Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
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1. What is the maximum voltage typically allowed for low-voltage
circuits in limited energy systems?
50 volts
Low-voltage circuits in limited energy systems, such as fire alarms
and telecom, typically do not exceed 50 volts to reduce shock
hazards.
2. Which type of cable is most commonly used for structured cabling
in data networks?
Cat5e/Cat6 twisted pair
Twisted pair cables are standard for Ethernet networks due to low
interference and ease of installation.
3. In fire alarm systems, what is the primary purpose of a NAC
(Notification Appliance Circuit)?
To provide power to alarms and notification devices
NAC circuits supply electrical power to horns, strobes, and
speakers to alert occupants during a fire.
4. What color coding is typically used for low-voltage control wires?
Red, black, and blue
, Low-voltage wires are color-coded to distinguish between positive,
negative, and common or control circuits.
5. Which of the following devices is considered a Class 2 power-
limited circuit device?
Smoke detector
Class 2 circuits limit current and voltage to reduce fire and shock
hazards; smoke detectors often operate on such circuits.
6. What is the minimum bend radius for a Cat6 cable?
Four times the cable diameter
Maintaining proper bend radius prevents damage to the twisted
pairs and preserves signal integrity.
7. Which tool is used to test continuity in low-voltage wiring?
Multimeter
A multimeter allows measurement of voltage, current, and
continuity, essential for troubleshooting circuits.
8. In a CCTV system, what is the primary purpose of a DVR?
To record video footage
A Digital Video Recorder stores camera video digitally for review
and evidence.
9. NEC Article 725 covers what type of wiring?
Class 1, 2, and 3 circuits
Article 725 addresses power-limited circuits including
communications and control wiring.
10. What is the typical spacing for fire alarm initiating devices in
a commercial building?
One device per 900 square feet
, Spacing ensures adequate coverage while minimizing gaps for
early detection.
11. In a structured cabling system, what does the term
"horizontal cabling" refer to?
Cabling from the telecom room to individual outlets
Horizontal cabling connects work areas to the telecommunications
room, usually within the same floor.
12. What is the recommended height for mounting a fire alarm
pull station?
42–48 inches from the floor
This height ensures accessibility according to ADA and fire code
standards.
13. Which of the following is a common testing method for low-
voltage circuits?
Insulation resistance testing
Insulation testing detects potential shorts and ensures safe
operation of low-voltage circuits.
14. What does PoE stand for in networking applications?
Power over Ethernet
PoE allows both data and electrical power to be delivered over a
single Ethernet cable.
15. For security systems, what does the term “fail-safe” mean?
The device unlocks when power is lost
Fail-safe ensures safety by defaulting to an unlocked state in
power loss, common for exit doors.