Abstract: Process for washing insulators supporting the conductors of an overhead electric live line, with the line energized, by means of a washing head (T) connected to means feeding a detergent fluid to a plurality of spray nozzles (14, 114) carried by the washing head (T) for spraying detergent fluid in close proximity to and over the surface of said insulator (3, 3A), characterized in that the washing head (T) is centered and anchored onto the insulator, and the washing of the insulator is carried out by feeding the detergent fluid to at least part of a plurality of tubular members (13, 113) connected to the washing head, the tubular members being positioned one above the other so as to be insulated one from the other and, in use, at least partially surrounding the insulator.