Various embodiments of electric connector assemblies, each of which includes a connector body having a frustro-conically shaped outlet end portion that converges toward the outlet opening with a complementary frustro-conically shaped external ring circumscribing the outlet end portion wherein the frustro-conical retainer ring is integrally formed with a locking tang and electrical grounding tangs arranged to be snap fitted to a knock-out hole of an electric box, in combination with an internal unidirectional snap-fit wire conductor retainer disposed in the inlet end portion of the connector body to facilitate the connection of a wire conductor to the connector body and whereby unintentional separation of the wire conductor therefrom is prohibited.