Replacing a blown fuse with a fuse of the same amperage rating ensures

• A. The circuit will blow immediately
• B. The circuit remains protected at the intended current
• C. The wire will corrode
• D. The voltage increases across the fuse

Answer: (B)

Fuses protect circuits by interrupting current when it exceeds a safe level. Replacing a blown fuse with one of the same amperage rating keeps the protection the same because the circuit will only be allowed to carry current up to that rating before the fuse opens. Under normal operation, the current stays below that threshold, so the fuse remains closed and the circuit is protected. If a fault causes a surge beyond the rating, the fuse will still melt and break the circuit to prevent damage. The other options don’t fit because simply replacing the fuse with the same rating doesn’t cause an immediate blow, corrosion isn’t driven by fuse replacement, and the voltage across the fuse isn’t what the rating controls—it's the current that the fuse is meant to limit.