When inspecting a commercial fire alarm system, the inspector notes that the NAC (Notification Appliance Circuit) uses Class B wiring. What distinguishes Class B from Class A wiring?
-
A
Class B uses shielded cable; Class A does not
-
B
Class B has no return path and a single open fault can disable devices beyond the fault
-
C
Class B requires 2-hour fire-rated cable throughout
-
D
Class B allows wireless devices only