A duplex electrical connector providing two inbound end apertures to conduct two helically wound armored or metal clad electrical cables through a single hole in an electrical junction box and secure it thereto. The duplex connector includes a housing with spring steel cable retainers at its inbound end to secure the cables and prevent their forceful withdrawal from the box. A spring steel adapter is included at the outbound end of the housing to provide easy snap-in attachment to the box. Two embodiments include an insert for attaching the cable retainers to the housing and a third embodiment includes a housing that accepts the cable retainers without the need for a separate insert.