RCDD (RCDD): Case Studies and Concepts 3 — Questions and Answers
Question 1: An RCDD is reviewing a proposed outside plant conduit installation crossing under a busy highway. The design uses directional boring. What minimum conduit fill percentage should be maintained for future cable pulling per ANSI/TIA-758-B?
- 53% (Correct answer)
- 40%
- 75%
- 60%
Correct answer: 53%
ANSI/TIA-758-B recommends a maximum 53% conduit fill ratio to allow for future cable additions and ease of pulling.
Question 2: A manufacturing plant case study shows that data cables must run parallel to 480 V power feeders for 30 m. According to ANSI/TIA-569-D, what is the minimum separation required between unshielded data cables and these power conductors?
- 50 mm
- 100 mm (Correct answer)
- 150 mm
- 300 mm
Correct answer: 100 mm
ANSI/TIA-569-D requires a minimum 100 mm separation between UTP cabling and power conductors of 480 V or less.
Question 3: The RCDD is designing a building automation system (BAS) network and must choose between CAT 6A UTP and shielded twisted pair. The facility has significant electromagnetic interference from HVAC motors. Which cabling approach is most appropriate?
- CAT 6A UTP with increased separation from EMI sources
- CAT 6A F/UTP with proper shield grounding at both ends
- CAT 6A S/FTP with grounding at the TR only (Correct answer)
- CAT 5e UTP with ferrite chokes
Correct answer: CAT 6A S/FTP with grounding at the TR only
S/FTP (individually shielded pairs plus an overall foil shield) with proper grounding at the TR provides the best EMI protection in high-noise environments.
Question 4: A case study presents a legacy Token Ring network being replaced with Gigabit Ethernet. The existing CAT 3 cabling is still in place. What does the RCDD recommend?
- Reuse CAT 3 cabling with new Gigabit transceivers
- Install CAT 6 or higher cabling to support Gigabit Ethernet (Correct answer)
- Deploy fiber only since copper cannot support Gigabit
- Use CAT 5e adapters on existing CAT 3 runs
Correct answer: Install CAT 6 or higher cabling to support Gigabit Ethernet
Gigabit Ethernet over copper requires at minimum CAT 5e, and the RCDD should recommend upgrading to CAT 6 or higher for longevity.
Question 5: An RCDD is asked to design telecommunications infrastructure for a LEED-certified building. Which practice best aligns with LEED sustainability goals while maintaining TIA standards compliance?
- Using plenum-rated cable in all spaces regardless of air handling
- Maximizing cable length to reduce future moves, adds, and changes
- Designing a centralized cabling architecture to reduce total cable volume (Correct answer)
- Installing fiber instead of copper to eliminate grounding requirements
Correct answer: Designing a centralized cabling architecture to reduce total cable volume
A centralized architecture reduces total cabling material used, which aligns with LEED goals for reduced environmental impact while maintaining standards compliance.
Question 6: In a case study, an RCDD must select the correct grounding conductor size for a telecommunications main grounding busbar (TMGB) bonded to the building's electrical service entrance. Per TIA-607-C, what is the minimum conductor size?
- 6 AWG
- 4 AWG (Correct answer)
- 2 AWG
- 1/0 AWG
Correct answer: 4 AWG
TIA-607-C specifies a minimum 6 AWG insulated conductor for bonding telecommunications equipment, but the TMGB to ESGB bond requires a minimum 6 AWG and typically 4 AWG or larger.
Question 7: A financial institution requires a Tier III data center with redundant power and cooling. Which ANSI/TIA standard provides the telecommunications infrastructure requirements for data centers that the RCDD should apply?
- ANSI/TIA-942-B (Correct answer)
- ANSI/TIA-568-C.0
- ANSI/TIA-1005-A
- ANSI/TIA-606-C
Correct answer: ANSI/TIA-942-B
ANSI/TIA-942-B (Telecommunications Infrastructure Standard for Data Centers) defines rated tiers and infrastructure requirements for data center design.
RCDD (RCDD): Case Studies and Concepts 3
An RCDD is reviewing a proposed outside plant conduit installation crossing under a busy highway.
The design uses directional boring.
What minimum conduit fill percentage should be maintained for future cable pulling per ANSI/TIA-758-B?