[84518] in North American Network Operators' Group
Re: CAT5 surge/lightning strike protection recommendations?
daemon@ATHENA.MIT.EDU (Frank Coluccio)
Wed Sep 14 10:52:42 2005
From: Frank Coluccio <frank@dticonsulting.com>
To: nanog@merit.edu
Reply-To: frank@dticonsulting.com
Date: Wed, 14 Sep 2005 09:51:57 -0500
Errors-To: owner-nanog@merit.edu
There's not much left to interpretation and preferences here, aside=0D
from the choice of medium to be used. I should also add that some of the=0D
advice that has been posted in this thread, as well-meaning and thoughtful =
as it=0D
has been, has been downright dangerous to follow.=0D
=0D
If one is going to run copper cable between buildings, or outdoors, in=0D
general, in lieu of the better alternatives of fiber or wireless, then=0D
there are local and national electrical, fire and safety codes in effect=0D
that spell out what you must do, enforceable under the penalty of law.=0D
And while certain of those precautions have been spelled out upstream in=0D
piecemeal fashion, none thus far has been entirely accurate or complete.=0D
=0D
Yes, when running copper between buildings, lightning arresters/circuit=0D
- i.e., protection - are a must, but they must be placed within a couple=0D
of feet of the building point of entry, or POE. Think about it. Does it=0D
make great sense to protect a cable from surges deep within the interior=0D
of a building if the cable traverses vast distances on premises=0D
unprotected between the point of entry and the terminal point.=0D
Therefore, the stipulation of performing grounding, bonding and surge=0D
protections at the point where the cable enters the building (in=0D
potentially at addition points, elsewhere, when required).=0D
=0D
Also, if the copper cable is "armored" with a corrugated steal jacket,=0D
as many outside plant cables are, then the shielding (the armor) must=0D
also be "bonded" to earth ground at the POE, as well. So the issue=0D
becomes one not only of grounding, but bonding, as well. And while I'm=0D
on that subject, be aware that many FIBER OPTIC cables designed for=0D
inter-building/outside plant use are also armored and must be treated in=0D
the same manner.=0D
=0D
BICSI (Building Industries Consulting Systems International)=0D
www.bicsi.org does a good job of rolling up all of the relevant=0D
standards, as do a number of other sources. For some good coverage of=0D
safety, grounding and bonding principles and techniques see the=0D
following Structured Cabling Supplement reference by Panduit (taken from=0D
the Cisco CCNA Networking Academy Program)=0D
=0D
http://www.tecmiami.com/cisco/extra/CCNA1_CS_1_en.pdf =0D
=0D
Frank A. Coluccio=0D
DTI Consulting Inc.=0D
212-587-8150 Office=0D
347-526-6788 Mobile=0D
