MCB (Miniature Circuit Breaker), RCCB (Residual Current Circuit Breaker), and MCCB (Molded Case Circuit Breaker) are essential components in electrical distribution systems designed to protect circuits and prevent damage or hazards such as overloads, short circuits, and electric shocks.

1. MCB (Miniature Circuit Breaker): The MCB is a compact electrical device used to protect circuits from overload and short circuits. Typically rated for low voltage, MCBs are used in residential and small commercial installations. When the current exceeds a safe limit, the MCB automatically trips, breaking the circuit and preventing further damage. They are available in various current ratings and types, such as B, C, and D, each designed for different applications and load types.
2. RCCB (Residual Current Circuit Breaker): The RCCB is a safety device that detects leakage currents caused by faults or imbalances in the electrical system. When there is a difference between the live and neutral currents, indicating potential leakage, the RCCB trips to prevent electric shocks and fire hazards. RCCBs are commonly used in areas where electrical equipment may come into contact with water or moisture, such as bathrooms or kitchens.
3. MCCB (Molded Case Circuit Breaker): The MCCB is a larger, more robust version of the MCB, typically used in high-power applications such as industrial settings, large commercial installations, and high-voltage systems. MCCBs provide adjustable protection for overload, short circuit, and earth fault conditions, and they can handle higher currents (up to several thousand amperes). They are commonly used in main distribution panels to protect large electrical circuits.

These devices are crucial in preventing electrical accidents and ensuring safe operation of electrical systems. Each device serves a specific purpose, ensuring that the electrical system is adequately protected based on its application and current load.