EEC 129 Practical

UNESCO-NIGERIA TECHNICAL & VOCATIONAL EDUCATION REVITALISATION PROJECT-PHASE II

NATIONAL DIPLOMA IN ELECTRICAL ENGINEERING TECHNOLOGY

L N

ELECTRICAL BUILDING INSTALLATION COURSE CODE: EEC 129

YEAR I- SEMESTER II PRACTICAL Version 1: December 2008

1

TABLE OF CONTENTS Week 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

Practical Work

WEEK 1

Title: REALIZATION OF ONE WAY SWITCH CIRCUIT using PVC conduit

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 in domestic premises to control either a fluorescent lamp or an incandescent lamp. This ractical work familiarizes the student with the connection of the one way switch circuit and further improves the student skill and ability to handle heavy gauge steel conduit.

Equipment 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.

Practical Work

WEEK 1

Layout Diagram

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.

Practical Work

WEEK 1

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 for connections. 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.

Practical Work

WEEK 2

Title: REALIZATION 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 two doors.fig.1.2 shows the circuit connection and the symbol representation of the switch. Line or Load Symbol representation

Equipment and tools:

- 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 - An electrician tool box.

Load or Line Wiring connection

Practical Work

WEEK 2

Layout Diagram

L2

E

E

E

J.B

C.R

E

L1

Controls the Lamp 1 Controls the Lamp 1 & 2

General scheme

L3 E

E

Practical Work

WEEK 2

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.

Practical Work

WEEK 3

Title: REALIZATION 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 in domestic premises to control either a fluorescent lamp or an incandescent lamp. This ractical work familiarizes the student with the connection of the one way switch circuit and further improves the student skill and ability to handle heavy gauge steel conduit. Line

Load 1 Load 2

Symbol representation

Wiring connection

Equipment and tools:

- 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. - An electrician tool box.

Practical Work

WEEK 3

Layout Diagram

L1

E

L2

E

E

J.B

J.B

E

General scheme Controls the Lamp 1

Controls the Lamp 1 & 2

L3 E

Practical Work

WEEK 3

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. 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 for connections. 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.

Practical Work

WEEK 4

Title: REALIZATION OF A LIGHTING 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 intermediate switches together with two 2-way switches. Two controls locations will be provided by the two 2-way switches and the other locations will be provided by the number of intermediate switches used in the circuit. See Fig. 2 Way switch

2 Way switch

Any number of intermediate switches as required N number of locations of control

Line or Load

Load or Line Wiring connection

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 mm2 P.V.C cable (red, black and green/yellow). - Hacksaw. - Grip vice - Fish tape. - Bending spring - Electrician tool box.

Practical Work

WEEK 4

Layout Diagram

L1

C.R

L2 E

E

E

J.B

C.R

E

E

J.B E

General scheme &

Controls the Lamp 1 & 2

Controls the C.Rs

E

E

J.B E

Practical Work

WEEK 4

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. 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 for connections. 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.

27

Practical Work

WEEK 5

Title: REALIZATION OF A RADIAL 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 a radial 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 mm2 cable/ protected by 20A circuit breaker and serves one room of maximum areas 20 m2, 2. Wired with 4 mm2 cable/ protected by 30A circuit breaker and serves a maximum area of 50m2.

L

30A E

N Execution

Equipment and tools: - 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 mm2 P.V.C cables. Red/ black, green/yellow. - 2.5 mm2 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.

Practical Work

WEEK 5

Layout Diagram

E

E

J.B

E

J.B

J.B

E

E

E

E

E

E

E

E

E

E

General scheme

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 conduits then secure them to the boxes and board. Step 6: Install the 2.5 mm2 cables in the trunking and draw the 1.5 mm2 cables in the conduits as shown by the layout diagram. Step 7: Strip the terminals and connect up the circuits.

Practical Work

WEEK 5

Step 8: Test the circuit for correct wiring/ using an ohmmeter Step 9: Supply the circuit with power and ensure operation.

Safety notg; The student must not connect the circuit to the supply without the permission of his teacher.

REALIZATION OF A RING MAIN CIRCUIT USING P.V.C TRUNKING

WEEK6

Objective:

To connect a ring main circuit correctly and to consolidate the student skill in connecting the one way switch. Introduction: Every residential installation contains at least one ring main circuit. The ring circuit uses 13A socket outlets/ wired with 2.5mm2 cable and protected by a 30A circuit breaker. The circuit can serve a maximum area of 100m2 and the maximum 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 ring circuit. 30A

-cT\ N

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

31

Chapter One: Domestic Installations

REALIZATION OF A RING MAIN CIRCUIT USING P.V.C TRUNKING

WEEK6

Layout diagram

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)

^ C ontrol ' P .1 J.b ' • U s the A y< Contr ols L2 (\ C ^^^ Contr ols L- . R , i nt S p and &: m Tools 1 e conduits size- 20 mm with their accessories P.V.C P.V.C trunking (253xl6 mm) 3 13 A socket outlets 1 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

B ^

J . AC B ^

REALIZATION OF A RING MAIN CIRCUIT USING P.V.C TRUNKING

1 elbow 3 surface boxes 1.5 mm2 cable 2.5 2

mm cable Hacksaw

WEEK6

- 1 intermediate switch - 1 two gang switch - 1 ceiling rose 1 fluorescent lamp

and grip vice Smooth

32

file Bending spring Fish tape Electrician

Procedure:

tool box

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 using fish 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.

REALIZATION OF A RING MAIN CIRCUIT USING P.V.C TRUNKING

WEEK6

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

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

33

REALIZATION OF A STAIRCASE CIRCUIT USING WEEK TIME DELAY SWICTH 7

Objective: To install a time delay circuit 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 manually and ^

could remain ON all night when forgotten, which isn't desirable. To overcome this problem a time delay switch is used. This switch consists of a coil and a mechanical system allowing the control 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 to go up the stairs/ for example/ Fig. (1.8) shows a simple circuit which indicates the connections of the time delay switch and the lamps. Stair 1

Fig. (1.8) 34

Push button s

Chapter One: Domestic Installations

REALIZATION OF A STAIRCASE CIRCUIT USING WEEK TIME DELAY SWICTH 7 Layout diagram

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Time

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i itc delay h sw

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Tools and Equipment:

-

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

-

4 end boxes. 1.5 mm2 P.V.C Cable ( red/ black/ yellow/green).

-

4 push buttons.

-

4 lamp holders. Hacksaw.

-

Smooth file.

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REALIZATION OF A STAIRCASE CIRCUIT USING WEEK TIME DELAY SWICTH 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.

36

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 pole controls, (e.g one-way switches) are connected in the phase conductor only. In addition the test confirms that socket outlets "\J' terminals are connected to the phase conductor/ "N" terminals are connected to the neutral conductor and the "E" terminals are connected to the earth continuity 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 of the 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 with approved and fused leads and test probes can be used. Fig. (1.9 ) shows how polarity test is carried out on an "E.S" lamp holder.

Distribulkin ,—r" board ex- I"* consumer urni 1

N

B

SP switc h

r h ——} \ • ES 7Q lampho \ i C teter ; ( ontin i t uity i e stor i )

^- •?— T ' e nporary ^ n n link from ^ supply n. p se tc h earth ?•— a when rd —^ b is Fig, (1.9) The testofor isolated correct polarity on Edison screw lamp holder. a Ir o n '

Circuit diagram

Equipment and Material: - 20 mm P.V.C conduits and their accessories. - 2.5mm2 P.V.C cable. - 13A socket outlets. - 3 flash boxes. - Hacksaw. - Smooth file. - Multimeter ( polarity tester). - Electrician tool box.

Procedure: Step 1: Connect up the circuit on the board.

Step 2:

Connect one lead of the tester to the line termined in the D.B/ and the other 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 phase conductor 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.

REALIZATION OF EARTHING TEST

WEEK 9

Objective: To connect up a lighting circuit and to perform the earthing test on it. Introduction: This test is required to find the resistance of the continuity conductors (ECC) in order to verify that these conductors are correctly connected and electrically sound. This is important from safety point of view. It shows that when an earth leakage fault occurs, the resistance to the fault current flowing through these conductors (ECC) is low enough to result in melting the fuse or opening the circuit breaker protecting the circuit. The readings obtained for the resistances of the (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 into account by this test/ and the test for this impedance is outside the scope of this book.

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 circuit conductors. Fig. (1.12). a - Insulation test between conductors ( L and N) b - Insulation test between conductors and earth ( "L/ N" and E) The instrument used for making this test is the megger. The testing voltage should be twice 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 of outlets (i.e switches, lighting fittings/ socket outlets/ etc), the moisture and dirt being present on the wiring/ fittings and accessories. Before carrying this test/ it is essential to disconnect any neons and capacitors from the circuit because they will upset the readings/ obtained. In addition any device which contain semi-conductor components must also be disconnected as they can be damaged by the test voltage.

X-

Checking the insulation resistance between L and N conductors

Fig. (1.12) 43

REALION OF INSULATION RESISTANCE TEST

WEEK 10

Circuit Digram

Fig. (1.13) Equipment and tools: - P.V.C conduits with accessories. - One-way switch. - Ceiling rose. - A lamp and a patten lamp holder. - 2 flash boxes. - 1.5mm2 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:

REALION OF INSULATION RESISTANCE TEST

WEEK 10

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 .

REALION OF INSULATION RESISTANCE TEST 45

WEEK 10

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 and are good conductors in that, their resistance is zero or nearly zero. The instrument used to carry out this test is the continuity tester or a low-reading ohmmeter. In ring main circuits the test is made to ensure that the conductors (Line/ neutral earth) are electrically continuous 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 will remain 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. - 2.5mm2 P.V.C cables (Red/ black, green/yellow). - Hacksaw - Grip vice - Smooth file - Electrician tool box. Circuit Diagram

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 earth conductors. Step 6: Join the ends of L conductors again and connect one lead of the instrument to the join/ Fig. (1.16). Step 7: Connect the other lead to the 'L' terminal of each socket outlet.

Fig. (1.15)

Step 8: Read the ohmmeter and complete table ()/ in your workbook. Step 9: Repeat steps (6)/ (7) and (8) for the nature and earth conductors.

Fig. (1.16) 47

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 for announcements. 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 down transformer. Equipment, tools and materials -

Electrician tool box P.VC conduit Wire with a cross sectional area of 1.0 mm2 Junction box Service box Push button Step down transformer with a proper secondery voltage (240/4v/8vand 12v) Bell (4V/ 8V or 12V) Distribution Board Fuse

Layout

E

^^

Bell Push

7^

^-

E

/• -'•^ ^

20/12 V

^7 Bell

D.B

Fig. (3.1) 81

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

BELL CIRCUIT

Week 12

June Bo io n x V.

C^ J 6 . -> 7 ^ 1-1 —— ory^ fiS f rENL

Metal r$ the cove mer transf er / -^ w

> \ C

Bell Push

u B ell

l

Distrib rransf ution orme 3oard

r

Fig. (3.2)

Procedure: 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) and follow these steps. Connections between the junction box, distribution board and the transformer.

82

BELL CIRCUIT

Week 12

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

BELL INDICATOR CIRCUIT

WEEK 13

BELL INDICATOR CIRCUIT Objective: To realize a bell indicator circuit.

Introduction: Indicator 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 used to 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 1.0m2- Junction box- Service box. - 3 - push buttons. - Step down transformer with a proper secondery voltage (240/4v/ 8v and 12v) Indicator panel board of (4V, 8V or 12V). - Distribution board. - Fuse. 84

BELL INDICATOR CIRCUIT

WEEK 13

Chapter Three: Low Power Circuits,

Layout

Fig. (3.4)

Connection Diagram

Fig. (3.5) 85

BELL INDICATOR CIRCUIT

WEEK 13

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 mm2 Step 4: Draw the cables in the conduits according to the wiring diagram shown in Fig. ( 3.5 ) and follow the following steps. Connections between junction box, distribution board and transformer. 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 mentioned above 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 pushes. Step 7: Run one wire to the first bell push/ then loop it to the second and third bell push switches.

BELL INDICATOR CIRCUIT

WEEK 13

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 transformer through the reset push button. Bell indicator connection with the second terminal of the secondary side of the transformer. Step 10: Connect the second terminal of the bell indicator to the secondary side terminal of the transformer/ as shown in Fig. ( 3.5 ). Testing the circuit: 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 board and then supply the circuit.

Safety Note:

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

DOOR LOCKING CIRCUIT

WEEK 14

DOOR LOCKING CIRCUIT Objective: To realize a door locking circuit Introduction: The door lock is a small device located inside the door. It is used in many houses to facilitate the opening of the main door automatically. The door locking circuit consists of an electromagnet/ 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 the intercom circuit in the next chapter.

240V Latch Door

Fig. (3.6) Door locking circuit. Equipment, tools and material^

-

Electrician tool box. P.V.C conduit. Twin wire with a cross sectional area of 1mm2. Junction box. Service box.

-

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

88

DOOR LOCKING CIRCUIT

WEEK 14

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

240/12 V

D .B

N

Fig. (37)89

DOOR LOCKING CIRCUIT

WEEK 14

Chapter Three: Low Power Circuits Connection Diagram: Fig. (3.8 ) shows the execution plan of the door locking circuit.

Push Button

Doorlocking

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 1mm2 Step 5: Draw the wires in the conduits according to the wiring diagram shown in Fig. (3.8) and follow these steps. 90

Coil Latch es

DOOR LOCKING CIRCUIT

WEEK 14

CONNECTION BETWEEN JUNCTION BOX DISTRIBUTION BOARD AND TRANSFORMER

WEEK 15

Connections between the junction box. distribution 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 push. 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.

91

CONNECTION BETWEEN JUNCTION BOX DISTRIBUTION BOARD AND TRANSFORMER

WEEK 15

Testing the circuit: Step 11: Test the circuit with an Ohmmeter/ to make sure that your connections are correct. Powering the Circuit Step 12: Connect an extension wire with red/ black, & earth to the distribution board terminals and then supply the circuit/ after checking it by the teacher.

CONNECTION BETWEEN JUNCTION BOX DISTRIBUTION BOARD AND TRANSFORMER 92

WEEK 15