EEC 129 Practical

8/12/2019 EEC 129 Practical

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1

UNESCO-NIGERIA TECHNICAL &

VOCATIONAL EDUCATION

REVITALISATION PROJECT-PHASE II

L

N

YEAR I- SEMESTER II

PRACTICAL

Version 1: December 2008

NATIONAL DIPLOMA IN

ELECTRICAL ENGINEERING TECHNOLOGY

ELECTRICAL BUILDING

INSTALLATION COURSE CODE: EEC 129


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TABLE OF CONTENTSWeek 1: REALISATION OF ONE WAY SWITCH CIRCUIT USING PVC CONDUIT-1

Week 2: REALIZATION OF two 2- WAY SWITCH CIRCUIT------------------------4

Week 3: R EALIZATION OF TWO GANG SWITCH CIRCUIT ------------------------8

Week 4: REALIZATION OF A LIGHTING CIRCUIT WITH INTERMEDIATE----9

Week 5: REALIZATION OF A RADIAL USING P.V.C TRUNKING-------------------12

Week 6: CONNECT A RING MAIN CIRCUIT----------------------------------------------16

Week 7: INSTALL A TIME DELAY CIRCUIT TO CONTROL THE LIGHT IN FOUR-20

Week 8: POLARITY TEST-----------------------------------------------------------------------23

Week 9: INSULATION TEST------------------------------------------------------------------26

Week 10: REALIZATION OF INSULATION RESISTANCE TEST------------------27

Week 11: REALIZATION OF POLARITY TEST-----------------------------------------31

Week 12: REALISE A BELL CIRCUIT USING STEP DOWN TRANSFORMER--33

Week 13: BELL INDICATOR CIRCUIT-----------------------------------------------------36

Week 14: DOOR LOCKING CIRCUIT-------------------------------------------------------40

Week 15: TESTING THE CIRCUIT-----------------------------------------------------------44


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Practical Work WEEK 1

Title :

REAL IZATION OF ONE WAY SWITCH CIRCUIT usi ng PVC co nd uit

Objective : To realize a circuit consisting of a one-way switch controlling two lamps in parallel

Introduction:The most commonly used switch in domestic installation is the one way switch. It is used indomestic premises to control either a fluorescent lamp or an incandescent lamp. This racticalwork familiari zes the student with the connection of the one way switch circuit and furtherimproves the student skill and ability to handle heavy gauge steel conduit.

Equi pment and tools:

- PVC conduits and their accessories).

- 2 end boxes ( 3/4 in .).

- 1 steel conduit box with knockouts ( 3/4 in .).

- 5 sockets and male bushes (3/4 in .).

- 5 spacer bar saddles (3/4 in .).

- A pipe vice and a hacksaw.

- Pipe reamer or half round file.

- Stock and die set. > - Cutting oil or tallow.

- A bending machine.

- An electrician tool box.


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L ayout Di agram

J.B

General scheme

Procedure:

Step 1:Draw the execution plan of the circuit.

Step 2:Layout the route of the conduits and the position of the boxes on the board.

Step 3: Cut the conduits to the lengths given by the layout diagram.

Step 4: Prepare and bend the conduit using bending spring.

Step 5:Secure the conduit ends to the boxes, use adapters where necessary.


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Step 6:Secure the conduits on the board by the saddles.

Step 7:

Draw the cables in the fittings and ensure the terminals at the boxes long enough forconnections.

Step 8:Strip the terminals and connect the circuit according to the layout.

Step 9: Test the circuit for correct wiring by an ohmmeter.

Step 10: Supply the circuit with power and ensure proper operation.


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Title :

REAL IZATION OF two 2- WAY SWITCH CIRCUIT

Objective :

To connect a 2 way switch circuit

Introduction:

Two 2 way switches are use whenever it is required to control a Lighting circuit from two

position. This is useful in controlling the lighting of halls, stair cases and any room with twodoors.fig.1.2 shows the circuit connection and the symbol representation of the switch.

Wiring connection

Loador

Line

Symbolrepresentation

Lineor

Load


- P V C conduits and their accessories,

Two 2 way swiches.

One way switch.

Ceiling rose.

Lamp and lamp holders

PVC cable 1.5mm.Hacksaw.

PVC con duit bending spring.

Electrcian tool box



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L ayout Di agram

J.B

L1

General scheme

L 2

C.R L3E E E

E E

E

Controls the Lamp 1

Controls the Lamp 1 & 2


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Procedure:

Step 1:

Draw the execution plan of the circuit.

Step 2: Layout the route of the conduits and the location of the boxes on the board.

Step 3: Cut the conduit according to the sizes given on the layout diagram.

Step 4: Make the required 90 bends as shown on the layout diagram. See Fig. (1.3 a, b), for

bending springs and methods of bending.

Step 5:

Secure the conduit ends to the boxes, use adopters where necessary.

Step 6: Secure the conduits to the board by saddles.

Step 7:

Draw the cable and ensure the termina; in the boxes and project enough for connection

Step 8:

Strip the terminals in the boxes and connect up the circuit in a layout diagram.

Step 9:

Test the circuit for correct wiring using an ohmmeter

Step 10:

Supply the circuit with power and ensure proper operation.


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Title :

REAL IZATION OF TWO GANG SWITCH CIRCUIT

Objective : To realize a circuit consisting of a one-way switch controlling two lamps in parallel

Introduction:The most commonly used switch in domestic installation is the one way switch. It is used indomestic premises to control either a fluorescent lamp or an incandescent lamp. This racticalwork familiari zes the student with the connection of the one way switch circuit and furtherimproves the student skill and ability to handle heavy gauge steel conduit.

Wiring connectionSymbolrepresentation

Line Load 1

Load 2


- Heavy gauge steel conduit ( 3/4 in .).

- 2 end boxes ( 3/4 in .).

- 1 steel conduit box with knockouts ( 3/4 in .).

- 5 sockets and male bushes (3/4 in .).

- 5 spacer bar saddles (3/4 in .).

- A pipe vice and a hacksaw.

- Pipe reamer or half round file.

- Stock and die set. > - Cutting oil or tallow.

- A bending machine.



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L ayout Di agram

J.B

General scheme

L 2

L3E E E

E E

J.B

L 1

Controls the Lamp 1



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Procedure:







Step 7:Draw the cables in the fittings and ensure the terminals at the boxes long enough forconnections.





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Title :

REAL IZATION OF A L IGHTING CIRCUIT WITH INTERMEDIATE

SWITCH USING P.V.C CONDUIT

Objective : To connect an intermediate switch correctly in a lighting circuit and to improve the

student skills in handling and using P.V.C conduit.

Introduction:

A lighting circuit can be controlled from any number of locations by the use of intermediateswitches together with two 2-way switches. Two controls locations will be provided by thetwo 2-way switches and the other locations will be provided by the number of intermediateswitches used in the circuit. See Fig.

Wiring connection

Loador

Line

Lineor

Load

2 Wayswitch

2 Wayswitch

Any number of intermediate switches asrequired N number of locations of control

Equipment and tools:

- 20 mm P.V.C conduits and their accessories.- One intermediate switch.- Two 2-way switches.- Two ceiling roses and two patten lamp holders.- Two lamp holders.- 1.5 mm 2 P.V.C cable (red, black and green/yellow).- Hacksaw.- Grip vice

- Fish tape. - Bending spring- Electrician tool box.


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L ayout Di agram

J.B

General scheme

E E E

EE

E

J.B

L 1


Controls the C.Rs

J.B

E

E

E

L2C.RC.R

&


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Procedure:







Step 7:Draw the cables in the fittings and ensure the terminals at the boxes long enough forconnections.




27


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Title : REAL IZA TION OF A RA DIAL USING P.V.C TRUNKING

Objective :

To connect a radial circuit and to consolidate the student ability in using P.V.C trunking

P.V.C conduit and connecting the intermediate switch correctly.

Introduction:Socket outlets are widely used in residential installation. They are connected either as aradial circuit or as a ring circuit. Both of these circuits utilize 13A socket outlets.

Two types of radial circuits , each with maximum number of six socket can be used.

1. Wired with 2.5 mm 2 cable / protected by 20A circuit breaker and serves one room ofmaximum areas 20 m2,

2. Wired with 4 mm 2 cable / protected by 30A circuit breaker and serves a maximumarea of 50m 2.

EL

N

Execution

30A


- P.V.C conduits (20 mm ) with their accessories.- P.V.C trunking (25x16 mm) -3 socket outlets (13A)

- Two-way switches- Intermediate switch.- 1.5 mm 2 P.V.C cables. Red / black , green/yellow.- 2.5 mm 2 P.V.C cables. Red , black / green/yellow.- 4 flash boxes (P.V.C) and one end box.- 3 surface boxes (P.V.C).- Hacksaw and grip vice.- Smooth file.- Bending spring.- Fish tape.- Electrician tool box.


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L ayout Di agram

J.B

General scheme

E E E

E

E

J.B J.B

E

EEE

E E E

E

Procedure:

Step 1: Draw the execution plan of the circuit.

Step 2: Mark the routes of the conduits and trunking/ as well as the locations of all boxes on the

board.

Step 3: Cut and prepare the trunkings/ then fix them on the board according to the layout diagram.

Step 4: Fix all boxes on the board / according to the positions and dimensions given to you.

Step 5: Cut / prepare and bend the condu its then secure them to the boxes and board.

Step 6: Install the 2.5 mm 2 cables in the trunking and draw the 1.5 mm 2 cables in the conduits asshown by the layout diagram.

Step 7:Strip the terminals and connect up the circuits.


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Step 8:Test the circuit for correct wiring / using an ohmmeter

Step 9:

Supply the circuit with power and ensure operation.

S a fety n o t g ;

The student must not connect the circuit to the supply without the permission of histeacher.


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REALIZATION OF A RING MAIN CIRCUIT USINGP.V.C TRUNKING WEEK6

Objective:

To connect a ring main circuit correctly and to consolidate the student skillin connecting the one way switch.

Int r od uction: Every residential installation contains at least one ring main circuit. The ring

circuit uses 13A socket outlets / wired with 2.5mm 2 cable and protected by a 30Acircuit breaker. The circuit can serve a maximum area of 100m 2 and themaximum number of sockets it can contain is 10 with 2 spur.

Fig. (1.7 ) indicates the way by which sockets are connected to form a ringcircuit.

Fig. (1.7) 3 socket outlets connected to form a ring circuit.

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Chapter One: Domestic Installations

30A

- c T\

N


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Layout diagram

qu

^

) ^ - C

Control

s theContr ols L2(\ Contr ols L-

' ' ^ A y<

.

^ ^ ^

i

nt

P.V.C conduits size 20 mm with their accessoriesP.V.C trunking (25 xl6 mm)3 13 A socket outlets1 one way switches

3 lamp holders

2 end boxes ( P.V.C) + 1 angle box + 1 through box.8 flush boxes- 2 two way switches


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- 1 intermediate switch- 1 two gang switch

- 1 ceiling rose 1 fluorescent lamp

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Procedure:

Step 1:

Draw the execution plan of the circuit.

Step 2: Mark the routes of the conduits and trunking/ then locate the positions

of all boxes.

Step 3:Fix all boxes on the board as indicated by the layout diagram

Step 4: Cut the trunking to the correct length then fix them on the board.

Step 5:Cut / bend and prepare the conduits , then secure them to the board, with

space bar saddles.

Step 6:

Install the cables in the trunking and draw them in the conduits usingfish tape.

Step 7:Strip / the terminal / in the boxes / and connect up the circuit as shown by the

layout diagram.

Step 8:Test the circuit by an ohmmeter for correct wiring.

1 elbow3 surface boxes

1.5 mm 2 cable 2.5

mm 2 cable Hacksaw

and grip vice Smooth

file Bending spring

Fish tape Electrician

tool box


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Step 9:Supply the circuit with power to ensure proper operation.

Safety Note: Never supply the circuit with power without the teachers permission.

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REALIZATION OF A STAIRCASE CIRCUIT USING

TIME DELAY SWICTH

WEEK

7

Objective: To install a time delay circ u it to control the light in four stair

building.

Introduction: This circuit can be accomplished by using two-way and two intermediate switches. In this case

the circuit is controlled manuall y and^

could remain ON all night when forgotten , which isn 't desirable. To overcome this problem atime delay switch is used. This switch consists of a coil and a mechanical system allowing thecontrol of a main contact. When the coil is energized the main contact closes / turning ON the

circuit. The circuit is turned OFF automatically after a determined time , the time necessary togo up the stairs / for example / Fig. (1.8 ) shows a simple circuit which indicates the connectionsof the time delay switch and the lamps.

Stair 1

Fig. (1.8) 34

Chapter One: Domest ic Instal la t ions

Pu s hbuttons


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TIME DELAY SWICTH

WEE

7

Layout diagram

/// 1

'4h 0

J.B

111

H i

^ 1 '// -; -;

- - J.B ti l ' 11 r-1/1 0

-5 S JR

^

'//

nr '4i-

0 -0 i-

- J.B ^f W- -

iJI

Time //// itc

i dela

Tools and Equipment:

- P.V.C trunking ( 25 x 16 mm).- T ime delay switch.- 8 flash boxes.

- 4 end boxes.- 1.5 mm 2 P.V.C Cable ( red / black / yellow/green).

- 4 push buttons.

- 4 lamp holders.- Hacksaw.

- Smooth file.


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TIME DELAY SWICTH

WEE

7

- Electrician tool box.

Procedure:

Step 1: Draw the execution diagram.

Step 2: Mark the route of the trunking and locations of boxes on the board.

Step 3:Fix all boxes on the board.

Step 4: Cut the trunking to the required length and fix them.

Step 5:

Install the cables in the trunking and boxes.

Step 6:Strip the terminals in the boxes and connect up the circuit

Step 7:Test the circuit for correct wiring by an ohmmeter.

Step 8:Supply the circuit with power and ensure proper operation.

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TITLE: REALIZATION OF POLARITY TEST

Objective: To connect a simple circuit and to perform the polarity test on it.

Introduction: This test is carried out to ensure that all protective devices and single polecontrols , (e.g one-way switches) are connected in the phase conductoronly. In addition the test confirms that socket outlets "\J' terminals areconnected to the phase conductor / "N" terminals are connected to theneutral conductor and the "E" terminals are connected to the earthcontinuity conductor (E.C.C) It also confirms that the centre contact of

Edison-type screw (E.S) lamp holders are connected to the phase side ofthe supply.

Tests are carried out with all switches dosed, lamps and equipment removed.

The test instrument can be a continuity tester , or a low- reading ohmmeter if no main supply is available. If the circuit is "live" a test lamp withapproved and fused leads and test probes can be used. Fig. (1.9 ) showshow polarity test is carried out on an " E.S" lamp holder.

Distribulkin -, r" b oar d ex- I"*consumerurni 1

N B SP s wi tch

r

h } ESlamphoteter ontinuity

stor

7Q \ i;i i i

)

C(t

e-

' ^-

Tenphab

?

' nporary ^

n . n s upply ^

? ^

Fig, (1.9) The test for correct p olar i ty on Ediso n sc rew lamp hold er.


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Circuit diagram

Equipment and Material:

- 20 mm P.V.C conduits and their accessories.- 2.5mm 2 P.V.C cable.- 13A socket outlets.- 3 flash boxes.- Hacksaw.- Smooth file.- Multimeter ( polarity tester).- Electrician tool box.


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Procedure:

Step 1: Connect up th e circui t on the board.

Step 2: Connect one lead of the tester to the line termined in the D.B/ and theother one to the " L" terminal of each socket.

y&^^ai'lfflKyHiaffllMEBffiSH'BHg!": 'aa'^HBtfHa'S^

Note: If a reading is obtained on the ohmmeter then the polarity of the phaseconductor is correct.

Step 3: Repeat step (2) for the neutral and earth conductors.

Procedure:

Step 1: Draw the execution diagram.

Step 2: Mark the route of the trunking and locations of boxes on the board.

Step 3:Fix all boxes on the board.

Step 4: Cut the trunking to the required length and fix them.

Step 5: Install the cables in the trunking and boxes.

Step 6:Strip the terminals in the boxes and connect up the circuit

Step 7:Test the circuit for correct wiring by an ohmmeter.

Step 8:

Supply the circuit with power and ensure proper operation.


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REALIZATION OF EARTHING TEST WEEK 9

Objective: To connect up a lighting circuit and to perform the earthing test on it.

Introd uction:

This test is required to find the resistance of the continuity conductors (ECC) in order to verifythat these conductors are correctly connected and electrically sound. This is important fromsafety point of view. It shows that when an earth leakage fault occurs , the resistance to the faultcurrent flowing through these conductors (ECC) is low enough to result in melting the fuse oropening the circuit breaker protecting the circuit. The readings obtained for the resistances ofthe (ECC) should not exceed 1 ohm. Fig. (1.10 ) shows how this test is carried out in socket

circuits.

Note that the resistance or impedance of the complete earth-fault path is not taken intoaccount by this test / and the test for this impedance is outside the scope of this book.


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REALION OF INSULATION RESISTANCE TEST WEEK 10

REALIZATION OF INSULATION RESISTANCE TEST

Objective: To perform insulation tests on a simple circuit.

Introduction: The purpose of the insulation-resistance (IR) test is to ensure that the quality of the

insulating materials used in the installation is good / particularly the insulation of the circuitconductors. Fig. (1.12).

a - Insulation test between conductors ( L and N) b - Insulation test between conductorsand earth ( " L / N" and E)

The instrument used for making this test is the megger. The testing voltage should betwice the working voltage of the installation in order to stress the insulation to check if it has

been damaged or deteriorated. The minimum acceptable value of insulation resistance is 1M -n- / but this value will not always remain the same. It depends on many factors like / the number ofoutlets (i.e switches, lighting fittings / socket outlets / etc) , the moisture and dirt being present onthe wiring / fittings and accessories.

Before carrying this test / it is essential to disconnect any neons and capacitors from thecircuit because they will upset the readings / obtained. In addition any device which containsemi-conductor components must also be disconnected as they can be damaged by the testvoltage.

Fig . (1.12) 43

X- Checking the insulationresistance between L

and N conductors


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Circ u it Digram

Fi g . (1.13)


- P.V.C conduits with accessories.

- One-way switch.

- Ceiling rose.

- A lamp and a patten lamp holder.

- 2 flash boxes.

- 1.5mm 2 P.V.C cable ( red , black / yellow/green).

- Insulation resistor tester ( Megger).

- Hacksaw and grip vice.

- Electrician tool box.

Procedure:

Connect the circuit as shown in Fig. (1.13).

Test 1:


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Insulation - resistance test between conductors and earth.

Before testing.

-a) Disconnect mains supply by opening main switch and removing main fuses.

44

b) Make sure that all lamps are in their lampholders. c) Place all switches in the ON position.

d) See that all circuit breakers are in the ON position.e) Connect one lead of the tester to the joined L and N. f) Connect the other lead of the tester to main earth terminal.g) Operate the tester / obtain a reading and record it in your work

book.

Test 2:

Insulation test between conductors / Fig. (1.13).

Before testing. a) Disconnect main supply.

b) Place all switches in the ON position.c) Remove all lamps from their holders.e) See that all circuit breakers are in ON position.f) Connect one lead of the tester to the terminal and the other lead to

the neutral terminal.

g) Operate the tester and record the reading in your workbook .


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45


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REALIZATION OF CON TINUITY TEST WEEK 11

Objective: To perform the continuity test.

Introduction: This test is made to ensure that the conductors are continuous throughout their length andare good conductors in that, their resistance is zero or nearly zero. The instrument used tocarry out this test is the continuity tester or a low-reading ohmmeter. In ring main circuitsthe test is made to ensure that the conductors (Line / neutral earth) are electricallycontinuous and to make sure that there is no breaks or disconnection in these conductors.An actual break could exist in the ring circuit without detection because one conductor willremain connected to the supply and could thus be overloaded.

Equipment and tools:- P.V.C conduits with accessories.- 3 13A socket outlets- 3 flash boxes.- 2.5mm 2 P.V.C cables (Red / black , green/yellow).- Hacksaw- Grip vice- Smooth file- Electrician tool box.

Circuit Diagram


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REALIZATION OF CON TINUITY TEST WEEK 11

Procedure:

Step 1: Connect the ring main circuit as shown in Fig. (1.14).

Step 2:Disconnect the ends of the line conductor in the distribution board Fig. (1.15).

Step 3: Connect the tester between the two ends of the line conductor as shown in the figure.

Step 4: Read the value and record it in your work book.

Step 5:Repeat steps (2) , (3) and (4) for the neutral and earthconductors.

Step 6:Join the ends of L conductors again and connect onelead of the instrument to the join / Fig. (1.16).

S tep 7: Connect the other lead to the 'L' terminal of each socket

outlet.

Step 8:Read the ohmmeter and complete table ()/ in yourworkbook.

Step 9: Repeat steps (6 )/ (7) and (8) for the nature andearth conductors.

F i g . (1.15)

Fig. (1.16)

47


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BELL CIRCUIT Week 12

Objective: To realize a bell circuit using step down transformer.

Introduction: The bell is a device used widely in houses , schools , buildings etc. It is also used with fire and

burglar alarm systems. The purpose of the bell is to alert people and attract their attentions forannouncements. Most bells operate on low voltages which are obtained from step down

transformers or batteries. This exercise is intended to execute a bell circuit using step downtransformer.

Equipment , tools and materials

- Electrician tool box

- P.VC conduit- Wire with a cross sectional area of 1.0 mm 2 - Junction box- Service box- Push button- Step down transformer with a proper secondery voltage (24 0/4v /8va nd 12v)- Bell (4V / 8V or 12V)- Distribution Board Fuse

Connection Diagram

Fig. (3.2) shows the execution plan of the bell circuit.

Layout

E^ ^ Bell Push

7^ E

^ -

20 / 12 V

D.B

/ - '^

^

^7 Bell

Fig . (3.1)

81


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Jun e Bo ionx

Metalcove

transf e r /

-^ w

r$ themer

> BellPush \

u Bell

V.

^ J l -> ^ -

r Distribution3oar d

rransf orme ory^ fiS

f r- E N L

Fig. (3.2)

Proced ure:

Step 1: Point out the rout of the conduits and the locations of the boxes. Step 2:

Cut the conduits to an appropriate length. Step 3:

Joint the conduits boxes. Step 4:

Draw the wires in the conduits according to the wiring diagram shown in Fig. (4.7) andfollow these steps.

Connections between the junction box , distribution board and the transformer.

82


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Step 5:Connect three wires (red / black & green) between the junction box and the distribution board.

Connections between junction box and primary side of the transformer.

Step 6: Connect again three wires between the junction box and the primary side of the transformer.

Note:

Make sure to connect 240V to the primary side.Connections between the Secondary side of transformer and the bell.

Step 7:Run one wire from the secondary side of the transformer to one terminal of the bell.

Connections between the secondary side of the transformer and the bell push.

Step 8:Run the second terminal of the Secondary side of transformer to one terminal of the bell

push.Connections between the bell push and the bell. Step 9:

Connect the second terminal of the bell push directly to the second terminal of the bell.

Testing the circuit:

Step 10: Test the circuit with an Ohmmeter/ to detect any fault in it. Powering the circuit:

Step 11: Connect an extension wire with red / black / & earth to the distribution board terminals and

then supply the circuit.The circuit must be checked by the teacher before connecting the |H supply .

83


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BELL INDICATOR CIRCUIT WEEK 13

BELL INDICATOR CIRCUIT

Objective:To reali ze a bell indicator circuit.

Introduction:Indica tor panel boards are necessary in industrial administrations and establishments

offices. They are used to notify labourers or servants by a flag.

The numbers which are posted on each flag of the panel as shown in Fig. (3.3), are usedto indicate office number for labourer. The announcement can be done through several push

buttons installed inside each administration office.

Flag dropped

Fig. (3.3) Indicator Panel Board.

Equipment tools and materials

- Electrician tool box.- P.V.C conduit.

Wire with a cross sectional area of 1.0m 2- - Junction box - - Service box.- 3 - push buttons.

- Step down transformer with a proper secondery voltage (24 0/4v / 8v and 12v) Indicator panel board of (4V, 8V or 12V).

- Distribution board.- Fuse.

84


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Chapter Three: Low Power Circuits ,

Layout

Fig. (3.4)

Connection Diagram

Fig.

(3.5) 85


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Procedure:

Step 1:

Point out the route of the conduit and the locations of the boxes.

Step 2:

Cut the conduits to the appropriate length and then / join them with the boxes.

Step 3: Select a suitable twin wire of 1 mm 2

Step 4:

Draw the cables in the conduits according to the wiring diagram shown in Fig. ( 3.5 ) andfollow the following steps.

Connections between j u nction box, distribution board and transformer .

Step 5:

Connect three wires (red / black & green) between the junction box and the distribution

board.

Connections between j unction box and primary side of the transformer.

Step 6:

Connect again three wires between the junction box mentioned above and the primaryside of the transformer.

Note:

Make sure to connect 240V to the primary side.

Connections between the secondary side of transformer and the bell pushes.

Step 7:

Run one wire to the first bell push / then loop it to the second and third bell push switches.


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Indicator panel board connections with bell push button.

Step 8:

Connect each push button with its corresponding flag coil as shown in Fig. ( 3.5 )

Bell indicator connections with reset push button.

fftep 9:

Connect one terminal of the bell indicator to the secondary side of the transformerthrough the reset push button.

Bell indicator connection with the second terminal of the secondary side of thetransformer.

Step 10:

Connect the second terminal of the bell indicator to the secondary side terminal of thetransformer / as shown in Fig. ( 3.5 ).

Testing the circ u it:

Step 11 ;

Test your circuit with an Ohmmeter device to clear your circuit from any fault.

Powering the circuit

Step 12:

Connect an extension wire with red / black & earth terminals to the distribution boardand then supply the circuit.

Safety Note:

The circuit must be checked by the teacher before connecting the supply.


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DOOR LOCKING CIRCUIT WEEK 14

DOOR LOCKING CIRCUIT

Objective: To realize a door locking circuit

Introduction: The door lock is a small device loca ted inside the door. It is used in many houses to

facilitate the opening of the main door automatically. The door locking circuit consists of anelectromagnet / latch release , push button and a transformer. When the push button is pressed / the electromagnet attracts the latch release and the door opens.

Fig. (3.6 ) shows a simple diagram of the door locking. This circuit will be added to theintercom circuit in the next chapter.

Fi g . (3.6) Door locking circui t . Equipmen t, tools

and material ^

- Electrician tool box.- P.V.C conduit.- Twin wire with a cross sectional area of 1mm 2. - Junction box. Service box.

- Push button.- Step down transformer (240/12V).- Door locking device.- Distribution Board.- Fuse.

88

240V

LatchDoor


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Chapter Three: Low Power Circuits-^ - G [>-^

E 240 /1 2 V

Fi g. (37)89

N

.B


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Chapter Three: Low Pow er Circui ts

Connection Diagram:

Fig. (3.8 ) shows the execution plan of the door locking circuit.

E N

Fig. (3.8)

Procedure:

Step 1: Point out the route of the conduits and the locations of

boxes.

Step 2: Cut the conduits to appropriate length.

Step 3: Join the conduits with the boxes.

Step 4: Select a suitable twin wire of 1mm 2

Step 5: Draw the wires in the conduits according to the wiring

diagram shown in Fig. (3.8 ) and follow these steps.

90

Push Button

Doorlocking

CoilLatches


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CONNECTION BETWEEN JUNCTION BOX

DISTRIBUTION BOARD AND TRANSFORMER

WEEK 15

Connections between the junction box . distrib u tion board and the transformer.

Step 6: Connect three wires (Red / Black / Green) between the junction box and the distribution

board.

Connections between junction box and primary side of transformer.

Step 7:Connect again three wires between the junction box and the primary side of the transformer.

Note: Make sure / td^MSct 240V to the primary side.

Connections between the secondary side of the transformer and door locking unit,

Step 8:Run one wire from the secondary side of the transformer to one terminal of the door lock.

Connections between the secondary side of transformer and the bell p ush.

Step 9: Run the second terminal of the secondary side of the transformer to one terminal of the bell

push.

Connections between bell push and the door lock.

Step 10:Connect the second terminal of the bell push directly to second terminal of the door lock.

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Testing the circ u it:

Step 11: Test the circuit with an Ohmmeter/ to make sure that your connections are correct.

Powering the Circ u it

Step 12:

Connect an extension wire wi th red / black , & earth to the distribution board terminals andthen supply the circuit / after checking it by the teacher.


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EEC 129 Practical