Leakage protector is used to short-circuit and disconnect the current when leakage occurs, providing protection, while lightning protection module is used to quickly discharge the lightning current when lightning strikes the line, protecting the equipment from lightning strikes.

RCD, also known as residual current device, is a residual current protector used to prevent personal electric shock. Generally, it is 30mA for civilian use. Once leakage occurs due to personal electric shock, line wear or moisture, and the current reaches 30mA, the RCD will trip to protect personal safety. There is a test button on the residual current device for periodic verification of the effectiveness of the RCD. When pressed, the RCD will trip, indicating that it is in normal working condition.
The lightning protection module, abbreviated as SPD in English, is used to protect against lightning strikes or overvoltage in the power grid. The standard name is surge protector, commonly known as lightning arrester. Low voltage lightning arrester is divided into three-phase and single-phase.