a system is provided for mounting a connecting device to a substrate with relative floating movement therebetween . the system includes a connector housing adapted for mounting on the substrate and including at least one elongated channel in a side of the housing . the channel extends generally perpendicular to the substrate and has an elongated restricted mouth opening at a side thereof . an elongated fastening post is snap - fit into the channel past the restricted mouth thereof to a preload position . a cross - dimension of the channel is larger than a cross - dimension of the fastening post so that the post can float relative to the housing . a fastener engages with the substrate and is operatively associated with the fastening post for tightening the post against the substrate , leaving the connector housing with floating movement relative to the substrate in a direction generally parallel to the substrate . the post may be longer than the channel to provide for floating movement of the housing relative to the substrate in a direction generally perpendicular to the substrate . in an alternative embodiment , at least a pair of connector housings are stacked on the substrate one on top of another . the elongated fastening post is long enough to snap - fit into the channels of both housings .