Please Help Me On This Scholars

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i. Draw a neat sketch of the layout of wiring from the suppliers` electric pole to the distribution board of a consumer taking single phase supply, show the meter, main switch and the distribution board. Explain the purpose of each of these appurtenances. ii. Draw a neat sketch of the layout of wiring from the suppliers` pole to the distribution board of a consumer taking three phase supply, show the meter, main switch and the distribution board. Explain the purpose of each of the devices. iii. Explain why the loads in an electrical installation is divided into sub-circuits. iv. Describe the various final sub-circuit outlets for distributing electrical loads in buildings. v. List two methods adopted for wiring final circuit to power socket vi. Specify the minimum size of cable and the fuse rating for protecting the following circuit: (a) lighting circuits (b) ring circuit (c) fixed appliances. vii. In a three-phase service consisting of four-wire installation with a neutral wire, (a) what is the voltage between any of the two-phase wires and (b) the voltage between any phase wire and neutral wire? viii. Explain the purpose(s) or function(s) of the following in building electrical installations: (a) consumer control unit (CCU) (b) Distribution Fuse Board (DFB) (c) Earth electrode (d) Miniature circuit breaker (MCB). ix. Explain the purpose of neutral and earth wires in a three phase-four wire distribution system. x. With the aid of diagrams, mathematical expressions and relevant equations where necessary, analyse how the appliances, equipment and the occupants of a building can be protected adequate against the following: (a) excess current and overload (b) electric shock (c) earth-leakage current (d) short-circuit. xi. Draw a neat sketch of the meter board and the distribution fuse board, show clearly how the cables enter the meter and leave the distribution board. xii. Using line diagram only show the connection to various load points from the distribution board. xiii. What is meant by the term “ring circuit”? Sketch neatly the wiring diagram of a typical ring circuit. xiv. Define the term “Diversity” as it is used in building electrical services. Give reasons why it is necessary to diversify building electrical installation loads? xv. Explain by which of a neat sketch how (a) underground and (b) overhead service connections are provided to a consumer from a low voltage distribution system. xvi. With the aid of good diagram, discuss the methods adopted for wiring lighting and power circuits and explain the limitation of each method. xvii. Explain the difference between cable insulation and cable sheathing xviii. What is the difference between a conductor and an insulator? Give two examples of conductors and insulators commonly used in building electrical services. xix. What is the permissible voltage drop on an installation as recommended by the IEE Regulations? xx. In an electrical design and wiring, discuss the various steps that must be taken to ensure selection of cable size of adequate current carrying capacity. xxi. A typical three-bedroom estate house with single phase supply having the following electrical loads: two lighting circuits, three ring mains to 13A power socket, five sockets on radial circuits, one 3kW immersion heater, one 12kW cooker and one shower. Determine the cable cross-sectional area for the installation. xxii. Produce a typical floor plan for a 2-bedroom flat with the electrical load requirement of the various rooms as follows. Show distinctly the appliances on the installation plan. Light (60w each) Fan (200w) each Ring circuit A/C (2Hp each) Water heater (1200w) Electric cooker (6000w) Bedroom 1 Bedroom 2 Sitting room xxiii. Refer to question (xxii) above, determine the maximum expected load required to design the required cable size using necessary diversity factor. xxiv. The electrical installation in a private house consists of the following loads: 15-60watts incandescent lamps lamp; 8-40watts fluorescent lamps; 2-2.5kw electric water heater, 3-2HP air conditioners. The floor area is 370m2. Determine the number of final sub-circuit to be used in the installation. xxv. A large factory shed consisting of 300 fluorescent lamps each of 80w rating. Calculate the power in kW and the current of the circuit if the supply is 240V single phase supply. xxvi. You have been chosen to design and construct the electrical services for the on-going projects at Federal University of Technology, Akure. The projects are located 50 km away from the sub-station located at the university main entrance gate where power will be tapped. Using line diagrams only and with inclusion of all safety devices, show how electrical power can be supplied and distributed to the following: (a) six-storey office building (b) commercial/industrial building (c) residential/domestic building (d) state the type(s) and size(s) of cable that you will use to carry out the following installations: service entrance, from meter board to distribution fuse board, lighting point, socket outlet to portable (ring main circuit) and fixed appliances (water heater, cooker control unit and air-conditioner). (a) Draw a neat sketch of the layout of wiring from the supplier`s pole to the distribution board of a consumer taking three phase supply, showing the meter, main switch and the distribution board. Explain the purpose of the each of the components. (b) The electrical installation in a private house consists of the following loads: 15 Nr - 60watts lamp, 8 Nr - 40watts lamp, 2 Nr - 2.5kW electric water heater, 3 Nr – 2H.P air conditioner. The floor area is 370m2. Determine the number of final sub-circuit to be used in the installation. (c) Define the term “Earthing”. Succinct discuss the reasons for providing earthing for electrical installations? (d) List the two types of earth electrode commonly used in building electrical services and explain the need for adding common salt (sodium chloride) into the ground while installing earth electrode. (a) Discuss the procedures for electric power generation, transmission and distribution (b) What do you understand by the term “Sub-circuit” Discuss the various final sub-circuit outlets for distributing electrical loads in buildings. (c) Explain why the electrical loads in building is divided into sub-circuits (d) Estimate the total daily energy consumption of the electrical appliances shown in Table 1 below. Hence, determine the monthly energy bill for the month of March, 2018 if the average cost of energy is N15.80 per kilowatt-hour Table 1 Power rating (W) Period of use 2Nr. Toaster 3Nr. Water heater 4Nr. Television 28Nr. Lamps 3Nr. Electric iron 1 hour 2Nr. Pumping machine 1 hour Your company has been chosen to design the supply and distribution of electricity for the on-going project at the Redeemer University, Ede. Using line diagrams only, show how electrical power can be distributed to the following consumers: (a) a consumer on single phase supply (b) a consumer on three phase supply In all cases, discuss the function(s) of each of the appurtenances. (c) If the electrical installation in one of the buildings consists of the following loads: 15Nr-60 W lamp, 8Nr-40 W lamp, 2Nr-2.5 kW electric water heater, 3 Nr-2 HP air conditioner, determine the number of final sub-circuit to be used in the installation. The floor area is 370m2. (d) Enumerate the various final sub-circuits necessary for distributing electrical loads in these buildings (e) List the type and size of cable that can be used to carry out the following electrical loads in the building: lighting load, socket outlet to portable electrical load and fixed appliance. (a) Define the term “Earthing” and explain the reason(s) for providing earthing to electrical installations. (b) List the two types of earth electrode commonly used in building electrical services and explain the rationale for adding common salt (sodium chloride) into the ground during the installation of earth electrode. (c) Draw a neat sketch of the meter board and the distribution board showing clearly how the cables enter the meter and leave the distribution board. (d) Explain the causes of the following electrical phenomena: (i) excess-current and overload (ii) electric shock (iii) earth-leakage current (iv) short-circuit. Analyse how appliances, equipment and the occupants of a building can be adequately protected against the phenomena. (e) Explain the difference between running and stating current. (a) The electrical installation in a private house consists of the following loads: 15-60watts lamp, 8-40watts lamp, 2-2.5Kw electric water heater, 3-2H.P air conditioner. The floor area is 370m2. Determine the number of final sub-circuit to be used in the installation (b) State the size of cable and method of protection for lighting circuit, socket outlets to portables appliances, cooker control unit and air-conditioning system to ensure safety of the installations. With the aids of diagrams, sketches, mathematical expressions and relevant equations etc discuss the causes and analyse how the appliances, equipment and the occupants of a building can be adequately protected against (i) excess-current and overload (ii) electric shock (iii) earth-leakage current (iv) short-circuit.

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