Ferrules ensure reliable electrical connections when terminating conductors in screw clamp terminal blocks. Fraying and breaking of wire strands is prevented and the possibility of an unreliable connection is minimized. Insulated ferrules prevent conductor breakage due to bending, wire stress or vibration, while facilitating wire insertions into the terminal block clamp. Ferrules are the preferred alternative to twisting wire stands or tinning the wire end before terminating into a terminal block. Ferrules are thin-walled copper tubes, which are mechanically crimped onto the ends of stranded wires.