What the residual current circuit breaker detects is the residual current, that is, the algebraic sum of the instantaneous valuesof the phase and neutral currents in the protected circuit (including the three-phase unbalanced current and harmonic current in the neutral). For this reason, the setting value of the RCD, that is, its rated operating current IΔn, only needs to avoid the normal leakage current value, which is measured in mA, so the RCD can cut off the ground fault of the protection circuit very sensitively, and can also be used as a Backup protection against direct contact electric shock.

The residual current circuit breaker is a relay protection device that can automatically disconnect the circuit or send an alarm signal when the residual current in the protected circuit exceeds the set value under specified conditions.

As a protective electrical appliance, residual current circuit breaker is an effective facility to prevent personal electric shock, electrical fire and damage to electrical equipment.

low voltage circuit breakers are also called automatic air switches or automatic air circuit breakers or short circuit breakers. It is an electrical device that has both manual switching functions and automatic power failure, undervoltage, overload and short circuit protection.

low voltage circuit breakers are also called automatic air switches or automatic air circuit breakers. The low voltage circuit breakers sold on the market can not only be switched manually, but also equipped with automatic switching. If a short circuit occurs in the circuit or the current is too high, it can automatically interrupt the circuit and take on a protective function in time.

low voltage circuit breakers are widely used in low voltage power distribution systems at all levels, to control the power of various mechanical devices, and to control and protect power connections.