C7 Low Voltage System Design & Installation 2

Question 1

What is the maximum allowable voltage for a Class 2 circuit under the California Electrical Code?

Accepted Answer

30 volts AC or 60 volts DC

Answer

Class 2 circuits are limited to 30V AC or 60V DC to reduce shock and fire hazards per CEC Article 725.

Question 2

When installing Category 6 cable in a plenum space, which cable jacket type is required?

Accepted Answer

CMP (Communications Plenum)

Answer

CMP-rated cable is required in plenum air-handling spaces due to its low-smoke, flame-retardant jacket properties.

Question 3

In a structured cabling installation, what is the maximum distance allowed for a horizontal cable run from the telecommunications outlet to the horizontal cross-connect?

Accepted Answer

90 meters (295 feet)

Answer

ANSI/TIA-568 limits horizontal cable runs to 90 meters, reserving 10 meters for patch cords and equipment cables.

Question 4

Which conduit fill percentage applies when pulling three conductors through a conduit in a low voltage installation?

Accepted Answer

40%

Answer

NEC/CEC Table 1, Chapter 9 limits conduit fill to 40% of internal cross-sectional area for three or more conductors.

Question 5

What grounding method is required for the cable sheath of coaxial cables used in CATV systems entering a building?

Accepted Answer

Bond to the building's grounding electrode system at the point of entry

Answer

CEC Article 820 requires coaxial cable shields to be bonded to the grounding electrode system at the building entry point to protect against lightning surges.

(C7) California C7 Low Voltage Systems Contractor Certification Practice Test

(C7) California C7 Low Voltage Systems Contractor Certification Practice Test

C7 Low Voltage System Design & Installation 2