nanog mailing list archives

Re: CAT5 surge/lightning strike protection recommendations?


From: "Marshall Eubanks" <tme () multicasttech com>
Date: Tue, 13 Sep 2005 20:58:24 -0400


On Wed, 14 Sep 2005 12:24:39 +1200 (NZST)
 "Mark Foster" <blakjak () blakjak net> wrote:


I have a bunch of cat5 buried about 1 ft below the surface connecting
multiple
buildings on a campus (short runs) and lightning strikes nearby have
caused
surges along one or more of the cables and burnt out switch ports. I would
like to protect the switch ports -- there seem to be lots of products on
the
market.

Anyone have recommendations (tested/practical is best :-)?

The APC Protectnet PNET1 and PRM24 seem quite nice and not too expensive
--
if they work....pros? cons?


Adi,

Is there a reason that your between-building runs aren't being done with
Fibre?
It being non-conductive is one immediate advantage....

I would agree with Mark. Even buried copper can make an
excellent guide for lightning to come right into your equipment, and it can only be
isolated so much. (Remember, the electrical  potential of the ground can vary over
a cable  run, and will vary if there are elevation changes.) Fiber is the way to go.

Regards
Marshall Eubanks



Also if your grounding is inadequate you may like to take a squiz at the
ISO or TIA Standards as they pertain to cabling.
In NZ we have a variety of standards which all point back to ISO, the ANSI
equivalents are TIA/EIA 568-B (Cabling), TIA/EIA-569-A (Pathways and
Spaces) and TIA/EIA-607-A (Electrical Wiring, relevant as it pertains to
Earthing etc).

Even for short runs, If I need to run between buildings externally I won't
even look at copper.

Mark.



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