Explain how MCB is different from ELCB
Both are circuit breakers but MCB trips if there is a short circuit while ELCB trips if it is earth leakage or we can say if anyone touches the bare conductor or bare conductor touches the ground.
ELCB is sensitive to any minute current leakage and it will Trip the Main Circuit Breaker. But the MCB alone will only Trip according to its set full load ratings or short circuit fault.
mcb = miniature circuit breaker. Principle of working: bimetallic strip deflect when heated by overloaded the circuit and breaks the circuit. Works for overload as well as short circuit fault.
COELCB = current operated earth leakage circuit breaker. Operates based on ZCT ( zero volt coil). When phase & Neutral or three phases & Neutral runs normally, ie there are no contacts between phases or Neutral with the body or earth, in the ZCT senses zero volts. If there is any of the phases gets in contact with the body or earth, in that particular phase conductor current rushes to the earth. So there will be no zero volts in the ZCT. So it activates and trips the breaker (ELCB)
RCD is the residual current detector.
RCBO is a combination of MCB and ELCB.
MCCB = molded case circuit breaker: the working principle is electromagnetic,
MCBs are meant for lesser than 100A. MCCBs for above 100A ( 30A , 40A, 60A, 80AMCCBs are there too but frame size is 100/125A.