MCB (Miniature Circuit Breaker) and ELCB (Earth Leakage Circuit Breaker) are both types of circuit breakers used in electrical installations for protection against electrical faults, but they serve different purposes and provide different types of protection:

1. MCB (Miniature Circuit Breaker):

   • MCB is primarily designed to protect electrical circuits and equipment against overloads and short circuits.
   • It monitors the current passing through the circuit and trips (opens) the circuit when the current exceeds a preset threshold, thereby preventing damage to the wiring, devices, and appliances connected to the circuit.
   • MCBs are available in various current ratings and tripping characteristics to suit different applications and load requirements.
   • They are commonly used in residential, commercial, and industrial electrical distribution panels to provide protection to individual circuits.

2. ELCB (Earth Leakage Circuit Breaker):

   • ELCB, also known as RCCB (Residual Current Circuit Breaker), provides protection against electric shock due to earth faults or leakage currents.
   • ELCB detects the imbalance in the incoming and outgoing currents caused by a leakage to earth and trips the circuit to disconnect the power supply, thereby preventing electric shock hazards.
   • It does not provide protection against overloads or short circuits like MCBs do.
   • ELCBs are classified into two types:
     • Voltage-Operated ELCB (VO-ELCB): These devices operate based on the voltage imbalance between the live and neutral conductors caused by a leakage current. They are less common nowadays due to limitations and safety concerns.
     • Current-Operated ELCB (CO-ELCB): These devices operate based on the residual current flowing through the circuit. They are more widely used and considered safer than VO-ELCBs.
   • ELCBs are commonly used in conjunction with MCBs or as part of an RCBO (Residual Current Circuit Breaker with Overload protection) to provide both earth fault protection and overload/short circuit protection in electrical installations.

In summary, MCBs protect against overloads and short circuits, while ELCBs provide protection against electric shock hazards due to earth faults or leakage currents. They serve complementary roles in ensuring the safety and reliability of electrical systems.