Electrical Systems for Fire Protection Flashcards
6 cards from real NICET practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Electrical Systems for Fire Protection flashcards as text
What wire gauge is most commonly used for fire alarm initiating device circuits?
Answer: 22 AWG
18 AWG wire is most commonly specified for fire alarm initiating device circuits, balancing resistance, cost, and mechanical durability.
In a two-wire smoke detector circuit, how is the detector powered?
Answer: From the same pair of wires that carries the alarm signal
Two-wire smoke detectors receive operating power and transmit alarm signals over the same pair of wires connected to the initiating device circuit.
What is the purpose of an isolation module in an addressable fire alarm loop?
Answer: Isolate a section of the loop that develops a short circuit while keeping the rest operational
Isolation modules detect and isolate short circuits on a segment of an addressable loop, allowing the remainder of the loop to continue operating normally.
Which type of power supply provides the MOST reliable protection against AC power interruptions for fire alarm systems?
Answer: Online UPS with sealed lead-acid batteries
An online UPS provides instantaneous, seamless switchover to battery power during AC outages, ensuring uninterrupted fire alarm system operation.
What does a ground fault trouble signal on a fire alarm panel indicate?
Answer: An unintended electrical connection between a circuit conductor and ground
A ground fault indicates that one of the fire alarm circuit conductors has an unintended connection to a grounded conductor or metallic conduit.
According to NFPA 72, what is the maximum time a fire alarm control unit may take to indicate a trouble condition after a fault occurs?
Answer: 100 seconds
NFPA 72 requires the fire alarm control unit to indicate a trouble condition within 200 seconds of a fault occurring on a supervised circuit.