Difference Between Miniature Circuit Breaker(MCB) and Fuse

difference between miniature circuit breaker and fuse

Every industry and residential building uses circuit protection devices to safeguard from any electrical misconduct. Use of the protection devices like Miniature Circuit breakers and the fuse has been the most effective solution to stop electrical damage.

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What Is Miniature Circuit Breaker (MCB) and How Does It Work?

Miniature Circuit Breakers (MCB) are electrical switches that automatically operate to protect the electrical circuit damage from current overflow, overloads, or short circuits. It is an electromechanical device used as a safety major, designed to trip whenever there is an inevitable overload with enormous damage.

The working principle of Miniature Circuit Breaker (MCB)

MCB has two different types of arrangements in its operating system. One of those is an electromagnetic effect caused by the overcurrent, and the other is the thermal effect also caused by the overflow of current.

Thermal effect: The thermal effect in the Miniature Circuit Breaker is caused by the bi-metallic strip whenever there is a continuous overflow of current through MCB.

It is achieved when the bimetallic strip is heated and starts bending—the deflection in the metallic strip release the metallic latch, which results in the circuit breaker opening.

Electromagnetic effect: Overflow of current during the short circuit causes the electromagnetic effect. It results in the displacement of the plunger, which is attached to the tripping coil of the MCB.

It strikes with the trip lever, which immediately releases the latch mechanism and opens the circuit breakers.

What Is Fuse and How Does It Work?

The fuse is an electrical device protecting against the overcurrent flow and the short circuit. It consists of two poles and a metal wire. The metal wire is the most crucial element, which melts when the current overflows, cutting the power supply.

Fuse is an essential device to protect the appliance and the wiring when something goes wrong.

Working principle of fuse

Before getting into the working principle of fuse, you must understand two concepts:

  1. Current Flows in a loop
  2. Heating effect of current

Current Flows in a loop: The conductor's electrical current flow happens only when the circuit is completely formed. When there are certain breaks inside the electric loops, the electrical charges cannot flow through, resulting in the electrical switch operating. 

Heating effect: The various components like the wire or the devices offer resistance to the current flow, which presents itself in the form of heat, known as the "heating effect."

When the stipulated quantity of current runs through the circuit, the fuse wire doesn't suffer any harm. In typical circumstances, the fuse wire is a part of the circuitry, contributing to a complete loop for charges to flow through it. When an excessive current travels through a fuse wire, the current's heating impact leads the fuse wire to melt. It is due to the fuse wire being chosen for its low melting point. This breaks the loop, halting the passage of charges through the circuit.


What are the differences between the Miniature Circuit Breaker (MCB) and fuse? 

Miniature Circuit Breaker (MCB) and Fuse are both electrical devices that are operated to give protection in case of a short circuit caused by the overload of the current. Even when the working point of both MCB and Fuse are the same, they have various components that make a vast difference between them. 

Differences Between Miniature Circuit Breaker (MCB) And Fuse



Miniature Circuit Breaker (MCB)


Fuse is capable of providing both detection and interruption processes.

Miniature Circuit Breakers (MCB) depend on a relay system to detect the faults. It only performers the process of interruption.


Fuse is specialized in protecting only the overloads.

MCB protects both the short circuits and overloads.


Fuse is very low in price in comparison to the Miniature Circuit Breakers.

The cost of the MCBs is very high according to their types.

Operating principle

The operating system of the fuse is based on the heating structure of the conductor.  

Miniature Circuit Breakers are operated with the switching mechanism.

Breaking Capacity

The breaking capacity of the fuse is shallow.

The breaking capacity of MCB is very high compared to fuse.


Fuse has only a single-pole version.

MCB has multiple pole versions.

Operating mode

The fuse is entirely operated automatically.

MCB has operated automatically as well as manually.

Action on switching

Fuse is based on the ON/OFF switching methods.

MCB is based on the ON/OFF switching methods.

The durability

The fuse wire has to be replaced once it gets used. 

MCB can be used a lot of times compared to fuse.

Indication of status

It doesn't give any indication.

MCB indicates the status.

Operating time

The operating time of the fuse is significantly less, which is 0.002 secs.

The operating time of the MCB is a bit more than that of the fuse, which is 0.002-0.005 secs.

Characteristics curve

Because of the aging effect, the Fuse characteristic tends to shift.

The characteristics of the MCB don't shift.


It doesn't depend on the ambient temperature.

Miniature Circuit Breaker depends on the ambient temperature.

Auxiliary Contact

Fuse doesn't require Auxiliary contact.

Circuit Breakers are Available with auxiliary contact.


It is mainly used in applications that draw a low level of current.

MCB is used in heavy motors and applications that draw high currents.


Fuses are a cheap solution that provides circuit protection. Its main advantage is faster circuit protection over a miniature circuit breaker. When it comes to protecting sensitive electrical equipment, it is crucial.

Similarly, for three-phase applications, circuit breakers provide better protection. Because circuit breakers are not sacrificial and do not need to be replaced like fuses, power can be restored more quickly without locating a spare fuse.