Understand MCB and MCCB

The MCB and MCCB both are circuit breaker and most people confused with its difference. The key difference between the circuit breaker is rating. Circuit breaker are made to ensure there is not electricity over flow, where may cause by short circuit or overload. The location of circuit breaker in every structure should be known to the people who reside in it.

MCB (Miniature Circuit Breaker)
MCB current limit rated under 100A with an interrupting rating of under 18kA (18,000A). Their trip characteristic may not be adjusted since they basically cater to low power circuit. They will found in commercial (house main switch) use.

MCCB (Molded Case Circuit Breaker)
MCCB current limit rated as high as 2500A or as low as 10 with an interrupting rating can be around 10kA to 20kA. Their come with an adjustable trip characteristic. It will use for high power equipment/circuit.
There have some MCCB for electrical motor load limit where they can be tripped using only a remote control. They will found in industrial use or heavier power requirements.

The MCB and MCCB are classified under low voltage circuit breaker, therefore, their standards set by the IEC 947.

Main parameter for circuit breaker
Current rating and Interrupting rating are main parameter for circuit breaker.
Current rating is limit where circuit breaker will open circuit when the short-circuit current is exceeded.
Interrupting rating is limit where circuit breaker able to withstand the destructive energy of short-circuit currents. If the short-circuit current exceeded the interrupting rating, the circuit breaker may have explosion, rupture could result, or permanence damage. The easy explanation is maximum short-circuit current rating.
[P.S.] Interrupting rating is not equal to Interrupting capacity.

Example choosing circuit breaker for load:- 
If you have load (motor or contactor), you have to know the load start-up peak current.
You circuit breaker current rating must equal or higher than start-up current, because the inductance load will have spike current (high current) at initial.
The short-circuit current calculation study is need to choose right interrupt rating or try to using higher interrupt rating circuit breaker.