In order to be able to solder all the housing parts of a vacuum interrupter for low-voltage contactors, including the tubular screening, in a single operation, the invention calls for the metal cap (9) which surrounds the two contacts (1, 2) and is made of silver-plated copper to have a shaped pattern (10, 11) running round the rim (19) which is to be soldered to one end of the hollow cylindrical insulator (12). The tubular screening (16) has a flange-like rim (17) running round its circumference with, disposed at intervals round the rim, spacer knobs (20) by means of which the screening rests on the same end of the insulator (12).