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.

24

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.

28

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.

29

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.

31

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

33

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

35

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

53

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

54

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