Estimation of Electrical Wiring Short Question and Answer

Estimation of Electrical Wiring Short Question and Answer Points : estimation of electrical wiring short question and answer Q # 1: What should be the resistance of earth continuity conductor in the completed installation? Answer: Circuit-breaker measured from the connection with the earth electrode to any points in the earth continuity conductor in the completed installation shall not exceed one ohm. Q # 2: What should be the estimate of length of wire for wiring? Answer: The length of wire can be taken as 2.5 times the length of conduit for looping system and 2 times for junction box system. Q # 3: What should be the estimate of length of wire for switch boxes? Answer: The length of the looping wire etc. in switch boxes shall not be lesser than 0.5 times of the height of the box itself. Q # 4: What should be the estimate form the main board for connection to meter board? Answer: The length of wire to be provided form the main board for connection to meter board shall not be more than 7.5 meters and should be one size higher than the actual size selected for wiring. Q # 5: What should be the clearance provided between ceiling and the running installation on the wall Answer: The c1erance provided between ceiling and the running installation on the wall normally is taken as 0.25 to 0.5 meters. However this should be judged only by the type of building, beams crossing etc. Appearance should also be given due consideration. Q # 6: What is the mounting rule for control switches in power wiring? Answer: All the controlling switches in power wiring shall be mounted on the’ metal frame of suitable design. Q # 7: Is wiring of power and light circuit separated from each other? Answer: The wiring of power and light must be separated from each other, from the commencement of supply itself and shall not be run on the same conduits. Q # 8: What is the rule for providing earth to sub-circuits and lighting loads? Answer: All the sub-circuits must have its own continuous earth wire. There is no necessity of providing separate earth for the lighting loads by the consumer; supplier’s earth shall be sufficient. Q # 9: Wharf should be the percentage for material handling? Answer: For material handling (i.e., transporting charges of materials to the site) will usually be judged by route length and available cargo movers. Any how it should not be more than 5% (max.) of material cost. Q # 10: What estimate of overhead charges will generally be assumed for a project? Answer: Overhead charges will generally be assumed as 10% to 15% of the total cost. In large installations, tool charges are to be included. It is usually 3 to 5% of the total cost. Q # 11: How much any wiring system has to last? Answer: Any wiring system has to last for 25 years. Hence high quality materials are to be used, high quality workmanship must be executed through qualified contractors, hence materials cost and labour charges will be high. Q # 12: What technique is used for 3 pin plug points at switch boards? Answer; Provide 3 pin plug points at switch boards, with switch controls and solidly earth third pin. Q # 13: How many earth electrodes be provided for single phase supply and 3 phase supply? Answer: The consumer should provide ONE earth electrode for single phase supply and TWO earth electrodes for 3 phase supply. Earth pipe dimension: 40 mm dia and 2.5 M length. Q # 14: What is the status earthing for more than one eatlhing system? What should be, the minimum size of earth lead? Answer: If more than one electrode is provide, all earth electrodes must be linked, for combined low resistance. Water them periodically. Use a minimum of 14 SWG Tinned Copper (2.0320 mm diameter) for earth leads.