How the rccb works?

An RCCB (Residual Current Circuit Breaker) works by constantly monitoring the current flow between the live and neutral wire.

In normal operation with the two lines in balance the circuit works. If for any reason, even a small amount of imbalance in detected (as small as 30 milliamps) the breaker will trip in no more than 200 milliseconds. This is well within the limits of preventing both fire and bodily harm.

Installation of these breakers is fast becoming mandatory around the world, especially on electrical circuits in areas prone to water (bathrooms, kitchens, etc...).

It should be noted however, that if an impedance load (such as a motor) in introduced to a circuit protected by an RCCB there may be a problem with nuisance tripping of the breaker. So in most instances the bus bar in a breaker panel can be cut and the RCCB only installed on on side. This provides the protection required in areas where an RCCB is recommended, and allows standard breakers to be used in areas where the more expensive RCCB is not required or may affect equipment operation.