CCTV CCTV Installation and Maintenance 5 — Questions and Answers
Question 1: A technician notices condensation forming inside an outdoor camera housing. What is the most effective long-term solution?
- Replace the camera lens
- Install a desiccant pack inside the housing and ensure the gasket seal is intact (Correct answer)
- Increase the camera's IR intensity
- Switch to a dome camera model
Correct answer: Install a desiccant pack inside the housing and ensure the gasket seal is intact
Desiccant packs absorb internal moisture, and an intact gasket seal prevents humid air from entering the housing, eliminating condensation buildup.
Question 2: Which recording schedule is most appropriate for a retail store that wants to conserve storage while ensuring coverage during business hours and overnight?
- Continuous 24/7 recording at maximum resolution
- Continuous recording during open hours and motion-triggered recording overnight (Correct answer)
- Motion-only recording at all times
- No recording during closed hours
Correct answer: Continuous recording during open hours and motion-triggered recording overnight
Continuous recording during business hours captures all activity, while motion-triggered recording overnight conserves storage without missing security events.
Question 3: What is 'camera tampering detection' in modern CCTV systems?
- A feature that detects when camera resolution is changed
- An alert triggered when the camera is covered, moved, or spray-painted (Correct answer)
- A log of all user logins to the NVR
- An alarm when the camera exceeds its operating temperature
Correct answer: An alert triggered when the camera is covered, moved, or spray-painted
Tampering detection algorithms identify when a camera's view is suddenly obstructed, shifted, or defocused and send an alert to the monitoring system.
Question 4: What grounding technique helps prevent ground loop interference in analog CCTV systems?
- Connecting all camera grounds to a single common ground point (Correct answer)
- Using multiple separate ground points for each camera
- Removing ground connections from the DVR
- Installing ferrite beads on power cables only
Correct answer: Connecting all camera grounds to a single common ground point
A single common ground point (star grounding) eliminates potential differences between camera grounds, which is the root cause of ground loop interference and video hum bars.
Question 5: A newly installed IP camera shows video on the NVR but the image is severely pixelated and buffering. What is the most likely cause?
- The camera IR LEDs are malfunctioning
- Insufficient network bandwidth or a bottleneck switch port (Correct answer)
- The NVR hard drive is full
- The camera housing is the wrong color
Correct answer: Insufficient network bandwidth or a bottleneck switch port
Pixelation and buffering on IP camera streams typically indicate that the network switch, cable, or bandwidth is insufficient to handle the camera's bitrate.
Question 6: When calculating storage requirements for a CCTV system, which three factors are most critical?
- Camera brand, lens focal length, and housing type
- Number of cameras, recording resolution/bitrate, and retention period (Correct answer)
- Camera color, frame rate cap, and NVR brand
- Cable length, IP address range, and motion sensitivity
Correct answer: Number of cameras, recording resolution/bitrate, and retention period
Storage size is a direct product of how many cameras are recording, at what bitrate (quality), and for how many days footage must be retained.
Question 7: Which maintenance task should be performed on a CCTV system at least once per year?
- Replacing all coaxial cables
- Cleaning camera lenses, checking housing seals, and verifying recording integrity (Correct answer)
- Upgrading all cameras to the latest model
- Changing the NVR's IP address
Correct answer: Cleaning camera lenses, checking housing seals, and verifying recording integrity
Annual preventive maintenance includes cleaning lenses for image clarity, inspecting weather seals for moisture ingress, and verifying recordings are being captured and stored correctly.
CCTV CCTV Installation and Maintenance 5
A technician notices condensation forming inside an outdoor camera housing.
What is the most effective long-term solution?