Why mcb is used in electrical systems? Do you know?
Any electrical equipment works on its rated required current, otherwise, they are malfunctioning or damaged.
Electrical equipment can be damaged by an overload current, in some cases, may cause even a fire! Most fire accidents across the country are a result of overload current or short circuit current that was not cut off the circuit at the right time.
To protect your electrical equipment and gadgets, you use a fuse or an MCBs. Both cut off the circuit and protect equipment. But due to some advantages mcb is preferred instead of fuse.
In this article, you would find out the answer to why mcb is used instead of fuse? And some other information related to MCB. Let’s look at it in detail.

What is Fuse? How does it work?
Fuse is an electrical safety device, protect against the overload current and short circuit current. As you know that, its components include a wire or strip that melts when excess current flows through it in circuits.
When excess current melts the wire or strip of fuse, it breaks the circuit and protects our equipment. Once it has to serve a purpose then it must be replaced or rewired depending on the type.
Also read: Top 10 wire company in india.
What is MCB? Why MCB is used?
MCB stands for Miniature Circuit Breaker. It is an electromechanical device that works based on the thermal as well as the electromagnetic properties of the electric current. MCB is used for the protection against overload and short circuit protection.
Why is much better than fuse?
MCB has several advantages over the fuse. Due to that mcb is preferred instead of fuse.
- MCB is more sensitive to current than the fuse. Mcb immediately detects any abnormalities and breaks the circuit. This prevents excess current and protect equipment against short circuit and overload current.
- MCB has less maintenance and replacement cost. It is the best advantages of mcb. Sometimes fuse required replacement whenever it goes faulty.
- Handling and using an mcb is safer than using a fuse. This is because replacing a fuse wire or strip is a tedious process.
- With help of mcb, after the fault cleared supply can be resumed immediately. You just need to push the knob of MCB back to the On position. But in the case of a fuse, the entire fuse wire needs to be replaced.
How mcb is much different from the fuse:
MCB | Fuse |
Works on the switching principle and electromagnetism | Works on the thermal and electrical properties of the conducting materials |
It gives an indication of overloads | It doesn’t give any indication of overloads |
Overload & short circuit protection. | Overload & short circuit protection. But fuse mainly preferred for short circuit protection. |
Costly than fuse | Cheaper than mcb |
Low to medium | Low to high |
Not required to replace. You just need to push the knob of MCB back to the On position. | Required to replace wire |
High breaking capacity | Low breaking capacity compared to the circuit breaker |
Operating time of the circuit breaker is 0.02 – 0.05 seconds | Operating time of fuse is 0.002 seconds |
More sensetive | Less sensitive. |
Yes. It can be used as a switch. | Can not be used as a switch |
Very high | Very low |
Conclusion for Why mcb is used:
MCB has several advantages over fuse. It are more sensitive to current than fuses. They immediately detect any abnormality and break the circuit. Due to this reason mcb used in electrical wiring system.
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FAQ: Why MCB is Used?
Why mcb is used in ac?
MCB used in various appliance as a protective devices against the short circuit and the overload conditions. A miniature circuit breaker is the same as the fuse. The only difference is that when a fuse is served its purpose it needs to be replaced wire whereas when a MCB is overloaded it can be easily reset with push of a button at ON position.
Why mcb is not used for motor protection?
MCB is not sensitive to phase failures. A phase failure in a motor is a serious issue that causes a surge in current in the other phases, again leading to overheating and damage to the winding. Due to that reason mcb is not used for motor protection.
Which MCB is best?
There are many mcb manufacturing company in India. Among these Havells, Finolex, Legrand, Siemens are best company for mcb.
Which metal is used in MCB?
Current carrying parts of mcb are made of electrolytic copper or silver alloy.
Which type of MCB is used in home?
According to finolex company blog, type C mcb best suited for domestic appliances with medium load current.
Thanks for the clear explantion, Such a useful information, It means a lot.