Question

The wiring between a fire alarm control unit and the control appliance or relay for an emergency function cannot be of which of the following classes?

1) Class A
2) Class B
3) Class C
4) Class D

Answer 1

The wiring between a fire alarm control unit and the control appliance or relay for an emergency function cannot be of Class D. Classes A, B, and C are commonly used for fire alarm circuits.

Step-by-step explanation:

The wiring between a fire alarm control unit and the control appliance or relay for an emergency function cannot be of Class D. Classes A, B, and C are commonly used for fire alarm circuits. Class A wiring provides redundancy by using two separate paths for the signal, ensuring that if one path is damaged, the other can still carry the signal.

Class B wiring uses a single path but can still provide reliable operation. Class C wiring is typically used in areas where a loss of power to the alarm system is expected, as it does not rely on external power sources.