ELECTRICAL INSTALLATION AND MAINTENANCE WORKS: Measuring , Marking and Striking Tools; types and preparation cables – types and preparation of cables

A Cable is defined in the I.E.E Regulations as a length of insulated single conductor (solid or stranded) or of two or more such conductors each provided with its own insulation, which are laid up together.

A cable consists of three essential parts. These parts are:

1.      The conductor to carry the current

2.      The insulation to provide the means to prevent the leakage of current

3.      External overall protection against mechanical damage, fire etc

Types of cables and their uses

	types of cables	Uses
1	P.V.C. insulated cable non- sheated	In conduit, cable ducting or trunking, but not in such conduits etc buried underground
2	Circular P.V.C. insulated and sheathed	i.            General indoor use other than embedding        ii.            Underground in conduit pipe
3	Flat P.V.C insulate and sheated	i.            General indoor use        ii.            On extension surface walls       iii.            Overhead wiring between buildings     iv.            Underground in conduit pipe
4	P.V.C flexible cords non-sheathed	i.            for pendants        ii.            ii. for wiring lighting fittings
5	Vulcanized rubber insulated cables (V.R.I) and T.R.S cables	They can be used in areas where temp is below 0°c
6	Polychloroprene sheated (p.c.p) cable	They are suitable for farm installation particularly in dairy
7	Butyl-rubber insulated cable	May be used where temp does not exceed 80°c
8	Silicone rubber insulated cable	May be used where temp does not exceed 145°c
9	House service overhead system	Suitable for outside wiring such as on external walls and house to house wiring
10	Paper insulated lead sheath cable	It is used for underground installation
11	Mineral insulated metal sheated cable	They are used in boiler houses, heat treatment shops. They are most preferred for flame proof situation