What is the basic difference between MCB,MCCB & MPCB?
Do we need to use motor thermal overload relay along with MPCB?
Up to what rating is MPCB available and why it is not available for higher rating?

MCB = Miniature Circuit Breaker or sometimes Main Circuit Breaker (old meaning)
MCCB = Molded Case Circuit Breaker
MPCB = Motor Protection Circuit Breaker

Circuit breaker - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Circuit_breaker)

MCB = Miniature Circuit breaker, is having overload and
s.c. protection & used in domestic application

MCCB = Moulded case Circuit breaker, is having overload and
s.c. protection & used in Industrial application & Having
high s.c. capacity

MPCB use for O/L,S/C & E/F protection .