MCB means miniature circuit breaker--It is thermal &
magnetic trip device operating upto 100 A. It's range is
fixed not selectable.
MCCB means Moulded Case Circuit Breaker---It is operated
upto 1000 A and High voltage MCCB also operates on 1200 A
also...And it's range is selectable..
ELCB means Earth Leakage Circuit breaker---It is operated
on leakage current only..It is not operated on short
circuit or overload current.
RCCB means Residual Current Circuti Breaker---it's Working
principle is same as ELCb..It is also operated on Leakage
current..Main differance between it and ELCB is that it is
also operated on Short circuit current
mccb-minurate current circuit breaker it used upto 1000A,
it should withstand that capacity
mcb-miniurate ciruit breaker it used upto 63A only for
elcb-earth leakage circuit breaker it used for any leakage
current in cable, then it should trip under earth fault