Fuses in motor branch-circuits primarily provide

• A. Motor running overcurrent protection
• B. Motor short-circuit protection
• C. Protection against single-phasing
• D. Protection against motor overheating

Answer: (B)

Fuses in motor branch circuits are meant to interrupt dangerous fault currents quickly, providing short-circuit protection to protect wiring and equipment from damage and fire risk. They are selected to blow when current spikes due to a fault exceed the fuse rating, which helps limit damage during a short circuit. Separate overload protection, such as a thermal overload relay in the motor starter, handles normal motor overload conditions and motor overheating. Fuses don’t detect or prevent single-phasing, and overheating protection is usually handled by the motor’s thermal protection, not by the fuse itself.