<span style="color:#333333;font-family:" background-color:#ffffff; High voltage column insulators are used for insulation and supporting wires in high-voltage overhead transmission and distribution lines, generally classified into five levels according to the approved voltage: 6, 10, 15, 20, and 35KV. Column insulators are made by bonding ceramic parts and steel feet with Portland cement of no less than 525 grade and ceramic sand adhesive. The surface of the porcelain parts is white or brown, and the surface of the steel feet is hot-dip galvanized. Column insulators shall comply with the provisions of international GB1000 "High Voltage Line Needle Insulators" and GB772 "Technical Conditions for Porcelain Components of High Voltage Needle Insulators".