Abstract: A two-part, self-locking electrical connector (10) consists of a male plug (12) with prongs (16, 18, 20) and a female receptacle (14) with sockets and contact blades (28, 30, 32), which engages the respective prongs. The female receptacle has a self-locking device which automatically locks both parts of the connector after insertion of the prongs (16, 18, 20) into respective sockets for electric contact with the blades (28, 30, 32). The self-locking device comprises a rectangular block (48) located in a recess (44) of the receptacle's body. The block is constantly urged toward the prongs by a compression spring (56). The block has tapering side surfaces (58, 60), which exert wedging action to expand the prongs, so that the prongs are pressed against the blades and are maintained in this position by a frictional force which is increased by the action of the spring (56).