In an household electrical circuit:
(a). Where is the MCB(miniature Circuit Breaker) connected?
(b).What is the function of ELCB(Earth Leakage Circuit Breaker)?

Hint: Miniature Circuit Breaker is a safety device used during electrical installation which will automatically cut the power supply to appliances when there is a leakage current or overflow of current. It works just like a fuse but has higher sensitivity. Earth leakage Circuit Breaker is a safety device used during electrical installation. Earth Leakage Circuit Breakers have high earth impedance which will help in preventing shock.

Complete step by step answer:
(a) Miniature Circuit Breaker (MCB): Miniature Circuit Breaker is a safety device which automatically switches off the circuit when there is a fault in the circuit or if there is overloading. Miniature Circuit Breaker functions just like a fuse but the MCB have much more sensitivity than the fuse, and they can detect a small amount of leakage current or overloading.
Like a Fuse , A MCB is connected in series with the main line in the household circuit.


(b) Earth Leakage Circuit Breaker (ELCB): An Earth Leakage Circuit Breaker is a safety device used during the installation of house-hold circuit with high earth impedance to avoid shock. ELCB can identify a small amount of leakage voltage to earth and introduce the circuit if dangerous voltage is identified. The main purpose of Earth leakage circuit breaker (ECLB) is to prevent the damage to humans and animals due to electric shock due to leakage.
When the Earth Leakage Circuit Breaker notices a faulty currents of human or animal to the earth it will turn off the power and remain off until manually rearranged.

Note:
Miniature circuit breakers have high sensitivity to changes in temperature within their operating environment. As the temperature increases in the surrounding environment or by the heating effect it affects the bending of the metal strip present inside the MCB , decreasing the lifetime of the MCB.
ELCB does not allow splitting of a single building system into multiple sections with independent fault protection because the earthing system is bonded to pipework. The earthing system may be tripped by the external voltage from the metal pipe connected to the earthing system.