Which Class pathway does not have a redundant path and operation stops at a single open?

Which Class pathway does not have a redundant path and operation stops at a single open?

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

Answer: (B)

Redundancy in circuit pathways determines whether a single fault will stop signaling. Class B wiring has a single nonredundant path, so an open anywhere in that path interrupts the circuit and operation stops at the fault. Class A wiring provides an alternate route; even if part of the run opens, current can reach devices via the other path, preserving operation. Class C and Class D describe other configurations that don’t describe the no-redundancy case in the same way, so they don’t fit the criterion. Therefore, the pathway without a redundant path is the Class B wiring.

Redundancy in circuit pathways determines whether a single fault will stop signaling. Class B wiring has a single nonredundant path, so an open anywhere in that path interrupts the circuit and operation stops at the fault. Class A wiring provides an alternate route; even if part of the run opens, current can reach devices via the other path, preserving operation. Class C and Class D describe other configurations that don’t describe the no-redundancy case in the same way, so they don’t fit the criterion. Therefore, the pathway without a redundant path is the Class B wiring.