Parts of Cable

Parts of Cable Points : Parts of Electric Cable Wires used in electrical circuits are of many types but all consist of the following main parts:
(a) Conductor
(b) Insulation
(c) Mechanical protection (a) Conductors Conductors are usually made of copper, the conducting cores being formed from strands of copper wire so that the cable is more flexible than if solid cores were used. If vulcanized rubber insulation is to be used the copper conductors are tinned to prevent corrosion of the copper by the sulphur which is present in vulcanized rubber. The size of wires used in domestic installations is normally stated as: No. of strands / Diameter of each strand; e.g., a wire commonly used for lighting circuits is 3/,029; this means that the wire consists of three strands each of .029 in-diameter. For larger types of wire the effective cross-secticna1 area of the core is often quoted as the size. (b) Insulation Insulation of wires used in domestic installations is normally of vulcanized rubber insulation (magnesia) is employed the wire has a copper outer sheath, this type of wire being known as Mineral Insulated Copper-sheathed. (c) Mechanical Protection Mechanical Protection is provided to prevent damage to the wire during installation and throughout its subsequent service.