Abstract: The invention relates to a sealing device for a chamber partition, the partition having an orifice enabling a strand of conductor wires to pass between the outside and the inside of the chamber. The device includes a plug through which passes the strand, and an apparatus to keep the plug pressed against the partition. The conductor wires can be kept away from one another inside the plug to ensure the seal-tightness of the plug itself. Advantageously, the plug is pressed into a void of a counter-form, the internal shape of the void substantially complementing an external shape of the plug. The form/counter-form assembly provides for a perfect seal-tightness.