MCB stands for Miniature Circuit Breaker. It automatically switches OFF electrical circuit during any abnormal condition in the electrical network such as overload & short circuitconditions. However, fuse may sense these conditions but it has to be replaced though MCB can be reset. The MCB is an electromechanical device which guards the electric wires &electrical load from overcurrent so as to avoid any kind of fire or electrical hazards. Handling MCB is quite safer and it quickly restores the supply.When it comes to house applications, MCB is the most preferred choice for overload and short circuit protection. MCB can be reset very fast & don’t have any maintenance cost. MCB works on bi-metal respective principle which provides protection against overload current&solenoidshort circuit current. 
ELCB stands for Earth Leakage Circuit Breaker. They have the same function as RCCB but are voltage sensor devise. However, this is an old technology & is not in common use. RCCB being a current sensitive device have a better advantage over ELCB as under:
Size : All Size MCB, RCCB & ELCB Available
Make : Siemens, L&T, Schneider, Legrand, ABB, Any Make