For ordinary residual current operated household protectors, the test is usually carried out by pressing the test button on the protector to manually trip the protector. However, this method can only detect whether the mechanical operating mechanism of the protector can operate normally, and cannot detect whether the electrical installation is working properly

When the vector sum of the current flowing through the transformer in the protector is not equal to zero and there is a difference between the return current flowing through the neutral line, this difference is the residual current value. If the difference is higher than the rated operating current of the RCD, the RCD will trip, thereby cutting off the power supply

As an electrical product that is subject to mandatory national safety certification, the quality of RCD will directly affect the safety of users' lives and property.

. In low-voltage distribution systems, installing qualified RCDs is an effective technical measure to prevent electrical fires and equipment damage accidents caused by personal electric shock and leakage. Especially in rural low-voltage power grids, RCD has achieved significant results in reducing personal electric shock injuries and preventing electrical equipment damage

In order to ensure the normal operation of RCD, in the event of leakage, the power supply must be quickly and reliably cut off. It is necessary to detect RCD that cannot function properly as soon as possible and provide timely maintenance or replacement. Therefore, electrical personnel must regularly test RCD