Domestic Wiring Chapter 2
Conduit Wiring
There are three types of conduit wiring
(a) Concealed conduit wiring
Concealed conduit wiring. Here the conduits are embedded along the wall in plaster at the time of construction.
The VIR or PVC cables are drawn into the conduits by means of GI wire of 18 SWG.
The conduit should be electrically and mechanically continuous and connected to earth at some suitable places using earth wire.
This method of conduit wiring is preferred for domestic over other methods as it maintains the beauty of the house and no projected pipes are visible.
(b) Surface conduit wiring
Surface conduit wiring. As the name suggests the conduit is spaced from the wall by means of small wooden spacers below the conduits along its length at regular intervals .
This system is commonly used in industrial wiring but is not recommended for domestic wiring as itspoils the beauty ofthe house.
The usual size ofthe conduit is 25 mm diameter for domestic wiring.
(c) Flexible conduit wiring.
Flexible conduit wiring. This method ofwiring is used to provide mechanical protection to cables between rigid conduits (surface conduit) and electric machine or any other electrical device.
However, this is not a general method of wiring.
It is used for connecting rigid conduit with machine terminal box in case ofmotor wiring and energy meter with main switch in case of Industrial and domestic wiring.
The following are the advantages and disadvantages ofconduit wiring :
Advantages :
✓ It provides protection against mechanical injury to insulated cables and against short circuits.
✓ Since conduits can be made water tight, the conduit wiring provides protection against moisture.
✓ Gives better appearance.
✓ Relatively longer life.
Disadvantages :
✓ It is a relatively costlier system of wiring.
✓ Highly skilled workmanship is required and it is more time consuming.
The method ofwiring is normally recommended where cost is not the consideration e.g. in
big hotels, workshops and factories and places of storing inflammable materials.
Comments
Post a Comment