In today’s time related to electricity and power supply, most of us have heard the terms MCB and MCCB. But a layman will hardly be able to differentiate between them. Even though both are used as the circuit breaker in case of emergency, still there are some specific differences which we should know. Here, first of all, let us understand what the abbreviations MCB and MCCB stand for. Then we will see their meaning in detail. Then ahead of it, this article will deal with the difference between MCB and MCCB. The MCB is the Miniature Circuit Breaker, whereas the MCCB is Moulded Case Circuit Breaker. Their differences are relevant for the application-specific electric circuit.
What miniature circuit breaker i.e. MCB?
It is an electromagnetic device that carries a complete molded insulating material. Its main function is to switch the circuit. It means it automatically opens the circuit connected with it, while the current passing through the circuit goes beyond the predefined limit. We can manually switch ON or OFF this device, just like the normal switches whenever necessary.
Actually these are time-delay tripping devices. And the operating time is controlled by the magnitude of overcurrent passing through it. Thus, this device functions whenever there is an overload existing for longer periods. MCBs will never respond to the transients like motor starting currents or switches surges. In a typical way, these devices can operate at less than 2.5 milliseconds during the short circuit faults and on the other hand between 2-120 seconds in case of overloads.
What Moulded Case Circuit Breaker i.e. MCCB?
An MCCB is an electric device designed to protect the circuit due to overloading. But, unlike the MCB, it is useful in places where adjustable tripping is required. It is mainly useful for high current applications. MCCB features the manually operated switch for tripping the circuit. MCCB has two arrangements, one for the over-temperature while the other one for over current.
It has a bimetallic contact, which is easily expandable with the change in temperature. Under normal operating conditions, its contact allows the current to flow through the circuit. But, with the rise in current beyond the specified limit, this contact will get warm and expand until they get open. Due to this, the circuit gets disconnected from the main supply, and hence there will be the protection of the equipment from damage.
Difference Between MCB and MCCB
The important difference between MCB and MCCB
|Definition||It is of the type of electrical switch which protects the circuit from overload or short circuit.||It is the device to protect the equipment from over-temperature and fault current.|
|Voltage||It is a low voltage circuit breaker device.||It is also of low voltage to meet international standards.|
|Remote on/off||It is not possible.||It is possible.|
|Current limit||MCBs has less than 100 amps||MCCBs goes high as 2500 amps|
|Interrupting rating||Interrupting rating under 18000 amps||The Interrupting rating ranges from 10000 to 200000 amps|
|Trip adjustment||Trip characteristics cannot be adjusted||The Trip characteristics can be adjusted|
|Use||It is useful for low energy requirements such as small electronic circuits or home wiring.||
Let us learn more about MCB and MCCB, after studying the difference between MCB and MCCB.
Overview of MCB:
- These are the devices having a thermal or thermo-magnetic base.
- These give protection against overcurrent and short circuits both.
- These are available up to 100A with the maximum short circuit capacity of 25kA.
- We use these commonly in lighting circuits.
- Their trip level cannot be varied.
- These are having varieties as single, two, three, and four-pole versions.
Overview of MCCB:
- These are the devices having a thermal or thermo-magnetic or electronic trip type.
- These provide protection against over-current and short circuit.
- Also, can protect against Earth Fault, Residual Currents, Under voltage, etc
- These are available up to the rating of 2500A.
- Their trip level can be varied in adjustable trip type MCCBs.
- These are commonly useful for loads over 100A and motor protection circuits.
- Some MCCBs are also having a microcontroller base.
- These are available in single, two, three, and four-pole versions.
FAQs about MCB and MCCB:
Q.1: What is the maximum normal current rating of MCB and MCCB?
Solution: Maximum normal current rating of MCB is 125A and that of an MCCB is 1600A.
Q.2: What is the maximum short circuit capacity of MCB and MCCB?
Solution: The maximum short circuit capacity of MCB is 15kA and that of MCCB is 85kA