Ferrules are crimped onto the ends of electrical wires to provide a solid and reliable electrical connection. Because all of the bare wire strands are contained within the ferrule, they cannot come loose and possibly short against another connector. The ferrules also make it easier to insert the wire into connector blocks or terminals, and provide better conductivity and lower electrical resistance. With a crimping tool, ferrules are easy to apply, and help to ensure a good connection is made.
Choose an appropriate sized ferrule for the wire you are using. It should be able to slide over the bare wire strands without being too loose.
Strip the insulation from the end of the wire. The length of insulation that should be stripped is equal to the barrel length of the ferrule. For example, if you are using a ferrule with a barrel length of 8mm, you should strip 8mm of insulation from the end of the wire. Some crimp tools also have an inbuilt wire stripping tool with a measuring guide, which helps to cut off the correct amount. If your crimp tool does not have this feature, measure the amount of insulation to be stripped with a ruler and then remove with a sharp utility knife.
Place the ferrule over the bare metal strands of the wire. Around 0.5mm of bare strands should be left outside of the ferrule barrel.
Insert the ferrule and wire into the closest-sized notch on the crimp tool. Squeeze the handles of the crimp tool together firmly to lock the ferrule onto the end of the wire.
Insert the wire with crimped ferrule into a terminal or connector block.