unit 4 domestic wiring and instruments.pptx

DOMESTIC WIRING AND
INSTRUMENTS
UNIT IV
6/8/2022
1

SYALLABUS
 Types of wiring
 Domestic wiring
 Specification of Wires
 Energy Auditing
 Earthing methods
 Protective devices
 Classification of instruments
 Operating Principles of indicating Instruments
 Moving iron, Moving coil and wattmeter.
6/8/2022
2

FUNDAMENTALS OF WIRING
 The home you have constructed should be electric
shock proof. To achieve this, lots of precautions are
required to be taken during wiring.
 Therefore we advise to follow the best practices of
the industry and following the wiring rules laid down
by Bureau of Indian standards
 Few of them are listed below for your guidance.
6/8/2022
3

1.CARRY OUT WIRING ON DISTRIBUTION
SYSTEM
 The wiring should be carried out on distribution
systems with main and branch distribution boards
to convenient centers.
 It is without isolated fuses. As for an possible all
conductors should run along the walls and ceilings
so that they are easily accessible for thorough
inspection.
6/8/2022
4

2.DON’T ALLOW WIRING TO RUN ABOVE
CEILING
 In any case, the wiring should not run above ceiling.
The circuit on opposite side of three wire systems
or on different phases of three phase system is kept
on far apart as possible in all cases and the
minimum distance between two circuits should be 7
feet.
 Medium pressure wiring and all associated
apparatus should comply with ISI specifications.
6/8/2022
5

3.DON’T EXCEED THE LOAD ON CIRCUIT
 The number of points in light circuits should not
exceed 10 or the total load on circuit should not
exceed 800 watts.
 One circuit can be explained on one connection
from electrical meter or from main fuse circuit.
 For power wiring circuit the number of points in a
circuit should not be more than 2 and the size of
wire should be 1.5mm square for copper and 2mm
square for aluminium.
6/8/2022
6

4.FIX SWITCH BOARDS AT PROPER HEIGHT
 Switch boards should be fitted as a height of 1.5m.
Horizontal of wiring should be as a height of 3
meter.
6/8/2022
7

5.USE EARTH WIRE OF PROPER GAUGE
 Earth wire should be 14 SWG in case of copper
and 4 mm in case of aluminum. Fuse wire should
be connected to phase wire and neutral link should
be connected to neutral wire.
 Connect all switches in phase wire. Minimum size
of earth wire for light circuit is 4mm square for
copper and 1.5mm square for aluminum.
6/8/2022
8

6.MAKE USE OF COPPER CONDUCTORS
 All conductors should be made of copper. They
should have a cross sectionless than
0.0020sq.inches. Nominal area (3/0.029 inches)
and every conductors should be stranded.
6/8/2022
9

7.NEVER UTILISE DAMAGED WIRING OR
ELEMENTS
 Burnt element, cut/broken wiring, loose/open
connection and rusted points should never be used
to avoid open circuit fault.
 Never make one of damaged insulation wiring to
avoid short circuit fault.
 Damaged and loose connection should never be
done in any appliance to avoid earth fault.
 Provide earthing to enhance voltage and protect
human beings from sudden electric shock.
 You must for lightening wire earth into the ground to
protect building from cloud lightening.
6/8/2022
10

TYPES OF DOMESTIC WIRING
1. Cleat wiring
2. Wooden casing and capping wiring
3. TRS or Batton wiring
4. Surface conduit wiring
5. Concealed conduit wiring
6/8/2022
11

1. CLEAT WIRING
6/8/2022
12
 In this system of wiring the cables are gripped and
supported between cleat made of porcelain. These
cleats are made in two halves; the lower part is
grooved to accommodate, the cable and the upper
part is put over it.
 After the cable is put-between the cleats, these are
then screwed on wooden plugs also known as
gutties. The gutties should first be fixed into the wall
at regular intervals of about 50 cm.
 The screws used are of size 38 mm length. For 250
volts supply, the cables will be placed 2.5 cm apart
centre to centre for single core cables.

1. CLEAT WIRING…
6/8/2022
13
 Only one cable is passed through each groove of
the cleat. While screwing too much pressure should
not be applied so that its insulation remains intact.
The cables normally used in cleat wiring are VIR
(Vulcanised India rubber) cable, PVC cables etc.
 In this system of wiring sharp bends and undue
twisting should be avoided. Also, whenever cable
has to pass through walls, floors or any other
concealed location, the conduit pipe of suitable
length should be used for that portion of wiring.
Cleats for two wires are shown in Fig.

1. CLEAT WIRING…
6/8/2022
14

ADVANTAGES :
1. The installation and dismantling is simple and fast
and hence is very useful for temporary wiring.
2. The cable can be inspected easily and if there is
any problem with the wiring the same can be
rectified without much problem.
6/8/2022
15

DISADVANTAGES
1. The appearance of the wiring is not good.
2. It cannot be used in damp places.
3. As the wiring is exposed to atmosphere, its life
span is short.
6/8/2022
16

2. WOODEN CASING AND CAPPING WIRING
 This method of wiring is one of the very old method
and is in use even as of now. This system is
suitable for the voltages installations using VIR or
PVC cables.
 The Casing and Capping form two parts of the
wooden or PVC, the Casing and Capping have
grooves. The cable is placed in the grooves of the
Casing and this is then covered by capping as
shown in Fig.
 The Capping is fitted to the casing with the help of
screws of 12. 7 mm length. The Casing and
Capping should be made of teak wood.
6/8/2022
17

 The casing should be spaced from the wall by
means of small porcelain blocks or disc insulators
not less than 6.5 mm thick so that direct contact to
the wall is avoided and hence it is protected against
dampness of wall.
6/8/2022
18

6/8/2022
19

ADVANTAGES
1. It is relatively cheaper as compared to conduit but
costlier as compared to cleat-wiring.
2. Short-circuit of wire i.e. between phase and neutral
is avoided as the two are placed in different
grooves.
3. Physical inspection of wiring makes it simple to
carry out any repair if required (by opening the
capping).
4. PVC casing capping gives better look and is
economical as compared to wood.
6/8/2022
20

DISADVANTAGES
1. In case of a short-circuit, there is risk of fire (use of
wood or PVC).
2. Normally not recommended for damp places.
6/8/2022
21

3.TOUGHENED RUBBER SHEATH {TRS OR
CTS) OR BATTON WIRING
 In this case the cables are carried on seasoned
teak wood perfectly straight and well varnished teak
wood batton of thickness not less than 1 cm.
 The cables are fixed on the batton by means of
tinned brass or aluminium link clips already fixed on
the batton with small nails before laying cables.
6/8/2022
22

 The battons are fixed to the walls by means of
gutties with countersink headed wooden screws.
The screws are to be fixed on the batton at an
interval of about 75 cms.
 The minimum width of batton is 13 mm for two
wires. It is found suitable where acids and alkalies
are stored. The various sizes of batton available are
13, 19, 25, 31, 38, 44 and 50 mm width.
 Depending upon the no. of cables to be run, a
suitable size of batton should be used.
6/8/2022
23

6/8/2022
24

ADVANTAGES
1. Easy to instal and economical as compared to
casing cappings or conduit wiring.
2. Easy to detect fault if any and has good
appearance.
3. Relatively good life span.
6/8/2022
25

DISADVANTAGES
1. Not suitable if exposed to sun and rain or places
where dampness exists.
2. Risk of fire high.
CTS stands for Cab Type sheathed.
6/8/2022
26

4. 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 it
spoils the beauty of the house. The usual size of
the conduit is 25 mm diameter for domestic wiring.
6/8/2022
27

5. 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.
6/8/2022
28

ADVANTAGES
1. It provides protection against mechanical injury to
insulated cables and against short circuits.
2. Since conduits can be made water tight, the
conduit wiring provides protection against moisture.
3. Gives better appearance.
4. Relatively longer life.
6/8/2022
30

DISADVANTAGES
1. It is a relatively costlier system of wiring.
2. Highly skilled workmanship is required and it is
more time consuming.
The method of wiring is normally recommended
where cost is not the consideration e.g. in big
hotels, workshops and factories and places of
storing inflammable materials.
6/8/2022
31

SPECIFICATION OF WIRES
 Usually cables or wires have a no. of strands
twisted together. Standard stranding consists of 6
wires around 1, then 12 around 6, followed by 18,
24 and so on. A stranded conductor is expressed as
7 /0.1 where the first number stands for the no. of
strands used and the second number corresponds
to the diameter of each strand in mm.
 Some times the second number given corresponds
to the gauge of the strand used e.g. , 3/20 which
means a cable with three strands each of
20SWG(Standard wire gauge).
6/8/2022
32

All electric cables consist of three essential points
(a) the conductor for transmitting electrical power,
(b) the insulation, an electrical insulating medium,
needed to insulate the conductor from direct
contact with earth or other objects, and
(c) external protection against mechanical damage,
chemical or electro-chemical attack, fire or any
other dangerous effects external to the cable.
6/8/2022
33

 Copper conductor has extensively been used for cables
but of late aluminum is being used to a considerable
extent.
 To obtain flexibility number of wires are made up into a
strand which makes it easier to handle, less liable to
kink and break and to a large extent eliminates risk to
the conductor breaking through the dielectric.
 The wires in a stranded conductor are twisted together
to form lays.
 The successive layers usually are stranded in opposite
direction i.e., if the wires of one layer have a right-
handed lay, the next layer has a left-handed lay.
6/8/2022
34

 In regard to specification of cables, it is important to
mention all possible details regarding the particular
type of cable in terms of size (in mm or mm2) types
of conductor whether copper or aluminium, type of
insulation PVC or VIR and voltage grading.
6/8/2022
35

SIZE OF COND UCTOR
Following points must be kept in mind while
determining the size of the conductor for internal
wiring for a given circuit.
(i) Minimum size of the conductor for mechanical
reason
(ii) Current carrying capacity
(iii) Voltage drop
6/8/2022
36

MINIMUM SIZE OF CONDUCTOR
(i) Wire. The minimum size of copper conductor in
use is 1/1.2 mm based on permissible wattage of
800 watts in the subcircuit. The aluminium
conductor of size 1/1.4 mm is used for a subcircuit
in domestic wiring and minimum size of conductor
for power wiring is 4 mm^2 and 1/2.24 mm.
(ii) Underground cables. The area of cross section of
conductor for two core cables should not be less
than 6 mm^2 and for three and four core cables it
should not be less than 25 mm^2. The minimum
area of cross section of a three and half core cable
should be 50 sq. cm.
6/8/2022
37

CURRENT-CARRYING CAPACITY
 When current is passed through a wire a certain
amount of power is wasted in the wire which
appears in the form of heat which results in
increase in temperature of the conductor which may
again decrease the life of insulation and, therefore,
the rating should be such that when that current is
allowed to flow continuously it does not affect the
insulation of the cable.
 However, it should be able to carry a relatively
larger current. (Varying between 1.5 to 2 times the
continuous rated current. ) for a short duration
without affecting the insulation.
6/8/2022
38

VOLTAGE DROP
 Before deciding a proper size of cable to be used in
a circuit, due consideration must be given to
voltage drop. This voltage drop in the cable from
distribution board to the point of device (lamp, fan,
motor etc.) is due to the flow of current through the
cable.
 The permissible voltage drop from supply terminal
to any point on the wiring system should not exceed
2% + 1 volt for light loads and 7.5% for declared
supply voltage of power loads.
6/8/2022
39

ENERGY AUDITING
 Energy audit is the key to a systematic approach for
decision making in the area of energy
management. It attempts to balance the total
energy inputs with its use, and serves to identify all
the energy streams in a facility.
 It quantifies energy usage according to its discrete
functions. Industrial energy audit is fundamental to
a comprehensive energy management programme
and is defined in EC Act 2001 as follow:
6/8/2022
40

ENERGY AUDITING…
 Energy audit means the verification, monitoring and
analysis of use of energy including submission of
technical report containing recommendations for
improving energy efficiency with cost benefit
analysis and an action plan to reduce energy
consumption.
6/8/2022
41

NEED FOR ENERGY AUDIT
 In any industry, the three top operating costs are often found
to be energy (both electrical and thermal), Labour and
materials. Among the three, energy has the highest potential
for cost reduction.
 Energy audit will help to understand move about the ways
energy is used in the industry, and help in identifying the areas
where waste can occur and where scope for improvement
exists.
 Such programme will review variation in energy costs,
availability and reliability of supply of energy, decide on
appropriate energy mix, identify energy conservation
technologies, retrofit for energy conservation equipment etc.
 In general, energy audit is the translation of conservation
ideas into realities, by evolving technically feasible solutions
with economic and other organizational considerations within
a specified time.
6/8/2022
42

TYPES OF ENERGY AUDIT AND APPROACH
 The type of energy audit to be performed depends
on the type of industry, the depth to which final
audit is needed, and the potential and magnitude of
cost reduction desired. Thus energy audit can be
classified into the following types.
 Preliminary Audit
 Targeted Energy Audits
 Detailed Audit.
6/8/2022
43

PRELIMINARY ENERGY AUDIT
 Preliminary energy audit, which is also known as
Walk-Through Audit and Diagnostic Audit, is a
relatively quick exercise and uses existing, or easily
obtained data.
6/8/2022
44

PRELIMINARY ENERGY AUDIT…
The scope of preliminary energy audit is to
 Establish energy consumption in the organization
(sources energy bills and invoices)
 Obtain related data such as production for relating with
energy consumption
 Estimate the scope for energy savings
 Identify the most likely and the easier areas for attention
(eg. Unnecessary lighting, higher temperature settings,
leakage etc.)
 Identify immediate (especially no-low-cost)
improvements/savings
 Set up a baseline or reference point for energy
consumption
 Identify areas for more detailed study/measurement
6/8/2022
45

Some example of no-cost energy management
measures are:
 Arresting leaks (steam, compressed air)
 Controlling excess air by adjusting fan damper
some examples or low-cost energy management
measures are:
 Shutting equipment when not needed (e.g. idle
running of motors)
 Replacement with appropriate lamps and
luminaries
6/8/2022
46

Areas for detailed study/measurement are:
 Converting from direct to indirect steam heated
equipment and recovery of condensate
 Installing/ upgrading insulation on equipment
 Modifying process to reduce steam demand
 Investigating scheduling of process operation to
reduce peak steam or water demands
 Evaluating waste heat streams for potential waste
heat recovery
6/8/2022
47

TARGET ENERGY AUDITS
 Targeted energy audits often results from
preliminary audits. They provide data and detailed
analysis on specified target projects. For example,
an organization may target its lighting system or
boiler system or steam system or compressed air
system with a view of effecting energy savings.
 Targeted audits therefore involve detailed surveys
of the target subjects and analysis of the energy
flows and cost associated with the targets. Final
outcome is the recommunication regarding actions
to be taken.
6/8/2022
48

DETAILED ENERGY AUDIT
 Detailed energy audit is a comprehensive audit and
results in a detailed energy project implementation
plan for a facility, since it accounts for the energy
use of all major equipment.
 It considers the interactive effects of various
projects and offers the moist accurate estimate of
energy savings and cost.
 It includes detailed energy cost saving calculation
and project implementation costs.
6/8/2022
49

DETAILED ENERGY AUDIT…
 One of the key elements in a detailed energy audit
is the energy balance. This is based on an
inventory of energy-using system, assumptions of
current operating conditions, measurements and
calculations of energy use.
a. Pre audit phase
b. Audit phase
c. Post audit phase
6/8/2022
50

TEN STEPS METHODOLOGY FOR CONDUCTING
DETAILED ENERGY AUDIT
StepN
o
Plan of action Purpose results
Phase I-Pre Audit Phase
1 Plan and Organise.Walk
through Audit
Informal Interview with
Energy Manager,
Production/
Plant Manager
Establish/organize a Energy audit team
Organize instruments and time frame
macro data collection (suitable to tyep of
industry)
Familiarization with process/plant
activities
First hand observation and Assessment
of current level of operation and
practices.
6/8/2022
51

DETAILED ENERGY AUDIT….
6/8/2022
52

6/8/2022
53

6/8/2022
54

6/8/2022
55

PHASE I:PRE AUDIT PHASE
 An initial study of the site should always is a pre-
requisite for an effective audit. An initial site visit
should take only one day and gives the energy.
 Auditor an opportunity to meet the personnel
concerned, to familiarize with the site and to assess
the procedures accuracy to carry out the energy
audit.
6/8/2022
56

PHASE I:PRE AUDIT PHASE…
During the initial site visit the Energy Auditor Engineer
should carry out the following actions
 Explain the purpose of the audit and indicate the
kind of information needed during the facility tour
 Discuss economic guidelines associated with the
recommendation of the audit.
 Analyze the major energy consumption data with
the relevant personnel.
 Obtain site drawings where available plant building
layout, steam distribution, compressed air
distribution, electricity distribution etc.
 Tour the site accompanied by site representative
6/8/2022
57

PHASE I:PRE AUDIT PHASE…
The outcome of this visit should be
 To finite Energy Audit team
 To know the expectation of management from the audit
 To identify the main energy consuming areas/plant items
to be surveyed during the audit
 To identify existing instrumentation and additional
metering required prior to audit e.g. for measurement of
electricity, steam, oil or gas consumptions.
 To plan for audit with time frame
 To collect macro data on plant energy resources, major
energy consuming equipments
 To build up awareness and support for detailed energy
audit
6/8/2022
58

PHASE II: DETAILED ENERGY AUDIT PHASE
 Depending on the nature and complexity of the site,
a detailed audit can take from several weeks to
several months to complete. Detailed studies would
involve investigation and establishment of material
and energy balances for specific plant departments
or process equipment.
 Whenever possible, checks of plant operations are
carried out over extended periods of time, at night
and at weekends as well as during normal daytime
working hours, to ensure that nothing is overlooked
6/8/2022
59

PHASE II: DETAILED ENERGY AUDIT PHASE..
Typically, Energy Auditor should ask
1. What function does this system serve?
2. How does this system sever its function?
3. What is the energy consumption of this system?
4. What are the indications that this system is
probably working?
5. If this system is not working, how can it be restored
to good working conditions?
6. How can the energy cost of this system be
reduced?
6/8/2022
60

The information to be collected during the detailed
audit includes
1. Sources of energy supplies (e.g. electricity from the
grid or self-generation)
2. Energy cost and tariff data
3. Generation and distribution of site services (e.g.
compressed air, steam, water, chid water).
4. Process and material flow diagram.
6/8/2022
61

The information to be collected during the detailed audit
includes
5. Material balance data (raw materials, intermediate and
final products recycled materials, use of scap or waste
products, production of by-products for re-use in other
industries, etc.)
6. Energy consumption by type of energy by department
by major process equipment by end-use
7. Potential for fuel substitution, process modifications,
and the use of co-generation system
8. Review of ongoing energy management procedures and
energy awareness training programs.
6/8/2022
62

Energy audit team should ensure that the following
baseline data are I collected:
 Quantity and type of raw materials
 4Technology, process used and equipment used
 Capacity utilization
 Efficiency/ yield
 Percentage rejection / reprocessing
 Quantity and types of wastes
 Consumption of fuel, water, steam, electricity,
compressed air, cooling water, chilled water
6/8/2022
63

 Energy auditor must specially interview the
supervisors and equipment operators as they have
information related to the equipment.
 Maintenance manager is often the primary person
to talk about types of lighting. lamps, sizes of
motors, A/c plant and electrical load and related
performance problems.
6/8/2022
64

unit 4 domestic wiring and instruments.pptx

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Ähnlich wie unit 4 domestic wiring and instruments.pptx

Ähnlich wie unit 4 domestic wiring and instruments.pptx (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

unit 4 domestic wiring and instruments.pptx