Insulators for overhead lines with a nominal voltage above 1 000 V. Ceramic insulators for AC systems. Characteristics of insulator units of the long rod type|Alternating current, Ceramics, Marking, Overhead power lines, Overhead power-line fittings, Dimensions, Electric insulators, Strength of materials, Mechanical properties of materials, Tolerances (measurement), Length, Electrical properties and phenomena, Design, Withstand voltage, Diameter, Designations, Pollution, Rated voltage, Leakage paths, Frequencies, Electric substations, Electric power transmission lines, Voltage, Alternating-current power transmission