17 differences between MCB breaker and Fuse

We use an MCB circuit breaker and fuse in the electrical circuits for protecting the electrical circuits. But there are many differences between the MCB breaker and a fuse. I will explain 17 differences between the MCB breaker and fuse.

The MCB (miniature circuit breaker) is an electromechanical device that protects the electrical circuit from short circuits and over electrical current.

The fuse is a metal wire, which melts and opens the electrical circuit due to heating from too much electrical current flow in the circuit.

Differences between MCB and fuse

There are the following differences between an MCB circuit breaker and a fuse:

1. The MCB trip is as per the thermal and magnetic concepts, and disconnect the electrical circuit just by opening a contact in the circuit. But the fuse works on the principle of the thermal characteristic of the fuse wire material. The material of the wire melts due to overheating, and so the electrical circuit becomes open.
   
2. The size of the MCB breaker is big. But the size of the fuse is small.
   
3. The cost of the fuse is much less than as compared to the cost of the MCB breaker.
   
4. We use a fuse in electronic cards in place of MCB due to its small size. It is difficult to use MCB in small-size electronics as the size of the MCB is quite large.
   
5. After tripping, we can reset the MCB and reuse it again and again. But we have to replace the fuse, as we can not reuse the fuse. So the running cost is less for the MCB.
   
6. In case of fault, quick restoration is possible in MCB, just by switching the ON operation. But we can not restore the fuse without replacing it.
   
7. MCB is more sensitive to overcurrent than a fuse.
   
8. MCB can automatically switch off the circuit during overload also.
   
9. The handling of the MCB is safer than the use of the fuse in electrical circuits.
   
10. The fuse is available in a single-phase version only. The MCB is available in 3 phase version also.
    
11. The fuse operation is faster than MCB.
    
12. The MCB breaker has manual operation also. But the fuse has no manual kind of operation.
    
13. We can use the MCB for switching ON and OFF operations also. But we can not use a fuse for switching operations in a circuit.
    
14. The fuse is available for low-current use. The MCCB type breaker is available in the high-current version also.
    
15. For very high-voltage circuits, we use the breaker along with an isolator. We do not use fuse for very high voltage applications.
    
16. In absence of the electric supply, it is easy to disconnect the circuit in case of a fuse, just by removing the fuse. This act like extra safety. Then we can work and do some observations or modifications. However, the MCB breaker can not be removed too easily and fast.
    
17. Special-type breakers can have many built-in protections like leakage current, arc detection ( by AFDD breaker), etc. But the fuse just protects from short-circuit electrical current.

Circuit breakers are available in different types like MCB, MCCB, AFDD, high voltage breakers, etc. The fuses also are available in different types.

Advantages of MCB over a fuse

As discussed above, the MCB has the following advantages over fuse:

• It is easy to restore the supply in the case of MCB
• It is electrically safer to use MCB
• MCB breaker is reusable after trip

Disadvantages of MCB circuit breaker over a fuse

MCB has some of the following disadvantages over the fuse:

• MCB is more expensive
• It is big in size
• More difficult to replace than fuse, if required

Extra knowledge as per experience

In the small circuit, we may use the fuse. But we did not use a fuse in our many electronic circuit cards. This is because the use of electronics was limited to a certain system and the connection was fixed. And there was no chance of wrong use. Further our many circuit outputs were electronically protected for short circuits.

But in panels, we used the MCB and MCCB circuit breakers both extensively as per requirements.

In many panels, we use the breakers and fuse both. But we did not use fuses for every part of the circuit. Individual block of the circuit was protected by MCB only.

For further knowledge watch, the MCB working concept video below:

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Further, read the difference between MCB and RCCB breakers.

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