Question

Which is best RCB or MCB?

Answer 1

RCB (Residual Current Breaker) and MCB (Miniature Circuit Breaker) are both important safety devices used in electrical systems, but they serve different purposes.

- **MCB (Miniature Circuit Breaker)**:
  - It is designed to protect circuits from **overcurrent** or **short circuit**.
  - It works by automatically disconnecting the circuit when the current exceeds the predefined limit.
  - It does not detect leakage currents (current flowing to the ground).
  
- **RCB (Residual Current Breaker)**:
  - It is designed to protect against **earth leakage** or **residual current**.
  - It works by detecting any leakage current that flows from a live wire to the ground (due to faulty insulation or other issues).
  - RCB is useful for preventing electric shock and electrical fires caused by leakage currents.

### Which is better?
- It’s not a matter of one being better than the other; both are essential for different types of protection:
  - **MCBs** are crucial for preventing overloads and short circuits.
  - **RCBs** are necessary for protecting people from electric shocks and preventing leakage-related hazards.

In many modern electrical installations, both are used together for comprehensive protection—**MCBs** for overcurrent protection and **RCBs** for leakage protection.