CSLB C-7 Low Voltage Systems (Trade Exam) — All Questions
12 questions
How does the federal cabling specification prepare a fiber backbone cable for pulling?
- a.Pull on the fibers themselves with a grip
- b.Tape the jacket end and pull by the jacket
- c.Tie the strength members to the pulling eye✓
- d.Fusion splice a pull string to one fiber
The specification cuts the outer jacket back about 10 inches, leaves the strength members exposed, twists them together and attaches them to the pulling eye. Pulling on the fibers or on the jacket alone strains parts not designed to carry load, and a fiber cannot be spliced to a pull string.UFGS 27 10 00 (2025), para. 3.4.1 (fiber backbone cable)
A crew wants to use dish soap to ease a long cable pull. What does the federal cabling specification allow?
- a.Household soap that rinses clean
- b.Lubricants approved by the cable manufacturer✓
- c.No lubricant on communications cable
- d.Any lubricant, if tension stays under 25 lbf
The specification says to use only lubricants approved by the cable manufacturer. Household soap is not an approved lubricant, staying under the tension limit does not make an unapproved product acceptable, and approved lubricants are permitted.UFGS 27 10 00 (2025), para. 3.4.2 (horizontal cable)
Which cable tray support method does the federal cabling specification prohibit?
- a.Wall-mounted brackets
- b.A single center hanger✓
- c.Supports at the manufacturer's spacing
- d.Ceiling-hung brackets
The specification says not to install cable tray using a single center hanger. Wall-mounted brackets, ceiling-hung brackets and supports at the manufacturer's spacing are the methods it allows.UFGS 27 10 00 (2025), para. 3.3.3 (cable tray)
How are adjacent metal cable tray sections joined under the federal cabling specification?
- a.By butting the sections end to end
- b.With duct tape over the seam
- c.With cable ties at each joint
- d.Connector plates matching the tray✓
Adjacent tray sections are bonded together by connector plates identical in type to the tray sections, keeping the tray mechanically and electrically continuous. Cable ties and tape are not structural or bonding connections, and butted ends leave a gap in continuity.UFGS 27 10 00 (2025), para. 3.3.3 (cable tray bonding)
Cable passes straight through a junction box in a conduit run. How must the conduits enter and exit the box?
- a.On opposite sides of the box✓
- b.On adjacent sides, forming a 90-degree turn
- c.On the same side of the box
- d.Through the box cover
Conduit entries are arranged so cables passing through a box enter and exit at opposite sides. Entering and leaving on the same or adjacent sides forces tight bends inside the box, and pull boxes are not to be used as changes in direction.UFGS 27 10 00 (2025), para. 3.3.1 (interior distribution)
A cable route above a ceiling would rest the cables directly on a sheet-metal duct for 20 feet. What does the federal cabling specification say?
- a.Ducts are acceptable if the cable is plenum rated
- b.Ducts are acceptable for runs under 50 feet
- c.Ducts are not acceptable; cable must not touch them✓
- d.Ducts are acceptable supports if grounded
Cable must not be run through structural members or in contact with pipes, ducts or other potentially damaging items. Grounding, run length and a plenum rating do not turn a duct into an approved cable support.UFGS 27 10 00 (2025), para. 3.3.4 (non-continuous cable supports)
New underground conduit is installed to a gatehouse for future cable. What pull rope does the federal criterion require in it?
- a.200-lb rope, 5 ft slack each end✓
- b.A light string, cut flush with the conduit ends
- c.No pull rope until cable is ordered
- d.A steel fish tape left in place
The criterion places a pull string, rope or tape rated at least 200 pounds in each new conduit, with at least 5 feet of slack at each end tied to the plug. Flush-cut string can be pulled back into the conduit, a steel tape is a tool rather than a permanent pull line, and leaving none defeats the purpose.UFC 3-580-01 (2024), para. 3-6.12 (pull string, rope, tape)
How deep does the federal criterion place warning tape above underground communications conduit?
- a.At least 12 inches below the surface✓
- b.Directly on top of the conduit
- c.At the surface, as a visible marker
- d.At least 48 inches below the surface
Warning tape is installed at least 12 inches below the surface and kept at least 6 inches above the conduit or cable. At the surface it is not a buried warning, directly on the conduit gives no warning before an excavator reaches it, and 48 inches is the minimum cover for directly buried fiber.UFC 3-580-01 (2024), para. 3-6.9.2 (warning tape)
In the standard 25-pair color code, which colors identify pair 1?
- a.Violet-grey
- b.Red-blue
- c.White-blue✓
- d.White-orange
Pairs 1 to 5 have a white tip, and the first ring color is blue, so pair 1 is white-blue. Red-blue is pair 6, white-orange is pair 2, and violet-grey is pair 25.UFC 3-580-01 (2024), para. 3-9.5.1 (copper cable color code)
An outlet has two Category 6A cables. How should they be terminated in the telecommunications room under the federal criterion?
- a.On two different floors' panels
- b.Same panel, each one identified✓
- c.On a 66 block with no identifiers
- d.On one jack, splitting pairs between them
Cables from the same outlet are terminated on the same patch panel and individually identified, and copper cables are not split between connectors. Different panels scatter one outlet's cables, splitting pairs breaks the cable's geometry, and unidentified terminations defeat administration.UFC 3-580-01 (2024), para. 2-3.3.2.1 (CAT6A termination)
What does the federal criterion say about color coding of telecommunications components?
- a.Required for TIA-606 compliance
- b.Required for fiber, not copper
- c.Prohibited in favor of numbers
- d.Recommended, but it is not required✓
The criterion states that color coding of telecommunications infrastructure and components is recommended but not required; identifiers and printed labels are what administration relies on. Making it a TIA-606 requirement, prohibiting it, or requiring it for fiber all misstate the criterion.UFC 3-580-01 (2024), para. 2-5 (system administration)
Cable will run exposed under a raised floor in a computer room. What rating does the federal cabling specification require?
- a.Plenum rated✓
- b.General purpose
- c.Limited use
- d.Riser rated
The specification requires cable routed exposed under raised floors to be plenum rated and to comply with the code's plenum flammability requirements. Riser, general-purpose and limited-use ratings are lower fire ratings than plenum.UFGS 27 10 00 (2025), para. 3.3.4 (raised floors)