In short
When the electricity is flowing normally, the fuse permits the power to pass unobstructed across its filament, between circuits. If an overload occurs, the filament melts, stopping the flow of electricity. Fuse is a one time use device and melts when excess current passes through it and protects the other devices in the circuit.
MCB or miniature circuit breaker are either electromagnet or a bi-metal strip. In either case when turned on, the breaker allows electrical current to pass from a bottom to an upper terminal across the solenoid or strip. When the current reaches unsafe levels, the magnetic force of the solenoid becomes so strong that a metal lever within the switch mechanism is thrown, and the current is broken. Alternately, the metal strip bends, throwing the switch and breaking the connection. To reset the flow of electricity after the problem is resolved, the switch can simply be turned back on, reconnecting the circuit.
The Difference Between Fuse and Circuit Breaker is given below in the tabulated form
BASIS FUSE CIRCUIT BREAKERWorking Principle | Fuse works on the electrical and thermal properties of the conducting materials. | Circuit breaker works on the Electromagnetism and switching principle. |
Reusability | Fuses can be used only once. | Circuit breakers can be used a number of times. |
Status indication | It does not give any indication. | It gives an indication of the status |
Auxiliary contact | No auxiliary contact is required. | They are available with auxiliary contact. |
Switching Action | Fuse cannot be used as as an ON/OFF switch. | The Circuit breaker is used as an ON/OFF switches. |
Temperature | They are independent of ambient temperature | Circuit breaker Depends on ambient temperature |
Characteristic Curve | The Characteristic curve shifts because of the ageing effect. | The characteristic curve does not shift. |
Protection | The Fuse provides protection against only power overloads | Circuit breaker provides protection against power overloads and short circuits. |
Function | It provides both detection and interruption process. | Circuit breaker performs only interruption. Faults are detected by relay system. |
Breaking capacity | Breaking capacity of the fuse is low as compared to the circuit breaker. | Breaking capacity is high. |
Operating time | Operating time of fuse is very less (0.002 seconds) | Operating time is comparatively more than that of the fuse. (0.02 – 0.05 seconds) |
Version | Only single pole version is available. | Single and multiple version are available. |
Mode of operation | Completely automatically. | Manually as well as automatically operated. |
Cost | Cost of fuse is low. | Cost of circuit breaker is high. |