the electric lamp has a lamp vessel having an end portion which is fixed inthe lamp cap by means of polyethersulphone as a thermoplastic synthetic resin , which has adhered both to the lamp vessel and to the lamp cap . the end portion has non - circular cross - sections where it is in contact with the synthetic resin due to projections projecting into the synthetic resin . a current supply wire can be clamped between the synthetic resin and the sheath portion of the lamp cap in order to establish electrical contact therewith . the lamp can be assembled by arranging in the hot state of the end portion a polyethersulphone ring around this end portion and by providing the lamp cap in the hot state around the polyethersulphone ring . fig . 1 .