For the overhead power lines and power overhead cable terminal, suspension, joints and other connections Pre-twisted wire with the earliest in the 20th century 40-50 appeared in the United States, the initial product for the bare wire stress concentration and electrical corrosion, arc burning Loss of position protection of the spiral line protection. After years of development, at present, pre-twisted wire has been widely used in transmission and distribution, optical fiber communications, electrified railway, cable television, construction, agriculture and other fields.