Flexible cord

flexible cord is the name given to a particular types of cable . It is one which is flexible and in which the cross-sectional area of each conductor does not exceed 4mm square . Flexible cords are used for suspending luminaires and for connections to portable domestic appliances having lowe power consumption. THey are , therefore  , usually left exposed in rooms and , to be suitable for such use , are made with a variety of coverigs .
  Ordinary lighting flex consists of a stranded copper conductor with PVC insulation , covered with an outer layer of PVC , as shown in FIgure 2.7 . Circular flex is made for the connection to household appliances such as irons , kettles , and so on , and consists of rubber-insulated cable inside an external cotton braiding . Either two or three rubber-insulated cables may be used and to obtain the circular cross-section  , cotton padding is wound around them inside the outer braiding . This is illustrated in figure 2.8. There are also flexible cords made with silicone rubber insulation with a covering of braided varnished glass fibre . Flexibles hich have glass-fibre insulation and an outer glass-fibre braid have already been mentioned .

Lead
Cables insulated with paper and sheathed with lead hae already been described .

Metal
The metal sheathing of MIMS cable is an integral part of the cable and has already been described

Bare risers
These have already been described . They sometimes have a covering of thin PVC which is put over them for extra protection for maintenance personnel who may be working on a system with some of the conductors live . The covering does not perform the protective function of the other kinds of sheathing discussed .