ABSTRACT
This chapter explain why some conductors are stranded rather than solid and describes how the cross-sectional area of a stranded conductor may be determined. It also explains the relationship between a cable's length and the resistance of its insulation and explores identify the function of a cable conductor by the colour of its insulation. Cables of the type used to wire residential and commercial buildings, having cross-sectional areas below 4 mm, are usually manufactured using solid conductors. Mineral-insulated cable can also withstand severe mechanical abuse, such as twisting, bending, and hammering without any appreciable deterioration in its electrical properties. The cable's dielectric, magnesium oxide, is non-toxic, chemically-stable, has a high melting-point, and high thermal and electric resistivities. Cables used in residential installation work will normally have a thermoplastic sheath, as the likelihood of mechanical damage is low because such cables are normally reasonably-protected from their surroundings by being run below floorboards, sunk into plasterwork.
