The invention relates to a line feedthrough for the vessel wall of an HVDC component. Said feedthrough comprises a feedthrough element in the form of an electrode tube (25) or a conductor bolt (23). Said feedthrough element has an encapsulation (26) made of a cellulose material, the specific resistance thereof being reduced by treatment according to the invention relative to that of cellulose material without such treatment. A greater dielectric strength of the insulation formed by the encapsulation (26) and further solid barriers (28) can thereby be achieved. The improved dielectric strength advantageously allows additional design freedom for the feedthrough.