The earth leakage protector in the corridor does not trip, and the distribution box or transformer always trips.

The first reason is that the design configuration is different

The design principle of the distribution system is to realize the step-by-step protection from the standard distribution room to the distribution box, then to the meter box, and finally to the indoor distribution box. For example, the rated current of the switch in our transformation and distribution room is 630A, and the running current is 500mA; the rated current of the switch in the distribution room is 400A, and the running current is 300mA; the rated current of the switch in the meter box is 63A, and the running current is 500mA The rated current of the switch in the meter box is 63A and the running current is 30mA;

Another point is that from the transformation and distribution room to the indoor distribution box, the action time of these leakage protectors is also the time of power running, and the action time is gradually reduced. The purpose of this design is to realize the step-by-step protection of leakage protectors when the power running occurs in the circuit, so as to avoid the occurrence of override trip phenomenon;

In the above problem, the leakage protector in the corridor does not trip. It is always the phenomenon of distribution box or transformer tripping, which is a typical override tripping phenomenon. Therefore, after we find this problem again, we should first check whether the configuration of switches at all levels is correct and whether the parameter setting is reasonable.

The second reason is that the leakage protector fails

If the leakage protector fails, it will malfunction or fail to operate. At this time, we need to check the leakage protector step by step to see if it can operate effectively and accurately. We can start from the power transformation and distribution room to switch on the power supply step by step, and close the first level switch to check the leakage protector of this level, until we check the distribution box in our home, and remove the leakage protector that can not operate effectively The electric protector is replaced to eliminate the override trip caused by the leakage protector itself.

The third reason may be caused by unbalanced load

The phenomenon that the leakage protector in the corridor does not trip due to unbalanced three-phase load, and the distribution box or transformer always trips, usually occurs in the new building. The occupancy rate of the new building is very low because it has just been delivered, especially in the initial decoration stage, it is very easy to appear unbalanced three-phase load;

When the three-phase load is unbalanced, the leakage protector in the corridor does not trip, and the distribution box or transformer always trips. There is no good solution. Only when the decoration of large families is realized, and the occupancy rate rises, this phenomenon will slowly disappear. This is neither the design reason nor the system fault. This is a protection function of the system.