MCBs (miniature circuit breakers) offer protection against overloads and short circuits. In this article about the difference between MCB and fuse, we’ll discuss the main features of these as well as their advantages and disadvantages. We’ll also touch on their different applications.

MCB and Fuse Difference

What is the difference between a fuse and a miniature circuit breaker? There are several differences. To understand them, let’s look at the meaning and operation method of each device.

Fuse Meaning

A fuse is a safety device that interrupts the electrical circuit in case of an overload or short circuit. That is, it breaks the circuit preventing fires or explosions.

The working principle of the fuse is based on the heating effect of the current. Fuses are made of a thin wire that melts when too much current passes through it, thus opening the circuit.

Nowadays, fuses are not used that much in low-voltage applications because other devices, such as the MCB, can do the job better. Below is the MCB meaning.

Miniature Circuit Breaker Meaning

A miniature circuit breaker or MCB is an electrical device that interrupts the circuit in case of an overload or short circuit. The basic principle of the MCB is similar to that of a fuse. Both devices open the circuit when there is an excessive current.

The main difference between MCB and a fuse operation is that whereas a fuse wire melts an MCB trips from the action of a bimetallic strip and/or solenoid. You can also reuse an MCB after it trips, but you have to replace a fuse.

Fuse vs. MCB

While both fuses and circuit breakers are used to protect against electrical hazards, there are several differences between these devices. Fuses and circuit breakers differ in the following ways: operation, construction, use, and cost among others.

Fuse vs. MCB: Operation

The main difference between a fuse and miniature circuit breakers is in their operation. A fuse wire melts, interrupting the circuit. On the other hand, an MCB trips, opening the circuit.

Fuses are made of a metal wire placed between two metal caps. The wire has a low melting point so that it can melt easily. In an overload or a short circuit, the current passing through the fuse wire increases, making it heat up and melt. That interrupts the circuit, thus protecting the electrical system.

The miniature circuit breaker operation is different. To break and safely isolate circuits in case of an overload or short circuit, it uses a bimetallic strip, a solenoid, or both to trip when the current passing through it exceeds the specified level.

Fuse vs. MCB: Construction

The construction of a fuse and an MCB is different. A fuse is a device that contains a thin wire that melts when too much current flows through it. The melting of the wire interrupts the flow of current and “blows” the fuse, opening the circuit.

MCBs, on the other hand, are electromechanical devices that use magnetic and thermal mechanisms to isolate circuits during a fault.

That makes the fuse a simple device. On the other hand, the MCB construction is more complex, consisting of different parts that make it more sensitive to current changes.

Fuse vs. MCB: Cost

Another key difference between MCB and fuse is in their cost. A fuse is cheaper than an MCB. That’s because the construction of a fuse is simpler than that of an MCB.

On the other hand, the cost of replacing a fuse every time it blows can be higher than the cost of MCB devices over time. That’s because you have to buy a new fuse every time the old one blows, while you can reuse an MCB after it trips.

Fuse vs. MCB: Use

Fuses and miniature circuit breakers are used differently to offer different benefits. When a fuse has blown, you have to replace it with a new one, while an MCB can be reused after it has tripped. That is, you don’t have to replace an MCB every time it trips.

This difference between fuse and MCB in terms of usage characteristics makes the latter a better option in most cases. An MCB is more convenient to use and, therefore, more popular than a fuse.

Fuse vs. MCB: Variety

There is greater variety in the types of MCBs than fuses. Miniature circuit breakers are available in different trip curves, voltage, current ratings or interrupting capacities, and sizes.

The variety of MCBs gives you more options to choose from according to your specific needs. In contrast, there are only two types of fuses: fast-blow and slow-blow. That’s because the operation of a fuse is simpler than that of an MCB.

Other MCB Fuse Differences

Other MCB and fuse difference examples include the following:

• Fuses are used to protect against overcurrents, while MCBs offer protection against both overloads and short circuits.
• Fuses have a fixed current rating, while MCBs may have adjustable settings.
• MCBs are available in both thermal and magnetic types, while fuses are only available in the thermal type.

As you can see, both fuses and circuit breakers are examples of electrical devices that are used to protect against electrical hazards. While there are several differences between these devices, the most significant difference is in their operation and construction.

Which is better, a fuse or a circuit breaker? In general, miniature circuit breakers are better at protecting circuits than fuses. So they have typically replaced the fuse in most applications today, offering many benefits as a result.

Conclusion

Fuses and miniature circuit breakers are different in many ways, from their operation to their construction, cost, and use. The most significant difference between fuse and MCB devices is in their design and operation:

A fuse wire melts, interrupting the circuit, while an MCB trips to open a circuit. As a result, you can reuse an MCB after it has tripped, while a fuse must be replaced after it has blown. This makes the MCB a better protection and switching device in many applications.