CAT Installation Techniques 3 — Questions and Answers
Question 1: An alarm technician needs to mount a keypad on a finished drywall surface. Which anchor should be used when no stud is available at the desired location?
- Standard wood screw driven at an angle
- Hollow-wall toggle bolt or drywall anchor rated for the keypad's weight (Correct answer)
- Adhesive mounting tape alone
- A concrete screw driven directly into drywall
Correct answer: Hollow-wall toggle bolt or drywall anchor rated for the keypad's weight
Hollow-wall anchors (toggle bolts or expansion anchors) distribute the load across the drywall when a stud is not available.
Question 2: When terminating stranded wire to a screw terminal on a control panel, what preparation step is critical?
- Spread the strands apart as wide as possible before inserting
- Twist the strands tightly together to prevent stray wires from causing shorts (Correct answer)
- Solder the strands to make them solid before insertion
- Cut all but one strand to simplify the connection
Correct answer: Twist the strands tightly together to prevent stray wires from causing shorts
Twisting stranded wire tightly before inserting it under a screw terminal prevents individual strands from contacting adjacent terminals and causing shorts.
Question 3: What is the maximum recommended distance for a typical 12 VDC powered wireless receiver's antenna lead before signal degradation becomes a concern?
- 50 feet
- 100 feet
- 10 feet (Correct answer)
- 6 inches
Correct answer: 10 feet
Antenna leads for wireless receivers should generally not exceed 10 feet to avoid impedance mismatch and signal loss.
Question 4: During the installation of a siren/speaker on the exterior of a building, which environmental consideration is most important?
- Ensuring the device faces north for optimal sound projection
- Selecting a weatherproof-rated device and sealing all wire entry points (Correct answer)
- Mounting it below the roofline to avoid wind noise
- Using only plastic hardware to prevent rust staining
Correct answer: Selecting a weatherproof-rated device and sealing all wire entry points
Exterior sounders must be weatherproof-rated and all wire penetrations must be sealed to prevent moisture intrusion and corrosion.
Question 5: A technician is running alarm cable through a drop ceiling in a commercial building. Which cable type is required per NEC for this plenum space?
- CM-rated cable in metal conduit only
- CMP (plenum-rated) cable (Correct answer)
- CMR (riser-rated) cable
- Any UL-listed cable is acceptable in a drop ceiling
Correct answer: CMP (plenum-rated) cable
NEC Article 800 and NFPA 72 require CMP (plenum-rated) cable in air-handling ceiling spaces because it produces lower smoke and toxic gas when burned.
Question 6: When installing a vibration detector on a safe, where is the optimal placement location?
- On the top exterior surface centered over the door (Correct answer)
- On the interior back wall of the safe
- On the floor directly beneath the safe
- On the front door exterior near the combination dial
Correct answer: On the top exterior surface centered over the door
Vibration detectors on safes are most effective when mounted on the top exterior surface where attack vibrations are most evenly transmitted.
Question 7: What is the purpose of installing a diode in a two-wire alarm zone circuit?
- To boost the voltage to connected devices
- To allow zone identification in a mixed-polarity two-wire loop configuration (Correct answer)
- To prevent radio frequency interference on the wire
- To replace the end-of-line resistor function
Correct answer: To allow zone identification in a mixed-polarity two-wire loop configuration
Diodes in two-wire zones allow a single wire pair to carry both power and signal in opposing polarities, enabling the panel to distinguish between zone types.
CAT Installation Techniques 3
An alarm technician needs to mount a keypad on a finished drywall surface.
Which anchor should be used when no stud is available at the desired location?