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Posted By: hbiss Anybody do lightning systems? - 02/16/05 01:23 AM
Anybody with lightning protection experience? I have a job coming up where I will have to run some #4 copper ground conductors on a pitched asphalt shingled roof from an antenna site installaton. I am thinking that this is done regularly with lightning protection systems and the same cable fasteners should work well for this application.

I see that there are basically only two types of fasteners- a copper loop or strap with a nail or screw through it and a square copper pad that gets stuck to the roof with pitch or adhesive. Problem is all the lightning protection systems I have seen have been on buildings with flat roofs and masonry construction so anything I saw won't really apply here.

I'm leaning towards the nail and strap with maybe a dab of sealant but I'm not liking that. Anybody done this before?

-Hal
Posted By: Trumpy Re: Anybody do lightning systems? - 02/16/05 10:34 AM
Hi Hal,
What sort of Antenna system is the grounding conductor protecting?.
Personally I would agree with your statement on the fastening of the Grounding Conductor, it does need to be as strong as possible.
Coming from a PoCo background, I have seen Grounding wires wrapped around 11kV conductors, a long way above the position where the should have been connected.
During a lightning strike, the Energy levels are HUGE!.
Posted By: Big Ed Re: Anybody do lightning systems? - 02/16/05 12:56 PM
We have just replaced all of the aerial lightning protection on our two cooling towers. We used the copper loop type support. Ours was a different roof than you are dealing with, but they are very secure.

Just out of curiosity, how will you be connecting to ground and to the antenna? The reason that we replaced our system was due to mechanical compression fittings. They had to be replaced with exothermic welds. It is really not that difficult to do, but there is a bit of up-front costs and you have to be careful not to set your roof on fire.

I have a buddy who does roofing. I will see him tonight and will try to remember to ask him about the fasteners.

Have a great day
Ed
Posted By: hbiss Re: Anybody do lightning systems? - 02/16/05 02:25 PM
Thanks guys. This is a 1.2m sat dish mounted on a steel channel framework as well as some VHF TV/FM antennas located a short distance away. We normally use compression connectors (lugs) and have not had any problems. Just never had to do this on this type of roof before. I'm a bit leery of putting nails or screws through the shingles.

-Hal
Posted By: dereckbc Re: Anybody do lightning systems? - 02/17/05 01:21 AM
Hal, I do a lot of the designs or should I say I used too. There are several companies that make the products, I used Advance Lightning Protection Technologies. They have non-metalic clamps to use and you fasten them to the roof using either black-top cement or epoxy.
Posted By: hbiss Re: Anybody do lightning systems? - 02/17/05 03:24 AM
Thanks Dereck. Non-metalic is interesting, never found them anywhere, should be similar to the copper ones I have seen. Can't find Advance Lightning Protection Technologies. Any ideas?

-Hal
Posted By: dereckbc Re: Anybody do lightning systems? - 02/17/05 03:36 AM
Let me do some checking with some of my ex employees tommorow and see if they are still in biz.
Posted By: dereckbc Re: Anybody do lightning systems? - 02/17/05 03:23 PM
Advanced Lightning Technologies
122 Leesley Lane
Argyle, TX 76226
940-455-7300 www.advancedlightning.com

Moderators this is not an advertisement, just info I am passing along as requested.

Hal if the info gets deleted PM me on that other web site I hang out at, and I will resend via PM.
Posted By: hbiss Re: Anybody do lightning systems? - 02/17/05 06:25 PM
Thanks Dereck, got it.

-Hal
Posted By: Clydesdale Re: Anybody do lightning systems? - 02/18/05 02:33 AM
is #4 copper typical for lightning protection?

[This message has been edited by Clydesdale (edited 02-17-2005).]
Posted By: hbiss Re: Anybody do lightning systems? - 02/18/05 05:16 AM
No,usually much larger. It's actually overkill though (per NEC) for grounding antennas, only #10 is required.

-Hal
Posted By: dereckbc Re: Anybody do lightning systems? - 02/18/05 02:57 PM
Clydesdale, the down and bonding conductors come with UL designations of Class 1 and Class 2 conductors. Both are similar in design and do not look anything like you are use to. They do not come in standard sizes like # 6, 1/0, or 500 MCM, rather something like 29x17 woven or 32x17 ropelay. Which means the cable is 29 strands of 17 gauge wire in a woven pattern. It looks like a braided wire like a coax shield, so it has a lot of surface area. It is about the size of 1/0 and 3/0 depending on the Class.
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