By routing the cables that support and drive the mobile platform of a Cable-Driven Parallel Robot (CDPR) to the moving parts of an end-effector (EE) installed on said mobile platform, it is possible with combined motions of the winches of the CDPR to drive this EE, such as the opening and closing of a gripper. Compared to CDPRs without internal EE, the cable tension distribution is then modified. In this paper, the static equilibrium of a CDPR platform with an internal EE driven by the supporting cables is analyzed, showing that an additional platform wrench needs to be balanced when force is applied on the EE. Both the magnitude of the wrench on the EE degrees of freedom and the way the cables generate motion at the EE influence this additional platform wrench. Considering a cable configuration and an external wrench applied on the EE, several EE designs are proposed where the EE motion is driven by one or two cables leading to different results in terms of workspace and wrench feasibility.