Introduction on indian codes as applied in electrical design

Introduction on Indian codes &Introduction on Indian codes &
regulation as applied in electricalregulation as applied in electrical
designdesign
ByBy
Asif EqbalAsif Eqbal
By Asif Eqbal

ContentContent
Major codes & standard followed in India for electrical design
Objective of codes & standard
Indian Code for Industrial Lighting System
Indian Code for Earthing System
Indian Code for Lightning Protection System
By Asif Eqbal

Major codes & standard followed inMajor codes & standard followed in
IndiaIndia
 Indian Electricity rules, 1956 as amended up to 25TH Nov., 2000
 Bureau of Indian standards
 Central electricity authority guidelines
 CPCB norms (central pollution control board)
 National building code
 CBIP manuals (Central board of irrigation & power)
 Oil Industry safety directorate (OISD) for oil & gas industry
IE rules & IS takes precedence over all the standards. None of the Indian
standard contradicts each other, they only supplement each other in a way
that what is not mentioned in one standard is available in another.
By Asif Eqbal

Indian Electricity RulesIndian Electricity Rules
 Indian electricity rues are based on Indian Electricity Act,1910 recommended
by Central Electricity Board of India.
 IE rules are mandatory as they have been prepared and implemented by
legislation of government of India.
 All the statutory clearances and approval for any project is provided by
central electrical inspector to that province where the location of project is
and also the local provincial inspector. Central electrical inspector carries the
inspection as per the guidelines of IS and IE rules.
 IE rules defines the eligibility criteria for any person to operate or undertake
maintenance of any type of industrial electrical installation.
Major guidelines provided are as follows:
 Clearance above ground of the lowest conductor.-
No conductor of an overhead line, including service lines, erected across a
street shall at any part thereof be at a height of less than-
(a) for low and medium voltage lines 5.8 meters
(b) for high voltage lines 6.1 meters
By Asif Eqbal

No conductor of an overhead line including service lines, erected elsewhere
than along or across any street shall be at a height less than -
 for low, medium and high voltages lines up to and including 11,000 volts, if
bare 4.6 meters
 for low, medium and high voltage lines up to and including 11,000 volts, if
insulated 4.0 meters
 for high voltage lines above 11,000 volts 5.2 meters
 For extra-high voltage lines the clearance above ground shall not be less
than 5.2 meters plus 0.3 meter for every 33,000 volts or part thereof by
which the voltage of the line exceeds 33,000 volts;
Provided that the minimum clearance along or across any street shall not be
less than 6.1 meters.
By Asif Eqbal

 Routes; Proximity to aerodromes, Transporting and Storing of material near
overhead lines are also defined in IE rules.
 Other features and area covered by IE rules are:
I. GENERAL SAFETY REQUIREMENTS
II. Testing of consumer’s installation
III. Installation and Testing of Generating Units
IV. Test for resistance of insulation
V. ELECTRIC TRACTION
VI. ADDITIONAL PRECAUTIONS TO BE ADOPTED IN MINES AND OIL-FIELDS
VII. Connection with earth & Earth leakage protective device
VIII. Identification of earthed and earthed neutral conductors and
IX. position of switches and cut-outs therein
X. Earthed terminal on consumer’s premises
XI. Accessibility of bare conductors 15
XII. Danger notices
By Asif Eqbal

As per IE rules voltage are categorized as
 “ low” where the voltage does not exceed 250 volts under normal
conditions.
 “medium "where the voltage does not exceed 650 volts under normal
conditions.
 “ high "where the voltage does not exceed 33,000 volts under normal
conditions.
 “ extra high "where the voltage exceeds 33,000 volts under normal
conditions.
 However as per general practice 415 and lesser is considered as low,
above 415 and less than 33kV is considered as medium and 33kV and
above is considered as high. Above 400kV is considered as EHV.
By Asif Eqbal

Central Electricity authority (CEA)Central Electricity authority (CEA)
 Standard Technical Specification for Sub- critical Thermal Power Project -
2x(500MW or above).
 Because of unprecedented growth being witnessed by the power sector
with a capacity addition of over 78,000 MW envisaged during 11th Plan and
about 80,000 MW in 12th Plan, every possible opportunity for enhancing
pace of capacity addition is explored and fully exploited. In this context,
there has been a long felt need to standardize the technical specification of
thermal power stations with a view to reducing the time for pre-award
activities, design & engineering and the manufacturing by equipment
manufacturers. To do this, a Committee was set up by CEA under the
chairmanship of Member Thermal) in May 2007 with participation from
major utilities and manufacturers for developing standard technical
specifications for main plant equipment for coal based thermal power plant
having 500MW and higher capacity sub-critical units.
By Asif Eqbal

Central Electricity authority (CEA)Central Electricity authority (CEA)
 This guideline covers the design, engineering, manufacture, inspection and
testing at manufacturer's works, supply, packing and delivery at project site,
unloading, storage and in plant transportation at site, erection, supervision,
pre-commissioning, testing, successful commissioning, performance testing
and handing over of main plant package for sub-critical thermal power
project having two (2) units of 500 MW (or above) consisting of steam
generator, steam turbine– generator, electrical system, and C&I system
along with all associated auxiliaries and accessories and associated civil
works.
 These guidelines are framed by Government of India, Ministry of Power,
New Delhi.
By Asif Eqbal

Central Pollution Control Board NormsCentral Pollution Control Board Norms
(CPB)(CPB)
 The Central Pollution Control Board (CPCB), statutory
organization, was constituted in September, 1974 under the
Water (Prevention and Control of Pollution) Act, 1974. Further,
CPCB was entrusted with the powers and functions under the Air
(Prevention and Control of Pollution) Act, 1981.
 CPCB norms are framed by ministry of environment.
 Every industrial installation requires to get the clearance from
CPCB before being commissioned.
 In electrical industry/installation the most widely and important
CPCB norm is installation and exhaust of emergency diesel
generator.
 Stack height for exhaust gases from diesel generator as per CPCB
norm is given by the following formula:
H = h + 0.2(kVA)0.5
H = Height of stack
h = Height of building in meter where DG is installed.
kVA = Total electrical power output of diesel generator.
By Asif Eqbal

Central Pollution Control Board NormsCentral Pollution Control Board Norms
(CPB)(CPB)
 The stack height was originally evolved for those to be evolved in
metropolitan areas of Delhi.
 The idea was to avoid the problem of road side discharge from stack and
built up of pollutants in ambient air.
 For factories set up away from metropolis which use the emergency diesel
set occasionally are given some relaxation with respect to height of stack .
Hence for non residential and commercial area the height of stack as per
CPCB should be 2.5 times the height of building where DG set is installed
or height of that building within factory premises where people are working.
 CPCB norms also specifies the emission norms for diesel engine rating
more than 800kW for power plant generator set application and other
requirements.
By Asif Eqbal

National Building codeNational Building code
 National building code is the prime code applicable for commercial
buildings.
 The National Building Code of India (NBC), a comprehensive building
Code, is a national instrument providing guidelines for regulating the
building construction activities across the country. It serves as a Model
Code for adoption by all agencies involved in building construction works be
they Public Works Departments, other government construction
departments, local bodies or private construction agencies. The Code was
first published in 1970 at the instance of Planning Commission and then
revised in 1983. Thereafter three major amendments were issued, two in
1987 and the third in 1997.
By Asif Eqbal

National Building codeNational Building code
 All the wiring installations for lighting and power receptacles are carried out
as per the NBC guidelines and IS 732.
 The Code mainly contains administrative regulations, development control
rules and general building requirements; fire safety requirements;
stipulations regarding materials, structural design and construction
(including safety); and building and plumbing services general requirements
of telecommunication, fire safety, earthing and lightning protection and
earthing for high rise buildings (Apartments, shopping malls, hotels and
official complexes) is also covered in this code.
By Asif Eqbal

Central Board of Irrigation &Central Board of Irrigation &
Power (CBIP)Power (CBIP)
 Central Board of Irrigation & Power (CBIP), a Premier Institution, rendering
dedicated services to professional organizations, engineers and individuals
for more than 81 years, resulting in accelerated development in Water
Resources, Energy and Allied Fields, including renewable energy, in the
country and abroad. CBIP has grown into an eminent organization of
international importance while serving the nation equally with great
distinction. CBIP is Indian chapter for 10 international organizations related
to aforesaid sector.
 Today, Central Board of Irrigation and Power presents a shining example of
a pioneer organization and has enabled Indian industry to set higher
benchmarks and attain international standards in excellence by creating a
unique platform for growth and progress of these sector.
 Some important features of CBIP norms are that lot of figures are clearly
mentioned in this code which are not mentioned in any other Indian codes.
Some examples are:
Loss figure for oil type power & distribution transformer
By Asif Eqbal

Central Board of Irrigation &Central Board of Irrigation &
Power (CBIP)Power (CBIP)
 Loss figure for oil type power & distribution transformer
 Standard ratings for bus ducts at various voltage level
 Complete step by step procedure for S/S earthing
 Earthing and transformers are the two electrical package where the CBIP
manuals are widely used. IS 3043 is supplemented by this standard as IS
does not mentions details about earth mat design for switchyard or S/S.
 IS for power transformer is also supplemented by this standard as none of
the IS mentions the loss figure, relation between ONAN and ONAF rating
over fluxing capability etc…..for any transformer.
By Asif Eqbal

Objectives of codes & standardObjectives of codes & standard
 The Electrical System shall be designed to provide:
 Safety to personnel and equipment both during operation and
maintenance.
 Reliability of Service.
 Minimum fire risk.
 Ease of maintenance and convenience of operation.
 Automatic protection of all electrical equipment through selective relaying
system.
 Electrical supply to equipment and machinery within the design operating
limits.
 Adequate provision for future extension and modification.
 Cost effective.
By Asif Eqbal

Objectives of codes & standardObjectives of codes & standard
 The design shall be in accordance with established codes, Standards, Specifications,
sound engineering practices and shall conform to the statutory regulations applicable in
India and at Site Location. In case of conflict in the various documents and drawings and
various Codes and Standards followed, the most
stringent shall govern.
By Asif Eqbal

Indian Code for Industrial LightingIndian Code for Industrial Lighting
SystemSystem
 IS 3646 : CODE OF PRACTICE FOR INTERIOR ILLUMINATION
 IS 6665 : CODE OF PRACTICE FOR INDUSTRIAL LIGHTING
By Asif Eqbal

Design GuidelinesDesign Guidelines
 Plant Illumination System comprise of following:
 Normal 230V, ac lighting system.
 Normal-cum-emergency 230 V, ac lighting system having DG backup.
 Critical DC Lighting having DC Battery backup.
 20-25% of total Plant Lighting should be emergency lighting
having DG Back-up.
 Critical Areas of Plant such as sub-station, control room, exit points
should have critical DC Lighting having DC battery backup.
 During normal operation, normal & emergency lighting fed by
normal power source.
 On failure of normal supply, emergency lighting load shall transfer
to emergency source.
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 Illuminance ranges recommended for interior or activity :
• Middle value (R) for working interiors
• Higher value (H) for visual work
• Lower value (L) where accuracy is non-important
By Asif Eqbal

TYPE OF LOCATION LUX
CONTROL ROOM- GENERAL LIGHTING 400-700
- REAR OF INSTRUMENT PANEL 250
- OUTSIDE, NEAR ENTRANCES 150
PUMP AND COMPRESSOR HOUSE 100
SWITCHROOM AND PIB’S 150
OUTDOOR OPERATIONAL AREAS 50
OUTDOOR NON-OPERATIONAL AREAS 10
DRAWING OFFICES 700
OFFICES 400
WORKSHOPS - INTERIOR 250
- EXTERIOR 50
STAIRWAYS,PLATFORMS & WALKWAYS 50
ROADS/ MAIN ACCESS 5
ROADS MINOR 5
By Asif Eqbal

Type of Lighting SystemType of Lighting System
Type of Lamp
Lum /
Watt Color
Rendering
Index
Typical Application
Life
(Hours)
Range
Avg.
Incandescent 8-18 14 Excellent Homes, restaurants, general
lighting, emergency lighting
1000
Fluorescent Lamps 46-60 50 Good w.r.t.
coating
Offices, shops, hospitals, homes 5000
Compact fluorescent lamps (CFL) 40-70 60 Very good Hotels, shops, homes, offices 8000-10000
High pressure mercury (HPMV) 44-57 50 Fair General lighting in factories,
garages, car parking, flood
lighting
5000
High pressure sodium (HPSV)
SON
67-121 90 Fair General lighting in factories, ware
houses, street lighting
6000-12000
Low pressure sodium (LPSV)
SOX
101-
175
150 Poor Roadways, tunnels, canals, street
lighting
6000-12000
By Asif Eqbal

Lighting CalculationLighting Calculation
 Dia-LUX is a 3D-software used for effective and professional light planning.
 It is possible to import CAD model of Architectural Building and plan lighting
arrangement on exact location as desired and perform Lighting Calculation
to achieve desired Illumination Level on work-plane area.
 Dia-LUX can be used for planning of Indoor Lighting, Exterior Lighting and
street lighting.
 It issue normative documentation to validate the design.
By Asif Eqbal

Indian Code for Earthing/GroundingIndian Code for Earthing/Grounding
SystemSystem
 IS 3043 : CODE OF PRACTICE FOR EARTHING
By Asif Eqbal

 The earthing system shall be provided for;
 Equipment earthing for personnel safety
 System neutral earthing
 Static earthing
 Protection against lightning
 The earthing conductor shall be adequately sized to carry the maximum earth fault
current.
Earth resistance shall be less than 1 ohm.
The number and depth to which the electrodes are driven depend upon soil
condition s and soil electrical resistivity levels.
 All medium voltage equipment shall be earthed by two separate and
distinct connections with earth.
 In case of High and extra high voltage, the neutral point shall be earthed
by not less than two separate and distinct connections with earth, each
having its own electrode at the sub-station.
By Asif Eqbal

 Main switchboards and MCCs shall be provided with an earth bar running the full
length of the board, which shall be connected to sub-station main earthing grid.
 Separate clean earth system for instrumentation, DCS, PLC etc shall be provided
as required.
 A separate earth conductor shall be laid along the cable trays and all other trays
shall be interconnected at every 10m distance.
 Lighting fixtures, receptacles, switches, conduits and junction boxes shall be
properly earthed using 12 SWG GI wire run along the entire length of the conduit.
By Asif Eqbal

Earthing CalculationEarthing Calculation
Step-1 To Determine minimum size of Earth Conductor (As per IS:3043)
S = I√t
k
Where,
S = Conductor cross section area in mm²
I = Fault current in amperes.
t = Fault duration in seconds
k = Constant depending on material of earthing conductor, its
insulation, the initial and final temperature.
Step-2 Calculate Resistance of Earth Electrode (As per IS:3043)
Re = (100 X ρ X Ln (4L/D))
2ΠL
Where,
Re = Resistance of earth electrode
L = Length of pipe in cm
ρ = soil resistivity in ohm-m
D = Diameter of pipe in cm
By Asif Eqbal

Step-3 Calculate Net Resistance of Earth Electrode (As per IS:3043)
Rearth = Re
N
Where,
Rearth = Net resistance of Earth Pits
Re = Resistance of Pipe Electrode
N = No. of Earth Electrode considered
Step-4 Calculate Resistance of Earth Strip (As per IS:3043)
Rs = (100 X ρ X Ln (2L2
/(wXt)))
2ΠL
Where,
RS = Resistance of earth strip
L = Length of conductor in cm.
w = Depth of burial of electrode in cm
t = width of the electrode in cm or twice the diameter of
conductor in cm.
By Asif Eqbal

Step-5 Calculate Total Grid Resistance (As per IS:3043)
RTotal = Rearth X Rs
Rearth + Rs
Where,
Rearth = Net resistance of Earth Pits
Rs = Resistance of Earth Strip
RTotal = Total Grid Resistance
By Asif Eqbal

Indian Code for Lightning ProtectionIndian Code for Lightning Protection
SystemSystem
 IS 2309 : PROTECTION OF BUILDINGS AND ALLIED STRUCTURES
AGAINST LIGHTNING
 IEEE: 142 : IEEE RECOMMENDED PRACTICE FOR GROUNDING OF
INDUSTRIAL AND COMMERCIAL POWER SYSTEM
By Asif Eqbal

 Lightning is a natural hazard, being the discharge of static electricity generated
in storm clouds, which may cause damage to structures.
 The need for providing the lightning protection system shall be established by
calculating risk index value for each building structure etc as per procedure
give in IS: 2309 and any building whose overall risk factor is more than 10-5
shall be provided with lightning protection.
 Lightning protection system shall consist of vertical air termination roads,
horizontal roof conductors, down conductors and earth electrodes.
 Air termination and down conductors for buildings shall be of GS flat. Electrodes
shall be GS rod.
 Each down conductor shall be connected to a rod electrode, which in turn shall
be connected to the station earthing system through test links.
 Conductors of lightning protection system shall not be connected with
conductors of safety earthing system above ground level.
By Asif Eqbal

 Galvanized Steel (GS) is used as the material for lightning protection conductor.
 The sizes of the conductors for lightning protection system are decided based on
mechanical strength. The minimum size for air terminations and down conductor,
as per IS-2309, table-4 is 20X3 mm GS. However, higher size is selected
considering mechanical strength.
 Air termination network may consist of vertical or horizontal conductors or
combination of both which is provided for the buildings requiring lightning
protection according to IS : 2309.
 Down conductors shall be as short and straight as practicable and shall follow a
direct path to earth electrode.
 As per IS 2309, article no. 12.2.5, Steel column can be acted as Down Conductor
and as per IS 2309, article no. 9.0.1, Metal roof can be acted as Air termination.
By Asif Eqbal

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