Which of the following wiring classes is not permitted for the interconnection from the fire alarm control unit to the emergency function control device?

• A. Class A
• B. Class B
• C. Class C
• D. Class D

Answer: (C)

The key idea is that interconnecting a fire alarm control unit to an emergency function control device must use a signaling circuit that stays reliable even if part of the wiring is damaged. Signaling-class wiring is designed for fire alarm signaling and emergency actions, with Class A offering redundant paths and Class B providing a dedicated signaling path. The option described as a wiring class meant for non-fire-alarm control circuits does not provide the necessary signaling reliability for emergency functions, so it is not permitted for this interconnection. The other options are signaling-class wiring appropriate for fire alarm interconnections and are allowed.