Abstract: A round plug socket including a conductor securing portion and a cylindrical spring arm base portion provided with spring arms connected to the front edge of the spring arm base portion, the spring arms being spaced from one another and being bent inward. A plug ring is provided on the front side of the spring arms. The plug ring is embraced by a ring portion of an over-spring which is slit in a longitudinal direction of the round plug socket. Securing members for unreleasably seating the over-spring ring portion on the round plug socket are provided, which preferably also limit the opening of the over-spring to protect against any over-bending of the spring arms during contact thereof with a male plug inserted into the round plug socket.