CommScope Drop Cable - Manual (Page 54)

Overview
Commercial installations differ from residential and MDU installations in several ways. Fire safety requirements are
more strict. There may be cable raceways and ladders already in position to aid installation. The cable volume
may be greater.
The general scheme of bonding to an exterior point such as the electrical meter still holds. The cable then will
probably transition inside to a wiring closet with a crossconnect box for distribution within the facility. Depending
on the size of the building, this main closet may connect to subclosets in other parts of the structure, or on differ-
ent floors. Like MDU installations, you may need to consult a design engineer about using line amplification, or
may wish to upgrade to a longer reach cable such as QR 320.
Wiring Closets
Wiring closets (or telecommunication closets or TCs) can be rather complex. Literally hundreds of communication
cables (phone, UTP, fiber) can be gathered here and interconnected through an array of patch panels and blocks.
For specific instructions on connecting these types of cables, consult BICSI’s excellent volume Residential Network
Cabling published by McGraw-Hill.
Riser and Plenum Cables
Any time a cable penetrates a floor (goes vertically between one or several floors), you must either use a riser-rat-
ed cable (CATVR) or install your cable in metal conduit. You can also use the plenum (air-handling) space above
a dropped ceiling to run plenum-rated cables (CATVP) without using conduit. These cables are more flame-retar-
dant and produce less smoke during a fire. Many office cubicle systems have built-in raceways that allow you to
drop cables from the plenum ceiling directly to the desktop.
Article 830 Considerations
The same rules apply concerning aerial distances (page 5.1), burial depth (page 6.1) and use of raceway or
conduit within 8 ft (2.5 m) of the ground as residential installation. Article 830 also permits you to transition up to
50 ft (15.2 meters) of cable to meet an interior-mounted NIU. Longer runs require that the cable be run in metal
conduit or within the wall like electrical wiring.
11.1 Commercial Installations
Overview