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Connecticut Low Voltage Practice study materials
Connecticut Low Voltage Practice study resources

Connecticut Low Voltage Practice: Security, Access Control, and CCTV Systems

Connecticut Low Voltage Practice · Work through your exam, one topic at a time.

All guide sections

Security, Access Control, and CCTV Systems

Domain 6 tests security, access control, and CCTV as low-voltage systems with power, signal, and life-safety constraints. Expect questions on PoE budgets, lock types, egress, camera power, lens and lighting, bandwidth, and grounding. The best answer usually satisfies the security function and the building code at the same time.

Power and signal

  • PoE follows IEEE 802.3af, at, and bt; the copper channel is limited to 100 m (328 ft), including patch cords. Higher power does not extend distance.
  • Calculate the switch power budget with connected-device draw and design margin; do not assume every port can deliver maximum power simultaneously.
  • Access control includes a reader, controller, request-to-exit (REX) device, door contact, and lock. Fail-safe locks unlock on power loss; fail-secure locks remain locked. Egress and fire-alarm release requirements override convenience.

CCTV and cameras

Camera selection depends on resolution, lens angle, minimum illumination, IR range, and WDR. Higher resolution increases storage and bandwidth. Verify the scene's lighting before promising identification; lux ratings and IR distance are not interchangeable.

Worked example

A 24-port PoE switch is rated 370 W. The design has 24 cameras at 11 W and six access controllers at 18 W. Camera load = 264 W; controller load = 108 W; total = 372 W. The switch is already over budget, and a common 80% design margin (296 W) would be exceeded much earlier. The correct fix is a second switch, a higher-power chassis, or local power supplies-not simply assuming the 370 W rating covers all ports.

Traps that cost marks

  • Reversing fail-safe and fail-secure.
  • Omitting a REX or fire-alarm release on an electrified lock.
  • Exceeding 100 m on a PoE copper run.
  • Ignoring low-light performance and promising identification from a wide overview camera.
  • Underestimating storage and uplink bandwidth.

Exam-ready summary

Check power first, then egress and life safety, then image performance. A security system that locks people in or fails on a fire alarm is a failed design.