Lightning Protection Testing

[Sparky83]

Hi all,

Hope this is inthe right section,

I have been asked to quote for testing the lightning protection on a small sized building, i have read about testing across the joints and needing to get a certain reading etc but other than that im not sure what is required.

Is it that difficult a job to carry out?

What exactly is involed?

I've had a bit of a search on the world wide web but most of the stuff i found is about installing not testing it.

Any help would be great,

Cheers
Shawn

 

[Sintra]

Have a read through this site and it will let you know about what's involved.

 

[Sparky83]

Cheers, thanks for that. Good read.

 

[UNG]

Not that difficult to do

As with alot of jobs the specialists will look to frighten you off

Testing the earth rods can be awkward on some sites they can be buried with no access without digging don't assume a good connection without digging if needed

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

 

[Sparky83]

Thanks for the info.

 

[neeraj]

Hi all,

Hope this is inthe right section,

I have been asked to quote for testing the lightning protection on a small sized building, i have read about testing across the joints and needing to get a certain reading etc but other than that im not sure what is required.

Is it that difficult a job to carry out?

What exactly is involed?

I've had a bit of a search on the world wide web but most of the stuff i found is about installing not testing it.

Any help would be great,

Cheers
Shawn

Hi Shawn, Well Actually there is no direct short cut way of testing the lightning test but I feel that you can do a resistance/ megger test of the lightning grounding path and the rest of the building surface nearthe conducting strip used for the grounding purpose. The Megger should be 10 KV or above and you should check the resistance between conducting strip anywhere in the building and the earth. Also you should check the resistance between theconducting strip and the surface of the biulding i.e wall or windows and fans or TV. In the first case the resistance shouldbe zero. and in the second case the resistance should be in gega or tera ohms or inifinity.

 

[dasersc]

Has anyone got a generic certificate for LPS tests etc?? or know where is there such a thing.

 

[netblindpaul]

You will also need the LPS standards to refer to just like you need 7671 & the EM Ltg etc.

 

[Engineer54]

Hi Shawn, Well Actually there is no direct short cut way of testing the lightning test but I feel that you can do a resistance/ megger test of the lightning grounding path and the rest of the building surface nearthe conducting strip used for the grounding purpose. The Megger should be 10 KV or above and you should check the resistance between conducting strip anywhere in the building and the earth. Also you should check the resistance between theconducting strip and the surface of the biulding i.e wall or windows and fans or TV. In the first case the resistance shouldbe zero. and in the second case the resistance should be in gega or tera ohms or inifinity.

You've obviously never conducted a lightning protection testing procedure in your life!!! Never heard such a load of garbage.... Since when would you require conducting an IR test on a lightning protection system, ....let alone using a 10KV unit!! Total rubbish!!!

 

[La Poste]

I would love to know more about lightning protection systems.

Does anyone have any good links they could recommend?

Thanks.

 

[Engineer54]

Hi all,

Hope this is inthe right section,

I have been asked to quote for testing the lightning protection on a small sized building, i have read about testing across the joints and needing to get a certain reading etc but other than that im not sure what is required.

Is it that difficult a job to carry out?

What exactly is involed?

I've had a bit of a search on the world wide web but most of the stuff i found is about installing not testing it.

Any help would be great,

Cheers
Shawn

What readings were you quoted for ''across'' joints Shawn?? Sintra has given you a broad outline of what is required on testing a lightning protection system, but it doesn't really go into too much detail really. You WILL need a dedicated earth testing kit, don't try and get by with a MFT. Also it's better to use a Ductor tester ( m Ohms) for your joint testing. For your overall Ra value use the LP releasable test point. It should be under 10 ohms, but i can't remember ever getting such a high value. Well designed LP systems will have the ground rods linked with at least one or maybe even two removable link points so that sections of the LP system can be tested separately. Older systems, or cheaper installations won't have the earth rods linked and down connectors will extend to each individual rod. If that is the case then each down conductor should have it's own test point on the building 1.6m OFGL. especially when earth rods are not accessable, (no earth box) These should be exothermic welded connections (maintenance free joint)

The copper air conductor tape fixings and any air conductor spikes should be checked for soundness they shouldn't ever be in anyway loose. There shouldn't be any bends over 90 deg or you can have flash overs. All mechanical plant such as AHU's, AC ducting, Fans, Aerial masts, and other metallic structures etc should be bonded to the LP system with not less than 50mm CSA copper cables/tape, preferably hard drawn copper cable. Much depends on the system installed and how complicated the system is, as to how difficult the testing procedure will be. You say a small building, so shouldn't be that difficult. Remember that anything remotely to do with signal gathering will need a surge arrester in-line with any bonding arrangement.

 

[UNG]

The copper air conductor tape fixings and any air conductor spikes should be checked for soundness they shouldn't ever be in anyway loose. There shouldn't be any bends over 90 deg or you can have flash overs. All mechanical plant such as AHU's, AC ducting, Fans, Aerial masts, and other metallic structures etc should be bonded to the LP system with not less than 50mm CSA copper cables/tape, preferably hard drawn copper cable. Much depends on the system installed and how complicated the system is, as to how difficult the testing procedure will be. You say a small building, so shouldn't be that difficult. Remember that anything remotely to do with signal gathering will need a surge arrester in-line with any bonding arrangement.

With any radio equipment the type of surge arrestor used needs careful selection as some do not pass DC voltage which is needed with some radio equipment with active outdoor units also in some situations the downleads will need bonding as well

 

[Engineer54]

With any radio equipment the type of surge arrestor used needs careful selection as some do not pass DC voltage which is needed with some radio equipment with active outdoor units also in some situations the downleads will need bonding as well

Yes, i'm aware of that, i was basically only giving a broad overview in my post. There is much more to several other points in testing LP systems too but to write it all out verbatim, it'll end up as long as a text book...lol!!

 

[mrc]

go onto the furse website and get a copy of the guide to the new bs