A condenser core for being positioned around a high voltage main electrical conductor, the condenser core including an electrically insulating body; a longitudinal through hole for accommodating the main electrical conductor; a plurality of electrically conductive foils encircling the through hole and being surrounded by the body such that each foil is insulated from any other of the foils; a potential electrical conductor for establishing an electrical connection between one of the foils and the main electrical conductor when the main electrical conductor is accommodated in the through hole; and a fastening device configured to mechanically connect the potential electrical conductor to the main electrical conductor when the main electrical conductor is accommodated in the through hole. A bushing, a high voltage application and a method of producing a bushing are also provided.