Download - 1st training report
DEPARTMENT OF ELECRICAL AND INFORMATION ENGINEERING
FACULTY OF ENGINEERING
UNIVERSITY OF RUHUNA
INDUSTRIAL TRAINING REPORT SUBMITTED IN PARTIAL FULFILMENT OF
THE DEGREE OF BACHELOR OF SCIENCE IN ENGINEERING
1th June 2015
ACCESS ENERGY SOLUTIONS (PVT) LTD
ACCESS TOWERS
UNION PLACE, COLOMBO-02
(From 26th January 2015 to 26th April 2015)
THANUJAN V. (EG/2012/2092)
I
ACKNOWLEDGEMENT
It is my privilege to thank the people who contributed to make my training period such a
great experience. Firstly, I am grateful to Dr. P.D Chandhana Pereira, Dean, Faculty of
Engineering, University of Ruhuna, and Dr. J.M.R.S. Appuhamy, Coordinator, Engineering
Educational Center, Faculty of Engineering, University of Ruhuna and all the
academic an nonacademic staff of the Department of Electrical and
Information Engineering, facul ty of engineering, univers ity of Ruhuna.
Also I take this opportunity to extend my gratitude to National Apprentice a n d Industrial
Training Authority (NAITA) for making necessary arrangements to provide me a
valuable training period.
Also I am so Indebted to Mr. Rohal Perera, CEO of Access Energy Solutions (pvt.) Ltd for
providing us all the facilities in order to have a valuable training. I take this opportunity to
extend my profound thanks to the Director Board of Access Engineering (pvt.) Ltd. Also I
am so indebted to all other Engineers in Access Energy Solutions (pvt.) Ltd for dedicating
their valuable time on behalf of our own goodness & for providing us a faculty of
knowledge. Next I am thankful to all the employees of Access Energy Solutions (pvt.) Ltd
for giving us their kind co-operation.
And finally I extend my regards to all the emplo yees of Access Engineering (Pvt) Ltd.
for all the supports given to have a valuable training.
Thank you!
Thanujan V,
EG/2012/2092,
Faculty of Engineering,
University of Ruhuna.
II
PREFACE
This report on industrial training prepared by myself was done so not only as an
exercise to fulfill a part of the training requirements set out by NAITA, but also as a
testimony on the actual l industrial training I had. Hereby, a detailed account of my
training programmed at Access Energy Solutions (pvt.) Ltd is included.
The idea behind this compilation is that anyone going through this report should get a
comprehensive understanding of all technical aspects of my training. In making this a
reality, I tried my best to keep to the guidelines stipulated by NAITA. This is
succeeded by my own training experience, which is detailed to the most possible extent.
III
TABLE OF CONTENTS
01. INTRODUCTION ......................................................................................... 1
1.1 Access Group ................................................................................................... 1
1.2 Vision and Mission of the Company ............................................................... 2
1.2.1 Vision ........................................................................................................ 2
1.2.2 Mission ..................................................................................................... 2
1.3 Access Energy Solutions Pvt. Ltd. .................................................................. 2
1.4 Organizational Structure .................................................................................. 3
02. TECHNICAL DETAILS .............................................................................. 4
2.1 Introduction to Projects .................................................................................... 4
2.2 Electrical Drawings ......................................................................................... 4
2.2.1 Symbols in Electrical Drawings ............................................................... 4
2.3 Sample Electrical drawings ............................................................................. 7
2.4 Circuit Breakers ............................................................................................... 9
2.5 Cables and Wiring ......................................................................................... 20
2.5.1 Structure of Cable ................................................................................... 22
2.5.2 Selection of Cables ................................................................................. 23
2.5.3 Type of installation ................................................................................. 23
2.5.4 Voltage requirement ............................................................................... 23
2.5.5 Ampacity requirements ........................................................................... 23
2.5.6 Heating conditions .................................................................................. 24
2.5.7 Special conditions ................................................................................... 24
2.5.8 Current rating for wires .......................................................................... 24
2.6 Electrical conduit ........................................................................................... 26
2.6.1 Types of conduit ..................................................................................... 26
2.7 Distribution Board ......................................................................................... 28
2.8Electricity providing to the Building .............................................................. 29
2.8.1 Feeder Pillar ................................................................................................ 30
2.9 Lighting System Wiring ................................................................................ 31
2.10 Power System Wiring .................................................................................. 33
2.11 Wiring Methods ........................................................................................... 34
2.11.1 Ring and Radial circuits ........................................................................ 35
2.12 lightning protection systems ........................................................................ 38
2.12.1 Lightning Rods ..................................................................................... 40
IV
2.12.2 Franklin Lighting Rod .......................................................................... 40
2.12.2 ESE Lightning Rod ............................................................................... 41
2.12.3. The Different Types of Lightning Protection Systems ........................ 42
2.13 Earthing System ........................................................................................... 44
2.13.1Types of Earthing .................................................................................. 44
2.13.2 The main objectives of the earthling..................................................... 44
2.13.3 The qualities of a good earthling system .............................................. 44
2.15.4 IEC terminology of earth systems ........................................................ 45
2.13.5 Earth Rod Installation ........................................................................... 45
2.14 Degrees of Protection .................................................................................. 47
2.15 DATA & Telephone System ....................................................................... 49
2.15.1 CAT6 Cable .......................................................................................... 49
2.15.2 Data Rack .............................................................................................. 50
2.15.3 Patch Panel ............................................................................................ 51
2.15.4 Switch ................................................................................................... 51
2.15.5 Router ................................................................................................... 52
2.15.6 PABX .................................................................................................... 53
2.16 CCTV Security System ................................................................................ 53
2.16.1 CCTV Camera ...................................................................................... 54
2.16.2 DVR ...................................................................................................... 55
2.16.3 Display .................................................................................................. 56
2.16.4 Cables ................................................................................................... 56
2.17 Fire Detection and Fire Protection System .................................................. 57
2.17.1 Fire Detection ....................................................................................... 57
2.17.2 Fire Protection ...................................................................................... 59
03. MANAGEMENT DETAILS ...................................................................... 60
3.1 Site Management ........................................................................................... 60
3.2 Working Procedure ........................................................................................ 60
3.3 Safety ............................................................................................................. 60
3.3.1 Ear Plugs and Mufflers ........................................................................... 61
3.3.2 Safety Gloves .......................................................................................... 61
3.3.3 Goggles, Helmets and Safety Shoes ....................................................... 61
04. SUMMARY AND CONCLUSIONS .......................................................... 63
4.1 Summery ........................................................................................................ 63
4.2 Conclusions .................................................................................................... 63
V
LIST OF FIGURES
Figure 1.1: Organization Structure ............................................................................ 3 Figure 2.1: Power system drawings ........................................................................... 7 Figure 2.2: Lighting System Drawing ....................................................................... 8
Figure 2.3: Fire System Drawing ............................................................................... 8 Figure 02.4: Data&CCTV Drawing .......................................................................... 9 ................................................................................................................................. 11 Figure 2.5: Miniature Circuit Breaker ..................................................................... 11
................................................................................................................................. 11 Figure2.6 – Internal Structure of a MCB ................................................................. 11 Figure 2.7 – Tripping curve of MCB ....................................................................... 12
Figure 2.8 – ELCB Figure 2.9 – 2-Pole and 4-Pole RCCB ............. 13 Figure 2.10 – Wiring Diagram of the RCCB ........................................................... 14 Figure 2.11 – MCCB ............................................................................................... 14 Figure 2.12 - ACB ................................................................................................... 16
Figure 2.13 – Face Plate of a MCCB ....................................................................... 17 Figure 2.14 – Shunt Coil .......................................................................................... 19 ................................................................................................................................. 20
Figure 2.15 – UVT Coil ........................................................................................... 20 Figure 2.16: Several types of Cables ....................................................................... 22
Figure 2.17: PVC Conduits. ..................................................................................... 27 Figure 2.18: Flexible nonmetallic conduit ............................................................... 28
Figure 2.19: Main Distribution Board ..................................................................... 29 Figure 2.20: Meter Board of the Building ............................................................... 29
Figure 2.21: Feeder Pillar ........................................................................................ 30 Figure 2.22: Cu/PVC Cable ..................................................................................... 32 Figure 2.23: Cu/PVC/PVC Cable ............................................................................ 32
Figure 2.24: A part of Lighting System Wiring Drawing ....................................... 32 Figure 2.25: A part of Power System Wiring Drawing ........................................... 34
Figure 2.26: Radial Lighting Wiring Circuit ........................................................... 35 Figure 2.27: Radial Power Wiring Circuit ............................................................... 35
Figure 2.28: Ring Lighting Wiring Circuit .............................................................. 36 Figure 2.29: Ring Power Wiring Circuit ................................................................. 37 Figure 2.30: simple lightning protection system ..................................................... 38 Figure 2.31: Franklin Lightning Rod ....................................................................... 41 Figure 2.32: ESE Lightning Rod ............................................................................. 41
Figure 2.33- The simple lightning rod ..................................................................... 42 Figure 2.34: The lightning rod with taut wires ........................................................ 42 Figure 2.35: The lightning conductor with meshed cage (Faraday cage) ................ 43 Figure 2.36: Earth Rod Installation ......................................................................... 46 Figure 2.37: Protection degree ................................................................................. 48
Figure 2.38: CAT6 Cable ........................................................................................ 49 Figure 2.39: RJ45 8P8C Modular ............................................................................ 49
Figure 2.40: Data Rack ............................................................................................ 50 Figure 2.41: Patch Panel .......................................................................................... 51 Figure 2.42: Switch .................................................................................................. 52 Figure 2.43: Router .................................................................................................. 52
VI
Figure 2.44: PABX .................................................................................................. 53 Figure 2.45: CCTV camera ...................................................................................... 54 Figure 2.46: Several types of DVRs ........................................................................ 55 Figure 2.47: Displays ............................................................................................... 56
Figure 2.48: Cables for cameras .............................................................................. 56 Figure 2.49: Heat Detectors ..................................................................................... 57 Figure 2.50: Sprinkler .............................................................................................. 58 Figure 2.51: Manual Call Point ............................................................................... 58 Figure 2.52: Fire Protection System ........................................................................ 59
Figure 3.1: Ear Plugs and Mufflers .......................................................................... 61 Figure 3.2: Safety Gloves ........................................................................................ 61 Figure 3.3: Goggles, Helmets and Safety Shoes ...................................................... 61
VII
LIST OF TABLE
Table 2.1: Wire sizes for Current ratings ................................................................ 25 Table 1.2: Selecting appropriate cable according to the phase wire ........................ 25
Table 2.3: The Specification of CAT6 Cable .......................................................... 50
1
CHAPTER ONE
01. INTRODUCTION
1.1 Access Group
Access group is one of the fastest growing conglomerates in Sri Lanka. Launched in 1990
with a simple business idea, Access today has grown and diversified into many fields,
drawing strength from its core business areas such as engineering, telecommunication, power
& energy, healthcare, information technology & general trading.
Since its inception, the company has been highly successful in securing major projects for
infrastructure development in Sri Lanka, funded by bilateral & multilateral donor agencies.
In addition the Group has the franchise for many world renowned brands for domestic sales.
The strategic goal of the Group focuses on consolidating and strengthening existing
enterprises, while continuing on an aggressive growth plan of entering vital new ventures
and markets with innovative products and services.
Led by a dynamic and adventurous management team, Access has chartered its course
successfully into many challenging territories emerging as one of the most recognized
business entities in Sri Lanka.
Access group contains the several sub companies from that I was appointed to the Access
Energy Solution Pvt. Ltd.
2
1.2 Vision and Mission of the Company
1.2.1 Vision
To be a leading and dynamic Sri Lankan business enterprise with a global reach.
1.2.2 Mission
To add value and develop strong long term relationships with all our stake holders.
To meet the challenges and increasing demands of a globalized business environment
Through implementation of high quality standards, human resource development &
innovative technology.
To actively contribute to the development of Sri Lanka, and participate in regional and
global business opportunities relevant to the core activities, related strengths and interests of
the company.
To be a conscious corporate citizen and support and participate in programmed activities
aimed at uplifting the communities’ living standards and value systems.
1.3 Access Energy Solutions Pvt. Ltd.
Access Energy Solutions (Pvt.) Ltd, (AESL), provides reliable technologies and advanced
solutions in electrical engineering and energy related products and services.
Specialists in electrical engineering, energy management and power solutions; they act as
consultants and contractors in developing turn-key projects. Their in-depth knowledge of
engineering and vast experience in project management, enable us to undertake
implementation of large and medium scale projects, island wide.
Solutions of the Access Energy Solutions (Pvt) Ltd are custom designed, client specific,
energy efficiency systems which are built to enhance client profitability while improving
work conditions with no hindrance to required comfort levels.
Access Energy Solutions serves an impressive portfolio of energy users in Sri Lanka, from
both the industrial and commercial sectors, and are on the constant look out to serve more
discerning clients who aspire to improve their own productivity.
3
1.4 Organizational Structure
Figure 1.1: Organization Structure
4
02. CHAPTER TWO
02. TECHNICAL DETAILS
2.1 Introduction to Projects
One of the project that there was proposed residence for Mr.Rohana Fernando Police park
Colombo -3. In this project it was just a beginning to wire the building. Therefore in this
project the fields of conduit laying, wiring, estimating are covered.
After that I was visited Niru lanka (Diamond cutter factory) during my end of the training
period this project was in final stage. There were testing wired circuits and identify some
part of wiring equipment panel board, bus bars, bus risers, cable trucking etc.
2.2 Electrical Drawings
Graphic representations of the electrical requirements of a project, including power
distribution, lighting, and low-voltage specialty wiring, such as for fire alarms,
telephone/data, and technology wiring. Any electrical working drawing consists of "lines,
symbols, dimensions, and notations to accurately convey an engineering's design to the
workers, who install the electrical system on the project”
2.2.1 Symbols in Electrical Drawings
Power symbols
DISTRIBUTION BOARD
MCCB / MCB
RCCB
5
Lighting symbols
1 NOS 5A SOCKET OUTLET
2 NOS 5A SOCKET OUTLET
2 NOS 13A SOCKET OUTLET
6
DATA Telephone symbols
ELV & PA symbols
VOLUME CONTROL
DATA
OUTLET
TELEPHONE
OUTLET
CEILING MOUNTED
SPEAKER
CCTV
CAMERA
7
Fire Detection & Protection symbols
S
H
2.3 Sample Electrical drawings
SMOKE DETECTOR
HEAT DETECTOR
Figure 2.1: Power system drawings
8
Figure 2.2: Lighting System Drawing
Figure 2.3: Fire System Drawing
9
2.4 Circuit Breakers
A circuit breaker is an automatically-operated electrical switch designed to
protect an electrical circuit from damage caused by overload or short circuit. Its basic
function is to detect a fault condition and, by interrupting continuity, to immediately
discontinue electrical flow. Unlike a fuse, which operates once and then has to be
replaced, a circuit breaker can be reset (either manually or automatically) to
resume normal operation. Circuit breakers are usually able to terminate all current flow
very quickly. There are several types of circuit breakers as follows.
Figure 02.4: Data&CCTV Drawing
10
1. MCB
2. MCCB
3. ELCB & RCCB
4. ACB
5. OCB
6. VCB
7. MPCB
From above circuit breakers, following six circuit breakers are well identified in my
training period.
2.4.1 MCB
MCB (Miniature Circuit Breaker) is a circuit breaker with optimum protection
facilities of over current and short circuit only. There are two arrangement of operation of
miniature circuit breaker. One due to thermal effect of over current and other due to
electromagnetic effect of over current.
The thermal operation of miniature circuit breaker is achieved with a bimetallic
strip whenever continuous over current flows through MCB, the bimetallic strip is heated
and deflects by bending. This deflection of bimetallic strip releases mechanical latch. As this
mechanical latch is attached with operating mechanism, it causes to open the miniature
circuit breaker contacts. But during short circuit condition, sudden rising of electric current,
causes electromechanical displacement of plunger associated with tripping coil or solenoid
of MCB. The plunger strikes the trip lever causing immediate release of latch mechanism
consequently open the circuit breaker contacts.
Normally breaking capacity of the MCB goes up to 10kA and operating current range
is 6A to 125A. It is available as single pole, double pole, three pole, and four pole MCB’s.
These are used for smaller loads -electronic circuits, house wiring etc.
11
Figure 2.5: Miniature Circuit Breaker
Figure2.6 – Internal Structure of a MCB
2.4.2 TRIPPING CURVE
Every circuit breaker has a tripping curve. It shows how the current through the
circuit breaker change against time in tripping situation. But in MCB the tripping curve is
very important when selecting suitable MCB. Because of the tripping time and other tripping
characteristic are changed according to the tripping curve.
12
Figure 2.7 – Tripping curve of MCB
Every MCB have a specified tripping curve, B,C,D or sometimes very
specialized curve that varies from MCB brand to brand (e.g. -: K & Z curves of ABB
breaker). B, C & D curves are defined in IEE regulations.
The relationship between current and tripping time is usually shown as a
curve, known as the MCB's trip characteristic. The most important curves are B, C and
D.
Type B MCBs react quickly to overloads, and are set to trip when the current
passing through them is between 3 and 5 times the normal full load current. They are
suitable for protecting incandescent lighting and socket-outlet circuits in domestic
and commercial environments (resistive loads), where there is little risk of surges
that could cause the MCB to trip.
Type C MCBs react more slowly, and are recommended for applications
involving inductive loads with high inrush currents, such as fluorescent lighting
installations. Type C MCBs are set to trip at between 5 and 10 times the normal full
load current. This type is generally used.
Type D MCBs are slower still, and are set to trip at between 10 and 20
times the normal full load current. They are recommended only for circuits with
very high inrush currents, such as those feeding transformers and welding machines.
K curves can also be used for motors and transformers but have improved
thermal characteristics at 1.05 to 1.2 times the rated current. The Z curves provide
protection to semiconductors, with instantaneous trip values at two to three times the
rated current.
13
2.4.3 ELCB and RCD
The Fault current overloads and short circuits can be detected by circuit breakers like
MCB’s MCCB’s and etc. But, Circuit breakers don’t detect leakage currents, which are
dangerous for humans and livestock and if not detected can lead to fire hazards. This is the
solution that detects such leakages currents and disconnects the circuits from the power
supply, RCD (Residual Current Device) also known as ELCB (Earth Leakage Circuit
Breaker) which provides protection against direct and indirect contact of personnel or
livestock and against probable fires.
However there were two types of ELCB. Current operated and voltage operated.
Current operated one worked the same as RCD's do. Voltage operated ones comprised of a
coil connected between the customers’ main earth terminal and an earth spike. If the voltage
on the customer’s earth system rose above about 50v with respect to the spike, the coil
tripped the ELCB.
The RCD or RCCB (Residual Current Circuit Breaker) also like a ELCB, but is a
very advanced and sensitive than ELCB. RCDs are extremely sensitive, disconnecting within
10 to 50 milliseconds of detecting a leakage current. This is usually 30 milliamps for
domestic residences but it is can be higher than it according to the equipment connects in to
system. This stops the flow of electricity through someone’s body to earth. Importantly, this
response time is much faster than the critical section of the cardiac cycle and therefore
significantly reduces the risk of death or serious injury. RCDs are available up to 300 amps.
There are double pole and four pole RCDs.
Figure 2.8 – ELCB Figure 2.9 – 2-Pole and 4-Pole RCCB
14
The incoming supply going through the toroid coil and due to the current flow there
is a flux induces if the electricity supply is balanced induced flux is zero. If the vectors sum
of the flux in the core due to the any leakage there is a flux induced and the trip coil induce
the current and trip the breaker.
Figure 2.10 – Wiring Diagram of the RCCB
2.4.4 MCCB
Normally MCCB are used for circuit protection in enclosures, switch boards,
lighting and power distribution boards as well as motor control centers. The Molded
Case Circuit Breaker is designed to protect systems against over current and short
circuit. Rather than the Miniature circuit breaker MCCB’s have high breaking capacities.
Also MCCB are suitable for application as main breakers and for protection of branch
and feeder circuits and connected equipment’s. MCCB are available in dual pole, three
poles and four poles.
Figure 2.11 – MCCB
15
The MCCBs are available in various types of tripping mechanisms.
1. Thermal magnetic type mechanism
2. Electromagnetic type mechanism
3. Hydraulic magnetic type mechanism
Thermal Magnetic Type
These types of Molded Case Circuit Breakers are working on base of bimetal and
electro-magnetic trigger. When you have overload current running through MCCB the
trigger is using bimetal’s nature and start to bend till circuit breaking. Normally the bimetal
trigger is calibrated at 40°C and for lower or higher temperatures of ambient we can expert
longer or shorter delay of breaking. At short circuit we have a big electromagnetic field,
which is cause for reaction of electromagnetic trigger.
Also there are two major types of molded case Circuit Breakers called as fixed type
and the adjustable Type. Rated current of a fixed type MCCB cannot be adjusted. But the
rated current of an adjustable type MCCB can be adjusted.
It is very important to select and apply the right MCCB for a long lasting and trouble
free operation in the power system. The right selection requires a detailed understanding of
the complete system and other influencing factors. The factors for selecting a MCCB are as
follows.
1. Nominal current rating of the MCCB (Ir)
2. Fault current (Icu/Ics)
3. Other accessories required
4. Number of poles
16
2.4.5 ACB
ACB (air circuit breaker) is an electric protecting apparatus which is installed
between an electric source and load units in order to protect a load unit and a load line from
an abnormal current generated on an electric circuit and to perform distribution function
for changing the electric power line to another line. The electr ical s ys t em s in
residential, commercial and industrial applications usually include a panel board for
receiving electrical power from a utility source. The power is then routed through over
current protection devices to designated branch circuits supplying one or more loads.
Electrical power distribution systems and their components need protection from
numerous types of malfunctions, including over current conditions, overvoltage conditions,
under voltage conditions, reverse current flow, and unbalanced phase voltages. If a
MCCB is used instead of an ACB it is essential to connect protection relays to protect
load from above malfunctions. Generally ACB is available from 1200A to 6400A for low
voltage applications
Figure 2.12 - ACB
Air circuit breakers include operating mechanisms that are mainly exposed to
the environment. Since the air circuit breakers are rated to carry several thousand amperes
of current continuously, the exposure to convection cooling air assists in keeping the
operating components within reasonable temperature limits. A typical air circuit
breaker comprises a component for connecting an electrical power source to electrical
power consumer or load. The component is referred to as a main contact assembly. A main
contact is typically either opened, interrupting a path for power to travel from the source
17
to the load, or closed, providing a path for power to travel from the source to the load. In
many air circuit breakers, the force necessary to open or close the main contact assembly
is provided by an arrangement of compression springs.
In many air circuit breakers, the mechanism for controlling the compression springs
comprises a configuration of mechanical linkages between a latching shaft and an
actuation device. The actuation device may be manually or electrically operated. In a
common construction of a low voltage air circuit breaker, the movable contact is
mounted on a contact arm that is pivoted to open the contacts by a spring powered
operating mechanism triggered by a trip unit responsive to an over current condition in
the protected circuit. Various accessory devices are used with such air circuit breakers
to provide auxiliary function along with over current protection. One such accessory is the
bell alarm accessory that provides local and remote indication as to the occurrence of
circuit interruption.
2.2.6 TECHNICAL DATA OF CIRCUIT BREAKERS
It is vitally important to know the parameters of a circuit breaker that are
essential when we selecting a proper circuit breaker. All the technical data of a circuit
breaker is printed in the face plate and it is vitally important to know the meanings of
them. Also studding the characteristic deeply the catalogue of the circuit breaker
should be referred. There also use these technical data.
Figure 2.13 – Face Plate of a MCCB
18
1. Rated Current (In) -: The current which the circuit breaker will carry
continuously under specified conditions and on which the time/current characteristics
are based. Unless otherwise stated in is based on a reference ambient temperature of 30
degrees centigrade.
2. Rated Operational Voltage (Ue) -: The nominal line to line voltage of
the system should not exceed Ue.
3. Rated insulation Voltage (Ui) -: .The highest operating voltage that will
not cause a dielectric strength failure. The rated insulation voltage is used as a
parameter for dielectric strength tes ts . The rated insulation voltage must
always be higher than the rated operating voltage (Ue).
4. Rated Impulse W i t h s t a n d V o l t a g e ( Uimp) -: The v o l t a g e
o n w h i c h clearance distances are based. The value of transient peak voltage the
circuit breaker can withstand from switching surges or lighting strikes imposed on the
supply .e.g. Uimp = 8kV, Tested at 8kV peak with 1.2/50µs impulse wave.
5. Ultimate Breaking Capacity (Icu) -: The maximum fault current which
can flow through without damaging the equipment. The calculated prospective fault
current at the incoming terminals of the circuit breaker should not exceed Icu.
6. Service Breaking Capacity (Ics)-: The max imum level o f faul t
current operation after which further service is assured without loss of performance.
7. Let Through Energy (I2t) -: A measure of energy required to blow the fuse
element and so a measure of the damaging effect of over current on protected devices;
sometimes known as the let-through energy. Unique I2t parameters are provided by charts
in manufacturer data sheets for each fuse family. The energy is mainly dependent on
current and time for fuses. When a fault is occurred, fault energy will flow through the
protective device. That energy is known as the let through energy. So a good quality
protective device must have a lesser value of let through energy
8. Utilization Category -:
Every MCCB has a utilization category, “Cat. A” or “Cat. B”.
Cat. A -: Category A designates circuit breakers not specifically intended for
selectivity with devices on the load side. In other words circuit breakers will
discriminate only up to certain fault levels, above which discrimination with devices
on the load side cannot be guaranteed.
Cat. B -: Category B designates circuit breakers specifically intended for
selectivity with devices on the load side. Such circuit breakers will incorporate some
19
form of time delay.
2.2.7 TRIPPING ACCESSORIES
Unlike RCDs (Residual Current Devices) MCCB has a tripping method, which
can operates fully mechanically. Even though power is not supplied to the breaker, if it is
in on position it can be tripped using the trip button. But RCD cannot be tripped when the
power isn’t supplied as its tripping method works from residual current (through an
electrical signal mechanical system is energized). There is also a method to do the tripping
function of a MCCB by using electrical signals (current). For this we have to use the
tripping accessories, shunt coil & UVT coil which is normally mounted in the right hand
seat of the case of the MCCB. Protection relays are connected to these coils.
Shunt Coil -: When a current passes through the shunt coil it passes tripping signal
to the MCCB. In the normal operation no current must be gone through shunt coil. If
power flow continuously through a shunt coil, it will burn. So current to the shunt coil is
supplies from outgoing of the breaker.
Figure 2.14 – Shunt Coil
UVT coil -: When current doesn’t pass through the UVT coil it passes tripping
signal to the MCCB. So to switch on a breaker with UVT coil, the coil must be provided
a voltage. So it must be connected to the incoming of the breaker.
20
Figure 2.15 – UVT Coil
2.5 Cables and Wiring
In electrical systems, cables are used for carrying electrical currents. Most times core of these
cables are made of copper or Aluminum to conduct current with minimum voltage drop.
Most cables have a protective insulation to protect the cable and also to protect living beings
from dangerous voltages.
Choosing a proper and an adequate wire or cable for any purpose is of very much importance.
And if we are choosing it for the electrical purpose then it is of utmost value to give proper
care and attention. Different electrical appliances require different current and voltage
requirements to operate. So for different devices the cable used should also be different.
Selecting the proper cable is of so much importance because it is connected with the security
of our house or other buildings.
Basic cable types are as follows:
21
Based on Shape
Coaxial cable
Multicore cable
Ribbon cable
Shielded cable
Single cable
Twisted pair
Twisting cable
Based on Construction
Mineral-insulated copper-clad cable
Twin ax cable
Flexible cables
Special
Arresting cable
Bowden cable
Helix cable
Direct-buried cable
Heavy-lift cable
Elevator cable
22
2.5.1 Structure of Cable
Figure 2.16: Several types of Cables
23
2.5.2 Selection of Cables
In selecting a wire or cable for primary and secondary power circuits certain requirements
should be kept in mind. They are:
Type of Installation
Voltage Rating
Ampacity Requirements
Heating Conditions
Special Conditions
2.5.3 Type of installation
The method we are going to follow to install a cable is a determining factor for the selection
of cable. We may use the cable in underground applications, outdoor applications, or indoor
applications. In each of these applications the requirement of cables are different. We must
give attention towards some particular points.
2.5.4 Voltage requirement
The voltage determination for the electrical device is necessary because it guide you in
buying the proper cable. The type and thickness of insulation is determined by the voltage
factor. It also helps in determining the minimum size of conductor that is suitable for small
loads. Besides that it is also important to know that whether grounded or ungrounded neutral
is used.
2.5.5 Ampacity requirements
Determining the final conductor size require the ampacity of KVA loading. The power
factor, current load, and KVA load should be known prior to finalize the size of conductor.
Sometimes the cable size is determined by voltage drop rather than only by heating. In any
uncertain situations the size is determined separately by voltage drop and by heating, and
then the bigger size must be chosen.
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2.5.6 Heating conditions
Heating conditions include the external thermal conditions which are responsible for
determining the temperature increment of a cable. The external factors affect the lasting and
proper functioning of cables. Some important factors which affect the selection of cables:
Ambient Temperature
Presence of Artificial Cooling
Number of Cables in a Duct Bank
Proximity to other Cables
Thermal Conductivity of Soil or other Surrounding Medium
Depth of Buried Cable
Nature of Surrounding Atmosphere
2.5.7 Special conditions
Except all the conditions and situations we discussed here, there may be some other special
conditions which might affect the performance of a cable. You must also consider those
points to ensure the better life of the cables.
Some of the common conditions are:
Presence of boilers, steam pipes or other big source of heat
Effect of magnetic material like pipes
Presence of corrosive substance in the surrounding
Interference occurring in telephone cables due to adjacent power cables
2.5.8 Current rating for wires
Current ratings for wires differ from manufacturer to manufacturer, though they are
almost similar. Below shows the approximated current ratings for given wire sizes under
standard condition
25
Table 2.1: Wire sizes for Current ratings
According to these current ratings appropriate earth cables have to be selected. According to
IEC regulations, selection of protective earth cable is as follows.
Table 1.2: Selecting appropriate cable according to the phase wire
Wire size (sq. mm) Current Rating (A)
1 12
1.5 16
2.5 19
4 24
6 32
10 40
16 60
25 100
35 125
50 160
70 200
70 225
95 250
120 300
150 350
185 400
Cross-sectional area of phase
Minimum cross-sectional area of
the
conductors S (sq. mm) corresponding protective conductor
(PE, PEN) Sq.mm
S ≤ 16 S
16 < S ≤ 35 16
35 <S ≤400 S/2
400 <S ≤ 800 200
800 < S S/4
26
Note that the values in table are valid only if the protective conductor is made of the same
metal as the phase conductors.
2.6 Electrical conduit
An electrical conduit is an electrical piping system used for protection and routing of
electrical wiring. Electrical conduit may be made of metal, plastic, fiber, or fired clay.
Flexible conduit is available for special purposes. Conduit is generally installed by
electricians at the site of installation of electrical equipment. Its use, form, and
installation details are often specified by wiring regulations, such as the US National E
electrical Code (NEC) or other national or local code. The term "conduit" is commonly used
by electricians to describe any system that contains electrical conductors, but the term
has a more restrictive definition when used in wiring regulations.
2.6.1 Types of conduit
Conduit systems are classified by the wall thickness, mechanical stiffness, and material
used to make the tubing. Materials may be chosen for mechanical protection, corrosion
resistance and overall economy of the installation (labor and material cost). Wiring
regulations for electrical equipment in hazardous areas may require particular types of
conduit to be used so as to provide an approved installation.
Rigid Non Metallic Conduit (PVC)
PVC is made from a combination of both plastic and vinyl. PVC pipes can be installed above
ground, underground or encased in cement. PVCs are most commonly used underground.
These pipes are light weight, flexible, impact resistant, non-conductive, ultraviolet resistant
and corrosion resistant. They are popular because they have watertight joints and low
installation costs. They are not interchangeable with other EC’s.
27
Figure 2.17: PVC Conduits.
Rigid Metal Conduit (RMC) / Rigid Steel Conduit (RSC)
RVCs and RSCs are your heaviest and thickest option, typically made of coated steel,
stainless steel, red brass or aluminum. These pipes can be installed above ground or
underground. They are similar in appearance to metal water pipes and are threaded at both
ends. The threads on the uncoupled end of the pipes are covered by industry color-coded
thread protectors, which protect the threads, keeping them clean and sharp. Although
RMCs and RSDs are generally corrosive resistant, a layer of PVC or zinc (see GRC) can
be added in areas that are wet or highly corrosive. If you opt for an organic coating you
check for heat restrictions. These types are interchangeable with GRCs.
Intermediate Metal Conduit (IMC)
Intermediate Metal Conduit (IMC) is steel tubing heavier than EMT but lighter than RMC.
It may be threaded.
Galvanized Rigid Conduit (GRC)
GRCs are created by taking one of your above RMC, RSD, or IMC and galvanizing it via
hot dipping it in zinc. The zinc coating provides extra coating in areas that are wet, or
highly corrosive. GRCs are interchangeable with most RMC, RSD, and IMC to use when
only an area of your piping is in need of additional protection. PVC coating can be added
on top of GRC coating for ECs that will be exposed to chemicals and other highly abrasive
materials.
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Flexible Metal Conduit (FMC)
This is your option for areas that need to sustain large amounts of movement and
vibration. They are found with stainless steel, galvanized steel or aluminum. They are
available as water proof if needed and are installed above ground. The appearance is
similar to that of metallic armored cable. They are often used when wiring motors and are
not interchangeable with other ECs.
Flexible Nonmetallic Conduit
Flexible Nonmetallic Conduit (NFC) is another term for a number of flame resistant types
of non-metallic tubing. This type of tubing is recommended as a raceway for the
installation of approved conductors with a nominal rating of 600 Volts or less for non-
hazardous locations. The interiors of this conduit may be corrugated or smooth.
Figure 2.18: Flexible nonmetallic conduit
2.7 Distribution Board
Distribution board is an important device, which placed in electrical duct and it is the
standard way to distribute the power to the particular circuits of a level. It also can be
operated by the client. Therefore it should be very safe and with user friendly operations.
Generally distribution board consists of MCCBs, RCCBs and MCBs. These components are
varied with the used power, either 3phase or single phase.
Tap-off box is given 63A TPN power for the Distribution board. It is divided in to single
phases through 3 separate panels. Each panel is supplied 32A current to the MCBs. Then
MCBs distribute the current which is needed each circuits. Normally there is a one of
distribution board placed in a duct of each level.
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Figure 2.19: Main Distribution Board
2.8Electricity providing to the Building
For project of residence of Mr. Rohana there were four main electrical supply lines. One
single phase supply and three number of three phase supplies. The electricity provider was
Ceylon Electricity Board.
Figure 2.20: Meter Board of the Building
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2.8.1 Feeder Pillar
A feeder pillar or power box is a cabinet for electrical equipment, mounted in the street and
controlling the electrical supply to a number of houses in a neighborhood. A power box is
simply a layman's term for a transformer, cutout enclosure, or other enclosure used in
conjunction with underground electrical distribution. In the United States, they are often
painted olive drab (an olive-like green color), gray or "sand", a light tan color.
Figure 2.21: Feeder Pillar
In Sri Lanka mostly feeder pillars are used to underground power distribution. Next to the
transformer there is a feeder pillar and the ground is dig from feeder pillar to necessary
location.
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2.9 Lighting System Wiring
In this building, for the lighting wiring there are used 1.5mm2 PVC/PVC/Cu cables.(Kelani
Cables) Typically each level has around 65-70 lighting circuits. And each circuit consists of
4-8 light points. So there is used 3phases and it divided to these all circuits. All light points
are wired with Live, Neutral and Earth wires. Earth wire is connected to the casing of the
fluorescent lamp.
Type : Cu/PVC/PVC
Nominal cross
Section area : 1.5mm2
No of conductors : 7
Standard : SLS 733, IEC 60227, BS 6004
Nominal Voltage : 300/500V
Insulation : 70 ºC rated PVC compound
Sheathing : PVC compound
Conductor : Soft annealed solid or stranded
Copper wires
Type : Cu/PVC
Nominal cross
Section area : 1.5mm2
No of conductors : 7
Standard : SLS 733, IEC 60227, BS 6004
Nominal Voltage : 450/700V
Insulation : 70 ºC rated PVC compound
Conductor : Soft annealed solid or stranded copper
Wires
32
Figure 2.23: Cu/PVC/PVC Cable Figure 2.22: Cu/PVC Cable
Figure 2.24: A part of Lighting System Wiring Drawing
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Electricians are wired the circuit according to the drawings. As an example this diagram
shows some lighting circuits. L1.DB.RP-2/Y3 and L1.DB.RP-2/R3 represent the circuit
name. It is consisted of,
L1- Level no 1
DB- Distribution Board
RP- Reliable power
2- No of DB
Y3- Y phase, Circuit of 3
The arrow also shows the direction of DB. If we consider L1.DB.RP-2/Y3 circuit, there
are 2sub circuits. (f2, g2) It means these 4 lamps are controlled by 2 switches.
First there are 3 wires (L, N&E) laid from the DB, the Live wire goes to the switch. Then
other 2 wires go to the light point. For this circuit two return wires laid from the switch
to f2 and g2 lamps. N & E wires are looped for all 4 light points. In this drawing, between
the f2 and g2 there is a hachure, it is shown these f2 and g2 are not connected together
with live wire.
2.10 Power System Wiring
In this building, for the power wiring there are used 2.5mm2 PVC/PVC/Cu cables.(Kelani
Cables) Typically each level has around 50-60 power circuits. And each circuit consists of
2-4 power points. So there is used 3phases and it divided to these all circuits. All power
points are wired with Live, Neutral and Earth wires.
34
Electricians are wired according to the power drawings as the wiring procedure that I
mentioned above. In here 2 DBs supply the power for the circuits: UPS (Uninterruptable
Power Supply) and RPS (Reliable Power Supply).
2.11 Wiring Methods
Circuit conductors should be grouped together. All conductors of a circuit must
be installed in the same conduit, trench, or cable tray etc..
Power conductors of different systems can occupy the same conduit, cable tray
or enclosure if all conductors have an insulation voltage rating not less than the
maximum circuit voltage.
Control, signal, and communications wiring must be separated from power and
lighting circuits so the higher-voltage conductors do not accidentally energize
them.
The circuits should be wired as ring or radial method.
Figure 2.25: A part of Power System Wiring Drawing
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2.11.1 Ring and Radial circuits
According to the IEC regulations, the lighting and power circuits of industry, can be wired
in radial or ring form. Because of advantages of these methods electrical engineers use them
to the field. In this building project all the lighting and power circuits have wired in form of
radial type.
Radial Circuit
Radial circuits are common way to feed the power for light points and socket outlets in
industry or domestic wiring. This is a simple method; use single cable set (containing live,
neutral and earth wires) starts from the DB, and connects to each light point or socket outlet
in turn for one circuit. Each light point or socket outlet is supplied with power by the previous
one and end with last one of the circuit. So the end of each circuit can be identified very
easily, as it will only have one cable set connected to it, not continues to ahead.
Figure 2.26: Radial Lighting Wiring Circuit
Figure 2.27: Radial Power Wiring Circuit
36
These figures are shown how the lighting and power circuits are wired in form of radial
method. It is used loops to continue the circuit to ahead. The loop should be two loop if
not engineers not approved them. Therefore electrician must care about it. Two loop
means one light point or socket outlet should have one input (supply power) and one
output (supply power to next point) not distribute the power, from one point to several
points like a tree.
If there is a fault in circuit, any faults on radial circuits are easy to locate. But there is a
break or damage anywhere along the cables; all of the socket outlets after the break will
no longer work.
This project use 20A MCB protection with 2.5mm2 cables for power circuits can be fed
an area not more than 50m2 also the maximum length of cable is 33m.
For lighting circuits, use 10A MCB protection with 1.5mm2 cables can be fed an area not
more than 40m2 and 30m is the maximum length of the cable.
Generally in larger buildings there is used radial circuits which are cheaper than ring
circuit method. Also additional circuits can be added to a radial circuit.
Ring Circuit
Ring circuit is another method that use for electrical wiring. It is also called as ring final
or ring main. The ring circuits are acted like a combination of two radial circuits,
proceeding in opposite directions around a ring.
The ring starts at the DB and supplies each light point or power socket outlet in turn, and
then returns back to the DB again. The ring is fed from a MCB in the Distribution Board.
Figure 2.28: Ring Lighting Wiring Circuit
37
These figures are shown how the lighting and power circuits are wired in form of ring
method. It is also used loops to continue the circuit to ahead, and end at the same started
point.
This design enables the use of smaller-diameter wire than would be used in a radial
circuit of equivalent total current. The load is evenly split across the two directions, since
the current in each direction is half of the total that allowing the use of wire with half the
current-carrying capacity. In practice, the load does not always split evenly, so thicker
wire is used in industry.
Ring circuits are commonly used in wiring for 13 A socket outlets. They are generally
wired with 2.5 mm2 cable and protected by a 32A MCB,
The IET Wiring Regulations (BS 7671) permit an unlimited number of socket outlets to
be installed on a ring circuit, provided that the floor area served does not exceed 100m2.
In practice, most small and medium houses have one ring circuit per store.
Figure 2.29: Ring Power Wiring Circuit
38
2.12 lightning protection systems
Figure 2.30: simple lightning protection system
Lightning storms are a natural occurrence that usually has very devastating outcomes. They
can cause great damage to property and lead to electrical overflows in buildings. Therefore,
it is important to protect your property from them. This will not only protect your electronic
devices and buildings but also save you money that you would spend on repairs and
replacements. There are many types of devices that are used for lightning protection Dayton
residents can use.
Lightning protection methods are normally used to prevent structures and vegetation from
the negative effects of lightning. They do this by redirecting the electrical charges from storm
clouds to the ground. This ensures that buildings and the inhabitants are safe regardless of
the conditions outside.
There are different devices that are used to arrest these bolts of charge. Some of them are
fixed to the ground while others are designed to sit on roof tops, where they can effectively
39
capture the charges from the storm clouds. The metallic rods were among the first devices
to be used in averting lightning bolts. They are common and can be seen in many buildings
that are in areas that experience storms frequently. They operate on a simple mechanism and
are easy to set up.
When tall metal rods are placed close to buildings and vegetation, they act as the highest
point. They provide the shortest passage through which charges from the atmosphere can
pass through as they head to the ground. Therefore, instead of bolts striking buildings and
vegetation, they strike the rods. They can either be fixed in the ground or placed on roof tops.
They are effective, though have one downfall. Though they conduct charges to the ground,
they do not offer protection against power surges.
Bonding and down conductors are another type of arrestors. Generally, down conductors are
configurations that are placed about 10 feet below the ground and are connected to a route
system that is located out of the building. Just like the metallic rods, they conduct the charge
into the ground away from the structures.
They are normally not painted. This is because painting affects their efficiency. Their design
also allows them to bend. This is a very important feature that enables them to prevent
flashover effects which can have a negative effect on the surrounding. Bonding is usually
used in metallic buildings and structures. It protects them from the effects of atmospheric
charges. Some of the structures that it can be used on include water pipes and signal lines.
Grounding is another method that is also used in the same effect. It uses a master bus bar
that connects the internal and external segments of the system. This greatly minimizes the
surges that are brought about by electrical currents. Simply put, it is a system that attracts
electrical energy away from buildings.
Transients and surges are very important in all the systems that have been mentioned here.
They give extra protection to the electrical systems. This is why many systems of lightning
protection Dayton residents use, have them installed.
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2.12.1 Lightning Rods
A lightning rod or is a metal rod or metallic object mounted on top of a building or structure
and bonded electrically using a wire or electrical conductor(copper tape) to interface with
ground /earth through an electrode.
The main function of the electrical installation protection system is to limit over voltage to
acceptable voltage value for the electric or electronic equipment. The electrical installation
system mainly focuses on the lightning effects. The basic principal for protection from the
lightning strikes is to prevent the over loading energy from reaching sensitive devices.
Therefore lightning rods are invented to protect the electric and electronic devices. They
should be capable to capture the lightning current and channel it to earth via a direct path,
and perform equipotential bonding of the installation. Mainly there are two types of lightning
rods according to the condition of the usage.
Franklin lightning rod
Early Streamer Emission lightning rod
2.12.2 Franklin Lighting Rod
This rod is normally used to protect small structures or zones such as communication
towers, water tanks (tower type), pylons, and aerial masts etc… this method also known
as catching end system. It is made up of 4 simple metal ends, landing conductor and ear
thing section used to protect tower type place from lightning. Metal ends are used to
attract lightning strikes by producing a local enhancement of the electric field strength in
air. It is able to protect an area determine with a fixed protection angle and radius. The
angle is selected according to the level of protection that is required to be calculated for
the installation. And the protection radius of this type of lightning conductor is limited
to around 30 meters. Area is varied according to the angle and to the height of the
catching end off from the ground.
41
2.12.2 ESE Lightning Rod
Early Streamer Emission lightning protection system is a relatively new approach in
solving the continuous problem of lightning strikes damages. Based on theoretically and
the some previous researches, the ESE is believed as the some effective against lightning
than the Franklin rod method. The new system is equipped with a special device that is
used to extend the effective range of protection over the Franklin rod.
Inside of the device there is a capacitor to charge and discharge the air when the lightning
strikes are happened. Before a strike, the clouds are charge with positively or negatively.
When this cloud is blown inside of the covering area of the lightning rod, area is charged
with opposite that cloud charged. Before the strike is happened ionized clouds are discharged
around 60% by the process of the rod. Therefore with helping rest of 40% charges, the
lightning strike is happened. The absorbed electrons from the top point of the rod next go
through the earth by conductors.
Figure 2.32: ESE Lightning Rod
Figure 2.31: Franklin Lightning Rod
42
2.12.3. The Different Types of Lightning Protection Systems
The simple lightning rod
Figure 2.33- The simple lightning rod
The lightning rod is a metallic capture tip placed at the top of the building. It is earthed by
one or more conductors (often copper strips)
The lightning rod with taut wires
Figure 2.34: The lightning rod with taut wires
These wires are stretched above the structure to be protected. They are used to protect special
structures: rocket launching areas, military applications and protection of high-voltage
overhead lines
43
The lightning conductor with meshed cage (Faraday cage)
Figure 2.35: The lightning conductor with meshed cage (Faraday cage)
This protection involves placing numerous down conductors/tapes symmetrically all around
the building. This type of lightning protection system is used for highly exposed buildings
housing very sensitive installations such as computer rooms.
The preferred method of protecting explosives operations from lightning flashes, as well as
from other external sources of electromagnetic radiation, is to enclose the operations or
facility inside a Faraday cage. A Faraday cage is an enclosure composed of a continuous grid
of conductors, such that the voltage between any two points inside the enclosure is zero,
when immersed in an electrostatic field. A Faraday cage or Faraday-like shield LPS is one
where the protected volume is enclosed by a heavy metal screen (i.e., similar to a birdcage)
or continuous metallic structure with all metallic penetrations bonded. The lightning current
flows on the exterior of the structure not through the interior. A Faraday-like shield (which
is not an ideal Faraday cage) is formed by a continuous conductive matrix that is properly
bonded and grounded.
44
2.13 Earthing System
The earthing material that is electrically conductive and a fault current will Flow to 'earth'
through the live conductor, provided. This is to prevent a potentially live conductor from
rising above the safe level. All exposed Metal parts of an electrical installation or
electrical appliance must be earthed.
2.13.1Types of Earthing
Supply & Installation of all type of earthling like maintenance free
Tripod jell earthling,
Plate earthling,
Pipe earthling,
Led Strip earthling for rocky areas
2.13.2 The main objectives of the earthling
Provide an alternative path for the fault current to flow so that it will not
endanger the user.
Ensure that all exposed conductive parts do not reach a dangerous Potential.
Maintain the voltage at any part of an electrical system at a known value, So as
to prevent over current or excessive voltage on the appliances or Equipment.
2.13.3 The qualities of a good earthling system
• Must be of low electrical resistance
• Must be of good corrosion resistance
• Must be able to dissipate high fault current repeatedly
45
2.15.4 IEC terminology of earth systems
International s t a n d a r d IEC 60364 distinguishes t h r e e f a m i l i e s o f e a r t h i n g
arrangements, using the two-letter codes TN, TT, and IT.
The first letter indicates the connection between earth and the power-supply equipment
(generator or transformer):
T - Direct connection of a point with earth (Latin: terra);
I - No point is connected with earth (isolation), except perhaps via high impedance.
The second letter indicates the connection between earth and the electrical device being
supplied:
T - Direct connection of a point with earth
N - Direct connection to neutral at the origin of installation, which is connected to the earth
According to this terminology there are different kinds of earth systems available in
the industry.
TN networks
TN-C System
TN-S System
T-N-C-S System
TT network
IT network
2.13.5 Earth Rod Installation
In the earthing system of the building there lot of elements used to achieve a good earthing
system.
Rods
Coupling
Driving Stud
Driving Spike
Soil Conditioning Agent
Inspection Pit
Earth Bar
Earth rod claps
46
Figure 2.36: Earth Rod Installation
2.13.6 Use of Soil Conditioning Agent
There are basically two type of soil conditioning materials available,
• Bentonite - Moisture Retaining Clay
• Bentonite is used as a backfill to reduce soil resistivity.
• When mixed with water it swells to several times its dry volume.
• The moisture content can be retained for a considerable time
• Further moisture can be absorbed during rainfall, etc.
• Marconite - Granulated Conductive Medium
• Marconite is a granulated conductive medium designed to replace the conventional
aggregated in concrete and thereby provide a medium with good electrical conductivity
and high strength
• It can provide a permanent solution to problems in electrical /contractual situations.
47
2.14 Degrees of Protection
Degrees of protection provided by enclosures for electrical equipment against solid foreign
objects, against water and against access to hazardous parts.
48
Figure 2.37: Protection degree
49
2.15 DATA & Telephone System
2.15.1 CAT6 Cable
There is a Data & telephone system in the building. So the building has a server room
for control data usage and voice receiving and transferring. Within my training period
only cable trays are fixing on the soffit for 2 levels, and not even start the cable pulling.
For the data cabling, the designed cable is CAT6.
Category 6 cable contains four twisted wire pairs, which uses 24 AWG wire. The increase
in performance with Cat 6 comes mainly from increased (22 AWG) wire size. Category
6 cables can be identified by the printing on the side of the cable sheath.
Cat 6 patch cables are normally terminated in 8P8C modular connectors (RJ45). If Cat 6
rated patch cables, jacks, and connectors are not used with Cat 6 wiring, overall
performance is degraded to that of the cable or connector.
Like earlier twisted-pair cable, CAT6 cable contains four unshielded twisted pairs (UTP)
of copper wires. It also has a separator helps in keeping equal spacing between pairs. The
heavier wire in some Cat 6 cables makes them too thick to attach to standard 8P8C
connectors without a special modular piece, resulting in a technically out-of-compliance
assembly. Because the conductor sizes are generally the same, Cat 6 jacks may also be
used with Cat 5e cable.
Cat 6 patch cables are normally terminated in 8P8C modular connectors. If Cat 6 rated
patch cables, jacks, and connectors are not used with Cat 6 wiring, overall performance
is degraded to that of the cable or connector
Figure 2.38: CAT6 Cable Figure 2.39: RJ45 8P8C Modular
Connector
50
Table 2.3: The Specification of CAT6 Cable
2.15.2 Data Rack
Data rack is a container which is contains of all networking and telephone devices in a
building. For example patch panel, switch, router, PABX and etc.
Figure 2.40: Data Rack
Conductor: Stranded Bare Copper (7 x 32 AWG)
Insulation:
HDPE (CMI-75E)Nominal Wall Thickness:
0.178mm
Min. Thickness: 0.153mm
Color Code:
Pair 1: Blue & White/Blue
Pair 2: Orange & White/Orange
Pair 3: Green & White/Green
Pair 4: Brown & White/Brown
Jacket (Grey):
75°C LSZH Compound Nominal Wall
Thickness: 0.585mm
Min. Thickness: 0.458mm
Overall Diameter: 5.8mm ± 0.3mm
Electric Requirements:
(Cable length: 100m)Characteristic Impedance
(Zo): 85~115Ω (1~250 MHz)
DC. Resistance Capacitance Unbalance: 5%
Pair-to-Ground Capacitance Unbalance: 330
pF/100m Max.
Conductor Resistance: 14.00Ω/100m 20o Max.
Mutual Capacitance: 5.6nF/m Max.
Spark Test: 2.5kV
Nominal Velocity of Propagation (NVP): 69%
51
2.15.3 Patch Panel
A panel of network ports contained together, usually within a telecommunications closet,
that connects incoming and outgoing lines of a LAN or other communication, electronic or
electrical system. In a LAN, the patch panel connects the network's computers to each other
and to the outside lines that enable the LAN to connect to the Internet or another WAN.
Connections are made with patch cords. The patch panel allows circuits to be arranged and
rearranged by plugging and unplugging the patch cords.
Figure 2.41: Patch Panel
2.15.4 Switch
A network switch (sometimes known as a switching hub) is a computer networking device
that is used to connect devices together on a computer network by performing a form of
packet switching. A switch is considered more advanced than a hub because a switch will
only send a message to the device that needs or requests it, rather than broadcasting the same
message out of each of its ports.
A switch is a multi-port network bridge that processes and forwards data at the data link
layer (layer 2) of the OSI model. Some switches have additional features, including the
ability to route packets. These switches are commonly known as layer-3 or multilayer
switches. Switches exist for various types of networks including Fiber Channel,
Asynchronous Transfer Mode, InfiniBand, Ethernet and others.
52
Figure 2.42: Switch
2.15.5 Router
A router is a device that forwards data packets between computer networks. This creates an
overlay internetwork, as a router is connected to two or more data lines from different
networks. When a data packet comes in one of the lines, the router reads the address
information in the packet to determine its ultimate destination. Then, using information in
its routing table or routing policy, it directs the packet to the next network on its journey.
Routers perform the "traffic directing" functions on the Internet. A data packet is typically
forwarded from one router to another through the networks that constitute the internetwork
until it reaches its destination node.
The most familiar type of routers are home and small office routers that simply pass data,
such as web pages, email, IM, and videos between the home computers and the Internet. An
example of a router would be the owner's cable or DSL router, which connects to the Internet
through an ISP. More sophisticated routers, such as enterprise routers, connect large business
or ISP networks up to the powerful core routers that forward data at high speed along the
optical fiber lines of the Internet backbone. Though routers are typically dedicated hardware
devices, use of software-based routers has grown increasingly common.
Figure 2.43: Router
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2.15.6 PABX
A PABX or private automatic branch exchange is an automatic telephone switching system
within a private enterprise. Originally, such systems - called private branch exchanges (PBX)
-required the use of a live operator. Since almost all private branch exchanges today are
automatic, the abbreviation "PBX" usually implies a "PABX."
Some manufacturers of PABX (PBX) systems distinguish their products from others by
creating new kinds of private branch exchanges. “Rolm” offers a Computerized Branch
Exchange (CABX) and “Usha” Informatics offers an Electronic Private Automatic Branch
Exchange (EPABX).
Figure 2.44: PABX
2.16 CCTV Security System
The CCTV security system is used to record videos of special places which need
security. When consider a CCTV system, there is three main components.
CCTV camera
DVR (Digital Video Recorder)
Display
There is a procedure to apply this CCTV system to a building or a relevant place. That
procedure is shown in below.
Planning - Decide the camera, DVR, display positions
Installing camera - Wiring and fixing cameras
Installing DVR – Fixing wires, DVR, display and power supply
Adjust viewing angle and focusing
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2.16.1 CCTV Camera
Figure 2.45: CCTV camera
CCTV (Closed-Circuit Television) cameras are available in different types such as digital,
analog, night vision and with several image qualities. When consider analog camera, it
produces analog signals. Therefore, it should connect to PC through graphic card. Otherwise
a DVR is required to do that purpose. But digital camera produces digital signals. So it can
be connected to PC directly.
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2.16.2 DVR
Figure 2.46: Several types of DVRs
DVR (Digital Video Recorder) records the data which send cameras. There is a memory
devise like computer hard disk to record videos. As well as, there is video output to display.
Otherwise wireless connections are also available to get the output like mobile phones.
DVRs are available with 4 channels, 8 channels and 16 channels like wise, due to quantity
of cameras can be connected.
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2.16.3 Display
Figure 2.47: Displays
A monitor or mobile phone can be used as the display according to requirement.
2.16.4 Cables
Figure 2.48: Cables for cameras
Normally coaxial cables are suitable as signal cable of camera. Because coax cables
carrying signals without distortion. But cat 5 cables also used in industry. There is four pairs
of wires in cat 5 cable. So other three pairs of wires are used as back up wires.
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2.17 Fire Detection and Fire Protection System
Fire Detection and Fire Protection System is very important for building, because safety is
the main thing. There are two systems which relevant to this system to detect fire and to
protect the building from fire.
Fire Detection System
Fire Protection System
2.17.1 Fire Detection
Fire Detection System is used to detect a fire and send that message to panel board. Then
fire alarm will be ring and exit lights will be blink. There are several types of devices to
detect fire.
2.17.1.1 Smoke and Heat Detectors
Figure 2.49: Heat Detectors
The heat detectors detect high temperatures and smoke detectors detect smoke and send that
message to panel board. Normally smoke detector can detect smoke within circle with 7.5m
radius. Engineers must decide detector positions as cover the all areas.
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2.17.1.2 Sprinklers
Figure 2.50: Sprinkler
This devise do the both detection and protection. The red bulb will explore if it is heated,
and sprinkle the water around it. The water supply line is pressured always. When bulb is
explored and water come out and then the pressure decrease. Then panel board detect it and
automatically pumps will be started and supply the water continuously.
2.17.1.3 Manual Call Point
Figure 2.51: Manual Call Point
If someone see the fire before detect by detectors, that person must push this button called
as manual call point. Then the bell will be ring. This is work as normal switch button.
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2.17.2 Fire Protection
Figure 2.52: Fire Protection System
After detect a fire somewhere the pumps are ready to start. Then someone should get the
hose real from cabinet. After that pumps will start and supply the water continuously. There
may be one or two pumps according to requirement. If there are two pumps, the panel is
designed by using contactors to work alternatively if need low amount of water or both
together if need more water. The water supply line should be made of GI pipes because,
always there is high pressure.
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CHAPTER THREE
03. MANAGEMENT DETAILS
3.1 Site Management
When consider site organization, site manager is the uppermost person at the site. He has to
manage everything and every field at site. Then site engineer and M&E engineer is there.
The site engineer is the responsible person in civil engineering and the M&E engineer has
to co-ordinate and manages all the electrical, mechanical and plumbing works. Then
assistant engineers have to assist them.
There is quantity surveyor to get amounts about finished works, balance works, cost and
payments for workers. As well he is the person who deals with BOQ and variations. The
draught person handles the drawing and makes the combine drawings. Then technical
officers and supervisors handle workers.
The safety officer is the responsible person about safety and he has to manage safety and
riggers. The store keeper is the responsible person about machines, equipment and materials.
The admin officer is the responsible person about needs of officers and workers as well about
attendance.
3.2 Working Procedure
There is a meeting for every two weeks. All the responsible people like Client, Consultant,
Architect, Engineers and subcontractors attend this meeting and discuss about progress and
plan the future works and targets. Then make a procedure and try to achieve that target.
3.3 Safety
In any organization safety of the workers or personals is the 1st thing which concerns in
operation. And the safety of the equipment is concerns as the second. So operations in any
industry is done while keeping personals and equipment safely.
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3.3.1 Ear Plugs and Mufflers
Ear Plugs and Mufflers are other main safety item because of the Sounds louder than 90dB,
over a period of time, can damage your hearing. Normal conversation registers in the range
of 45-60dB. Sound level in engine hall is greater than 100dB. When properly fitted, earplugs
and Mufflers can significantly reduce loud noises and prevent hearing damage.
Figure 3.1: Ear Plugs and Mufflers
3.3.2 Safety Gloves
The safety gloves should be worn when working in industry. It prevents fingers and palm
from injuries. The types of gloves are varying with the industrial application. For an
example, Welding gloves should be worn during welding, gas cutting processes and when
handling hot items.
Figure 3.2: Safety Gloves
3.3.3 Goggles, Helmets and Safety Shoes
Figure 3.3: Goggles, Helmets and Safety Shoes
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The person who enters the site must wear these safety equipment. The safety officer is
available at site to check it.
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CHAPTER FOUR
04. SUMMARY AND CONCLUSIONS
4.1 Summery
I gained the experience about M&E Engineering within training period. How to co-ordinate
Mechanical, Electrical and plumbing works. How to work as M&E engineer and
responsibility of M&E engineer. What are the problems encounters at the site normally when
we work, how to solve that problems. Sometimes we cannot do things which in drawings
practically, at that time we have to do big changes. Then we must redraw the changes and
submit to consultant to get approval.
I got the experience how to use the theories in practice which we learned. As well as I got
knowledge about M&E works. How to install the electrical equipment, How to put the
protections, What are the requirement of those things, Network system installing, CCTV
security system installing procedure and technical knowledge about it and technical
knowledge about fire detection and fire protection, as well as plumbing works
4.2 Conclusions
I’ve got a good opportunity to have my first compulsory session of industrial training in
Access Energy Solutions (pvt.) Ltd is one of the child company of Access Engineering,
which is the best construction company in Sri Lanka.
During this valuable period I was able to take so much of hand on experiences installation
and troubleshooting of M&E works.
Here I should mention that I was able to get a special opportunity to work together with
technicians as well as engineers and share their knowledge and experiences. Those things
gave me a good training as an engineering undergraduate. As well as The Access Energy
Solutions (pvt.) Ltd staffs are very friendly and guided me a lot in the training. So, it helps
me to gain a better experience and work made my training valuable and successful.
Although I am an Engineering student, I hadn’t clear idea about hoe to works with labors,
Engineers and other parties. But after having 12 weeks training at Access Energy Solutions
(pvt.) Ltd, I came to know that how to work with them. Also as an Engineering student I got
clear idea about how work as Engineer and how to handle administrative part of the company
as an Engineer. Because both technical and administrative operations at Access Energy
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Solutions (pvt.) Ltd are carried out by the Engineers. So I had the chance to meet talented
and experience Engineers and get valuable advice from them at my undergraduate training
session.
During the training period I had to face some problems due to the lack of practical
knowledge. So I had to learn them by myself and I had a huge support from M&E Engineer
and other people in the every section at the Access Energy Solutions (pvt.) Ltd.
According to my point of view I would like to mention that having an industrial experience
as an undergraduate training is so essential for an Engineering undergraduate student. It is
because; an Engineer should have somewhat industrial knowledge before going to industrial
field.
However finally I would like to mention that in simple words Access Energy Solutions (pvt.)
Ltd which is capable of providing very good experience for engineering undergraduates, is
an excellent place for industrial placement. Therefore my training experience at Access
Energy Solutions (pvt.) Ltd helps me to be such an Engineer who will be beneficial to the
country.
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References
Approved Drawings of the Project
http://www.accesspower.lk
http://www.access.lk/
Electrical Specification book of the Project
BOQ
Catalogues of Some Equipment
http://en.wikipedia.org
h t t p : / / w w w . e l e c t r i c a l 4 u . c o m / i n d e x . p h p
http://www.electrical-knowhow.com/2014/01/types-of-lightning-protection-
systems.html?m=1
www.kelanicables.com/
Surge Protection Overvoltage Devices pdf
www.schneider-electric.com/
http://www.electrolesk.com/Work/Wiring%20of%20Three%20%20Phase%20Distr
ibution%20Board.htm
IEEE Wiring Regulations