Abstract: The following specification describes a system for prefabricating a wiring harness by extending the conductors of flat ribbon cable in desired directions to specific or predetermined locations and slitting the insulating lengthwise at those locations to permit selected conductors to project for connection to a contactor terminal.A projecting conductor is also folded back if it is to be connected to a contact at another location, and to enable the folded back conductor and the other conductors to then extend in a smooth cable, the other conductors are folded at the end of the slit in two reverse legs or three bends corresponding in length to the projection of the connected folded back conductor.Contacts having insulation piercing shanks of unique design are provided for secure insulation piercing engagement with either folded projecting conductors or terminated conductors.