What is difference between mcb and mccb circuit breakers

It depends on where you are in the world. Officially for most of the world, MCB stands for Miniature Circuit Breakers and MCCB stands for Molded case Circuit Breakers. Unofficially, the term MCB is an IEC term and is relatively new to the North American workplace. Until recently MCB here meant "Main Circuit Breaker" which defined a function, not a style, but was typically an MCCB style device.

Also in the US, the IEC MCBs, as used over most of the world, do not meet the official requirements of what is called a "circuit breaker" because that terminology is reserved for a device tested and listed to UL standard #489. IEC MCBs then are / were called "Supplementary Circuit Protectors" (SCPs)and were UL listed under a new standard #1077. But UL-1077 disallows the use of SCPs unless there is are UL-489 listed circuit breakers upstream, which defeats the purpose for most people.

More recently, companies such as Siemens, ABB and Schneider have released modified versions of their MCB products that HAVE passed UL-489 and CAN be called "circuit breakers", but to differentiate them from the IEC MCBs, we call them "UL-489 MCBs".

All MCBs are, by definition, under 100Amp and typically have an "interrupting rating" of under 18,000Amps, which is the level of fault current at which they become shrapnel.

Molded Case Circuit Breakers are the common low (10Amp) to high (2000Amp) power, plastic encased breakers used in "low voltage" (defined as 690V and under) distribution systems. They can have an interrupting rating of anywhere from 10,000A to 200,000A

MCB stands for MINIATURE CIRCUIT BREAKER with rated current below 100 amperes whereas MCCB stands for MOULDED CASE CIRCUIT BREAKER with rated current from 10 amperes to 2000 ampers.MCB has breaking capacity upto 10kA, MCCB has breaking capacity above 10kA.

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MCB is miniature circuit breaker which is thermal oprated and use for short circuit protection in small current rating circuit. MCCB moulded case circuit breaker and is thermal operated for over load current and magnetic operation for instant trip in short circuit condition.under voltage and under frequency may be inbuilt. Normally it is used where normal current is more than 100A. Electrical test equipment is a handy tool today.