CSLB C-7 Low Voltage Systems (Trade Exam) — All Questions

What is the minimum conductor size for patch cords used with Power over Ethernet in the federal criterion?

• a.26 AWG
• b.24 AWG✓
• c.30 AWG
• d.28 AWG

The criterion requires PoE patch cords to be 24 AWG or larger, because thinner conductors heat more under power. Twenty-six, 28 and 30 AWG are all smaller (higher-numbered) gauges than 24 AWG, so none meets the minimum.UFC 3-580-01 (2024), para. 2-3.3.5 (bundling)

Over what maximum length does HDBaseT carry video, audio, power, Ethernet and control on one category cable, per the federal criterion?

• a.984 feet (300 meters)
• b.1,000 meters
• c.328 feet (100 meters)✓
• d.33 feet (10 meters)

The criterion says HDBaseT transports these signals over a single category cable up to 328 feet (100 meters). Ten meters is too short to describe it, 300 meters is OM3's 10-gigabit fiber reach, and 1,000 meters is a single-pair Ethernet reach, not HDBaseT.UFC 3-580-01 (2024), para. 2-3.5.2 (HDBaseT)

What jacket color does the TIA-598 scheme in the federal criterion assign to OM4 multimode fiber?

• a.Yellow
• b.Orange
• c.Slate
• d.Violet✓

The criterion's table lists OM4 as violet or aqua. Yellow is single-mode, orange is legacy OM2, and slate is legacy OM1.UFC 3-580-01 (2024), Table 2-3 (fiber jacket colors)

What bandwidth must passive CATV devices such as splitters and taps support under the federal criterion?

• a.500 MHz
• b.100 MHz
• c.1.0 GHz✓
• d.10 GHz

The criterion requires passive CATV devices to support 1 GHz bandwidth. One hundred and 500 megahertz are copper-cable test frequencies for Category 5e and 6A, and 10 GHz is not a CATV requirement in the criterion.UFC 3-580-01 (2024), para. 2-3.5.2 (CATV system)

Which coaxial cable does the federal criterion prohibit on CATV projects?

• a.RG-6
• b.RG-59✓
• c.RG-11
• d.625-series hardline

The criterion says not to use RG-59 for CATV projects. RG-6 is specified for drops, RG-11 is the minimum for trunks, and 625-series cable is suggested for longer trunk runs to reduce losses.UFC 3-580-01 (2024), para. 2-3.5.2 (CATV cabling)

A composite fiber-and-copper cable will power remote devices with low voltage dc. Why choose a larger copper gauge for longer runs?

• a.Larger copper removes the need for a UPS
• b.Larger copper makes the cable plenum rated
• c.Larger copper delivers power farther with less drop✓
• d.Larger copper raises the fiber's bandwidth

The criterion notes that larger-gauge copper delivers power over longer distances because voltage drop is lower. Copper size does not change fiber bandwidth or the cable's fire rating, and centralized power is still backed by a UPS for outages.UFC 3-580-01 (2024), para. 2-3.3.3.3 (composite cable)

Which NEC article does the federal criterion name for fault-managed power that can exceed the 100 watts of Class 2 and PoE?

• a.Article 800
• b.Article 90
• c.Article 760
• d.Article 726✓

The criterion cites NEC Article 726 for fault-managed power delivering more than the 100 watts afforded to Class 2 and PoE. Article 760 covers fire alarm systems, Article 800 communications circuits, and Article 90 is the code's introduction.UFC 3-580-01 (2024), para. 2-3.3.3.3 (fault managed power)

What is the smallest speaker cable allowed by the federal public address specification?

• a.18 AWG✓
• b.24 AWG
• c.22 AWG
• d.26 AWG

The specification says that in no case may speaker cable smaller than 18 AWG be used. Twenty-two, 24 and 26 AWG are all smaller conductors than 18 AWG.UFGS 27 51 16, Public Address Systems (speaker cable)

An entrance terminal will serve 40 used outside copper pairs. How many protector modules does the federal criterion call for?

• a.80
• b.40
• c.50✓
• d.45

Protector modules are furnished for all used pairs plus 25 percent, so 40 × 1.25 = 50, not to exceed the total pair count. Forty covers no spare, 45 is only 12.5 percent extra, and 80 doubles the count.UFC 3-580-01 (2024), para. 2-3.1.5.2 (protected entrance terminals)

How does the federal criterion terminate backbone fiber at patch panels?

• a.Twist the fibers together under heat-shrink
• b.Mechanical splices left unsupported in the tray
• c.Field-polish epoxy connectors on every strand
• d.Fusion-splice to factory pigtails or use MTP trunks✓

The criterion fusion-splices backbone fibers to factory-produced pigtails or uses factory MTP cables with breakout cassettes. Field-polished connectors and unsupported mechanical splices are not its methods, and twisting fibers together is not a splice at all.UFC 3-580-01 (2024), para. 2-3.3.1.2 (fiber backbone termination)

A clinic has 16 exam rooms with 2 drops each. Each run is 140 feet of path plus 10 feet of room slack and 1 foot of ceiling slack. How many 1,000-foot boxes are needed by total footage, before any waste allowance?

• a.5 boxes✓
• b.6 boxes
• c.3 boxes
• d.4 boxes

Each run is 140 + 10 + 1 = 151 feet, using the specification's room and ceiling slack; 32 runs × 151 = 4,832 feet, which needs 5 boxes. Four boxes (4,000 feet) is short, three boxes ignores half the cables, and six is a box more than the footage requires.UFGS 27 10 00 (2025), para. 3.4.2 (horizontal cable slack)

A rack design uses 32 rack units of equipment. How many total rack units satisfy the federal criterion's spare capacity rule?

• a.40✓
• b.64
• c.32
• d.36

The criterion requires 25 percent spare rack unit capacity, so 32 × 1.25 = 40 units. Thirty-two leaves no spare, 36 is only 12.5 percent extra, and 64 doubles the requirement.UFC 3-580-01 (2024), para. 2-3.1.5.3 (equipment racks)

Above what combined labor and material cost must a California home improvement job be in a written contract, per the CSLB?

• a.$5,000
• b.$1,000
• c.$250
• d.$500✓

The CSLB says the terms of all home improvement projects over $500 in combined material and labor costs must be in a contract. One thousand dollars is the licensing threshold for small jobs, $5,000 is not a contract threshold, and $250 is below the stated amount.CSLB, Terms of Agreement: A Consumer Guide to Home Improvement Contracts

A 70-year-old homeowner signs a contract for a home theater and network system. How long does the CSLB say the buyer has to cancel?

• a.Five business days✓
• b.Three business days
• c.No right to cancel
• d.Ten calendar days

The CSLB says a buyer has three business days to cancel, or five business days if the buyer is 65 or older, so this buyer has five. Three days applies to younger buyers, ten calendar days is not the rule, and the right to cancel does exist.CSLB, Terms of Agreement: A Consumer Guide to Home Improvement Contracts

Which device does the federal criterion recommend when pulling cable into underground ducts, to protect against over-tension?

• a.A steel fish tape
• b.A tighter cable tie at each duct
• c.A come-along with no gauge
• d.A rated breakaway swivel✓

The criterion recommends properly rated breakaway swivels and says not to exceed the manufacturer's pulling tension. A fish tape is for short pulls and has no tension protection, an ungauged come-along can overpull, and cable ties do nothing to limit pulling force.UFC 3-580-01 (2024), para. 3-9.1 (cable pulling tension)