lightning stroke 2

[extention]

Hi
I will like to protect a telephone system from lightning stroke.
There are a few buildings with underground tel lines. Sometimes, lightning stroke blow the stations connected to the underground lines. I bought TII 763 Indoor Network Interface Device (see address below) Am I using the right thing? I do not wish to ground it since the overcurrent is comming from the groud, am I right? How do I find out wich wire is tip or ring since it is my own underground telephone cable (red or green), do I have to bother about that when I install TII 763?

Any expert???
thanks
MB

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&category=58299&item=5740851366&rd=1&ssPageName=WDVW

http://www.comm-omni.com/tii/763.html

 

[skip555]

you dont need to ground it unless you actully expect it to do something to protect the lines

yes it does need to be grounded

I dont mean to be unkind but I think you really need to call someone in who knows what their doing.

proper grounding takes a bit more knowledge than you will glean here from a few responses also need some spealized clamps and fittings that you wont find on ebay

 

[pbxn]

Call your vendor, and ask that they perform an on-site power and grounding inspection. If they cannot personally do it themselves, have them refer you to a lic. electrician, and schedule a joint meet with your vendor and the electrician. Most vendors today have at least one tech. who is well versed in pbx power and grounding standards, which will include but is not limited by proper building ground, cable ground, and dedicated switch grounds.
Good luck

 

[johnpoole]

the tip side of a line has a ground ref, (green). you need a ground and you need gas protection on all cable pairs external to your site. if your getting power back on the output cable, it is induction cause by lightning, when you take a hit on an ungrounded switch, the current find it's evil way to the power ground, usually burning power supplies as well as the cards that it came in on. with the right ground, you will lose the card, nothing more. gas protection should stop that. you don't want to make your switch the best ground for 30 miles, but it does need to be grounded.

john poole
bellsouth business
columbia,sc

 

[SYQUEST]

There is a whole section dealing with proper grounding and bonding requirements in the NEC (National Electrical Code). Specifically section 800 is for communications. This is very good reading and should be a requirement for techs or anybody working at the hardware level.

Also there is a publisher, Mike Holt Enterprises, that publishes very good books on these subjects and really explains and simplifies the CODE with excellent examples of all kinds of applications with the DOs and DON'Ts.

Hope this helps!

....JIM....

 

[PERRYPJ]

HERE IN FLORIDA THERE IS NO SUCH THING AS A SURE THING LIGHTNING PROTECTION. I'VE SEEN THE BEST COME AND GO AND THEY STILL LEAVE THE CUSTOMER WITH DAMAGED EQUIPMENT

OLD ROLMEN WORKING ON NORTELS

 

[pbxn]

Regardless if there is not a sure thing about protection. It is about accountabilty and who is goin to flip the bill when damage occurs. I would personally much prefer have that burden on my vendors shoulders..

 

[ttech]

What you bought on ebay does not provide lightning protectiion anyway. If you notice the Brass nut on the left goes via a 24 guage wire to the green screw on the customer side. It is only a "convenience ground".

The ones with grouding hame a groundbar in the CO side and TII355M modules as seen at this place

http://smarthome-pros.com/techwire/demarc.html

 

[ISDNman]

There are a couple of different approaches, which are best combined.

First of all, makes sure the proper "Protector" with gas discharge tubes is installed correctly at the building entrance. This is primarily for safety, not for equipoment protection, but it is a necessary first step. You should also get a ground tester and verify the ground is good. Also, the telecom ground MUST be bonded to the power ground. This is required by NEC for good reason - if sufficient current is conducted to drive the ground to a higher voltage (and this does happen with the massive currents involved in a strike), you want all grounds to float up by the same amount. You want to avoid differences in ground potential.

In places like Florida a second stage of protection is advisable (this is also true in other places, depeding somewhat on the cost and vulnerability of the equipment to be protected). The goal hear is to prevent major voltage differences between the phone lines and the protected equipment. Again, if both rise together temporarily that is good, versus the phone line rising and the equipment laggign behind thereby permitting a difference.

In this second case the proetection is typicall MOV-based and should be installed as close as possible (less than 12 inches) to the equipment to be protected. For simple gear with modular plugs this is easy, insert it in series with a short 6" cable to the equipment. Then AND THIS IS CRITICAL to success, connect the surge protector ground wire to the grounded chassis of the equipment (again keep it short). This will serve to keep the two at the same potential.

A radio station Cheif Engineer freind has had very good luck in FL dramatically reducing problems using this approach. He typically uses the Polyphasor products, but he has proven again and again that this technique of referencing the surge protector to the chassis is the key to success.

Another technique that is very easy is the lightning choke. Simply wind 10 turns of wire around in a circles and wore tie. Even placing 3 or 4 knots in the cable has been proven to help. This creates and inductor. Inductors don't like to pass sudden changes in current, and since lightning is a very rapid change (e.g. a spike) this simple technique works well, is low cost, and is ideal to combine with the above.

In FL nothing will completely eliminate problems, but expect a dramatic reductions using these techniques.

 

[aarenot]

http://www.itwlinx.com/products/subcategory.asp?category=42&subcategory=91

try this. I believe the company provides some level of protection when the level of protection of the equipment is exceeded. Properly installed, they say they cover damage.