Which statement about Class A circuits is true?

Which statement about Class A circuits is true?

• A. Outgoing and return conductors must be routed separately; they may be installed in the same raceway
• B. They must be routed together in the same raceway
• C. They must be installed in separate rooms
• D. They cannot share raceways with any other circuits

Answer: (A)

Class A signaling circuits are designed with a looped path, so if a fault occurs somewhere along the line, the circuit can continue to operate through the other direction around the loop. To support that fault-tolerant behavior, the outgoing and return conductors must be kept separate rather than run as a single pair that could be compromised together. They should be routed separately to preserve independent paths, but they can be installed in the same raceway as long as they remain distinct and properly separated within the raceway. This is why the statement that outgoing and return conductors must be routed separately, though they may be in the same raceway, is true. The other options misstate the need for separation, or imply stricter isolation (separate rooms) or complete prohibition on sharing raceways, which isn’t required.

Class A signaling circuits are designed with a looped path, so if a fault occurs somewhere along the line, the circuit can continue to operate through the other direction around the loop. To support that fault-tolerant behavior, the outgoing and return conductors must be kept separate rather than run as a single pair that could be compromised together. They should be routed separately to preserve independent paths, but they can be installed in the same raceway as long as they remain distinct and properly separated within the raceway. This is why the statement that outgoing and return conductors must be routed separately, though they may be in the same raceway, is true. The other options misstate the need for separation, or imply stricter isolation (separate rooms) or complete prohibition on sharing raceways, which isn’t required.