Tiêu đề 22627-2022-Summer-model-answer-paper.pdf ✅

MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2013 Certified) SUMMER – 2022 EXAMINATION Subject Name: Electrical Estimation &Contracting Model Answer: Page 2 of 25 22627: EEC 8. All incandescent lamps, unless otherwise required, are to be hung at a height of 2.5 meters above the floor level. And ceiling fans are to be hung 2.75 meters above the floor. 9. Lights and fans may be wired on a common circuit. Each sub-circuit is not to have more than a total ten points of lights, fans and socket-outlets. The load on each sub-circuit is to be restricted to 800 watts. 10. No fuse and switch is to be provided in earthed conductor. 11. Every circuit or apparatus is to be provided with a separate means of isolation such as a switch. 12. All circuit or apparatus requiring attention are to be provided with means of access to it. 13. In any building, light and fan wiring and power wiring are to be kept separate. 14. In 3-Phase, 4-wire installation the load is to be distributed equally on all phases. 15. No additional load is to be connected to an existing installation unless it has been ascertained that the installation can safely carry the additional load and that the earthing arrangements are adequate. 16. Lamp holders used in bath rooms are to be constructed or shrouded in insulating materials and fitted with protective shield and earth continuity conductor is not to be size less than 7/0.915 mm. 17. The metal sheaths or conduits for all wiring and metal coverings of all consuming apparatus or applications is to be properly earthed in order to avoid danger from electrical shock due to leakage or failure of insulation. 18. Each sub-circuit is to be protected against excessive current (that may occur either due to over load or due to failure of insulation) by fuse or automatic circuit breaker. 19. All light conductors are to be insulated or otherwise safe guarded to avoid danger. After completion of work the installations are to be tested (the test are to be carried out as described) before energization. 20. Earth Resistance: should be very low for domestic installation it should be equal to or less than 5 ohms to 8 ohm c) Differentiate between non-industrial and industrial load. Ans: Sr. No. Basis Industrial Load Non-industrial Load 1 Location In industrial estate or MIDC area In highly population density Residential / commercial area 2 Cost More Less 3 Precautions All precautions should be taken All safety precautions should be taken 4 Supply Generally 3-ph, 400V AC supply is provided Generally 1-ph, 230V AC supply is provided 5 Tariff Time-of-Day tariff Block rate tariff 1 Mark for each of any two bits = 2 Marks d) State the purpose of guarding wire used in distribution lines Ans: Purpose of guarding wire used in distribution lines: Guarding wire is used to protect the personnel, lines or equipment in the event of fault. When distribution line conductor snaps (brakes down) during abnormal weather conditions such as heavy rains, storms and lightning, the live conductor touches the guard wire, which is earthed. Thus snapping of conductor creates earth fault, causing fuse to blow or protective relay to 2 Marks for correct answer
MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2013 Certified) SUMMER – 2022 EXAMINATION Subject Name: Electrical Estimation &Contracting Model Answer: Page 3 of 25 22627: EEC operate and disconnect the faulty line from supply. Thus snapped conductor becomes dead and no harm can occur even if somebody touches such conductor. e) Write the aim of public lighting installation. Ans: Aim of Public Lighting Installation: i) To improve the visibility to facilitate the flow of traffic and pedestrian. ii) Reduction in night time accidents. iii) Prevention of crimes and aid to police protection. iv) To enhance the appearance of roads at night. v) Promotion of business and working hours in industry during nights. 1 Mark for each of any two aims = 2 Marks f) State the purpose of estimating and costing. Ans: Purpose of Estimating and Costing: (a) Administration Approval/For Taking in Principle Decision to go Ahead: To take “In principle decision” to go ahead with house construction /project, which is commonly known as “Administration approval” in government departments. (b) Selection of Construction Materials/Technology: Once in principle decision is taken, the owner prepare design including planning & deciding right construction materials, to decide right technology, as well as the size and area of the project and, will finally decide whether to go ahead or not or what to change in the project? (c) Required Quantity of Materials: Once designs are ready one can work out detailed estimates and based on the same one can work out the quantity, cost of materials, required to complete the work. (d) Labour Requirement: To know the detailed cost of different categories of labour needed like masonry, excavation, RCC (reinforced cement concrete) work, plaster, painting etc. (e) Equipment, Tools and Plants Requirement: To know the detailed cost of equipment, tools, plants and machinery to be used in construction. (f) To Plan Time: To plan the time schedule of construction depending upon the cash flow i.e. availability of funds. (g) Final Decision: At this stage, one finally need to decide whether to go ahead with the construction plan or not. (h) Project Sanction: To give the sanction for the project with the modification in the plan if any, keeping budget & time in view. (i) Cost Control: Cost control is the main objective of estimating and costing. (j) To Invite Tender/ Quotations: To invite Tender/Quotations from contractors and compare rates with estimates and finalize the contractor based on quantity/rates and work items. (k) Valuation: Valuation of existing property. 1 Mark for each of any two purposes = 2 Marks