MCB Full Form: What is MCB?: MCB Full Form is a Miniature Circuit Breaker that can be called a good electrical invention. Which is slowly reducing the existence of the fuse. To manually turn on the MCB electrical circuit. Used for protection against over current and short circuits.
The function of MCB
MCB (Miniature Circuit Breaker) If any abnormality is found in the electrical circuit, immediately disconnects the circuit from the power supply itself. If there is any fault in the electrical circuit. Due to this, the electric current is spreading more. In such a situation, breakers like Circuit Breaker, MPCB, RCCB, and MCB are used to protect the circuit.
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How it works
In the condition of overload and short circuit, the current flowing through the circuit is much more than the normal condition. In such a situation, the MCB automatically binds the electrical power supply.
According to the law of nature, that which exists has to be destroyed. The condition of the fuse is similar today. Some type of fuse was used in the protection of electrical circuits, today MCB has replaced it.
Industrial and domestic are two places where there used to be a fuse earlier, but today MCB is visible there. Since the reliability and mileage of MCB are more than that of fuse, hence this change is beneficial.
MCB (Miniature Circuit Breaker) Working Principle
Over current and short circuit two protections are available in MCB (Miniature Circuit Breaker). The principle of operating in two nodes is different.
1. Overload Tripping
As the full form of MCB suggests, it breaks the circuit. In MCB, a bimetallic strip (two separate metal strips) through which electric current flows. Its calibration remains according to the capacity.
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Example: 10 Ampere capacity MCB, so up to 10 Ampere of current can flow through it. If the current spread more than that, then due to the increase in current and temperature in the bimetallic strip, it causes expansion and shrinkage according to its properties. Which tripped the MCB. To which the power supply is tied.
According to its characteristics, the more current is passed through the rating current, the sooner the MCB will trip. This is called thermal-magnetic protection.
2. MCB Short circuit Tripping
A short circuit in electricity can be called a dangerous situation. Single-phase or three-phase load remains after MCB. In which the direct connection of phase with either phase and neutral is called a short circuit.
In such a situation, too much current flows through the circuit. There is a solenoid in the MCB, in which more magnetic flux is generated by passing more current.
The magnetic flux pulls the plunger. And it is accompanied by a tripping coil, which trips the MCB immediately. It is also called electromagnetic protection.
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The principle of operation in MCB is different in both protection overload and short circuit. MCB breaks the circuit according to it.
Thermal magnetic works according to the load and time character stick in over current. And the Bimetallic strip works in it. In a short circuit, an instantaneous trip occurs in which solenoid coil or electromagnetic works.
What is KA in MCB (Miniature Circuit Breaker)?
Usually, when we buy an MCB (Miniature Circuit Breaker), we calculate our load and buy a little oversize MCB from our load.
Example: Understand that our load is of 8 amperes, then we buy a switch of 10 amperes, single-pole, two poles according to whatever we need. We never tell how much KA(Kilo Ampere) should be. Which is a very important parameter. KA means kilo ampere, it is called braking capacity.
When there is a short circuit in the electric circuit, then a high current is passed. In such a situation, how much high current can pass through the MCB, is shown in KA.
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For example, the MCB of 10 Ampere is of 6 KA, then it has the capacity to bear 6000 amperes during a short circuit. Or if there is any short circuit then it will sustain 6000 amps without any damage and will close the circuit. This 6000 ampere is called its breaking capacity.
In MCBs of the same rating, there is a huge difference in price due to different KA.
Example: If the 10-ampere ki MCB 6 KA is available then its price is lower. If the MCB of 10 amperes is 10 KA then its cost is higher.
- The use of MCB is very simple as compared to the fuse which can be operated by anyone easily.
- The reliability of MCB(Miniature Circuit Breaker) is much better than a fuse.
- If the MCB is tied due to a fault, then we can restart the power by turning it on quickly. Which is not possible in Fuse.
- If there is any problem in the circuit then it becomes easy to identify it.
- If the MCB trip happens then we can restart. The fuse cup has to be changed.
- Three-phase circuit The fuses of all three phases remain separate. If one fuse is faulty and it is not available, another rating is also put. Which is not good for the safety of the equipment. This is not the case in MCB.
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MCB (Miniature Circuit Breaker) Disadvantage
- MCB is more expensive than a fuse.
- The cost of the MCB board is higher than that of the fuse board.
- The MCB is not repaired while the fuse is reused.
- MCB does not have leakage current protection like RCCB. Protection is available only on overload and short circuits.
- MPCB is a better option than MCB for motor protection, in which starting current can be sustained.
1P – Single Pole
2P – Two Pole
3P – Three Pole
4P – Four Pole
Where 1P and 2P are used for a single-phase (240 Voltage) power supply.
Used for 3P and 4P three-phase (440 Voltage) power supplies.
Rated Current Of MCB
Available in ratings of 2A, 4A, 6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A ,80A, 100A. Which rating we have to put depends on a load of our equipment.
MCB (Miniature Circuit Breaker) Manufacturers
Which company is MCB from? For example, there are companies like ANCHOR, PHILIPS, SCHNEIDER, SIEMENS, ABB, Havells, L & T, HAVELLS in the market. And known for good quality. Hope this article helps you understand the full form of MCB and its other features as well.