RJV line: PVC insulated connecting line. A plurality of wires are twisted and then wrapped with a layer of PVC insulating plastic, which has a simple structure. The cross-sectional area of the conductor varies from 0.5 square to 10 square, which is mainly used for connecting wires in various devices; BV wire: copper-core PVC insulated wire. The structure is the same as RJV line, and the conductor is a single copper wire (the conductor of RJV line is composed of several thin copper wires). It is mainly used for internal wiring of mechanical equipment and home decoration wiring.