RCCB
Short for Residual Current Circuit Breaker.
Trips when line current and neutral current are different. Residual current is the difference between live and neutral currents. Provides protection against earth faults and leakage currents.
Consists of a solonoid coil.
Under normal operating conditions, two identical windings will carry the main current. Since the currents are equal and opposite through the two windings, there is emf balance and there will be no induced emf on the detector winding. Thus the operating coil will not be energized.
In case of a fault, the line and neutral currents will not be equal and the trip coil will be energized due to the induced currents in the detector winding.
Advantages of RCCB
Suppose the live wire is exposed. If somebody touches it, they may get a shock if a current passes through them.
In the case of voltage-operated ELCB, this earth current is not going through the tripping coil and will cause danger. But in the case of RCCB, the return path is going to loose part of the current, which passed through the human body, which in turn would cause a resultant flux within the ring energizing the tripping circuit.
Ratings
- Rated current
- Rated voltage
- Sensitivity