DCI Standards & Codes Compliance 5 — Questions and Answers
Question 1: ANSI/TIA-569-D specifies pathways and spaces for telecommunications. What is the minimum headroom required in a telecommunications room (TR)?
- 7 feet (2.1 m)
- 8 feet (2.4 m) (Correct answer)
- 9 feet (2.7 m)
- 10 feet (3.0 m)
Correct answer: 8 feet (2.4 m)
TIA-569-D requires a minimum ceiling height of 8 feet (2.4 m) in telecommunications rooms to allow safe equipment installation and maintenance.
Question 2: A cable labeled 'CMR' is rated for installation in:
- Plenum air-handling spaces only
- Vertical risers between floors (Correct answer)
- Outdoor direct burial
- Underground conduit
Correct answer: Vertical risers between floors
CMR (Communications Multipurpose Riser) rated cables are listed for use in vertical runs between floors (riser applications).
Question 3: Per TIA-606-C, each telecommunications infrastructure identifier (label) must be:
- Color-coded by cable type
- Unique within the administration system (Correct answer)
- At least 3 inches long
- Applied only at patch panels
Correct answer: Unique within the administration system
TIA-606-C requires each identifier to be unique within the scope of the administration system to prevent confusion.
Question 4: Which of the following is a key requirement of NEC 800.100 regarding the grounding of communications cable sheaths?
- Sheath must be grounded at every 50-foot interval
- Sheath must be bonded to the building's electrical grounding electrode system (Correct answer)
- Sheath grounding is optional for Category 6 cables
- Sheath must connect to a dedicated telecommunications earth ground rod
Correct answer: Sheath must be bonded to the building's electrical grounding electrode system
NEC 800.100 requires metallic cable sheaths entering buildings to be bonded to the building's grounding electrode system to prevent hazardous voltage differences.
Question 5: Under ANSI/TIA-568, the term 'permanent link' refers to:
- The complete channel including all patch cords
- The fixed installed cabling from the outlet to the patch panel, excluding patch cords (Correct answer)
- Only the horizontal cable without connectors
- The backbone cabling between buildings
Correct answer: The fixed installed cabling from the outlet to the patch panel, excluding patch cords
The permanent link is the installed cabling infrastructure from outlet to cross-connect, excluding the flexible patch cords at each end.
Question 6: A contractor is installing cables through a fire-rated wall. Which NEC article requires that the penetration be properly firestopped?
- Article 300
- Article 800
- Article 770
- Both Article 300 and the applicable communications article (Correct answer)
Correct answer: Both Article 300 and the applicable communications article
NEC Article 300.21 (general wiring methods) and the applicable communications article (e.g., 800, 820, 770) both require firestopping of penetrations through fire-rated assemblies.
Question 7: Which testing standard is used to verify that a cable pathway meets EMC (electromagnetic compatibility) requirements for shielded cabling systems?
- ANSI/TIA-568 TSB-155
- IEC 61935-1 (Correct answer)
- UL 444
- NFPA 70E
Correct answer: IEC 61935-1
IEC 61935-1 specifies test methods for installed balanced cabling, including transfer impedance measurements used to verify shielded system EMC performance.
DCI Standards & Codes Compliance 5
ANSI/TIA-569-D specifies pathways and spaces for telecommunications.
What is the minimum headroom required in a telecommunications room (TR)?