HOW AN RCCB WORKS
A Residual Current Circuit Breaker (RCCB) is an advanced electrical safety device designed to protect people from electric shock and prevent electrical fires caused by earth leakage currents. Unlike an MCB, an RCCB does not protect against overload or short circuits; instead, it continuously monitors the balance between the live and neutral currents.
Working Principle
During normal operation, the current flowing through the Live (Phase) conductor is exactly equal to the current returning through the Neutral conductor. Both currents pass through a toroidal current transformer inside the RCCB, producing equal and opposite magnetic fields that cancel each other, keeping the RCCB in the ON position.
If an insulation failure or accidental contact causes current to leak to earth, the balance between the live and neutral currents is disturbed. The toroidal transformer detects this difference, known as Residual Current, and immediately activates the tripping mechanism.
Once the leakage current exceeds the rated sensitivity of the RCCB (typically 30mA, 100mA, or 300mA), the breaker disconnects both the live and neutral supply within milliseconds, preventing electric shock and reducing the risk of electrical fire.
Protection Mechanism
Normal Condition: Equal current flows through the live and neutral conductors, allowing uninterrupted power supply.
Earth Leakage Condition: Any imbalance between the live and neutral currents is instantly detected, causing the RCCB to trip and isolate the faulty circuit.
Result
The RCCB continuously monitors leakage current and automatically disconnects the power supply whenever a dangerous earth fault occurs, ensuring maximum protection for people, electrical installations, and valuable equipment.
