A door with automatic closing adapted for use with an electrified enclosure, the door comprising an electrically conductive flexible barrier (2) adapted to close an entrance in the enclosure, and a hinge (1) to which the barrier is connected (2) which allows the door to open and close when a vehicle crosses the barrier (2), in which the barrier (2) can be opened on either side of a closed position, the hinge (1) comprising a first tube (4) connected to the barrier (2) and a second tube (3) telescopically coupled with the first tube (4) and to secure the hinge (1) to a rigid object, the first and second tubes (3, 4) being formed by a electrically non-conductive material and which additionally includes cam surfaces 8, whereby, the rotation of the tubes (3, 4) with each other when the barrier (2) opens and closes, causes the first tube (4) to raise and drop axially the second tube (3), a tension spring (11) within the tubes (3, 4) serve to drive said cam surfaces (8) to a coupling such that the door is arranged in the closed position, characterized in that the tension spring (11) is formed by an electrically conductive material to provide an electrical connection between the barrier and a metal bolt (12) connected to the tubes (3, 4), the metal bolt (12) serving to maintain an electrical connection to the door, in which the barrier (2 ) is coated with an electroconductive paint to provide an external conductive layer to form an electrical connection to said spring (11).Una puerta con cierre automático adaptada para su uso con un recinto electrificado, comprendiendo la puerta una barrera flexible eléctricamente conductora (2) adaptada para cerrar un entrada en el recinto, y una bisagra (1) a la que se conecta la barrera (2) que permite que la puerta se abra y se cierre cuando un vehículo cruza la barrera (2), en la que la barrera (2) puede abrirse a cualquier lado de una posición cerrada, comprendiendo la bisagra (1) un primer tubo (4) conectado a la barrera (2) y un se
