Abstract: A plug that makes it possible to fix in an impermeable manner an electric or telephone cable (2) to a circular opening (4) for passage of the cable. It comprises a hollow body (5) constituted by two shells intended to be fixed around the cable (2) and comprising at least two jaws (6, 7) which are retained radially in the body (5). Each jaw comprises a central opening (10, 11) for passage of the cable (2) and is supported radially on this cable at the time of fixing by clamping of the two shells to one another, the two jaws defining between them a chamber (12) intended to be filled with a sealing material. The hollow body (5) has structure for fixing it in a removable and impermeable manner to the circular opening (4) for passage of the cable.