Loop it !!!

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danharris

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I install wireless internet.We use a yagi antenna to mount on the customers eve or roof top to receive the 900 mhz signal.I have a question about lighting and grounding .I have been told by a customer(lawyer)don't worry about grounding my antenna , just put a loop in the cable . If lighting hits my antenna , the loop will keep my equipment (COMPUTER,ROUTER,HUBS ETC.) from getting damaged . Give me some in-put about this lawyers theory .

{Moderator's Note To the Original Poster: I have deleted an unkind statement that used inappropriate language. Don't do it again!)

Also give me some info on how you would ground this yagi antenna . Note; sometimes we install this antenna on a one foot mast pole off the customers eve or a twenty through fifty foot push pole .

[ May 18, 2004, 10:06 PM: Message edited by: charlie b ]
 
Re: Loop it !!!

I take it you are not familar with the NEC rules on Antenna Mast grouding in Art 810 and coax grounding in Art 820? Basically, every mast must be grounded and the coax grounded as well. You'll need to get a copy of the NEC and read article 810 and 820. The loop is actually a bad idea. Lightning does not like bends.
If you are a professional installer, then you and your customers will benefit from you installing the equipoment in a safe manner.
Also some areas require permits and inspections for the type of work you are doing.
 
Re: Loop it !!!

I'm familar with the LMR-4OO grounding kit I use one on every install . NOW IF ANYBODY CAN , please answer the question I asked . I know how to install a Wireless System . I need in-put from someone who installs wireless systems and other antenna installations to compare grounding techniques . Thank You
 
Re: Loop it !!!

Tom did answer the question, you must ground the antenna per NEC, no exception for loops :roll:

I have been told by a customer(lawyer)don't worry about grounding my antenna , just put a loop in the cable .
Click to expand...
If you want legal advice ask your lawyer customer, if you want to know proper grounding methods look in the NEC, forget about what the lawyer tells you to worry about.
 
Re: Loop it !!!

Originally posted by danharris:
Give me some in-put about this lawyers theory .

Also give me some info on how you would ground this yagi antenna
Click to expand...
Your lawyer does not have a clue what he is talking about.

You have to follow the minimum requirements outlined by NEC 810 and 820. I would ground the mast to the service ground electrode. Run the coax in such a manner where it enters the building at the electrical service entrance to facilitate grounding the coax and ADU to the service ground electrode to comply with 810 & 820.
 
Re: Loop it !!!

This lawyer is your customer. He has a conflict of interest and cannot render unbiased legal advice in this situation. If he tells you to run a proper and required ground it's going to cost him money. He's a cheapskate and wants to save his money for his Benz. OK, that was unwarranted speculation but you get my drift. Customers are very good at telling you what you do and do not have to do on their jobs. Once the job is done and all invoices and been paid if anybody gets hurt the lawyer will not hesitate to sue you as the deep pocket. Again, that is mean spirited speculation but you get my drift. If somebody gets hurt or if any property is damaged for lack of proper and required grounding you will be sued. To me all the #8 solid I have in my truck as a result of skimping on grounding will never make up for anybody getting hurt on my watch. I have to put my faith in the code making panels that they know something that my lawyer does not. Improper or absent grounding can lead to bodily or mechanical injury.
 
Re: Loop it !!!

Thank you dereckbc member#30.Thats in-put i'm talking about.Anybody can say ground the antenna per NEC.If I had a NEC,I proberly wouldn't be asking for in-put.I think an illustration or step by step is more useful.
 
Re: Loop it !!!

Danharris, your question requires substantial information from the NEC. You are looking for a quick and easy answer, we can't post that much information here.
Two resources:
1. Mike Holts Understanding Low Voltage and Limited Energy Systems, this text will cost you about $30 and will answer most of your questions.
2. Here is an article I wrote on traffic signal radio installations that will help somewhat:
http://www.imsasafety.org/journal/journal.htm

You will still need a copy of the 2002 NEC. For a starter get the Mike Holt text, then if you have any more questions please ask.

[ May 19, 2004, 02:57 PM: Message edited by: tom baker ]
 
Re: Loop it !!!

You might want to look at Underwriter Laboratories UL-96A the National Fire Protection Association NFPA-780 and the Lightning Protection Institute LPI-175 for lightning protection systems. When running your ground from the antenna avoid nice neat 90 bends. If you must make 90 bends then radius them 8 inches or more. There was a bit of truth in what the lawyer said. The straighter the path to ground for lightning the better. The loop in the coax is some benefit as far as lightning protection. However as you say it doesnt do anything for personal safety and will be a case you would not win in court.
 
Re: Loop it !!!

I forgot to mention that bends in the ground wire from the antenna should not be less than 90 degrees. I would also put the loop in the coax or twisted pair signal cable. I put a loop in my phone and TV cables to help with lightning protection of my TV and phones. Lightning is like high frequency. A bend or loop creates more magnetic or inductive coupling which makes the bend or loop have more impedance or resistance to the flow of lightning current. Too many loops would also give more impedance to the 900 mhz signal resulting in a weaker signal to the computer or tv.
 
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