overview MLY1-C40/385 series surge protector (hereinafter referred to as SPD) is suitable for T, TT, TN-C, TN-S, TN-C-S and other power supply systems of low-voltage AC power distribution systems, and is suitable for indirect lightning and direct lightning. Other instantaneous overvoltage surge protection. Class ll surge protector according to IEC61643-1:1998-02 standard. Class C surge protector SPD has common mode (MC) and differential mode(MD) protection methods. SPD complies with GB18802.1/IEC61643-1. Main structure and working principle SPD is a port, anti-shock protection, indoor fixed installation, voltage limiting type. The SPD has a built-in disconnector. When the SPD fails due to overheating or breakdown, the disconnector can automatically disconnect it from the grid, and at the same time give an indication signal. When the SPD is working normally, the visible window will display green, and it will display red after the failure and disconnection. 1P+N,2P+N, and 3P+N SPDs are composed of 1P,2P, and 3P SPD+NPE neutral ground protection modules, and are used in TT, TN-S and other power supply systems.