Electrical Lighting

Electrical lighting 

Electrical lighting has following advantages, 

1. Cleanliness

2. Easy to control

3. Economical

4. Easy to handle

5. Steady output

6. Better reliability

7. Suitable for almost all purposes etc.

1 Introduction

Introduction 

As we know that almost all human activities

depends on light. Sun is a prime natural source

of light but artificial lighting plays almost main

role in our daily life. These artificial lights are

produced by mechanical lamps and electrical

lamps.

But due to poor performance the mechanical light

are totally replaced by electrical lights. The

electrical lighting are mainly used for

decorative purpose, advertising, traffic control ,

medical field and street lighting etc.

ILLUMINATION BASIC SCHEME

TOPICS

1 Introduction 

2 Nature of light

3 Terms used in illumination 

4 Law of illumination 

5 Electrical method of producing light

6 Source of light

7 Arc lamp

8 Filament lamp 

9 Gaseous discharge lamps

10 Sodium vapour lamp

11 Mercury Vapour lamp

12 Fluorescent tube

13 Neon lamp

14 Halogen lamp

15 Compact fluorescent lamp 

16 Candle Power and its measurement 

17 Lighting scheme

18 Street light

19 Flood lighting 

Conductor Size Calculations

1 Current carrying capabilty 

2 Voltage Drop 

3 Distance between the service pole to energy meter 

1 Current carrying capacity 

2 Voltage Drop

For single Phase Supply permissible voltage drop is equal to 

2% of Voltage + 1 Volt

For example: If a house is energized with single phase 230 volts supply then permissible voltage drop is equal to : 2% X 230 + 1 v

= 5.6 volts

For three Phase Supply permissible voltage drop is equal to 

5% of Voltage applied

For example: If a house is energized with three phase 430 volts supply then permissible voltage drop is equal to : 5% X 430 

= 21.5 volts

3 Relation between voltage drop of wire and permissible voltage drop

Voltage drop Should be less than Permissible voltage drop

Voltage drop     <        Permissible Voltage drop

Friends this topic is based all numarical so see this carefully and step by step 

Numaricals:

Problem 1 

A residential building is energized with single phase 230 volts 50 hz supply. The total current requirement by load is 13 amps. The distance between the service main to energy meter is 10 meters. Find out the size of aluminum wire lying between service mains to energy meter.

Ans

Supply voltage = 230 volts

Frequency = 50 hz

I = 13 Amps

Length = 20 meters ( both phase and neutral)

Permissible voltage drop = 2 X 230/100.     + 1 volt

          =    5.6 volts

For 2.5 square mm wire voltage drop @ 15 A    =   20/2.5

              @  1 A.    =   20/(2.5 X 15)

              @ 13 A.   =    (20 X 13) / (2.5 X 15)

              =      6.9 volts

For 4 square mm wire voltage drop @ 20 A    =   20/2.9

              @  1 A.    =   20/(2.9 X 20)

              @ 13 A.   =    (20 X 13) / (2.9 X 20)

              =      4.48 volts      

Problem 2

A residential building is energized with single phase 230 volts 50 hz supply. The total current requirement by load is 5 amps. The distance between the service main to energy meter is 20 meters. Find out the size of aluminum wire lying between service mains to energy meter. 

Types of circuits

Circuits

1 Open 

2 Closed 

3 Series 

4 Parallel 

Why Do we need of Bus bar

Need of bus bar 

Busbar distribute electricity with greater ease and flexibility than some other more permanent forms of installation and distribution. Sometimes spelled bus bar or bussbar, they are often metallic strips of copper, brass, or aluminum that both ground and conduct electricity.

Application of Bus bar

Uses of bus bar 

In electric power distribution, a busbar (alsobusbar) is a metallic strip or bar
, typically housed inside switchgear, panel boards, and busway enclosures for local high current power distribution.

Bus bar Definition

Bus bar

In electric power distribution, a busbar is a metallic strip or bar, typically housed inside switchgear, panel boards, and busway enclosures for local high current power distribution. They are also used to connect high voltage equipment at electrical switchyards, and low voltage equipment in battery banks.

Selection of Distribution Board

1 Size of board

2 Position of board

3 Types of Distribution board - DPIC ,TPIC

1  DPIC ( double pole iron clad) 

2  TPIC (triple pole iron clad) 

Protection

Fuse 

A fuse is a type of low resistance resistor that acts as a sacrificial device to provide overcurrent protection, of either the load or source circuit. Its essential component is a metal wire or strip that melts when too much current flows through it, interrupting the circuit that it connects. Short circuits, overloading, mismatched loads, or device failure are the prime reasons for excessive current. Fuses are an alternative to circuit breakers. 

HRC FUSE

(1) This type of fuse contains a fuse wire in it, which carries the short circuit current safely for a given time period. During this period, if fault is removed, then it does not blow off otherwise it will melt and remove the circuit from electrical supply hence, the circuit remains safe.

(2) The common material, which is used to make an HRC fuse is glass, but this is not always the case. Other chemical compounds are also used in HRC fuse manufacturing and construction based on different factors. Its external enclosure is made fully airtight in order to avoid the effect of atmosphere on the fuse materials. The major objection on HRC fuse is low and uncertain breaking capacity of semi-enclosed fuse.

Wiring Accessories

Switch 

1 A switch is used to make or break an electrical circuit. It is used to switch ‘on’ or ‘off’ the supply of electricity to an appliance.  There are various switches such as 

2 surface switch

3 flush switch

4 ceiling switch 

5 pull switch

6 push button switch 

7 bed switch 

Classification of MCB

MCB classification 

By color                                         By Pole

1 Black MCB used in -  DC circuits  - Single pole

2 Blue  MCB used in -  Light circuits - Double Pole

3 Brown MCB used in - Power circuit - Triple  Pole

4 Red  MCB used in -  As isolator - Triple Pole neutral 

By Speed                   Used in 

1 Type  B - 3 to 5 times -  Generator 

2 Type C - 5 to 10 times- Residential 

3 Type D - 10 to 15 times - Motors 

Meaning of Rating in MCB 

1 B10

2 C25

3 D2

Select the MCB 

Select the MCB if current rating is 20A.

B20

C20

C25

B25

D20

MCB TYPES

Types of MCB

1 According to speed

2 According to Function 

3 According to color

Types of switches and protection MCB classification

Classification of MCBs

First a fall what is MCB 

Let see

Definition of MCB

(1)  Low‐voltage (less than 1,000 VAC) types are common in domestic, commercial and industrial application, and include: 

(2) MCB (Miniature Circuit Breaker) — rated current not more than 100 A. Trip characteristics normally not adjustable. Thermal or thermal‐magnetic operation. Breakers illustrated above are in this category. 

(3) MCCB (Molded Case Circuit Breaker)—rated current up to 2,500 A. Thermal or thermal‐ magnetic operation. Trip current may be adjustable in larger ratings. 

Components used  in  MCB

The design includes the following components: 

(1) Actuator lever ‐ used to manually trip and reset the circuit breaker. Also indicates the status of the circuit breaker (On or Off/tripped.

(2) Actuator mechanism ‐ forces the contacts together or apart. 

(3) Contacts ‐ Allow current when touching and break the current when moved apart. 

(4) Terminals 

(5) Bimetallic strip. 

(6) Calibration screw ‐ allows the manufacturer to precisely adjust the trip current of the device after assembly. 

(7) Solenoid 

(8) Arc divider/extinguisher 

 

Electrical Accessories & MCB or Wiring material

Termination ;

A wire termination means that end of the wire that allows to connect to the device socket ,connecter, terminals etc. Eg  like take the two wire and then end of wire to end in socket or any terminals it is called wire termination. 

Splicing or jointing 

Splicing is the process of combining 2 lengths of wires so they can carry a current. Before you splice your wires together, you need to prepare the wires by stripping them and turning off the power.

Switch :

There are mainly 3 types of switches:

1 One way switch 

2  two way switch 

3 intermediate switch 

1 one way switch : It is used  to control  single circuit and lamp. 

Eg on and off Normal switch 

2 Two way switch : It is used to divert the flow of current to either of two directions. The two switch can also be used to control one lamp from two different places as in case of staircase wiring. 

Eg :staircase wiring  two switch control one lamp 

3 Intermediate switch : It is used to control a lamp more than two locations. 

Electrical Accessories 

1 Termination 

2 splicing or jointing 

3 switch 

4 Holder

5 Junction box 

6 MCB

7 RCCB

8 Fuse

9 Lamp

10 Push Button 

Load Calculations

Load calculations 

Light load;  bulb, fan, 5A socket  these are  light load 

Power Load;  15A socket, Heater,AC ,gyser,  exhaust fan these are power load 

These 2 condition always friends you learn to do numarical  

Condition for circuits; 

Light load : 800w & 10 points

Power load : 3000w & 2 point 

First a fall we take a eg of 1 numarical  easily  understand friends 

Eg  Numarical 

1 The House has following Load :-

ROOM 1 :-  FAN              :-    1                                  Tube Light  :-   2

5A socket    :-    3 

     AC   1.5 ton :-    1

       Kitchen;               Tube Light   :-    2                                                    5A socket   :-   2 

                                                                          

                

ROOM 2 :-  FAN              :-    1         

               Tube Light   :-    2        

  AC   1 ton    :-    1

           Bathroom :-   Tube Light  :-  1 

                                                              Gyser (  15A socket ) :- 1

                     5A socket    :-    1

                   

Note :- ( Fan = 80 W , Tube light = 40 W , 1 ton AC = 1500 W , Gyser = 2200 W, 5A socket = 750 W )

Do step by step Numerical and write down all conditions for each type of load

Find out the Total Circuits in the house and Total no. of Mcb’s and Size of DB Box.Also find out size of wire

First a fall calculate total load of Room 1 and Room 2 

Room 1 

1 Fan  * 80 w =80

2 tubelight * 40w=80

3 5 A socket* 750w=2250

1 AC  1.5 ton*2250=2250

Total.                     4660w

Room 2 

1 Fan * 80

2 tube light  *40

1 5 A socket* 750

1 AC 1 ton* 1500

Total.         2310w

Kitchen 

2 tubelight * 40 

2 5 A socket * 750

   Total.          1500 w

Bathroom 

1 tube light * 40

1 15A socket * 2200

Total.             2240w

Calculate light load 

Light circuits;  7 

Power circuit;  3

There are 10 way to connect MCB in house

Size of Distribution Board is 10 way 

Same as MCB  size of DB

Total No. Of circuits : 10

Total No. Of MCB;  10

total No. Of Distribution board;  10- way 

I hope you understand step by step 

Conduit wiring

Conduit wiring 

Conduit wiring system is the best for domestic and commercial installation. 

It provides proper protection to the installation against fire hazards, shock, mechanical damage and dampness. 

The cabe used in this system is either V. I. R. OR P. V. C. Insulated and is run in mild steel or pvc pipes called as conduit wiring. 

Advantages 

1 Conduit provides prtection against mechanical injury and fire. 

2 The whole system is water proof.

3 Conductors are safely secure from moisture.

4 Conduit provide protection against chemicals. 

Disadvantages 

1 It is costly system of wiring. 

2 It requires more times for erection. 

3 It requires highly skilled labour. 

Application 

1 In workshop for lightning and motor winding.

2 Place where important documents are kept such as record room. 

3 Damp situation. 

Metal Sheathed Wiring

Metal sheated wiring 

This type of wiring is also adopted for low voltage installation. 

This system is more of less similar to CTS wiring except that the cable used is different in this wiring. 

In this system conductors used are insulated with V. I. R and the coverd with an outer sheath of lead aluminum alloy containing 95%  lead and 5% aluminum. 

Advantages 

1 Conductor are protected  against mechanical injury.

2 It has longer life. 

3 It is suitably employed under damp situation. 

4 Conductor are protected against chemical. 

Disadvantages 

1 Cables are costlier than CTS or TRS wires. 

2 In case of leakage there is eveey risk of shock.

3 Skilled labour and proper supervision is required. 

Application 

This wiring system is suitable for low voltage installation. 

It may be used in places exposed to sun and rain provided no joint is exposed. 

CTS or TRS wiring

CTS OR TRS WIRING 

This type of wiring is also used for house wiring and is quite cheap. 

Cab tyre sheathed wire or rubber sheathed wire is normally used as conductor for this wiring. 

The wires are run on the teak wooden battens which are fixed on the wall or the ceiling by means of screws and wooden pluge. 

Advantages 

1  It is easy to install and rewire. 

2 Its life is long

3 It is cheaper than the other types of wiring except cleat wiring. 

4 Conductor have strong insulation. 

Disadvantages 

1 The conductor are open and liable to mechanical injury therfore this type of wiring cannot be used workshop etc. 

2 Good workmanship is required to make a sound job in TRS wiring. 

Application 

1  This type of wiring is suitable for low voltage installation and is extensively used for lightning purpose. 

2 This type of  wiring is suitable where acids and alkalis are likely to be prescut. 

Wooden casing and caping wiring

Wooden casing capping wiring 

1 This is one of cheapest types of wiring and is commonly used for house wiring.

2 The cable used in this

    type of wiring is either 

    V.I.R or P.V.C or any

   other approved insulated   

   cables.

Advantages

1 Better appearance than cleat wiring. 

2 Cheap in cost.

3 Easy to install and rewire. 

Disadvantages 

1 Not suitable in damp places. 

2 Risk of fire 

3 This type of wiring can be used only on surface and cannot be concealed in plaster. 

4 Since it requires better workmanship labour cost is more. 

Application 

This type of wiring is suitable where acids and alkalis are likely to be prescut. 

Cleat wiring system

Cleat wiring 

1 Cleat wiring is normally used for temporary wiring purposes. 

2 As a permanent system of wiring it is not preferred in domestic premises.

3 It is quite suitable for taking a temporary connection such as for function marriages etc.

Advantages

1 It is the cheapest system of internal wiring. 

2 Its installation and dismantment is easy and quick. 

Disadvantages 

1 It is not good looking. 

2 It is quite temporary and perishes quickly. 

Application 

1 The wiring of this type is very  suitable for temporary installation in dry places. 

2 This is also accepted where appearance is not so important and cheapness is the main consideration. 

Wiring System and classification

Wiring system :

1 Cleat wiring system 

2 Wooden casing capping wiring system 

3 CTS or TRS wiring system 

4 Lead sheathed or metal sheated wiring system 

5 Conduit wiring system 

Wires & types of wire

Wire & types of wire 

Wire Material: 

1 Copper 

2 Aluminum 

Insulation of wire:

1   VIR: Vulcanised  Indian rubber 

2  TRS: Tough Rubber Sheath

3  PVC: poly vinyl chloride 

4  paper 

5  Enemel

6  Cotton

Size of wire:

0.75mm sq 

1 mm

1.5mm

2mm

2.5mm

4sqmm 

After 4 sq mm cable size start 

Core of wire : 

1 2 core

2 3 core

3 4 core 

Syllabus of IMEE

1  Wire & types of wires

2 Wiring system & Classsification

3 Load Calculations 

4 Wiring Material 

5 Types of switches & protection (MCB) 

6 Conductor size calculations 

7 Insulation Testing 

8 illumination

9 Earthing and types of earthing 

Principle of Homogeneity of dimensions

This principle states that

In a dimensionaly correct physical relation the dimension of each and every term on both sides of relation must be same.

 That is according to this principle;

1 We can add or subtract only those physical quantities which has same nature ( mean if they have same dimensions).

2 A physical relation must be dimensionaly homogeneous i.e. all the term on both sides of the relation must have the same dimensions. 

Dimensional Equation

An equation which indicates the relation between thr fundamental units of mass, length and time with their power and the derived units is called dimensional equation. 

UNITS AND DIMENSION

Physiscs;  physiscs is the branch of science which deal with the study of matter and energy 

PHYSICAL QUANTITIES 

All quantities in term of which law of physics can be expressed and which can be measured directly or indirectly are called physical quantities. 

Eg mass, length, time velocity etc. 

Physical quantities are two types;  

1 Fundamental quantities 

2 Derived quantities 

1 Fundamental quantities is that quantity which cannot be expressed in terms of any other physical quantity  eg mass, length, time etc. 

2 Derived quantities  All the physical quantities which can be expressed in terms of fundamental quantities are called derived quantities eg; 

 Area =length *Breadth = length *length 

Speed =distance /time = length /time 

System of Fundamental Units

The following system of fundamental units use here; 

1 CGS System(Centimeter gram second) 

2 FPS System (Foot pound second) 

3 MKS system (mass kilogram  second) 

4 SI System (System  International) 

MCQ 

1 Which out of the following is a fundamental quantity? 

1 velocity

2 Area

3 mass 

4 Force 

Ans 3rd 

2 which of the following is not fundamental quantity? 

 

1 angle of a plane 

2 temperature 

3 electric current 

4 electronic charge 

Ans 4th 

3 which of the following is not a derived quantity? 

1 force

2 surface tension 

3 speed

4 angle

Ans 4th 

4 which of the followingis not a system of units? 

1 MKS

2 SI

3 CGS

4 FCS

Ans 4th

5 which of the following distances is comparable with thr length of your index finger? 

1 10'-2

2 10cm 

3 0.05m

4 0.005m

Ans 3rd 

6 one nanaometer is equal to

1 10'9 cm 

2 10'-6cm

3 10'-7cm

4 10'-9cm

Ans 3rd 

7 one fermi equal

1 10'-6m

2 10'-8

3 10'-10m

4 10'-15m 

Ans 4th 

8 which of the following is not the unit of time? 

1 light year

2 leap year

3 microsecond 

4 lunar month

Ans 1st

9 which of the following represent value of 1 light year? 

1 1.5*10^11 m

2 3.1*10^16 m

3 9.5*10^15 m

4 10^10 m

Ans 3rd 

10 the suitable unit for measuring distance of sun earth is 

1 merer

2 light year

3 kilometer

4 nautical mile

Ans 2nd