10/22/2018
EE522 Electrical Installation Design
Tutorials
By
Dr. Y. S. Haruna
DEEE, ATBU Bauchi
Theoretical Questions
1.
2.
3.
4.
5.
6.
i)
iii)
v)
Give at least two purposes of outdoor light.
What do you understand by light pollution?
Mention three requirements of an outdoor light
Enumerate three basic types of lamps.
What do you understands by the term stroboscopic
effect? How can it be minimized?
Define the following terms with regards to electrical
installation;
Illumination, ii) Luminous Intensity,
Luminous Efficacy, iv) Luminous Flux and
Luminaire
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Theoretical Questions…
7. Give at least two methods of calculating
illumination
8. State the laws of illumination.
9. Enumerate any two of the Statutory laws you know.
10. In which of the area do we apply the IEE wiring
regulations?
11. Enumerate three health and safety responsibilities
of an employer.
12. Enumerate three health and safety responsibilities
of an employee
13. Enumerate the four safety signs you know.
Theoretical Questions…
14. Give the symbolic representation of the following
accessories;
i) Two-way switch, ii) Socket outlet,
iii) Single-pole, one-way switch, iv) Main control intake
v) Two-pole, one-way switch, vi) Lighting point or lamp
15. Using a schematic diagram, briefly explain the three
main parts of a cable.
16. Enumerate the effects of current flow in a conductor.
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Theoretical Questions…
17. Give one application each of heating, magnetic and
chemical effects caused by the flow of electrons in a
conductor.
18. Using a schematic diagram, briefly explain the
process of generating power from a generating
station to the end users.
19. What do you understand by the term Earthing
system? Enumerate three benefit of earthing system.
20. Enumerate three services provided by an electrotechnical industry.
Theoretical Questions…
20. With the aid of a schematic diagram, show how a
lamp, switch and junction box can be arranged for
safe and efficient operation of the lamp.
21. Using a schematic diagram, briefly show how you
can control one lamp using two, two-way switches.
22. What are the advantages of ring connections over
the radial connection in electrical installation?
23. Enumerate the basic types of wiring system you
know?
24. What are the factors to be considered in the choice
of a wiring system?
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Theoretical Questions…
25. Briefly explain the wiring systems you know.
26. List five wiring accessories.
27. Why is parallel connection in wiring installation
preferred over series connection?
28. Give two disadvantages each of conduit and surface
wiring systems
29. Enumerate two advantages each of conduit and
surface wiring systems.
30. What do you understand by the term ‘Main Intake’ in
electrical installation?
Theoretical Questions…
31. Using a schematic diagram, briefly explain the
arrangement of the main intake components.
32. Enumerate the correction factors used in cable
selection for the design of electrical installation.
33. What is the allowable voltage drop according to IEE
regulation?
34. Define the following terms with regards to fuse;
i) Current rating, ii) Fusing Current, iii)Fusing factor
and iv) Discrimination.
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Numerical Question No. 1
A light source of 900 cd is situated 3m above a working
surface.
i. Calculate the illuminance directly below the source.
ii. What would be the illuminance if the lamp were
moved to a position 4m from the surface?
Solution
Data Given: d = 3m, I = 900 cd
Using the formula,
i) Substituting for the values of I and d into the Eqn. will
yield
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Numerical Question No. 2
• A 250W sodium-vapour street lamp emits a light of 22
500cd and is situated 5m above the road. Calculate the
illuminance
i. directly below the lamp and
ii. at a horizontal distance along the road of 6m (Fig. Q2).
Lamp
Solution
θ
Data Given:
d=5m
B.
6m
A
.
.
6m
C
Numerical Question No. 3
• A work area at bench level is to be illuminated to a value
of 300lx, using 85W single fluorescent fittings having an
efficacy of 80lm/W. The work area is 10m X 8m, the MF is
0.8 and the CU is 0.6. Calculate the number of fittings
required.
Solution
Data Given: A = 10mX8m, Lamp rating = 85W, E = 300 lx,
Eff. = 80 lm/W, MF = 0.8 and CU = 0.6
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Numerical Question No. 4
• A building hoist lifts 20 bags of 50kg cement to the top
of a 50m high building. Calculate the power rating of
the motor to perform this task in 1 minute if the
acceleration due to gravity is 9.81m/s2.
Solution
Data Given: mass = 20 X 50kg, h = 50m, time = 1 X 60 sec,
g = 9.81m/s2
Numerical Question No. 5
• A 3-phase, 4- wire supply feeds the proposed new block of
CIS in ATBU Bauchi. The installation comprises the
following:
–
–
–
–
–
–
–
–
–
•
14 florescent tubes of 40W each @ N750;
19 light bulbs of 60W each @N1000;
6 ceiling fans of 60W each@N5,500;
12 nos. 13A single socket outlets ( 200W each ) @N650;
5 nos. 15A socket outlets (2 kW each ) N1500;
A 3kW cooker @N19,000;
3 nos. 3kW grinder@N15,000;
3 nos. single phase 415V, 4kW welding machine @N250,000;
A 3 – phase 415V, 3kW motor @N120,000.
ii) Draw up the complete BEME of the items.
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Question No. 5 Solution
• Based on the above information, the column for unit
price and amount has to be filled.
• Thereafter, the total cost of the installation can be
obtained.
• The complete BEME of the of the items provided can
be seen on the following Table
Question No. 5 Solution…
S/N Description of Item
Qnt. Unit Rate
Amount
(N)
(N)
14 No.
750
10500
1
38W Florescent Tubes Light Fitting
2
60 W Light Bulbs Fitting
19
“
1000
19000
3
4
5
6
7
8
60W Ceiling Fan Fitting
13A Single Socket Outlet (200W)
15A Socket Outlet (2kW)
3kW Cooker
3kW Grinder
A single phase, 415V, 4kW welding
machine
A three phase, 415V, 3kW motor
6
12
5
1
1
1
“
“
“
“
“
“
5500
650
1500
19000
15000
250000
33000
7800
7500
19000
15000
250000
1
“
120000
120000
Total Amount
481,800
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