Which sequence describes proper fuse coordination in a distribution system?

• A. Breaker protection first, then fuses
• B. Transformer fuses, branchline fusing, reclosers, substation circuit breakers
• C. Branchline fusing, reclosers, transformers, breakers
• D. Fuses only in one device whenever possible

Answer: (B)

Selective protection coordination means guarding the closest equipment first and letting upstream devices operate only if the fault isn’t cleared locally, so only the smallest part of the system is de-energized.

In this sequence, transformer primary fuses protect the transformer itself and clear faults there right away. If the transformer is healthy, the fault is handled further downstream by the branchline fuses, which isolate only the affected branch. If a fault is still present or a transient fault occurs, the reclosers provide a quick fault clearance with an automatic reclosing cycle to restore service if the fault clears. If the fault remains despite those steps, the substation circuit breakers act to disconnect the larger portion of the system, preventing a wider outage.

This arrangement ensures minimal disruption and avoids tripping larger portions of the network for faults isolated to a small area. Other patterns would either trip upstream devices too quickly, leave critical equipment unprotected, or rely on fuses alone without the staged, selective protection.