C7 Security System Design & Integration 3

Question 1

A passive infrared (PIR) motion detector triggers false alarms repeatedly near a south-facing window. What is the most likely cause?

Accepted Answer

Thermal gradients from sunlight heating the floor

Answer

PIR detectors sense infrared energy changes; sunlight warming surfaces near the detection zone creates thermal gradients that mimic body heat and cause false alarms.

Question 2

Which topology is recommended for a wired access control system serving 50 doors to minimize single-point-of-failure risk?

Accepted Answer

Distributed controller architecture with peer-to-peer mesh

Answer

A distributed controller architecture with peer-to-peer redundancy ensures that failure of one controller does not take down the entire access control system.

Question 3

What is the maximum allowable resistance for a supervised alarm loop using 1,000 Ω end-of-line resistors per typical burglar alarm panel specifications?

Accepted Answer

250 Ω

Answer

Most burglar alarm panels accept up to 250 Ω of loop resistance (wire resistance) when using 1,000 Ω EOL resistors before the panel flags a trouble condition.

Question 4

In IP video surveillance design, what does the term 'bandwidth aggregation' refer to?

Accepted Answer

The total network bandwidth consumed by all cameras simultaneously at full resolution

Answer

Bandwidth aggregation is the sum of all camera streams transmitting simultaneously, which determines the network infrastructure capacity needed.

Question 5

Which grounding method is required for a metal enclosure housing a low-voltage security control panel per NEC Article 250?

Accepted Answer

The enclosure must be bonded to the equipment grounding conductor

Answer

NEC Article 250 requires metal enclosures to be bonded to the equipment grounding conductor to ensure safe fault-current paths.

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

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

C7 Security System Design & Integration 3