What is the purpose of a fuse?

• A. To Safely Isolate a Fault Preventing Damage to Equipment.
• B. To Increase Current in a Circuit.
• C. To Store Energy.
• D. To Regulate Voltage.

Answer: (A)

Fuses are protective devices that open the circuit when current becomes excessive, preventing damage to wiring and equipment. Inside a fuse is a thin metal link designed to melt or vaporize when the current exceeds its rating. If a fault causes a surge—like a short circuit—the increased current heats the link until it breaks, isolating the faulty part of the circuit and reducing the risk of overheating, damage, or fire. After it blows, you replace it with a new one.

A fuse does not increase current, store energy, or regulate voltage, so those options don’t describe its function.