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Electrical wiring in Domestic
&&
Industries
Presented
By
PavanKumar.M
Reg.no:159Y1A0253
Department of EEE

2.
Discuss on following contents……
Electric Power supply Wiring.
Domestic Electric circuits.
 Domestic Wiring.
 Sub-circuits in Domestic Wiring.
Introduction.
 Methods of Wiring.
Industrial Electrification
 Types of lighting installations.
 Electrical Installations for power circuits.

3.
Introduction
 Now a day electricity Is used not only for domestic lighting
purpose, but it is also used for various modern equipment.
 which are very common to various houses like washing
machines ,mixers ,ovens ,televisions ,computers etc.
 Each consumer has a separate electrical circuit connecting for
different appliances and accessories.
 Depending upon the power, current and voltage ratings of
various appliances, it is necessary to select proper type of
wiring scheme for the domestic purpose.
 Thus a network of wires connecting various accessories for
distribution of electrical energy from the supplier meter board
to the numerous electrical energy consuming devices through
controlling and safety devices is known as Electrical Wiring.

4.
Electrical Power transmission
From Electric pole to Energy meter to Distribution board

5.
Domestic Electric Circuit
 Electric power is usually generated at places which are
far away from the places where it is consumed.
 At the generating station, the electric power is
generated at 11KV volts. This voltage alternates at a
frequency of 50 Hz.
 The power is transmitted over long distances at high
voltage to minimize the loss of energy in the
transmission.

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Domestic wiring
 The electric power line enters our house through three wires- namely
the live wire, the neutral wire and the earth wire. To avoid confusion we
follow a color code for insulating these wires.
 The red wire is the live wire, and the black wire is neutral. The earth
wire is given green plastic insulation

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Domestic Wiring
 The live wire has a high potential of 220 volts whereas the neutral
wire has zero potential. Thus the potential difference between the
live wire and the neutral wire is 220-0 = 220 volts.
 The earth wire is much thicker in size and is made of copper. One
end of it is connected to a copper plate buried deep under the
earth. The earth connection is made to the electric meter and then
to the main switch.
 In our homes, we receive supply of electric power through a main
supply (mains), either supported through overhead electric poles
or by underground cables.

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 The live wire and neutral wire, coming from the electric pole,
enter a box fitted just outside our house which has a main
fuse(F1) . The fuse is connected in series with the live wire.
 The fuse(F1) has a high rating of about 50A. Thus it prevents any
damage such as fire to the entire electrical wiring entering the
house due to short-circuit or overloading.
 The two wires then enter the electricity meter which records
lithe electrical power consumed by us in kilowatt-hour (kWh).
This meter is installed by the electric supply Department of our
city.
 These two wires coming out of the meter are then connected to a
main switch which is placed in a distribution box. Another fuse
(F2) is placed in series with the live wire in this box for the sake
of consumer safety.
 There are two separate circuits in a house namely lighting circuit
and power circuit.

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Sub circuits in Domestic wiring
It is Broadly classified into two categories:
1.Light , Fan sub-circuit and 2.Power sub-circuit.
(1) Light and Fan Sub-circuit:
The sub-circuit of the electrical installation feeding supply to
various light points, i.e. lamps, Lighting cable, Light switches,
tubes etc. and to fan points is termed as light and fan sub-circuit
respectively.
(2) Power circuit:
The part of the complete installation that supplies appliances like
hot plate , electric iron ,small single-phase motors of washing
machine , refrigerator etc. is generally called the power sub-
circuit.

10.
Methods of Wiring
 Wiring (a process of connecting various accessories for
distribution of electrical energy from supplier’s meter
board to home appliances such as lamps, fans and other
domestic appliances is known as Electrical Wiring) can be
done using two methods which are,
I. Joint box system or Tee system or Jointing system
II. Loop – in system.

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1.Joint Box or Tee or Jointing System
 In this method of wiring, connections to appliances are made through
joints.
 These joints are made in joint boxes by means of suitable connectors
or joints cutouts.
 This method of wiring doesn’t consume too much cables size.
 This method is suitable for temporary installations and it is cheap.

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2.Loop-in or Looping System
 This method of wiring is universally used in wiring.
 Lamps and other appliances are connected in parallel so that
each of the appliances can be controlled individually.
 When a connection is required at a light or switch, the feed
conductor is looped in by bringing it directly to the terminal
and then carrying it forward again to the next point to be fed.

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Advantages and Disadvantages of
Loop-In Method
Advantages :
 It doesn’t require joint boxes and so money is saved
 In loop – in systems, no joint is concealed beneath floors or in roof
spaces.
 Fault location is made easy as the points are made only at outlets
so that they are accessible.
Disadvantages :
 Length of wire or cables required is more and voltage drop and
copper losses are therefore more.
 Looping – in switches and lamp holders is usually difficult.

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Industrial Electrification
Is the process of powering by electricity and in many
contexts ,the introduction of such power by changing over
from an earlier power source.
Even the smallest interruptions can cause huge losses to all
industries served in terms of productivity and profitability.
So availability of quality power is most important for
industries.
i] It should produce sufficient illumination on the working
plane.
ii] It should provide uniform distribution of illumination.
iii] It should avoid glare and shadows.
iv] It should be easy to clean.

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Types of Installation
1.General Lighting:
 Under this scheme general lighting should be provided such that there will be
uniform distribution of light over the working plane.
 In such cases, the color of walls and surroundings are selected in such a way
that it adds effectiveness to the Illumination. Generally White color is
preferred.
2.Local Lighting:
 There are certain locations where fairly intense illumination is required.
 To provide sufficiently more illumination for such locations, local lighting is
provided.
 Local lighting is provided by means of adjustable fittings attached to the
working plane and lamps are mounted on reflectors to avoid the glare.
3. Emergency Lighting:
 There are some applications where emergency lighting has to be provided
such as:
 Control posts , first aid centre and speedy evacuation of personnel after main
lighting circuit is off.

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Electrical Installation for power circuits
 According to Indian Electricity Rules(No. 50 and 51), the wiring of
electrical motors in industries is to be carried out apart from meeting
local requirements on various conditions.
 Design consideration in case of motor wiring installation is different from
that of the lighting wiring installation. In case of lighting load, size of the
conductor l wire is decided on the total current of the load.
 But in case of motor wiring, size of the conductor should not be less than
corresponding to 3% of the motor full load current.
 The reason is that conductor should be capable of withstanding the
starting current of the motor which is generally 5 to 7 times the full load
current.

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Fig : Electrical installations of power circuits

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 Each motor takes a high current at the starting which may be 5
to 7 times full load current of the motor.
 Hence, to limit the voltage drop in the cable as well as to limit
huge starting current, a separate starting device, called starter
is used for each motor. Starter is located after the motor switch.
 In domestic installations, single earthing is sufficient but in
workshops or factory , double earthing is necessary from the
extra safety point of view.
 Calculate the full load current rating of the all resistive loads.
 Add to this 125% of full load current of the highest rated motor.

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Basics of industrial control panels
 Each motor takes a high current at the starting which may be 5
to 7 times full load current of the motor.
 Hence, to limit the voltage drop in the cable as well as to limit
huge starting current, a separate starting device, called starter is
used for each motor. Starter is located after the motor switch.
 In domestic installations, single earthing is sufficient but in
workshops or factory , double earthing is necessary from the
extra safety point of view.
 Let’s take a look at some specific guidelines ,as 1.Type&size
2.supply conductors 3.SCCR 4.Grounding
 5.maintenance etc.

20.
Bibliography
 Reference Books:
 Practical electrical wiring :Residential , farm,
commercial and industrial.
 Authors : Herbert P Richter , W . Creighton Schwan
 Publisher : McGraw-Hill,1996.

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THANK
YOU