Thursday 20 December 2012

Why We Terminate All CAT Cable Runs Outside The Enclosure

Our longest standing client is about to move after being in the same location for somewhere around 20 years.

Their current location required some wiring changes around 10 years ago and the electrical contractor wanted to terminate inside the enclosure. At that time, we had seen quite a few enterprise level racks that had that setup so we accepted that configuration.

The APC 24U enclosure has two bundles running into it with the patch panel mounted at the back and top of the APC.

Years ago we were looking to move the enclosure into a different location within the server closet but could not because the loops left in the ceiling were not long enough to allow much movement at all.

And today, we are in a position where we will need to cut the cables in order to move the enclosure out of the closet when it comes time to move.

Ever since that day we wanted to move that enclosure and could not we have always recommended that all CAT cabling be terminated in a patch panel that sits in a wall mount.

We would then use patch cables properly strung to remove any weight bearing on the cable ends plugged into the patch panel into the enclosure mounted switch or switches.

As of this writing our recommended network cabling setup is:

  • Minimum CAT5e with CAT6 being preferred.
    • A box of CAT6 is no longer that much more than CAT5e.
    • Home Depot shows CAT6 at $250 for 305m (1000’).
  • Prefer a minimum of _two_ cables per drop.
    • One for PC and one for Phone.
  • Patch Cables are CAT6 or CAT6a
  • Patch Panel is a minimum spec of CAT5e with CAT6 being the preference.
  • Wall mount for Patch Panel and cable management
    • 5U or 8U works fine.
    • Phone/VOIP on separate patch panel with different colour jacks.
    • Mounted above 6’6” so most folks won’t bump their head!
  • Contractor gives us a minimum of 5m (~15’) of loop in the ceiling.
  • Contractor gives a print-out of _all_ drop’s capabilities after job is completed.
    • We expect this. We have had problems with bad runs if an electrician versus an actual cabling contractor do the runs.

With the above specifications we are able to move any rack mount enclosure about a server closet or room by changing the length of the patch cables versus bringing in a contractor to re-wire the solution on the wall.

Philip Elder
Microsoft Small Business Specialists
Co-Author: SBS 2008 Blueprint Book

Windows Live Writer


Phil Wisch said...

Thanks for this Philip!

Philip Elder Cluster MVP said...


You are welcome! :)


Perth Systems said...

Thanks Phil.

A few thoughts

1) Over head or near ceiling height comms cabinets are a pain to work in. I don't carry a ladder, and generally most customers don't have one onsite. If it's low enough to reach into - as you mentioned it's a hazard for people walking into.

2) if you leave a long enough cable loop in the ceiling above your server cabinet it allows you to pull the patch panels and cabling back out of the cabinet and into it's own cabinet if you want to relocate the server cabinet.

I really like the idea of everything being in the one cabinet under one lock and key. I find it makes things easier when it comes to directing people over the phone as well. Saves the whole no no not that cabinet the other cabinet conversation! :)

Asides from that - completely agree with the rest of the specs.

Philip Elder Cluster MVP said...

The only thing to go on the wall mount rack unit is the patch panel.

From there, the patch cables plug into the patch panel and are routed into the rack mount enclosure.

Once a patch panel has been used to terminate all of the runs and patch cables are plugged in there should not be a reason to touch that unit again.

Unless of course more runs need to be added to the panel. But, that would be taken care of by the cabling contractor anyway.

All switching, edge/routers, and such are _in_ the rack mount enclosure under lock and key.

We no longer touch anything to do with cabling with rare exception.


Doug H. said...

Good post Philip.

1) I now specify that patch panels be modular. These give a lot more flexibility - e.g., moving from a 24-port to a 48-port patch panel would not necessitate re-punching down the original 24-ports, or where you're splitting voice and data to different ports, you could relocate a single pull to a different patch panel quite easily.

2) I don't particularly care where the wire terminates, but my offices have the wire terminate inside the cabinet for:
- appearance: the rack is in a location visible to staff and visitors
- security: the server room is also storage, so the locked rack is the only part that has extra restricted access.