GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
CONTENTS
Introduction……………………………………………………………1
Acknowledgement …………………………………………………….2
Preface…………………………………………………………………3
Abbreviations………………………………………………………….4
Assignment 1…………………………………………………………..5
Assignment 2…………………………………………………………..6
Assignment3…………………………………………………………...7
Assignment 4…………………………………………………………..8
Assignment 5…………………………………………………………..9
Assignment 6…………………………………………………………..10
Assignment 7…………………………………………………………..11
Catalogues……………………………………………………………...12
Overlays………………………………………………………………...13
1
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
INTRODUCTION
This hand out outlines the project undertaken by the author who is undergoing a National
Certificate study in Electrical Power Engineering at Gweru Polytechnic College. The publication
has been produced for use in the electrical installation of Mbizo Technical School. It is compiled
as the part of the requirements for the 2024 National Certificate in Electrical Power Engineering,
installation examination.
This gives us students a chance to apply certain sets of statutory regulation, for example the
Institute of Electrical Engineering (IEE) Regulations, Standard Association of Zimbabwe (SAZ)
wiring regulations, Zimbabwe Electricity Supply Authority (ZESA) and any other statutory
instruments that apply to electrical wiring system.
Therefore, in this project the Author will choose the best and most suitable types of luminaires
guided by institute of electrical engineering that has illumination levels almost the same as those
achieved using convectional light source and energy saving.
The project was written with a great logical approach, that is, all appreciation of special
conditions and assumptions were made.
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GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
ACKNOWLEDGEMENTS
My sincerest gratitude firstly goes to my GOD, for providing me with guidance and protection
throughout the process of my research. I am also humbled to say “thank you” to my academic
supervisor, Mrs Maposa for willingly offering advice and for supporting me with his patience
and knowledge throughout the course. My sincere acknowledgements also go to the Gweru
Polytechnic College Electrical Division staff members, Mrs Maposa, Mr Charumbira our H.O.D
and many other lectures for their unwavering support.
I am also indebted to my family members for providing me with the invaluable technical,
psychosocial, and financial support during my learning period. The first and foremost among
them being my father, who paid for every bill during this course. Furthermore, I am heartily
thankful to my dearest friends Tinotenda Mlenga, Patrick Pfumo, Mufaro Taungwa and Divine
Manyanye for their help and support, really it added value to my success “thank you”.
3
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
PREFACE
A special installation project that covers a wide range of regulations regarding electrical
installation. The project is subdivided into 7 assignments and was done guided by Institute of
Electrical Engineering (IEE) regulations, supplier’s regulations thus Zimbabwe Electricity
Supply Authority (ZESA) and also keeping in mind the local council regulation. IEE regulations
and BS Standards are part of what makes the project great, safe to the popular and successful,
relevant formulas were used to answer questions and come up with standard installation. For
confirmation of proper standards tables and catalogues have been included in the appendix.
The ZETDC supply is 380v, 50Hz three phase four wire services. The supply system is TN-C-S.
Circuit protection is by M.C.B to BS3871 type 2.
The installation is to be carried out in accordance with the 16th Edition of the IEE wiring
regulation.
Electrical symbols of BS3939 are to be used throughout the project.
An overlay was done separately on the attached plan showing all cable roots and spreading of
luminaires and their switches.
Clearly, in such a wide coverage such as presented in this project book, deficiencies may be
encountered. Thus, your commentary and criticisms are appreciated.
4
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
ABBREVIATIONS
IEE Institute of Electrical Engineering
DB Distribution board
CPC Circuit Protective Conductor
MCB Miniature Circuit Breaker
Sub DB Sub Distribution board
V Voltage
I Current
RI Room Index
N Number of luminaire
A Ampere (unit of current)
S.W.A Steel Wired Armoured
A.C Alternating Current
ZESA Zimbabwe Electricity Supply Authority
ZETDC Zimbabwe Electricity Transmission and Distribution
Company
CU Coefficient of Utilization
MF Maintenance Factor
E Illuminance
PVC Polyvinyl Chloride
BS British Standard
5
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Assignment 1
Below are the pictures for room index and their illuminances.
ASSIGNMENT 1
Question: Lighting
Indicate on the plan for both the ground and first floor, the positions for lights and switches in
each of the classrooms, clearly indicating the switches and the lights they control.
Definition of terms
Illuminance
Is the amount of luminous flux falling on a surface per unit area.
Luminous flux
considering factors including,
Lamp depreciation
Reflection charges
Dirt accumulation
Coefficient of utilization
is the ratio of the luminous flux received on the work plane to the total luminous flux emitted by
the light source.
Reflectance
is the ratio of the flux reflected from the surface to the incident upon it.
Room index
Is the total of visible light emitted by a light source in all directions measured in Lumen.
6
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Luminous Intensity
It the measure of the amount of light emitted by a light source in a specific directions measured
in Candela.
Maintenance Factor
Is the ratio of the initial illuminance to the minimum illuminance after a specified period
it is similar to the dimension of the room and it can be used when calculating the utilization and
characteristics of lighting installation
LIGHT SPECIFICATIONS
Room index table extracted from IEE Reg 16 Edition
Room 0.75 1.00 1.25 1.50 2.00 2.50 3.0 3.5 4.0
index
Cu 0.45 0.49 0.55 0.6 0.66 0.7 0.75 0.8 0.83
Light fittings are four feet 18 watts tubes for classroom and 9 watts two feet for stairs.
ROOM INDEX TABLE.
ROOM LENGTH WIDTH HEIGHT LUMEN AREA CO- MAINTENANCE ROOM
EFFICIENT FACTOR INDEX
OF
UTILIZATIO
N
Classroom 7.6585 5.615 2.55 2340 42.59 0.55 0.85 1.26
1,2,4,5,7,8,10,11
Classroom 5.615 3.858 2.55 2340 21.48 0.55 0.85 0.89
7
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
3,6,9,12
0ffice 1 and 2 5.615 2.858 2.55 2340 15.40 0.55 0.85 0.72
Stores 4.685 2.858 2.55 2340 13.39 0.55 0.85 0.74
Passages 28.080 2.380 3.4 2340 65.99 0.55 0.85 0.63
Toilets 4.685 2.743 2.55 2340 12.85 0.55 0.85 0.50
Stairs 4.685 2.398 3.4 2340 11.23 0.55 0.85 0.46
Porch 2.070 1.610 3.4 2340 3.33 0.55 0.85 0.29
CALCULATION OF LUMINARIES IN CLASSROOM 1,2,4,5,7,8,10 AND 11
working plane to be = (3.4 - 0, 85=2,55)
AREA = L × W
= 7,585 × 5,615
= 42,59 m²
ROOM INDEX = L ×W
H (L+W)
8
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
= 7,585 × 5,615
2,55 (7,585 + 5,615)
= 1,26
N= E × A
∅ × Cu × Mf
= 310 × 42 , 59
2340 × 0,55 × 0,85
= 12, 18W tubes
CALCULATION OF LUMINARIES IN CLASSROOM 3, 6, 9 AND 12
working plane (3.4 - 0,85 =2,55 )
AREA = L × W
= 5,615 × 3, 820
= 21, 45 m²
ROOM INDEX = L × W
H ( L+W)
= 5,615 × 3,820
2,55 ( 5,615 + 3,820 )
= 0, 89
N = E × A ÷ ∅ × Cu × Mf
= 310 × 21, 45 ÷ 2340 × 0,49 × 0, 85
= 6, 18W tubes
9
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
OFFICE 1 FOR BOTH GROUND AND FIRST FLOOR
working plan to be ( 3, 4 - 0, 85 =2,55 )
AREA = L × W
= 5, 615 × 2,858
= 15 , 40 m²
ROOM INDEX = L × W ÷ H (L +W)
= 5,615 × 2,858 ÷ 2,55 ( 5,615 + 2,743 )
0, 72
Therefore Cu = 0, 43
Mf = 0 ,85
∅ = 2340
E = 310
N = E × A ÷ ∅ × Cu × Mf
= 310 × 15,40 ÷2340 × 0,43 × 0,85
= 4, 18W tubes
CALCULATION OF LUMINARIES IN THE PASSAGES OF GROUND AND FIRST FLOOR
AREA = L × W
= 28, 080 × 2,350
= 65 , 99 m²
10
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
ROOM INDEX = L × W ÷ H ( L + W )
= 28 , 080 × 2,350 ÷ 3,4 ( 28, 080 + 2,350 )
= 0, 63
Therefore Cu =0,43
Mf = 0, 85
∅ = 23
E = 140
N = E × A ÷∅ × Cu × Mf
= 140 × 65, 99 ÷ 2340 × 0,43 × , 85
= 10, 9W tubes
CALCULATION FOR STORES
AREA = L × W
= 4,685 × 2,858
= 13, 39 m²
ROOM INDEX = L × W ÷ H ( L+ W )
= 5,615 × 2,858 ÷2,55 ( 5,615 + 2,858 )
= 0,74
Therefore Cu = 0,43
mf = 0,85
∅ = 2340
E = 180
11
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
N = E × A ÷ ∅ × Cu × Mf
= 310 × 13,39 ÷ 2349 × 0,43 × 0,85
= 4, 18W tubes
CALCULATION FOR MALE AND FEMALE TOILETS
AREA = L × W
= 4,685 × 2,743
= 12 , 85
ROOM INDEX = L × W ÷ H ( L + W )
= 4, 685 × 2, 743 ÷ 3,4 ( 4,685 + 2,743 )
= 0, 50
Therefore Cu = 0,43
∅ = 806
E = 110
mf = 0,85
N = E × A ÷ ∅ × Cu × Mf
= 110 × 12 , 85 ÷ 0,43 × 0,85 × 806
= 4, 18W tubes
CALCULATION FOR PORCH
Area = L X W
= 2.070 X 1.610
12
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
= 3.33m
ROOM INDEX: (L X W) ÷H(L+W)
=(2.070x1.610)/3.4(2.070+1.610)
=0.26
N= E x A ÷ Cu x Mf x ǿ
= 310 x 3.33 ÷ 2340 x 0.85 x 0.29
= 2, 18watts tubes
CALCULATION FOR STAIRS
AREA = L × W
= 4,685 × 2,398
= 11, 23 m²
ROOM INDEX = L × W ÷ H ( L + W )
= 4,685 × 2,398 ÷ 3,4 ( 4, 685 + 2,398 )
= 0 ,46
Therefore Cu = 0,43
mf = 0,85
∅ = 2340
E = 180
N = E × A ÷∅ × mf × Cu
= 180 × 11, 23 ÷
2340 × 0,85 × 0,43
= 2, 9W tubes
13
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
LUMENS AND NUMBER OF LIGHTS TABLE
ROOM LUMEN NUMBER OF LIGHTS
Classroom 1,2,4,5,7,8,10,11 2340 96
Classroom 3,6,9,12 2340 24
Office 1 and 2 2340 4
Stores 2340 8
Passage 2340 20
Male and female toilets 2340 8
Stairs 2340 2
Porch 2340 2
14
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
9W LED BULB
18 watts LED TUBE 4-FOOT
15
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
REFER to Insert 1 and 2 for the Lights and Switches
16
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
ASSIGNMENT 2
Power
a) On separate overlays for both ground and first floor, insert, stating your assumptions for
the position of socket outlets in all the classrooms. (40)
b) Given that ring circuit is to be employed for socket outlet circuits. Outline two (2)
advantages and two (2) disadvantages of the ring system. (5)
c) Show conduit routes for socket outlets for both ground and first floor. (30)
ASSUMPTIONS
Lifespan of socket outlets
Standard lifespan; Assume a typical lifespan of 10 to 15 years for socket outlets under
normal usage conditions.
Maintenance; Regular maintenance checks every 5 years to ensure functionality and safety.
Types of loads
Normal loads; Devices like computers, projectors and lighting
Abnormal loads; Occasional high power devices like space heaters or lab equipment.
17
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Circuit segmentation
Separate circuits; Design separate circuits for different areas or types of loads to prevent
overloading. For example one circuit for computers and another for projectors.
Load calculations; Calculate the total expected load for each circuit, including a safety
margin (typically 20 to 25%)
Over-current protection
Circuit breakers; Use appropriately rated circuit breaker for each circuit. For example, a 16A
breaker to carry up to 13A of loads.
RCD protection; Included Residual Current Devices protect against earth faults, especially in
areas where high-power devices might be used.
Wiring and Installation.
Cable sizing; Ensure cables are sized to handle the maximum expected load plus a safety
margin. For example, use 2,5mm cables for socket outlets.
Installation and standards; Follow local electrical installation standards and regulations such
as BS767.
Monitoring and maintenance.
Regular Inspections; Schedule regular inspections to check for wear and tear, especially in
high-use areas
Load Management; Educate users on managing loads to avoid overloading circuits.
18
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
2b. Advantages of ring circuits
Can handle higher loads as the currents are distributed around the ring.
Provides redundancy, if one part of the ring is broken, the circuit can still function.
Disadvantages of ring circuits
Complex Installation; More complex to install and requires more wiring
Single break can affect the entire circuit.
REFER to Insert 3 and 4 for the Socket outlets
Assignment 3
Main intake and distribution board
The main distribution board is located on the ground with the sub distribution board on
the floor.
Show the position of the main distribution board (see overlay)
Show the position of the sub distribution board (see overlay)
Give reasons of your choice of positions of boards
19
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
ASSIGNMENT 3c
Main Distribution Board
Position of Main Distribution Board
Ground floor: Typically, the Main Distribution Board is located on the ground floor for easy
access and maintenance.
It also minimizes the length of main supply cables, reduces voltage drop and energy loss.
Position of Sub Distribution Board
Sub Distribution Board should be located ;
near electrical loads ( e.g., lighting, equipment),
On each floor of the building,
First floor: Placing the sub distribution board on the first floor helps in distributing power
efficiently to that level, reducing the load on the main distribution board and ensuring
better management of electrical circuits.
Reasons for choice of positioning the Main Distribution Board
Accessibility: Easy access for maintenance, monitoring and emergency shutdowns.
Environmental Protection: Protected from harsh environments (e.g., moisture, dust)
Efficiency: Minimizes energy loss and voltage drop by reducing cable length
Visibility: Easily visible for monitoring and troubleshooting
Compliance: Meets regulatory requirements
20
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Reasons for choice of positioning the Sub Distribution Board
Proximity to load: Must be close to electrical loads (e.g., lighting, equipment)
Convenience: Easy access for maintenance and troubleshooting
Flexibility: Allows for future expansion or modifications
Space Efficiency: Compact design for limited spaces
Safety: Reduces risk of electrical shock and fire
REFER to Insert 5 and 6
Assignment 4
Water supply
To supplement water supply at the school, borehole has been sunk on the premises. It is
proposed that the three-phase induction motor controlled by a direct online stater be used
to drive the borehole pump. The control should enable the operator switch ON and switch
OFF the motor from two positions.
You are requested to:
Draw power and control diagrams for the borehole control. (see A3 paper)
Prepare a list of materials that are required so that the circuit can be wired.
21
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
ASSIGNMENT 4B
Prepare a list of materials that are required so that the circuit can be wired
Single pole 5A MCB
60A Triple pole MCB
Overload relay
2 × stop push buttons
2 × start push buttons
Contactor
2mm red wiring cable (control circuit )
2mm black wiring cable (control circuit)
4 core armoured cable to supply the main breaker
4 core armoured cable supplying motor
3 phase pump
Glands
Shrouds
2 Distribution Boards
Neutral bar
Earth bar
cable ties
DB mounting bolts
Selt taping screws
DIN rails
Jointing kits
22
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Tools to be used :
Cable stripper
Combination pliers
Flat screw driver
Star screw driver
Pump pliers
REFER to Insert 7 for the Control and Power circuits for Borehole control
Assignment 5
Schedule for the distribution board
What are the challenges that can be encountered on an installation without a
schedule for a distribution board (5marks)
Prepare the schedule for the main and sub distribution boards. The schedules
should include:
Reference
Rating of MCB
Function
Destination (20 marks)
Safety risk: uncertainty about circuit connections and load capacities can lead to electric
shocks, fire or explosions.
Circuit overloading: insufficient documentation can result in excessive load on circuits,
causing tripped breakers, overheating or equipment damage.
Power outages: unplanned shutdowns due to unclear circuit relationships can disrupt
critical operations.
Difficult troubleshooting: lack of documentation hinders quick identification and
resolution of electrical issues.
Maintenance and repair issues: unclear documentation complicates maintenance tasks.
23
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Upgrade and expansion challenges: lack of documentation makes future modifications
complex.
b) The schedule for the main and sub distribution boards including reference,
rating of MCB, function and destination.
For main distribution board;
Calculation of size of circuit breaker for lights
Wattage of each fitting = 18watts
Total load = 130 fittings x 18watts = 2340W
2280W to volt-ampere = 2340VA {assuming p.f = 1}
Phase current = VA÷ (1,73 × V)
= 2340/ (1,73×380)
= 3,6 Amps
Applying diversity factor = 3,6×0,8
= 2,9 amps
Size of MCB = 5Amps.
Calculation of size circuit breaker for borehole pump
Assuming the borehole pump is a 2hp pump then the power of the pump is =1494W
Design current = P÷ (1,73×V×pf)
Ib= 1494/ (1,73×380×0,85)
Ib = 3 Amps
Circuit Breaker = 5Amp
24
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
SOCKET OUTLETS
Socket outlet load for 13Amp (BS 1363)
Total load = 36 socket outlets × 13Amp
Total load = 468 Amps
Current per phase = Total load ÷3
Current per phase = 468/3
Current per phase = 156Amps
Applying diversity factor = 156Amps × 0,8
= 124,8 Amps per phase
MCB size selection = 200 Amps
TOILET LIGHTS
Wattage of each light = 9watts
Total load = 8 x 9watts = 72W
36W to volt-ampere = 36VA (assuming p.f = 1)
Phase current = VA÷ (1,73 × V)
Phase current = 72÷(1,73 ×380)
Phase current =0,11Amps
Applying diversity factor = 0,11×0,8
Total current = 0,088Amps
Circuit Breaker = 5 Amp
Size of the isolator
25
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
0,066A + 160A + 3A + 3,5A =167,16
Therefore, the size of the isolator is 250A (for future expansion)
Reference Rating of MCB Function Destination
D.B 250 Protection And Ground floor
Isolation
SDB 1-2 200 Sockets Ground floor
SDB 1-3 5A Borehole Borehole pump
SDB1-4 5A Lighting First floor
Sub D.B
Reference Breaker Rating Function Destination
SDB1-1 30A SOCKETS Ground floor
SDB1-2 5A LIGHTING GROUND FLOOR
SDB1-3 5A LIGHTING GROUND FLOOR
SDB1-4 5A PUMP BOREHOLE PUMP
SDB1-5 40A COMPUTER OFFICES
EQUIPMENT
SDB1-6 30A SOCKETS FIRST FLOOR
26
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
ASSIGNMENT 6
Inspection and testing
a. Outline the tests in sequence that should be carried out on the completed for a
distribution.
Pre Testing (Visual inspection)
Verify installation meets design and specifications and regulations
Check for proper cable routing, securing and labelling.
Ensure all connections are tight and secure
Verify correct wiring and polarity.
Phase1: Low voltage test
Continuity testing (cable and wiring)
Measure resistance between conductors
Verify no shorts and opens
Insulation resistance testing
Measure insulation resistance between conductors and earth
Ensure 1M ohms resistance.
27
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Earth bonding testing
Verify earth connections are secure.
Measure resistance between earth points
Phase 2: Distribution Board Testing
DB verification
Check DB layout and wiring.
Verify correct connections.
RCD testing
Test RCD trip time and sensitivity
Verify correct tripping and rating
Phase 3: Lighting and Power Testing
Lighting circuit testing
Verify lighting operates correctly.
Check for proper switching and dimming.
Power sockets testing:
Verify power sockets operates correctly.
28
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Check for proper polarity and voltage.
Phase 4: Safety Testing
Earth fault loop impedance testing
Measure impedance between phase and earth.
Ensure 1-ohm resistance.
Residual current devices (RCD) testing
Verify RCD trips within specified time.
Phase 5: Functional testing
Appliance testing
Verify appliance operates correctly.
Check for proper power and control
Control system testing
Verify control logic and sequencing.
Phase 6: Certification and Documentation
29
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Complete test reports and certification documents
Update electrical drawing and documentation
3) Obtain necessary certifications and approvals
TESTING TOOLS AND EQUIPMENT
1. Multimeter
2) Megohmmeter
3) Earth tester
4) RCD tester
5) MCB tester
6) Power analyser
7) Oscilloscope
8) Cable tester
Floor specific Test
Ground floor:
Test main distribution board
Verify earthing system
First floor:
30
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Test sub distribution board.
Verify lighting and power circuits.
Important task
1) Follow safety procedures and regulations
2) Ensure qualified personnel perform testing
3) Consult local electrical codes and standards
b) Explain the reason why the tests must be carried out in the sequence indicated .Upon
energising the installation, it was observed that not all the lights in passage on the first floor
were ON.
Safety
Prevent electrical shock or injury by verifying proper earthing, insulation, and wiring before
applying power.
Avoid damaging equipment or causing electrical fires.
Accuracy
Conducting tests in a logical sequence helps identify and isolate faults efficiently.
Reduces false positives or misleading test results.
Efficiency
31
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Sequential testing minimises rework and reduces the risk of damaging equipment.
Ensures that critical systems are tested before non -essential wants.
c) Upon energising the installation, it was observed that no lights in passage on the first
floor were ON. Suggest two reasons for the above challenge.
REASON 1
Electrical circuit issue
Overloaded circuits; too many devices connected to the same circuits exceeding its capacity.
Tripped circuit breaker or RCD; Automatic shutdown due overload, short-circuit or earth
fault.
Faulty wiring or connections; Loose, damaged or incorrect wiring connections.
Incorrect circuit configurations: Misconfigured or mismatched circuit components
REASON 2
Power supply or distribution issue
power supply interrupting ;Main electrical supply issue or interruption
Distribution board problem; Faulty DB, incorrect configuration, or overloaded DB.
Sub-distribution board issue: Faulty SDB, incorrect configuration, or overloaded SDB.
Voltage drop or fluctuation; Insufficient voltage supply or unstable voltage levels.
Additional Potential Causes:
32
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Faulty lighting fixtures or bulbs.
Incorrect lighting circuit design.
Insufficient earthing or grounding.
Electrical surge or transient issues.
Outline how you would get to the problem and rectify it .
STEP 1: GATHER INFORMATION
Review electrical drawings and schematics.
Consult with maintenance personnel or electrical contractors.
Check electrical logs and maintenance records.
STEP 2:
ASSIGNMENT 7
Incident on site
33
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Write a letter to the operation manager detailing your findings on what transpired, what
action you took after the incident, how this incident affected the work on site and give
recommendations on how such incidences can be avoided in future.
Shelton J Nyorovai
Site supervisor
Viper Electrical Services
21 September 2024
Reporting incident of worker injury from ladder fall
Dear Mr Mulenga
REF: DETAILED LETTER REPORT ON LADDER INCIDENT AND
RECOMMENDATIONS TO PREVENT SUCH INCIDENTS.
I am writing to provide a comprehensive account of the recent incident that occurred on-site
involving one of our workers, Tinashe, who fell from a ladder while performing his duties.
On 20 September at approximately 2 o'clock, Tinashe was using a ladder at Mbizo construction
site, fitting lights. Witnesses reported that he appeared to be following standard safety protocols,
but during the process, he lost his balance and fell approximately 7 meters resulting in bone
fracture on his hand.
34
GWERU POLYTECHNIC
CANDIDATE NUMBER: 1122007100029
CANDIDATE NAME :SHELTON J NYOROVAI
NC3 2024
PROJECT
Immediately after the incident, I took swift action by ensuring that first aid was administered and
the worker was transported to Kwekwe hospital, for further evaluation. I also secured the area
and initiated a preliminary investigation, interviewing witnesses and reviewing safety practices.
The worker’s fall not only caused concern among the crew but also led to a temporary halt in
operations at Mbizo construction site, affecting our productivity and project timeline.
I recommend the following actions, Implementing a mandatory refresher training program
focused on ladder safety and proper equipment handling for all workers. Conducting frequent
inspections of all ladders and scaffolding to ensure they meet safety standards and are in good
working condition. Providing and mandating the use of personal protective equipment that is
appropriate for the tasks being performed also helps, establish and enforcing clear protocols for
using ladders, including guidelines on how to secure them and the buddy system for additional
safety and lastly Improving our incident reporting system to allow for real-time feedback and
proactive measures to address any safety concerns.
While this incident was unfortunate, it serves as a critical reminder of the importance of adhering
to safety protocols and continually evaluating our practices. I believe that by implementing these
recommendations, we can ultimately create a safer working environment and minimize the risk
of future accidents.
Thank you for your attention to this matter. I look forward to discussing our next steps.
Sincerely,
Shelton J Nyorovai
+263 71 650 1516
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