Two installation ways include concealed and exposed installation. It is suitable for the circuit with AC 50Hz, voltage 220V or 380V, total current up to 125A. 18 mm analog circuit can be combined arbitrarily and assembled onto the standard guide rail (TH35-7.5). The product has many protection functions, such as electric leakage and shock, short circuit and overload, etc. The main body is made by galvanizing or spraying plastics after 1.2mm cold-rolled steel sheets are bended and welded. Equipped with zero line bar and ground line bar in the box, the connection is convenient and the appearance is luxurious. The cover is made of anti-ultraviolet ABS plastics which are strong, non-discoloring, safe and beautiful.