What is Earthing

Introduction:

The main reason for doing earthing in electrical network is for the safety. When all metallic parts in electrical equipments are grounded then if the insulation inside the equipments fails there are no dangerous voltages present in the equipment case. If the live wire touches the grounded case then the circuit is effectively shorted and fuse will immediately blow. When the fuse is blown then the dangerous voltages are away.

Purpose of Earthing:

(1)  Safety for Human life/ Building/Equipments:

  • To save human life from danger of electrical shock or death by blowing a fuse i.e. To provide an alternative path for the fault current to flow so that it will not endanger the user
  • To protect buildings, machinery & appliances under fault conditions.
  • To ensure that all exposed conductive parts do not reach a dangerous potential.
  • To provide safe path to dissipate lightning and short circuit currents.
  • To provide stable platform for operation of sensitive  electronic equipments   i.e. To maintain the voltage at any part of an electrical system at a known value so as to prevent over current or excessive voltage on the appliances or equipment .

(2)  Over voltage protection:

  • Lightning, line surges or unintentional contact with higher voltage lines can cause dangerously high voltages to the electrical distribution system. Earthing provides an alternative path around the electrical system to minimize damages in the System.

(3)  Voltage stabilization:

  • There are many sources of electricity. Every transformer can be considered a separate source. If there were not a common reference point for all these voltage sources it would be extremely difficult to calculate their relationships to each other. The earth is the most omnipresent conductive surface, and so it was adopted in the very beginnings of electrical distribution systems as a nearly universal standard for all electric systems.

Conventional methods of earthing:

(1)  Plate type Earthing:

  • Generally for plate type earthing normal Practice is to use
  • Cast iron plate of size 600 mm x600 mm x12 mm. OR
  • Galvanized iron plate of size 600 mm x600 mm x6 mm. OR
  • Copper plate of size 600 mm * 600 mm * 3.15 mm
  • Plate  burred at the depth of 8 feet in the vertical position and GI strip of size 50 mmx6 mm bolted with the plate is brought up to the ground level.
  • These types of earth pit are generally filled with alternate layer of charcoal & salt up to 4 feet from the bottom of the pit.

(2)  Pipe type Earthing:

  • For Pipe type earthing normal practice is to use
  • GI pipe [C-class] of 75 mm diameter, 10 feet long welded with 75 mm diameter GI flange having 6 numbers of holes for the connection of earth wires and inserted in ground by auger method.
  • These types of earth pit are generally filled with alternate layer of charcoal & salt or earth reactivation compound.

Method for Construction of Earthing Pit (Indian Electricity Board):

  • Excavation on earth for a normal earth Pit size is 1.5M X 1.5M X 3.0 M.
  • Use 500 mm X 500 mm X 10 mm GI Plate or Bigger Size for more Contact of Earth and reduce Earth Resistance.
  •  Make a mixture of Wood Coal Powder Salt & Sand all in equal part
  •  Wood Coal Powder use as good conductor of electricity, anti corrosive, rust proves for GI Plate for long life.
  • The purpose of coal and salt is to keep wet the soil permanently.
  • The salt percolates and coal absorbs water keeping the soil wet.
  • Care should always be taken by watering the earth pits in summer so that the pit soil will be wet.
  • Coal is made of carbon which is good conductor minimizing the earth resistant.
  • Salt use as electrolyte to form conductivity between GI Plate Coal and Earth with humidity.
  • Sand has used to form porosity to cycle water & humidity around the mixture.
  • Put GI Plate (EARTH PLATE) of size 500 mm X 500 mm X 10 mm in the mid of mixture.
  • Use Double GI Strip size 30 mm X 10 mm to connect GI Plate to System Earthling.
  •  It will be better to use GI Pipe of size 2.5″ diameter with a Flange on the top of GI Pipe to cover GI Strip from EARTH PLATE to Top Flange.
  • Cover Top of GI pipe with a T joint to avoid jamming of pipe with dust & mud and also use water time to time through this pipe to bottom of earth plate.
  • Maintain less than one Ohm Resistance from EARTH PIT conductor to a distance of 15 Meters around the EARTH PIT with another conductor dip on the Earth at least 500 mm deep.
  • Check Voltage between Earth Pit conductors to Neutral of Mains Supply 220V AC 50 Hz it should be less than 2.0 Volts.

Factors affecting on Earth resistivity:

(1)  Soil Resistivity:    

  • It is the resistance of soil to the passage of electric current. The earth resistance value (ohmic value) of an earth pit depends on soil resistivity. It is the resistance of the soil to the passage of electric current.
  • It varies from soil to soil. It depends on the physical composition of the soil, moisture, dissolved salts, grain size and distribution, seasonal variation, current magnitude etc.
  • In depends on the composition of soil, Moisture content, Dissolved salts, grain size and its distribution, seasonal variation, current magnitude.

(2)  Soil Condition:

  • Different soil conditions give different soil resistivity. Most of the soils are very poor conductors of electricity when they are completely dry. Soil resistivity is measured in ohm-meters or ohm-cm.
  • Soil plays a significant role in determining the performance of Electrode.
  • Soil with low resistivity is highly corrosive. If soil is dry then soil resistivity value will be very high.
  • If soil resistivity is high, earth resistance of electrode will also be high.

(3)  Moisture:  

  • Moisture has a great influence on resistivity value of soil. The resistivity of a soil can be determined by the quantity of water held by the soil and resistivity of the water itself. Conduction of electricity in soil is through water.
  • The resistance drops quickly to a more or less steady minimum value of about 15% moisture. And further increase of moisture level in soil will have little effect on soil resistivity. In many locations water table goes down in dry weather conditions. Therefore, it is essential to pour water in and around the earth pit to maintain moisture in dry weather conditions. Moisture significantly influences soil resistivity

(4)  Dissolved salts:

  • Pure water is poor conductor of electricity.
  • Resistivity of soil depends on resistivity of water which in turn depends on the amount and nature of salts dissolved in it.
  • Small quantity of salts in water reduces soil resistivity by 80%. common salt is most effective in improving conductivity of soil. But it corrodes metal and hence discouraged.

(5)  Climate Condition:

  • Increase or decrease of moisture content determines the increase or decrease of soil resistivity.
  • Thus in dry whether resistivity will be very high and in monsoon months the resistivity will be low.

 (6)  Physical Composition:

  • Different soil composition gives different average resistivity. Based on the type of soil, the resistivity of clay soil may be in the range of 4 – 150 ohm-meter, whereas for rocky or gravel soils, the same may be well above 1000 ohm-meter.

 (7)  Location of Earth Pit :

  • The location also contributes to resistivity to a great extent. In a sloping landscape, or in a land with made up of soil, or areas which are hilly, rocky or sandy, water runs off and in dry weather conditions water table goes down very fast. In such situation Back fill Compound will not be able to attract moisture, as the soil around the pit would be dry. The earth pits located in such areas must be watered at frequent intervals, particularly during dry weather conditions.
  • Though back fill compound retains moisture under normal conditions, it gives off moisture during dry weather to the dry soil around the electrode, and in the process loses moisture over a period of time. Therefore, choose a site that is naturally not well drained.

 (8)  Effect of grain size and its distribution:

  • Grain size, its distribution and closeness of packing are also contributory factors, since they control the manner in which the moisture is held in the soil.
  • Effect of seasonal variation on soil resistivity: Increase or decrease of moisture content in soil determines decrease or increase of soil resistivity. Thus in dry weather resistivity will be very high and during rainy season the resistivity will be low.

(9)  Effect of current magnitude:

  • Soil resistivity in the vicinity of ground electrode may be affected by current flowing from the electrode into the surrounding soil.
  • The thermal characteristics and the moisture content of the soil will determine if a current of a given magnitude and duration will cause significant drying and thus increase the effect of soil resistivity

(10) Area Available:

  • Single electrode rod or strip or plate will not achieve the desired resistance alone.
  •  If a number of electrodes could be installed and interconnected the desired resistance could be achieved. The distance between the electrodes must be equal to the driven depth to avoid overlapping of area of influence. Each electrode, therefore, must be outside the resistance area of the other.

(11)  Obstructions:

  • The soil may look good on the surface but there may be obstructions below a few feet like virgin rock. In that event resistivity will be affected. Obstructions like concrete structure near about the pits will affect resistivity. If the earth pits are close by, the resistance value will be high.

(12)    Current Magnitude:

  • A current of significant magnitude and duration will cause significant drying condition in soil and thus increase the soil resistivity.

Measurement of Earth Resistance by use of Earth Tester:

  • For measuring soil resistivity Earth Tester is used. It is also called the “MEGGER”.
  • It has a voltage source, a meter to measure Resistance in ohms, switches to change instrument range, Wires to connect terminal to Earth Electrode and Spikes.
  • It is measured by using Four Terminal Earth Tester Instrument. The terminals are connected by wires as in illustration.
  • P=Potential Spike and C=Current Spike. The distance between the spikes may be 1M, 2M, 5M, 10M, 35M, and 50M.
  • All spikes are equidistant and in straight line to maintain electrical continuity.  Take measurement in different directions.
  • Soil resistivity =2πLR.
  • R= Value of Earth resistance in ohm.
  • Distance between the spikes in cm.
  • π  =  3.14
  • P = Earth resistivity ohm-cm.
  • Earth resistance value is directly proportional to Soil resistivity value

Measurement of Earth Resistance (Three point method):

 

  • In this method earth tester terminal C1 & P1 are shorted to each other and connected to the earth electrode (pipe) under test.
  • Terminals P2 & C2 are connected to the two separate spikes driven in earth.  These two spikes are kept in same line at the distance of 25 meters and 50 meters due to which there will not be mutual interference in the field of individual spikes.
  • If we rotate generator handle with specific speed we get directly earth resistance on scale.
  • Spike length in the earth should not be more than 1/20th distance between two spikes.
  • Resistance must be verified by increasing or decreasing the distance between the tester electrode and the spikes by 5 meter. Normally, the length of wires should be 10 and 15 Meter or in proportion of 62% of ‘D’.
  • Suppose, the distance of Current Spike from Earth Electrode D = 60 ft, Then, distance of Potential Spike would be 62 % of D = 0.62D i.e.  0.62 x 60 ft = 37 ft.

Four Point Method:

  • In this method 4 spikes are driven in earth in same line at the equal distance.  Outer two spikes are connected to C1 & C2 terminals of earth tester.  Similarly inner two spikes are connected to P1 & P2 terminals.  Now if we rotate generator handle with specific speed, we get earth resistance value of that place.
  • In this method error due to polarization effect is eliminated and earth tester can be operated directly on A.C.

 GI Earthing Vs Copper Earthing:

  • As per IS 3043, the resistance of Plate electrode to earth (R) = (r/A) X under root(P/A).
  • Where r = Resistivity of Soil Ohm-meter.
  • A=Area of Earthing Plate m3.
  • The resistance of Pipe electrode to earth (R) = (100r/2πL) X loge (4L/d).
  • Where L= Length of Pipe/Rod in cm
  • d=Diameter of Pipe/Rod in cm.
  • The resistivity of the soil and the physical dimensions of the electrode play important role of resistance of Rod with earth.
  • The material resistivity is not considered important role in earth resistivity.
  • Any material of given dimensions would offer the same resistance to earth. Except the sizing and number of the earthing conductor or the protective conductor.

 Pipe Earthing Vs Plate Earthing:

  • Suppose Copper Plate having of size 1.2m x 1.2m x 3.15mm thick. soil resistivity of 100 ohm-m,
  • The resistance of Plate electrode to earth (R)=( r/A)X under root(π/A) = (100/2.88)X(3.14/2.88)=36.27 ohm
  • Now, consider a GI Pipe Electrode of 50 mm Diameter and 3 m Long. soil resistivity of 100 Ohm-m,
  • The resistance of Pipe electrode to earth (R) = (100r/2πL) X loge (4L/d) = (100X100/2X3.14X300) X loge (4X300/5) =29.09 Ohm.
  • From the above calculation the GI Pipe electrode offers a much lesser resistance than even a copper plate electrode.
  • As per IS 3043 Pipe, rod or strip has a much lower resistance than a plate of equal surface area.

 Length of Pipe Electrode and Earthing Pit:

  •  The resistance to earth of a pipe or plate electrode reduces rapidly within the first few feet from ground (mostly 2 to 3 meter) but after that soil resistivity is mostly uniform.
  • After about 4 meter depth, there is no appreciable change in resistance to earth of the electrode. Except a number of rods in parallel are to be preferred to a single long rod.

 Amount of Salt and Charcoal (more than 8Kg) :

  •  To reduce soil resistivity, it is necessary to dissolve in the moisture particle in the Soil.
  • Some substance like Salt/Charcoal is highly conductive in water solution but the additive substance would reduce the resistivity of the soil, only when it is dissolved in the moisture in the soil after that additional quantity does not serve the Purpose.
  • 5% moisture in Salt reduces earth resistivity rapidly and further increase in salt content will give a very little decrease in soil resistivity.
  • The salt content is expressed in percent by weight of the moisture content in the soil. Considering 1M3 of Soil, the moisture content at 10 percent will be about 144 kg. (10 percent of 1440 kg). The salt content shall be 5% of this (i.e.) 5% of 144kg, that is, about 7.2kg.

 Amount of  Water Purring:

  •  Moisture content is one of the controlling factors of earth resistivity.
  • Above 20 % of moisture content, the resistivity is very little affected. But below 20% the resistivity increases rapidly with the decrease in moisture content.
  • If the moisture content is already above 20% there is no point in adding quantity of water into the earth pit, except perhaps wasting an important and scarce national resource like water.

 Length Vs Diameter of Earth Electrode:

  • Apart from considerations of mechanical strength, there is little advantage to be gained from increasing the earth electrode diameter with the object in mind of increasing surface area in contact with the soil.
  • The usual practice is to select a diameter of earth electrode, which will have enough strength to enable it to be driven into the particular soil conditions without bending or splitting. Large diameter electrode may be more difficult to drive than smaller diameter electrode.
  • The depth to which an earth electrode is driven has much more influence on its electrical resistance characteristics than has its diameter.

Maximum allowable Earth resistance:

  • Major power station= 0.5 Ohm.
  • Major Sub-stations= 1.0 Ohm
  • Minor Sub-station = 2 Ohm
  • Neutral Bushing. =2 Ohm
  • Service connection = 4 Ohm
  • Medium Voltage Network =2 Ohm
  • L.T.Lightening Arrestor= 4 Ohm
  • L.T.Pole= 5 Ohm
  • H.T.Pole =10 Ohm
  • Tower =20-30 Ohm

 Treatments to for minimizing Earth resistance:

  • Remove Oxidation on joints and joints should be tightened.
  • Poured sufficient water in earth electrode.
  • Used bigger size of Earth Electrode.
  • Electrodes should be connected in parallel.
  • Earth pit of more depth & width- breadth should be made.
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About Jignesh.Parmar
Jignesh Parmar has completed his B.E(Electrical) from Gujarat University. He has more than 11 years experience in Power Transmission-Power Distribution-Electrical energy theft detection-Electrical Maintenance-Electrical Projects(Planning-Designing-coordination-Execution). He is Presently associate with one of the leading business group as a Assistant Manager at Ahmedabad,India. He is Freelancer Programmer of Advance Excel and design useful Excel Sheets of Electrical Engineering as per IS,NEC,IEC,IEEE codes. He is technical Author for "Electrical Mirror" and "Electrical India" Magazines. He is Technical Blogger and Familiar with English, Hindi, Gujarati, French languages. He wants to Share his experience & knowledge and help technical enthusiasts to find suitable solutions and updating themselves on various Engineering Topics.

56 Responses to What is Earthing

  1. Anil says:

    what is the minimum frequency of earthpit maintenence as per indian standards in a LV installation like for example in petrol pumps etc.
    Our office has incomer feeder of 11 kv with sanctioned load of 600 kw in delhi. What should be the value of grid resistance /Individual pit resistance and frequency of eart pit maintenance that should be observed in such instllations, asper the relevent indian IE rules.

    Thanks,
    anil

  2. umashankar says:

    Hi parmar,

    Nice to see u r aticle, its great and useful to other electrical engineers for their reference, i need to share and learn about the following points.

    1. Electrical clearance and creepage distance for air and oil medium, wat would be the minimum clearances required between two phase contacts and phase to earth clearance and phase to phase clearance inside the oil medium (transformer oil) and also outdoor with reference to study.

    2. sizing of copper conductor, how to choose the copper conductor size for 600 A and 2000 amps, how to derive and references copper contact will be single piece. wat would be the max amps that can allow per sqmm conductor, temperature withstand.

    thank you

  3. Laxmi Narayan Sharma says:

    good information

  4. Where does electricity go after it goes through our appliances?

    • m.janardhana reddy says:

      It is utilised by them as by converting into another form of energy (or) when earthed it will be nuetralised by earth potential (as earth is always at zero potential)

  5. Yallappa says:

    please mail

  6. Yallappa says:

    please post technical publications to my e-mail id

  7. Vishwa Murthy says:

    Sir, I have a small doubt regarding earthing of power transformer neutral..sir whether the earth pit connected to neutral of PTR is kept separately from the grid earth mat or this has to be connected with the grid earth mat and whats the reason behind this.??

  8. Upendra Badal says:

    sir,
    nice to read ur article its very useful.
    however i have a question regarding the difference between Body earthing and Neutral Earthing for Distribution Transformer and/or Diesel generating set is there any differences? and can we bond both earth station together or there should be different earthing?

  9. Asman says:

    Thanku very much Jignesh for of the share your experiance with us and we pray for you regarding u will share your expiriance with us and u go always boss

  10. Sridharan S says:

    To:Jignesh.Parmar

    Thank you very much for your article on “Impact of Floating Neutral”. I live in chennai in an apt where there are 11 flats and a transformer (3 phase, 1 neutral grounded) inside the premises supplied by the electricity board. We had 3 major “booms” from the transformer in the past one month and the flats suffered major losses of equipment (lights, fans, inverters, TV, lift etc). We called some specialists and they said the reason is the “floating neutral” (not grounded properly) on the distribution transformer side. The local EB staff came and have strengthened the earthing on the transformer side. They have also connected the neutral in the DB box of the transformer to the earth pit.

    On our side i.e. the Flat main distribution panel, they have recommended that we strengthen our earthing by installing 2 new earth pits and connecting them to the common neutral (coming from the transformer). Pls confirm whether the advise is ok; specifically can we also ground the neutral on our distribution panel.
    Thank you

    • If Transformer is dedicated to your Apartment and This transformer neutral is earthed at T/C and If Your main Panel is also in Your Premises near Transformer (Not so Long Distance) than It might be not make worse effect on your system but I have not yet done such type of Practice.
      Here please note that Neutral always drain to earth which have low impedance path so some of current may drain to your panel’s Neutral earth or some at Your T/C neutral earth.Both Neutral earth may be not at equal impedance so may be some potential difference hence at some time you may get Neural Back at either at T/c or Panel.
      System is always work in healthy condition when amount of feeding current from it’s feeding station (here T/C or Generator) is need to be back in same amount to it’s source and drain to earth.
      In your case If Distance between T/C neutral earth and Your Panel is huge, If Some Other load which are not feed from your panel but still connected on T/C may be get worse effect on system.
      Please concern Local authority for such type of connection.

      • Sridharan S says:

        Thank you for your reply

      • Sridharan S says:

        Dear Sir,

        Thank you for nice reply.

        We have a dedicated 3-phase, 4-wire 100 KVA transformer. As I told you in my earlier mail, we had major damages to our equipment-lift,lights, fans etc. in our apartments in the past one month. We measured the current at the consumer distribution panel and got the following values:

        Distribution panel currents:

        R-Phase 10.4 Amps
        Y-Phase 7.4 Amps
        B-Phase 8.4 Amps

        Neutral 5.6 Amps

        The earth resistance was also checked at the transformer side and we got the following value:

        Transformer Earth Pit: Earth Value: 4.2 Ohms.

        We have only body earth at the distribution panel. Neutral is not grounded.

        Kindly advise what needs to be done.

        Thanks & Regards
        Sridharan

      • Neutral of Your Panel need not to connect Neutral Earth Pit.
        Please measure Voltage between your neutral and Earth wire It should be less than 2Volt if You find more than 2Volts ,means You have still Problem of Neutral.
        First measure Voltage between Neutral and Earth..

      • S Sridharan says:

        Sir,
        Thank you for your reply.

        The current on the neutral wire at the Panel when checked with the clamp meter was 5.6 Amps. The voltage between Neutral and Earth at the Panel is 0 volt.

        We are planning to do the following:

        On the Transformer Side:
        1) Strengthen Existing Body earth on the transformer side
        2) Prepare another earth pit on the transformer side and connect the transformer neutral to this pit.
        3) If required,make one more earth pit on the transformer side and connect this also to the transformer neutral

        Hope we are on the right track. pls advise
        Thanks & Regards
        Sridharan

  11. K.Venkat Ramana says:

    Dear Sir Can you please explain me, with clear example of Star and Delta connection for a motor, why we use Star and Delta with a small ckt diagram.

  12. anoop sukumaran says:

    dear sir,

    by profession am a mechanical engineer and presently working as a MEP engineer in a landscaping company .so i need to do all the electrical landscape lighting also.i got a drawing of electrical lighting. the fixtures are connected from a LCP with distribution boards. each LCP having 6 or more circuits. in drawing each circuit is grounded at the last end point. also the lcp cabinet also grounded.does it required actually in the site??? then how we will select the earthing pit and electrode dimensions for purchase and installation…???

    i will be really thankful , if you help me in this….
    thanks and regards
    Anoop Sukumaeran
    UAE

  13. Venkatesh says:

    shall we use Earthing Backfill Compound for conventional earth pits???
    Sir please give a reply to my mail.

  14. K.Sudhesh says:

    For my house wiring what are all the standards to be adhered for earth pit measurements, pipe standard and related things for safe earthing. if i get a sketch reg. earthing it will be useful..

  15. nmr says:

    SIRS,
    A. IF THE DISTANCE BETWEEN TWO EARTH ELECTRODES IS LESS THAN 6 MTS ( 2 X 3=6 MTS) WHAT IS THE EFFECT ON THE ELECTRICAL SYSTEM.

    B.IF THE DISTANCE BETWEEN TWO EARTH ELECTRODES IS MORE THAT 6 MTS WHAT IS THE EFFECT ON THE ELECTRICAL SYSTEM.

    C. WHAT IS BASIC CALCULATION FOR ARRIVING NUMBER OF ELECTRODES ARE REQUIRED FOR A 3 PHASE 415 V WORK SHOP HAVING A CONNECTED LOAD OF 500 KW

    INFORMATION IS URGENTLY NEEDED PLEASE. PL SEND TO MY MAIL THANX VERY MUCH SIRS

  16. nmr says:

    SIRS,

    A. IF THE DISTANCE BETWEEN TWO EARTH ELECTRODES IS LESS THAN 6 MTS ( 2 X 3=6 MTS) WHAT IS THE EFFECT ON THE ELECTRICAL SYSTEM.

    B.IF THE DISTANCE BETWEEN TWO EARTH ELECTRODES IS MORE THAT 6 MTS WHAT IS THE EFFECT ON THE ELECTRICAL SYSTEM.

    C. WHAT IS BASIC CALCULATION FOR ARRIVING NUMBER OF ELECTRODES ARE REQUIRED FOR A 3 PHASE 415 V WORK SHOP HAVING A CONNECTED LOAD OF 500 KW

    INFORMATION IS URGENTLY NEEDED PLEASE.
    THANX sirs VERY MUCH SIRS urgent please.

  17. Rahul says:

    Dear Sir,

    My question is not related to the topic.

    It is related to cable sizing

    How will we choose the cable size in sqmm if only the ampere is given ,with out the help of any charts
    i mean like a thumb rule.

    i did’nt see any provision to ask questions in the website that is why i put my query here.
    I hope you will give me the answer.

    Thanks

    Rahul

  18. Ashish says:

    what are the chemicals like salt charcoal etc are used in chemical earth and purpose of each. How to make a good chemical earth pit. When measureing the earth resistance by fall of potential method using 3 pole eath testor (C1 & P1 shorted, P2 and C2) then at the time of measuring whether earth electrode going to electronic device should be disconnected or not. If not not disconnected then reading will be correct or not. Please reply.

  19. mvrahul says:

    dear sir;
    i have a doubt, we are using a plc block (cpu 224 ac/dc/rly) inside a panel. recently, the plc block got burnt. they say it was due to not providing earthing. my question is, whether not providing earthing will result in such a situation or is it due to their incoming supply which is coming from a diesel generator set.? please help?

  20. Aamir shahzad says:

    its good information. thanks
    Sir pls tell me the size of earth cablr for 1200kva transformer

  21. Samuel says:

    thanks for creating this forum where you can ask question and get response i was just thrilled reading through the various questions and answers provided. well thank and thank you.
    Sam.

  22. Aman says:

    Dear Sir,

    What would be good Depth of Dig for home earthing. Someone asks 100 feet Someone just 10 feet??

  23. upendra says:

    for Conventional plate earthing IS says: Plate burred at the depth of 8 feet in the vertical position

  24. DIRGHAYU GANDHI, VADODARA says:

    how can i calculate copper wire gauge? for plate earthing…

  25. Aman says:

    thx upendra, so 8-10 feet earthing pit would be good for home earthing.

  26. Arslan says:

    i want to ask you one thing that, should we go for separate pits for field instruments and control room. or we can use single pit for both.

  27. pit2014 says:

    Thanks a bunch for sharing this with all of us you actually understand what you are
    speaking approximately! Bookmarked.

  28. feroz says:

    Jigneshsir i have confusion the pipe earthing and plate earthing plz detail

  29. Mohammad yaqoob says:

    Does the eathing condutor use for neutral of distribution transformer grounding depends on the size of distribution transformer, if it does than could you please help me to calculate the required size of earth conductor for transformers of different capacities such as 250kva,500kva,1000kva,1500kva,2000kva.on what basis we can determine the size of copper earth conductor.
    I will apriciate your earl reply.
    Thanks,

    Engieer M.Yaqoob
    Electron UAE

  30. niklesh says:

    why earthing is necessary?

  31. Guru says:

    but one question is un-answered – why copper conductor is required for Nuetral earthing? -Guru

    • Normally We use copper for T/C Neutral earthing but As per My knowledge there is no any relevant IS or Other Code state that Copper is required for neutral earthing.

      • Guru says:

        Thanks Mr. Jignesh. We are facing problem in one of office bldg – everyone enter in office experience shock if he touch another person or Laptop. We checked earthing value which is 0.2 Ohm in grid. Considering Static electricity problem checked HVAC humidity. No Problem found in the same. What to do?

  32. Aviral Saigal says:

    Dear sir,
    Normally we follow the pipe earthing (treated or non treated type) depending upon the nature of job to be executed with a depth of 3.5 m. But sir is there any possibility of having a horizontal earthing for temporary basis with a depth of 0.5 m so that the purpose of earhing is met and with the earth resistance is maintained. As i am facing this problem due to hard rock area and for pipe type earthing to follow we need to mae a bore, but due to some or the other delay.
    Sir please help.

  33. mmpatel says:

    SIR,
    I wanted to know more about Chemical Earthing that is be installed in Hilly area (where hard rocks are underneath).

  34. dileep says:

    with reference to above calculation for plate earthing area in 0.004536m but ur showing that 2.88 please calrify my doubt. and also i didnt get the ans which ur showing. coming to pipe earthing calc length in cm u hav considered but resistivity ur taken ohm-meter. pl clarify my doubt.

    • Not getting Point…Please clarify with Quote”…””

      • dileep phani says:

        Dear Sir,

        Pl explain the calculation of plate and pipe earthing .

        1) How did u calculate the plate size?

        2) *(R) = (100**r**/2L) X loge (4L/d).* in formula you have given Cm. where as come to calculation u took the meters for resistivity.

        On Thu, Jan 23, 2014 at 12:34 AM, Electrical Notes & Articles wrote:

        > Jignesh.Parmar commented: “Not getting Point…Please clarify with > Quote”…”””

      • (1) Equation for Plate size is indicating in task bar of excel sheet Just press appropriate cell.
        (2) As per IS 3043, Equation for Resistance of Pipe or Rod R= (100ρ/2ΠL)*log℮(4L/d)ohms where Length of Road is cm but normally we use length of rod in meter so I converted meter to cm in equation…
        I think this is clear for your query..

      • dileep says:

        Dear Sir,

        Pl explain the calculation of plate and pipe earthing .

        1) How did u calculate the plate size?

        2) (R) = (100r/2πL) X loge (4L/d).
        in formula you have given Cm. where as come to calculation u took the meters for resistivity.

  35. dileep says:

    i didnt get reply till date sir

  36. dileep says:

    sir, u took the 100 ohm-meter. pl check in ur calculations. Plate size 1.2mX1.2 m = 1.44 sq-m. where as 2.88 how was it come.

    • Dear Dileep,
      It show both surface of Plate earthing because both surface of plate are with touch of soil so plate surface area would be double…
      I think this is enough clearness i may explain..

  37. John says:

    what is the formular to be used in calculating the size of a copper conductor required for earthing a 18MW substation.

  38. sir, this is indeed a fantastic and a very organised article. Can I have some detail as regards to the comparison of The Copper and GI with the cast iron plate or pipe electrodes and their conductivity values, my architect has been telling me about cast iron pipes a lot.

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