suitable for diploma electrical engineering course

3. 1.2.1 Types of wires
size e.g.1/18 guage,3/20
guage, 1.5.sq mm(mm
square) ,2.5 q.mm, 4
sq.mm,6 sq.mm

4.  Rubber is vulcanized
 Less mechanical strength
 Obsolete
 More prone to mechanical damage
 Chemical effects adversely to insulation
 Water, moisture affects adversely to
insulation.
 More heat can cause melting of rubber

5. More mechanical strength
compared to VIR
Rubber is used as
insulation.
Suitable for Residential
wiring and industrial wiring

6. Suitable for service
connection
More strength against
weather conditions
Obsolete

7.  Obsolete
 Pb is soft

8. Magnesium oxide is used as
insulation

9.  PVC is used as insulation.
 Advantages :
 (1) More mechanical strength
 (2) Long life
 (3) More dielectric strength
 (4) More protection against moisture

10. 1. life of installation
2. future extension or alterations
3. construction of building
4. fire hazards or other special conditions
5. corrosive fumes
6. dampness
7. type of wire and material used
8. nature of load (lighting of power)
9. safety of the system
10. cost of wiring system

11.  Single-phase two-wire system
 Three-phase three-wire system
 Three-phase four-wire system

12.  This type of wiring is also used for house wiring and is
quite cheap.
 Cab tyre sheathed (C.T.S) wire or tough rubber
sheathed (T.R.S) wire is normally used as conductor for
this wiring.

13.  The wires are run on the teak wooden battens which are
fixed on the wall or the ceiling by means of screws and
wooden plugs.
 C.T.S OR T.R.S cables used are not much affected by
chemicals , water, and steam.

14. Advantages
 It is easy to install and repair
 It gives better appearance
 Its life is long
 It is fire proof up to a certain limit
 It is cheaper than other types of wiring except cleat
wiring
 Conductors have strong insulations
 Chemicals do not affect the conductor insulation

15. Disadvantages
 The conductors are open and liable to mechanical
injury thus this type of wiring cannot be used in
workshops etc.
 Its use in places open to sun and rain is restricted
 Good workmanship is suitable where acids and alkalis
to be precuts.

16. Disadvantages
 cables are costlier than C.T.S OR T.R.S wires
 In case of leakage ,there is risk of shock
 skilled labour and proper supervision is required
 it is not suitable for places where chemical corrosion
may occur

17. Field of application
 This wiring system is suitable for low voltage (up to
250V) installations.
 It may be used in places exposed to sun and rain
provided no joint is exposed.
 It may be used in damp placed with a suitable
protective covering.
 This type of wiring is very common in use these days
except for some small installations and distribution
boards etc.