CAT Installation Techniques 2 — Questions and Answers
Question 1: When installing a motion detector in a room with a ceiling height of 12 feet, where should the device typically be mounted?
- At floor level on the baseboard
- At 6 to 8 feet above the floor on the wall (Correct answer)
- At the ceiling directly in the center of the room
- On the door frame at eye level
Correct answer: At 6 to 8 feet above the floor on the wall
Passive infrared (PIR) motion detectors are typically mounted 6–8 feet above the floor to optimize the detection pattern and coverage zone.
Question 2: Which wire type is most commonly specified for connecting smoke detectors in a supervised fire alarm loop?
- Unshielded Cat5e Ethernet cable
- 18 AWG twisted-pair, fire-rated (FPL) cable (Correct answer)
- 14 AWG solid copper THHN wire
- Coaxial RG-6 cable
Correct answer: 18 AWG twisted-pair, fire-rated (FPL) cable
FPL-rated 18 AWG twisted-pair cable is the industry-standard wiring for supervised fire alarm initiating device circuits.
Question 3: What is the primary purpose of using conduit when routing alarm system wiring?
- To increase signal transmission speed
- To provide mechanical protection and a neat installation pathway (Correct answer)
- To boost the voltage on long wire runs
- To eliminate the need for an end-of-line resistor
Correct answer: To provide mechanical protection and a neat installation pathway
Conduit protects wiring from physical damage and satisfies NEC and local code requirements for protected wiring methods.
Question 4: When a door contact switch is installed on a hollow metal door frame, which installation method is most appropriate?
- Surface-mount on the door surface with wood screws
- Recessed installation using a hole saw and recessed housing (Correct answer)
- Adhesive tape mounting on the interior face
- Through-bolt mounting only, with no housing
Correct answer: Recessed installation using a hole saw and recessed housing
Recessed contacts in a recessed housing provide a tamper-resistant, aesthetically clean installation on hollow metal frames.
Question 5: What does the term 'home run' wiring topology mean in alarm system installation?
- All devices share a single loop wire that returns to the panel
- Each device or zone has its own dedicated wire run back to the control panel (Correct answer)
- Wiring is run through the attic and returns to the basement
- Devices are daisy-chained in series from one end of the building to the other
Correct answer: Each device or zone has its own dedicated wire run back to the control panel
Home run topology means each zone or device has an individual cable routed directly back to the control panel, simplifying troubleshooting.
Question 6: When installing glass-break detectors, which factor most significantly affects placement?
- The color of the wall surface
- The acoustic range and line-of-sight to the protected glass (Correct answer)
- The proximity to the control panel
- The height of the ceiling in the room
Correct answer: The acoustic range and line-of-sight to the protected glass
Glass-break detectors rely on acoustic sensing, so they must be within the rated range and have a clear sound path to the glass being protected.
Question 7: What is the correct procedure before drilling through an existing wall to route alarm wiring?
- Apply drywall compound to seal potential gaps afterward only
- Use a stud finder and check for electrical wiring or plumbing using a wire tracer (Correct answer)
- Drill immediately using the largest available bit
- Remove the entire wall section and replace it after wiring is complete
Correct answer: Use a stud finder and check for electrical wiring or plumbing using a wire tracer
Checking for studs, existing electrical wiring, and plumbing before drilling prevents damage to utilities and structural components.
CAT Installation Techniques 2
When installing a motion detector in a room with a ceiling height of 12 feet, where should the device typically be mounted?