VDV Copper Cabling 5 — Questions and Answers
Question 1: What conductor gauge is specified for standard Cat5e/Cat6 horizontal UTP cabling?
- 24 AWG solid copper (Correct answer)
- 22 AWG solid copper
- 26 AWG stranded copper
- 23 AWG stranded copper
Correct answer: 24 AWG solid copper
TIA-568 specifies 24 AWG (American Wire Gauge) solid copper conductors for horizontal UTP cable runs.
Question 2: Which bonding method is required when terminating shielded twisted pair (STP) cable to maintain a continuous ground path?
- The cable shield must be bonded to the jack or panel ground at both ends of the link (Correct answer)
- The shield is bonded only at the telecommunications room end to prevent ground loops
- The shield is left floating at both ends; only the drain wire is connected
- Shielded cable does not require bonding when installed in metal conduit
Correct answer: The cable shield must be bonded to the jack or panel ground at both ends of the link
STP/FTP cable shields must be bonded at both ends to provide a complete ground return path; a shield grounded only at one end acts as an antenna rather than a shield.
Question 3: What is the maximum amount of untwisting allowed when terminating a Cat6 conductor pair to a 110-style IDC jack?
- 0.5 inches (13 mm) (Correct answer)
- 1.0 inch (25 mm)
- 1.5 inches (38 mm)
- 2.0 inches (51 mm)
Correct answer: 0.5 inches (13 mm)
TIA-568 limits pair untwisting during termination to 0.5 inches (13 mm) for Cat6 to preserve the cable's crosstalk rejection characteristics.
Question 4: A technician must document a copper cabling installation per ANSI/TIA-606. What information is minimally required for each cable record?
- Cable identifier, both end locations, and media type (Correct answer)
- Only the cable identifier and total length
- End locations and date of installation only
- Cable identifier, length, and technician name
Correct answer: Cable identifier, both end locations, and media type
TIA-606 requires each cable record to include a unique identifier, the locations of both termination ends, and the cable type/media as minimum documentation.
Question 5: What is the primary reason Cat6A U/UTP cable has a significantly larger outer diameter than Cat6 UTP cable?
- Thicker insulation and larger cable geometry are needed to reduce alien crosstalk (AXT) without a shield (Correct answer)
- The conductors are heavier gauge to support longer run distances
- An internal flooding compound is added for moisture resistance
- The spline must be larger to support 10G signaling frequencies
Correct answer: Thicker insulation and larger cable geometry are needed to reduce alien crosstalk (AXT) without a shield
Unshielded Cat6A achieves AXT suppression through increased pair separation provided by its larger cable body and internal geometry rather than a metallic shield.
Question 6: When using a toner and probe to locate a specific cable among a large bundle, what is the correct technique to avoid false traces?
- Set the probe sensitivity to low and trace from the tone generator end toward the far end (Correct answer)
- Set the probe sensitivity to maximum to detect the cable from the greatest distance
- Energize all pairs in the bundle simultaneously to create a reference field
- Wrap the probe tip around the entire bundle to identify the loudest cable
Correct answer: Set the probe sensitivity to low and trace from the tone generator end toward the far end
Using low sensitivity and working from the source forces the probe to respond only to the strongest (nearest) tone, preventing adjacent cables from triggering a false response.
Question 7: A TDR (Time Domain Reflectometer) test shows an impedance anomaly 47 meters from the test end. What does this most likely indicate?
- A physical fault such as a sharp bend, crush, or improper termination at that point in the cable (Correct answer)
- Normal attenuation pattern for a 47-meter Cat6 cable at 100 MHz
- The location of the far-end termination in a 47-meter link
- Alien crosstalk from a parallel cable that crosses at that distance
Correct answer: A physical fault such as a sharp bend, crush, or improper termination at that point in the cable
A TDR sends a pulse and measures reflections from impedance changes; an anomaly mid-cable pinpoints a physical defect such as a kink, crush, or bad connection at that distance.
VDV Copper Cabling 5
What conductor gauge is specified for standard Cat5e/Cat6 horizontal UTP cabling?