Difference between grounding fault protection and residual current protection in moulded case circuit breaker

Promulgator : TAIXIDate : 2018-06-21Views : 22

With the development of electronic technology, the electronic deionization unit has also been widely used in Moulded Case Circuit Breaker. At the same time, as people's awareness of personal electric shock and electrical fire protection is enhanced, the use requirements of the grounding protection function of Moulded Case Circuit Breaker are also paid more attention. Therefore, it is clear that the difference between grounding fault protection and residual current protection conforming to IEC60947-2 standard moulded case circuit breaker is clear.

1. The meaning of protection is different:
- Ground fault (ground fault) protection: protection of the fault caused by the accidental connection of the electrified conductor to the earth.
- Residual current (residual current) protection: protection of current vectors and non zero fault currents in low voltage distribution lines (including neutral lines).

2. The protective effects are different:
The grounding fault protection defined by IEC60947-2 (ACB and MCCB) is strictly a part of overcurrent protection in Moulded Case Circuit Breaker. In the single phase to ground fault system, due to various external factors caused by the rated current to ground fault current may be less than the value of the Circuit Breaker, the circuit breaker will not effectively cut off the fault current. The long time failure will also cause the non fault phase to rise to the ground voltage, which can reach the line voltage of the system. At the same time, it may also cause other parasitic disasters.
The remaining current protection defined by the IEC60947-2 standard Circuit Breaker (ACB, MCCB) is based on the requirements of the standard appendix B to provide protection for the electric shock hazard, while the overcurrent protection device of the circuit breaker can not be detected, but it may provide additional protection for a long time to cause fire or other hazards.

3. Different protection requirements:
Due to ground fault protection and residual current protection function is different, so the protection requirements are the same:
The Circuit Breaker grounding fault protection action current setting, primarily based on the rated current of In circuit breaker, usually in the range of In (0.2-1). At the same time, the action time is set.
And in line with the current action of residual current protection of appendix B setting, it is electric appliance manufacturers according to the criteria given in the range of 6mA-30A set different preferred value, adjusted by the user. At the same time can be set on the action time adjustment.

4. Selection of two types of circuit breakers:
In order to ensure the safe and efficient operation of the system, the moulded case circuit breaker (MCCB) plays an important role in the distribution protection of the branch circuit in the low voltage distribution system. In the selection of the overcurrent protection element without the protection of the personal electric shock and the requirements of the electric fire protection, the electronic formula with grounding protection is also adapted. Depot unit product.
For personal protection against electric shock and electrical fire protection requirements of the branch selection with residual current protection electronic module talk unit MCCB, attention should be paid to the electronic talk unit grounding protection closed, to assure the residual current protection function.