It is applicable to AC/DC power supply systems such as TN-S, TN-C-S, TT, IT and photovoltaic 1500VDC and below with AC 50/60Hz, 1000V and below. As lightning strike equipotential connection, its design basis complies with EN50539-11, GB/T 18802.31 and IEC 61643-31. The shell is designed to be installed on 35mm electrical guide rail. The product is equipped with a built-in failure release device. When the surge protector fails due to overcurrent, overheating and breakdown, the failure release device can automatically disconnect it from the power grid, At the same time, the visual alarm indication module changes from green (normal) to red (fault). Kevin wiring mode, remote signal output interface, SPI2 and SPI4 series surge protector modules can be replaced online.