Abstract: Electrical connection device lockable in an open position provided with a plug having a cylindrical body equipped with internal contact pins and a power transmitting female element in the form of a socket or a coupler socket of an extension cord, and having a casing equipped with internal contacts and an external rotational ring that projects by extending beyond the casing and intended to lock and unlock the plug from or into the connection position. Coupling is accomplished via paired guide elements provided on the plug and female element by at least one first translational movement of the plug in the female connection followed by a rotation and a second translation until the closed connection position is obtained.