Electrical Workshop Practice 2

ELECTRICAL WORKSHOP PRACTICE OBJECTIVE: To providing skill in the use of electrical tools and to improve the skill of students by making the house wiring small circuits and to develop the level of practical work.

DEFINITION OF WORKSHOP: “It is a place where we design, manufacture,

process the item or components according to scientific equipments.”

TYPES OF ELECTRICAL WORKSHOP 1) Electrical engineering workshop 2) Telecommunication workshop 3) Electronics workshop 4) Computer engineering workshop 5) Mobile phone workshop 6) Robotics engineering workshop ELECTRICAL WORKSHOP TOOLS

1) Screw drivers (Flat and Phillips Types) 2) Cutter 3) Pliers Flat Nose 4) Pliers Long Nose 5) Wire Gauge 6) Knife

7) Phase Tester 8) Crimping Tools 9) Drill Machine 10) Feeler Gauge 11) Hand Vice and Bench Vice

ELECTRICAL ACCESSOERIES 1) Switch Single Way

2) Switch Two Way 3) Electrical Sockets (Two pins) 4) Electrical Sockets (Three pins) 5) Power plugs (Two pins) 6) Power plugs (Three pins) 7) Bell push button 8) Bed Switch 9) Ceiling Rose 10) Circuit Breaker 11) Fuse Cell Type 12) Main Electric Switch 13) Electric Wire in Different Size (3/0.029” To 3/0.036’’ etc) 14) Insulation Tape 15) Breaker Holder Switch

16) Bulb Holder (pins/screw in types) ELECTRIC CIRCUIT SYMBOLS 1) Electric Bulb

2) Ac Supply

3) D.C Supply

4) Switch

5) Push Buttons

6) Electric Fan

7) Watt Meter

8) Meter/Machine

9) Volt Meter

10) Ampere Meter

11) Two pin socket (5amp)

12) Three pin sockets (5amp)

13) Rewire able Fuse

14) Electronic Fuse

15) Tube Rod

16) Starter 17) AC Voltage Source

18) Battery

19) Transformer

20) Galvanometer

21) Current Source

22) Ohm Meter

23) Wire by Pass

24) Energy Meter

25) Main Switch

26) Fan Regulator

27) Bracket Fan

28) Exhaust Fan

29) Pull Switch

30) Electric Bell

31) Buzzer

32) Thermostat

33) Chaises Ground

34) Ground/Earth

35) Circuit Breaker 36) Siren

37) Common Ground ELECTRICAL SAFETY

PRECAUTIONS

1) Avoid contact with live circuit.

2) Deal with tools carefully. 3) Always handle electrical equipments with proper care. 4) Always use rubber shoes while working on high voltage main line. 5) Always disconnect the power source before working on any electrical equipment. 6) Always try to use along single wire otherwise, If we use small wire in pieces it would be danger and Also short circuit could take place. 7) Green wire is ground always, red live wire and Black neutral wire. 8) All electrical made connections b/w two wires Should be covered with insulation tape, naked Wires connections are very dangerous. 9) All connections should be checked carefully before

Power on. 10) We should not on earth directly without wearing Leather or rubber shoes. 11) Always first aid kit must be present and it should be fully equipped in case of injured. 12) Always checked power cable to be sure. It is not naked (tap/cut wire), loose or damages. 13) Do not use loose jeweler or rings when working on electrical equipments because these things are good conductors and accidents cause take place. 14) Do not keep open liquids near electrical equipments. 15) Do not touch any electrical equipment unless you know it, is safe to do. 16) Do not involve in soldering the component without proper training.

17) Do not operate any electrical equipments if you have not been trained, please get help from your teacher or instructor. 18) Only use dry hands while making alive circuit. TO Study Standard Wire Guage & Measure the Size of Wire

with SWG

STANDARD WIRE GAUGE It is used to check the size of wire. It consists of steel disc type structure, having spots and holes in it just like gear. The size of wire is checked by simply inserting wire strands into the slots and measures the size of wire. • TYPES OF WIRE GAUGE • British wire gauge • American wire gauge • BRITISH STANDARD WIRE GAUGE

This type of wire gauge is generally used in Europe and also in Pakistan to measure size of wire, its measurement in inches and mm. It is generally abbreviated a “SWG”.It is also known as imperial wire gauge. It is made by HAWK Company in BARTAIN. • Example: A22WG 3/0.029’’ (Wire size) Where 22 is gauge number, 3 is total strands (no. of conductors) of wire and 0.029’’ is the diameter of wire. • AMERICANS STANDARD WIRE GAUGE It is also used to check the size of wire. It is somewhat different from British wire gauge. It is measure the size of wire in “MILS”.Where 1Mils=1/1000’’ It is made by general tool company in USA.

It mostly used to measure the aluminum size of wire. • DIFFERENT SIZE OF WIRE AND THEIR CURRENT CARRYING CAPACITY

SIZE OF WIRE 3/0.029” 3/0.036” 3/0.044” 7/0.029” 7/0.036” 7/0.044” 7/0.064’’ 7/0.052’’ 19/0.0036”

19/0.044’’ 19/0.064’’ 14/0.0076’’ 23/0.0076’’

CURRENT CARRYING CAPACITY 5amp-13amp 7amp-16amp 10.5amp only 8.5amp-21amp 13amp/28amp 21amp-34amp 33amp-56amp 43amp only 29amps only

47 amps only 105 amps only 03 amps 06 amps

• AC CURRENT STRENGTH READING OF CURRENT

Safe current values

VALUES 1 mA or less 1 mA to 8 mA

8 mA to 15 mA

Unsafe current values

EFFECTS No effect on human being body not felt. Sensation of shock, not painful.

Painful shock, but muscular control not lost.

When it passes through 20 mA to 50 mA chest, may stop breathing. 50 to 100 mA

Fibrillation: It most serious cause of death and there is no cure of it, it damages the heart into

small pieces & causing the stop of breathing.

200mA or above Severe burns, muscular contraction, fibrillation.

• HOW TO JOINTS OF PAIR OF WIRES ARE MADE 1) Remove the insulation of wires at about 10cm. 2) Remove the braid for about 2.5 cm if applicable. 3) Clean each of stands gently with sand paper. 4) Separate the strands of each wire by twisting the strands conductors in opposite directions. 5) Retwists the strands. 6) Bind the twisted wire with a binding wire if applicable. 7) Cut of middle strands with the help of pliers. 8) Spread the strands individual. 9) Bring the two wire and to end with all strands intersecting.

10) Hold one of the wires in left hand and wrap one of strand of the other wire around the twisted conductors in opposite direction. 11) Round off the ends with pliers. 12) The joint is the soldered if required. 13) When joint is made apply insulation on joints.

TYPES OF JOINTS 1) Britannia Joint: In this type of joint one extra wires is required to faster the two joints. 2) MARRIED WIRE: Intersecting of strands of two wires joint is known as married wire. It is mostly used to joint two wires having more than one conductor. 3) Simple Twist Joint: If two wire are simply twisted to each other known as simple twist joint.

• Tee Joint: It is required where it is necessary to tap the electrical energy from a running line and making T-shaped.

Termination of wires When it is required to terminate a wire to a screw the insulation from the wire is removal the conductor is bent in from of loop. It should be remembered that the loop of the wire must be made in the same direction in which the terminal screw is to be turned for tightening while making a termination of insulation of the wire, it is a wrong method to keep it away such a termination causes short circuit and also excess wire should

be cut off and the wire end is tucked inward to avoid exposing bare part of the conductor.

ELECTRIC EARTHING • INTRODUCTION: The meaning of term earthing or grounding is connecting to the electrical equipment to the gernal mass (6x1024 kg) of earth wire of negligible resistance. This brings the body of the electrical equipment to zero potential and thus will avoid the shock to the operator.

Q: Why earthing/grounding is required?

If insulation of wires of electrical equipment may defective and the phase wires (mains) may touch the metal frame of the electrical equipment, then in case of faulty circuit current will change the actual path in which it is flowing. So some of the current will also flow through the metal frame of the electrical equipment, it is known as leakage current and if the operator or any person will touch the electrical equipment, he will absorb an electrical shock in his body. In some cases death to the person may also take place due to severe electrical shock. But if electrical equipment will be earthed to ground mass of earth the current through metal frame will flow to earth ground and there will be no electrical shock to any person, because resistance of earth is less with comparable to human body. Current will always flow where resistance will be very low.

Diagram

PARTS OF EARTHING • Earthing led • Earth plate (copper) • Earth electrode (copper) • Earth continuity conductor • Lighting conductor • G.Pipe (galvanized pipe) • Copper plate (2’*2’*1/8’’) Silent features of grounding or earthing Must be… • The earth wire as a earthing or bonding connection must be of sufficient crossection

to carry the faculty current under worst condition. • The resistance of the grounding or earthing must be very low. • The earth wire must be strong enough so that it cannot be broken at any point. • The connection of the earthing wire must be perfect at both sides. • All earthing or boring connection should be protected against corrosion. Q: How earthing is necessary? Whenever there is a breakdown of insulation over the wires it is always accompanied by generation of heat and increase of temperature near about the fault persists which further increase the temperature of surrounding and if the temperature reaches ignition point, the

insulation starts burning and fire break out. Hence, to avoid the fires hazard earthing or bonding is a necessary.

CIRCUIT DIAGRAM 1.BASIC HOUSE HOLD CIRCUIT:

EXPERIMENT#1 • SERIES CIRCUIT: OBJECTIVE: •To show that a series circuit has only one path for current flow. • To show that the total resistance connected in series is the sum of individual resistance.

APPARATUS/TOOLS REQURIED: • Multimeter(DMM) • Phase tester • Wooden circuit • Plier long nose • Cutter • Insulation tape • Wires • Power supply (220v) • Bulbs/Bulb holders • Knife • Electric plug Two pins • Switch • Crinping tool

• BASIC INFORMATION: The fundamental idea of series circuit is that there is only one path for current flow. If other resistor or load is removed or if the wire are disconnected then no current will flow. This is the charactertics of a series circuit when any load is removed the circuit is open and no current is flow. Mathematically: The mathematical formula of series is: R1+R2+R3+……. FOR EXAMPLE:

IF R1=220A R2=330 OHM RT=220+330=550

In series circuit the current at each point throughout the circuit will remain to same but voltages will be divide.

PROCEDURE: •

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First of all issued the apparatus from lab store. After then put a circuit board and tight four bulb holders on it according to their place from circuit diagram. Then took a phase wire and remove undesirable insulation and then by using plier turns its conductors in a proper way. After then joined a terminal of this phase wire to bulb and other terminal with a switch.

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An ammeter is also attach b/w the load bulb and switch, such has one terminal is connected with neutral wire and other one with phase wire. After then check the circuit connection then put four bulbs in bulb holders with carefully. Then turn on the switch and note that either bulb is glow then check the circuit to the teacher and returned the apparatus to lab attendant.

• SAFETY PRECAUTIONS: •

Make all the live connections very carefully.

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Make sure all connections are not lose at any terminal points. Do not work with wet hand. Avoid from sparking connections making. Identify red wire for phase connection and black wire for neutral connection.

CIRCUIT DIAGRAM:

EXPERIMENT#2 • PARALLEL CIRCUIT

OBJECTIVE: • To show that parallel circuit may have many paths for current flow. • To show that in parallel circuit total resistance is less than the resistance of the smallest parallel resistance. APPARATUS/TOOLS REQURIED: Multimeter(DMM) Phase tester Wooden circuit Plier long nose Cutter Insulation tape Wires Power supply (220v) Bulbs/Bulb holders

Knife Electric plug two pins Switch Crinping tool

• BASIC INFORMATION In parallel circuit there is two or more path for current flow, show such a circuit, note that if any of the resistance is removed path for current flow still exist through remaining resistors.

MATHEMATICALLY:

The mathematically formula for parallel circuit is, 1/R1+1/R2+1/R3+……..

PROCEDURE: • First of all I issued the apparatus from the lab store. • Then I went on the working table and set the apparatus on table. • After then took a wooden board and set the bulb holders on it by joining the terminal of phase wire and neutral wire according to circuit diagram. • Then I took another wire which act as a neutral source and placed with ampere meter in parallel form with loads.

• Then I joined the connections of load and ammeter with switches according to circuit diagram. • After then again check all the joining terminals with very carefully and then switch on the power and note that in parallel form the current will alternate at each terminal. • Then returned the apparatus to lab in charge.

• SAFETY PRECAUTIONS 1. Make all the live connections very carefully. 2.Make sure all connections are not lose at any terminal points. 3.Do not work with wet hand. 4.Avoid from sparking connections making.

5.Identify red wire for phase connection and black wire for neutral connection.

EXPERIMENT#3 OBJECTIVE: To study the fan regulator circuit.

APPARATUS: • Multimeter (DMM) • Phase tester • Plier • Small fan • Fan regulator

• Wires as required • Insulation tape • Circuit board

• Switch button • Cutter • Screw drivers CIRCUIT DIAGRAM:

PROCEDURE:

• First of all I issued the apparatus from the lab store. • Then I went on the working table and set the apparatus on table. • After then took a wooden board and set the fan and fan regulator on a board according to circuit diagram. • Remove insulation as required from the phase and neutral wire. • Then join the phase wire with a fan and other end with regulator and neutral wire as well. • Then check all the joining terminals and then switch on the power. g.Now check the circuit to the teacher and returned the apparatus to lab in charge.

• SAFETY PRECAUTIONS: 1.Make all the live connections very carefully. 2.Make sure all connections are not lose at any terminal points. 3.Do not work with wet hand. 4.Avoid from sparking connections making. 5.Identify red wire for phase connection and black wire for neutral connection.

TYPES OF INSTALLATION OF WIRING SYSTEM

INTRODUCTION: The types of wiring to be adopted is dependent on various factors, each factor are explaining below. a. Durability: The type of wiring selected any premises should durable,i.e,it should be proper specification and as well as in accordance with the assessed life and type of building. Cleat wiring is suitable for temporary building will definitely be unsuitable for permanent factory building. Safety: While selecting the type of building one has to look into safety espect.In a factory

where a lot of fumes are produced the cleat or copping casing wiring will be unsuitable. Underground wiring is suitable in fumes factories. b. Appearance of a building: It must be taken into consideration that the wiring do not spoil the beauty of the premises. In a beautiful banlows,if one resort to cleat or copping casing type of wiring, the whole outlook of the building will deteriorate, which will create a bad impression on the capability of a designer or engineer? c.Cost: This is the most important factor. The executive or the designer has to see the funds

available with the clients for the such protat.Any there by arriving at the conclusion for type of wiring to be adopted and first have a meeting with clients. Advice to your client with his available resources.