Bissoy.com
Doctors Medicines MCQs Q&A

What should be the cross section when a copper strip is used as an earth wire?

What should be the cross section when a copper strip is used as an earth wire? Correct Answer <span style="">Not less than 25 mm × 1.6 mm</span>

Strip earthing:

  • This type of earthing is used at places that have rocky earth bed.
  • In this system of earthing, the strip electrode of the cross-sectional area not less than 25 mm × 1.6 mm if copper and 25 mm × 4 mm if GI or steel.
  • It buried in horizontal trenches of a minimum depth of 0.5 m.
     

Rod earthing:

  • This system of earthing is suitable for areas that are sandy in character.
  • This system of earthing is very cheap as no excavation work is involved.
     

Plate earthing: It is used for larger stations and transmission lines, where the fault current, likely to be high.

Pipe earthing:

  • It is used for ordinary soil or dry and rocky soil.
  • The size of the pipe depends upon the current to be carried and the type of soil.
  • Usually, the pipe used for this purpose is of diameter 38 mm and 2.5 meters in length for ordinary soil or of greater length in case of dry and rocky soil.

Related Questions

When the main switch of the house is put off it disconnects the: (A) Live wire only (B) Live wire and the earth wire (C) Live wire and the neutral wire (D) Earth wire and the neutral wire
A telephone switchboard 100 pair cable can be made up with either enameled wire or tinned wire. There will be 400 soldered connections. The cost of soldering a connection on the enameled wire will be P 1.65 on the tinned wire, it will be P 1.15. A 100- pair cable made up with enameled wire cost P 0.55 per linear foot and those made up of tinned wire cost P 0.75 per linear foot. Determine the length of cable run in feet so that the cost of each installation would be the same.
A group of 74 students of Class XI went on picnic. The number of students who went on picnic by each section is as follows: Section A = 15 Section B = 24 Section C = 15 Section D = 20 5 students from Section A spent as much as 4 students from Section B. 12 Section B students spent as much as 9 Section C students and 6 Section C students spent as much as 8 Section D student. If every student of a particular section spent the same amount and all the students spent Rs. 23,370 altogether, find the amount spent by each student of Section D?
Two wires have the same material and have the same volume. However wire 1 had cross sectional area A and wire 2 has cross sectional area 3A. If the length of wire 1 increases by ∆x on applying force F, how much force is needed to stretch wire 2 by the same amount?
A wire having an area of cross section = 10sqm and another wire having an area of cross section= 15sqm, have the same length and are made up of the same material. Which wire has more resistance?
Two wires are made having same length and area of cross-section A. Wire 1 is made of copper and wire 2 is made of aluminium. It is given that the electrical conductivity of copper is more than that of aluminium. In this context, which one of the following statements is correct?
Two wires are made having same length l and area of cross-section A. Wire 1 is made of copper and wire 2 is made of aluminium. It is given that the electrical conductivity of copper is more than that of aluminium. In this context, which one of the following statements is correct?
A wire of copper having length I and area of cross-section A is taken and a current / is flown through it. The power dissipated in the wire is P. If we take an aluminium wire having same dimensions and pass the same current through it, the power dissipated will be
A wire of copper having length I and area of cross-section A is taken and a current i is flown through it. The power dissipated in the wire is P. If we take an aluminium wire having same dimensions and pass the same current through it, the power dissipated will be
In the question below, are given a statement followed by three courses of actions numbered I, II and III. On the basis of the information given, you have to assume everything in the statement to be true, and then decide which of the following suggested courses of actions logically follow(s) for pursuing. Statement: Specialty steel and wire ropes maker Usha Martin's decision to sell one of its core businesses - steelmaking - to prune outstanding debt, marks the rare instance of an Indian corporate borrower meeting its loan obligations through divestment. The slump sale is a milestone in the six-decade history of the Kolkata-based company, whose board on Saturday approved the divestment of its one million ton steel business in favor of Tata Steel for Rs 4,600 crore.  Courses of action: I. Proceeds will be used to ‘first repay existing lenders of the company’. Usha Martin will retain a profitable wire ropes unit as residual business, and has plans to scale it up significantly.  II. As part of the transaction, Usha Martin has entered into a five-year deal with The Tatas for sale of steel at market price to the wire-ropes business.  III. Usha Martin is among the top four wire rope players globally. With oil prices going up and strong trend in demand in Europe, the Ebitda in the wire-ropes business has improved.