JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B. Tech III Year II Semester DESIGN ESTIMATION AND COSTING OF ELECTRICAL SYSTEMS Previous Question Paper (February - 2023 - R16)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory (25 marks). iii) In Part B, Answer any one question from each unit (10 marks each).
PART - A
Answer all questions:
What is a short circuit fault?
Answer
A short circuit fault is an abnormal, low-impedance connection between two points of different potential in an electrical circuit. This results in an excessive flow of current, often many times the rated capacity, which can cause severe thermal damage, fire hazards, and mechanical stress on electrical equipment.
What is the purpose of earth wire?
Answer
The primary purpose of an earth wire (or grounding conductor) is to provide a low-resistance path for fault current to flow to the ground. This ensures:
- Safety: It prevents the metal casing of electrical appliances from becoming live during an insulation failure, thereby protecting users from electric shock.
- Protection: It facilitates the operation of protective devices like fuses or circuit breakers by allowing sufficient fault current to flow, triggering an immediate disconnection.
- Voltage Stabilization: It helps maintain a stable reference potential for the electrical system.
Which type of wiring is used in commercial building?
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How to calculate pump load requirement in residential building?
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What is an underground cable?
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What are the features of a distribution line?
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What is a substation?
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Why a substation is needed?
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What is the full form of CFL?
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What are the objectives of illumination?
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PART - B
Describe the connection of three phase four wire distribution system.
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How to calculate the size of wire in electrical installations? Explain.
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How to estimate and cost the electrical installations? Explain.
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Discuss about the protection of electric installations against over load.
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What are the general rules and guidelines for electrical installations of residential buildings? Explain
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Explain the procedure of estimating and costing of the electrical installations of small industries
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What are the general rules and guidelines for electrical installations of small industries? Explain.
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Explain the procedure of estimating and costing of the electrical installations of commercial buildings
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What are the differences between over head and underground cables? Explain.
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Explain various types of support used in distribution lines in detail.
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Which material is used for distributed line? Explain.
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Explain the design of underground cables in detail.
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Estimate the quantity of material required for design of a floor mounted substation with neat sketch.
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What are the types of outdoor substations? Explain briefly the quantity of material required for it.
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State and explain the laws of illumination.
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How an LED works? Explain.
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What is the standard procedure to measure luminous intensity? Explain.
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Explain different types of light sources in detail.
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