Information Technology Reference
In-Depth Information
Wiring Closet
Wiring Closet
Third Floor
Backbone
Wiring
Third Floor
Backbone
Wiring
Second Floor
Second Floor
First Floor
First Floor
a. Daisy-chain (Hub to Hub)
b. Star (Hubs to Central Hub)
FIGURE 1.10
Backbone wiring may be implemented in a daisy-chain (hub-to-hub-to-hub) fashion, or in a
star fashion.
requirements and the safety and fire protection requirements for your installation.
If your installation requires Category 5e horizontal cable, for example, you should
use the Category 5e cable for your backbone wiring. It does not hurt to use a higher
category of cable than needed, so you might use Category 6 anyway. If you antici-
pate using your wiring system for multiple applications, double or triple each back-
bone wiring run. This will give you ample room for growth and the ability to rapidly
respond to new requirements.
Some standards require that all riser cable (cable that goes vertically between
floors) be riser rated, while some local authorities may require the tougher fire spec-
ifications of plenum cable. In any event, any openings you make between floors,
whether in cable ports or direct opening, should have fire-shop material properly
installed. This is particularly important in taller buildings. Consult the NEC, UL
standards, and local standards for more guidance.
When wiring between far-flung TRs or between floors, electrical grounding
and bonding requirements should be observed. EIA/TIA-607 describes the proper
practices in detail.
As fewer cables are used for backbone wiring, you may be tempted to termi-
nate the cables directly into an 8-pin modular male connector plug. Backbone
cabling uses solid copper wire, and since most 8-pin modular plugs are designed for
stranded wire, you could easily create a future problem. Just imagine an intermit-
tent network failure that cures itself when you touch the backbone cable plug! Solid-
