Which statement about Class A circuitry is true?

Which statement about Class A circuitry is true?

• A. They must always be used with fiber-optic pathways
• B. Fiber-optic or wireless pathways are Class A
• C. They require separate fault annunciation
• D. They cannot be used with duct detectors

Answer: (B)

Class A circuitry is designed to keep the fire alarm system operating even if part of the wiring is damaged by forming a continuous, redundant loop. Because of this loop concept, the signaling pathway between devices and the control panel can be implemented with different types of pathways, including fiber-optic or wireless. Fiber-optic pathways are commonly used for their insulation and immunity to electrical interference, and wireless pathways can also be used to create a Class A arrangement in situations where wiring is difficult. The system is not restricted to fiber only, and duct detectors or other devices can be part of Class A circuits; there’s no requirement for separate fault annunciation specific to Class A, and the option that it must always use fiber-optic pathways is not accurate.

Class A circuitry is designed to keep the fire alarm system operating even if part of the wiring is damaged by forming a continuous, redundant loop. Because of this loop concept, the signaling pathway between devices and the control panel can be implemented with different types of pathways, including fiber-optic or wireless. Fiber-optic pathways are commonly used for their insulation and immunity to electrical interference, and wireless pathways can also be used to create a Class A arrangement in situations where wiring is difficult. The system is not restricted to fiber only, and duct detectors or other devices can be part of Class A circuits; there’s no requirement for separate fault annunciation specific to Class A, and the option that it must always use fiber-optic pathways is not accurate.