An electrical connector for connection to a complementary mating connector includes a housing having at least one socket and at least one contact assembly which is disposed at least partially within the socket. A fastening element secures the contact assembly within the socket. A secondary retention means is movable between a pre-latched position and a final latched position, and, in the final latched position, prevents the fastening element from releasing securement of the contact assembly in the socket. The housing has a fastening groove extending along the socket at least along a portion of its length for securing the secondary retention means. In the final latched position, the secondary retention means engages by at least one latching element in the fastening groove.