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  1. #1

    Plenum vs. Other Cable

    I want to crimp my own cables for our cabinet and i noticed that most people use plenum cable (blue), I have about 4 boxes of normal indoor cable (the one you put in walls).

    Is there a reason that people prefer the plenum cable when wiring their cabinets/cages? or perhaps per fire code?

    Thanks!

  2. #2
    Join Date
    Aug 2004
    Location
    New Jersey
    Posts
    11
    The NFPA (National Fire Protection Agency) regulates the design and installation of all types of things fire related (National Electric Code included), in your case what type of cable can be used and different locations and applications of each type. Their concern is focused specifically on personal safety, never performance.

    The use of plenum rated cable is required within an area where air is circulated, i.e a plenum area; in an open data center, under a raised floor, within a room, down a hallway, in a building elevator riser, etc. The code does allow a certain amount of non-plenum rated cable to be used within a specific area but it's based upon the volume of the space and other factors too confusing to discuss here so it's best to just use plenum rated where required.

    My suggestion for a non-engineer or novice would be to contact your cable supplier and ask them when and where plenum rated cable must be used, use your specifics as a basis. Don't be affriad that they just try to sell you the higher priced cable. If that doesn't work go to some of the cable manufacturers' web sites and contact their customer support group. I'm sure they'll have guidelines and someone to help you out. If that doesn't work, contact any of your local Engineering firms and ask if they have a Telecom or Network Engineering, Fire Suppression, or Electrical design group. They may be able to point you in another direction.

    This is NOT a trivial issue and fines can be issued by the local building and fire code inspectors. Given recent events in building disasters and recent treds in regulatory agencies you'd best do you homework and do the right thing.

    Also, remember that just because it's plenum rated, it doesn't mean it won't burn, it just burns less than normal cable and gases less for a longer time. If your concern is fire and gases/fumes, there are higher priced solution to prevent that from ahppening too.

    Best of luck
    Scott McDonald
    Colocation Director
    Tyco Telecommunications
    Data Centers in most major cities: NY, CA, Japan, London, Germany, Portugal and others globally.

  3. #3
    Join Date
    Apr 2002
    Location
    North Kansas City, MO
    Posts
    2,565
    Plenum cable burns just like regular cable. The difference is that Plenum rated cabling does not release toxic fumes. Hence the reason it's required in open air enviroments.

    Aaron
    Aaron Wendel
    Wholesale Internet, Inc. - http://www.wholesaleinternet.net
    Kansas City Internet eXchange - http://www.kcix.net

  4. #4
    Join Date
    May 2002
    Location
    Raleigh, NC
    Posts
    699
    Is there such thing as stranded cat5 instead of solid-core? The cheap cat 5 cable (non-plenum) I have isn't as flexible as most store-bought patch cables.
    Tranquil Hosting

  5. #5
    Join Date
    Jun 2000
    Location
    Washington, USA
    Posts
    5,991
    True patch cables are made with stranded wire, which is more flexible and less likely to suffer from cable damage due to flexing.

  6. #6
    Join Date
    May 2002
    Location
    Raleigh, NC
    Posts
    699
    Is stranded harder to crimp? Any reason I cant make my own stranded patch cables?
    Tranquil Hosting

  7. #7
    Join Date
    Nov 2003
    Location
    Toronto, Ontario
    Posts
    641
    man i wish i had enough free time to make my own patch cables!
    Kevin

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