Rated voltage Rated operating voltage (Un), rated insulation voltage (Ui) and rated pulse voltage.
The rated operating voltage of the circuit breaker is the voltage value associated with the breaking capacity and the use category. For AC multiphase circuit finger circuit voltage. The rated operating voltage is numerically dependent on the rated voltage level of the grid. I standard standards for the exchange of 220,380,660 and 1140V, DC 220,440 V and so on. It should be noted that the same circuit breaker can be specified for use at several rated operating voltages, but the corresponding on-off capability is not the same.
The rated insulation voltage is the voltage value of the circuit breaker. The electrical clearance and creepage distance of the switchgear shall be determined according to this voltage value. Under normal circumstances, the rated insulation voltage is the maximum rated operating voltage of the circuit breaker.
Switch electrical work, to withstand the system occurred in the over-voltage. Therefore, the rated voltage withstand voltage is given in the rated voltage parameter of the switchgear (including the circuit breaker), which should be greater than or equal to the maximum overvoltage peak occurring in the system. Rated insulation voltage and rated pulse voltage together determine the insulation level of the switchgear.