There must be a gazillion ways to install premises cabling, depending on the design of the building and location of users. Let’s look at some of the guidelines included in TIA 568 or ISO/IEC 11801 standards. Answers and explanations are in red.
1. Within a building, cables may be run in __________.
A. Cable trays
B. Conduit or duct
D. Any of the above
Within the premises environment, cables may be run in any number of locations, using hardware appropriate for that application.
2. The __________ is where backbone and horizontal cable are connected.
A. Telecommunications room
B. Equipment room
C. Telecom space
D. Network space
The telecom room, formerly called telecom closet, is the location where hardware and electronics connect the backbone of a network to the horizontal cable runs.
3. Temperature and humidity in telecommunications spaces shall be controlled to provide continuous operating ranges between 18–27°C (64–81°F) and less than 60 percent relative humidity.
High heat and humidity are potentially harmful, particularly to electronics, so telecom rooms require careful environmental control.
4. Providing __________ entrance facilities and pathways inside the building can prevent catastrophic loss of communications.
Diverse pathways, particularly separated in different sections of a building, are good insurance against damage affecting all communications.
5. The telecommunications room should not be shared with electrical installations other than those for telecommunications.
Only the electrical services for the equipment in a telecom room are permitted.
6. All metal hardware in a cabling system must be __________.
A. Covered with rust-resistant paint
B. Kept away from electrical services
C. Securely bolted to the floor and wall
D. Properly grounded and bonded
Any conductive metallic hardware in a cabling system, including trays, racks, conduit, etc. requires grounding and bonding.
7. Co-installation of telecommunications cable and power cable is __________.
A. Governed by the applicable electrical code for safety
B. Never permitted
C. Allowed only for optical fiber cables
D. Limited to 115V AC electrical service
Electrical codes determine the allowed mixing of low voltage and electrical cables. The NEC has numerous references to where this is permitted.
8. Pull boxes can be used for __________.
A. Fishing a conduit run
B. Installing a pull string or cable
C. Intermediate pulls
D. All of the above
Pull boxes have several uses when placed strategically on a conduit run.
9. Cable trays shall be designed to accommodate a maximum calculated fill ratio of __________ percent to a maximum of 150 mm (6 in.) inside depth (see example). For planning cable tray pathways, the maximum pathway fill should be __________ percent.
A. 100, 50
B. 75. 50
C. 50, 25
D. 25, 25
Cable tray fill, calculated by cable cross-sectional area, should be planned to be 25 percent or less, although cable trays are designed for a maximum fill of 50 percent.
10. While the primary function of a firestop is to prevent fire, smoke or water from passing through a penetration, it may also provide __________.
A. Environmental protection
B. Sealing high temperature penetrations
C. Sealing penetrations that move axially or laterally
D. All of the above
Besides fire, smoke and water protection, firestops can be important for sealing penetrations for other reasons.
HAYES is a VDV writer and educator and the president of The Fiber Optic Association. Find him at www.jimhayes.com.