircraft to an iron rod connected to the ground.

 

There are no standards, because all you need is an iron rod connected to ground.

That's how you provide a local grounding path for a building, not how you determine the effects of a lightning strike on any piece of equipment nearby.

Even at that, you've oversimplified. There ARE standards for that rod, and they define the length and material for the rod(s) how deep they need to go, and how far apart they should be, depending on soil conditions, etc.

 

There are no standards, because all you need is an iron rod connected to ground.

Absolutely wrong:
Firstly, there is standard for maximum permittable ground resistance. I am now trying to remember it was 4 Ohms.
Secondly, the rod end must be sharp enough.
Thirdly, the wire cross section is reglamented as well.

All local demands are, by most of governments, published under the name `the local building code for fire safety, thunder safety and ... blablabla`, and it may differ from state to state.

 

What I meant is, we all buy a standard rod from the shop and put it in the ground, and that's it. None reads the standard for how low the ground resistance should be. Which is actually 10 on -7.

 

What I meant is, we all buy a standard rod from the shop and put it in the ground, and that's it. None reads the standard for how low the ground resistance should be. Which is actually 10 on -7.

That seems to depend a lot on the country. Here you have to have a project and a revision for the lightning rods, and if you don´t and your house burns down along with the neighbors than you get zero money from your insurance company and are in debt for life.
and 10^-7 of what? I doubt its ohms.

 

Yes, I agree its dependant on the country. Here there are no insurances, because the thieves do not prosper as much as in the US.

Its Ohm/Centimeters.

 

RE: ""and 10^-7 of what? I doubt its ohms""

I guess sooner the gigaohms. Because my last earthening job was a grand fail for this reason.

Just at yearly network inspection was turning out that institute earthening conture has 27 Ohms instead of demanded 4 Ohms.
As we had then high point of ground floor betonating jobs, I succeeded to purchase the zincked specialized earthening rods, specially manufactured for that aim, and by 40 kg heavy hammer I managed to beat the 6 points, where each point was 4 rods each 1,5 meters long.
Thus the 6 meters deep rods with area each hole about 4000 cm2 was switched parallely and after five minutes the concrete cystern was coming and pumped in the beton in 8 inch thick layer.
So, to measure the impedance was not enough time then. But when beton was dried after 21 day, the measurement we made, and it shown a ... 13 Ohms.

Absolute fail, and seems nowhere to beat an additional rods except the street pavement.

 

More over - that graph for soil resistivity probably works well in the Amazonian jungles where all the ground is centuries wet, but in the city environment where probably thousands of years old stone ruins stays just under the newspaper kiosk foundament or 11th century water drainage system is buried down there - thats completely another story, and if to immagine the Sweden where in Stocholms lan soil probably under the feet is ca 5 cm deep, where below is 1000 kilometers deep granite rock - thats an another story too.

 

When I was involved installing radio comms kit I was surprised a the number of lightning protection systems that had faults with the building owners / occupiers insisting they had a five year cert issued a few years previous by a specialist. Most common fault was the tape to rod connection badly corroded or rotted to the point of disconnection and which didn't look as if it had been inspected since it was installed. Also check that the rods / earth mat are still giving good readings when tested. You should probably contact a lightning specialist to ask for their assistance, until you get some more experience with this type of installation https://www.streamer-electric.com/