What is Earthing | Electrical Notes & Articles

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What is Earthing

NOVEMBER 27, 2011 59 COMMENTS(HTTP://ELECTRICALNOTES.WORDPRESS.COM/2011/11/27/WHAT-IS-EARTHING/#COMMENTS)

Introduction:

The main reason for doing earthing in electrical network is for the safety. When all metallicparts in electrical equipments are grounded then if the insulation inside the equipmentsfails there are no dangerous voltages present in the equipment case. If the live wire touchesthe 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. Toprovide an alternative path for the fault current to flow so that it will not endanger theuserTo 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. Tomaintain the voltage at any part of an electrical system at a known value so as toprevent over current or excessive voltage on the appliances or equipment .

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(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 analternative 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 separatesource. 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 mostomnipresent conductive surface, and so it was adopted in the very beginnings ofelectrical 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 useCast iron plate of size 600 mm x600 mm x12 mm. ORGalvanized iron plate of size 600 mm x600 mm x6 mm. ORCopper plate of size 600 mm * 600 mm * 3.15 mmPlate burred at the depth of 8 feet in the vertical position and GI strip of size 50 mmx6mm 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 useGI pipe [C-class] of 75 mm diameter, 10 feet long welded with 75 mm diameter GIflangehaving 6 numbers of holes for the connection of earth wires and inserted in ground by

auger method.


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These types of earth pit are generally filled with alternate layer of charcoal & salt orearthreactivation compound.

Method for Construction of Earthing Pit (IndianElectricity 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 andreduce Earth Resistance.Make a mixture of Wood Coal Powder Salt & Sand all in equal partWood 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 soilwill 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 withhumidity.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 Pipeto 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 alsouse 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 15Meters around the EARTH PIT with another conductor dip on the Earth at least 500 mmdeep.Check Voltage between Earth Pit conductors to Neutral of Mains Supply 220V AC 50 Hzit 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


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(ohmic value) of an earth pit depends on soil resistivity. It is the resistance of the soil tothe 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 poorconductors of electricity when they are completely dry. Soil resistivity is measured inohm-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 willbevery 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 bedetermined 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 soilresistivity. 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 moisturein 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 amountand nature of salts dissolved in it.

Small quantity of salts in water reduces soil resistivity by 80%. common salt is mosteffective in improving conductivity of soil. But it corrodes metal and hence discouraged.


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(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 resistivitywill 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 orgravel 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 ina 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 fillCompound 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, particularlyduring dry weather conditions.Though back fill compound retains moisture under normal conditions, it gives offmoisture during dry weather to the dry soil around the electrode, and in the processloses moisture over a period of time. Therefore, choose a site that is naturally not welldrained.

(8) Effect of grain size and its distribution:

Grain size, its distribution and closeness of packing are also contributory factors, sincethey 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 insoil determines decrease or increase of soil resistivity. Thus in dry weather resistivitywill be very high and during rainy season the resistivity will be low.


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(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 acurrent of a given magnitude and duration will cause significant drying and thusincrease 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 resistancecould be achieved. The distance between the electrodes must be equal to the drivendepth to avoid overlapping of area of influence. Each electrode, therefore, must beoutside the resistance area of the other.

(11) Obstructions:

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

(12) Current Magnitude:

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

Measurement of Earth Resistance by use of

Earth Tester:


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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 changeinstrument range, Wires to connect terminal to Earth Electrode and Spikes.It is measured by using Four Terminal Earth Tester Instrument. The terminals areconnected 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. Takemeasurement in different directions.Soil resistivity =2!LR.R= Value of Earth resistance in ohm.Distance between the spikes in cm." = 3.14P = 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 tothe earth electrode (pipe) under test.Terminals P2 & C2 are connected to the two separate spikes driven in earth. These twospikes are kept in same line at the distance of 25 meters and 50 meters due to whichthere will not be mutual interference in the field of individual spikes.If we rotate generator handle with specific speed we get directly earth resistance onscale.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 testerelectrode and the spikes by 5 meter. Normally, the length of wires should be 10 and 15Meter 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.


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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 areconnected 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 beoperated 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/2!L) X loge (4L/d).Where L= Length of Pipe/Rod in cmd=Diameter of Pipe/Rod in cm.The resistivity of the soil and the physical dimensions of the electrode play importantrole 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 thesizing 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 100ohm-m,The resistance of Plate electrode to earth (R)=( r/A)X under root("/A) =(100/2.88)X(3.14/2.88)=36.27 ohmNow, consider a GI Pipe Electrode of 50 mm Diameter and 3 m Long. soil resistivity of100 Ohm-m,The resistance of Pipe electrode to earth (R) = (100r/2"L) 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 thaneven a copper plate electrode.

As per IS 3043 Pipe, rod or strip has a much lower resistance than a plate of equal


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surface area.

Length of Pipe Electrode and Earthing Pit:

The resistance to earth of a pipe or plate electrode reduces rapidly within the first fewfeet 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 theelectrode. 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 theadditive substance would reduce the resistivity of the soil, only when it is dissolved inthe 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 contentwill 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. (10percent of 1440 kg). The salt content shall be 5% of this (i.e.) 5% of 144kg, that is, about7.2kg.

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% theresistivity increases rapidly with the decrease in moisture content.If the moisture content is already above 20% there is no point in adding quantity ofwater into the earth pit, except perhaps wasting an important and scarce nationalresource like water.


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Length Vs Diameter of Earth Electrode:

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

Maximum allowable Earth resistance:

Major power station= 0.5 Ohm.Major Sub-stations= 1.0 OhmMinor Sub-station = 2 OhmNeutral Bushing. =2 Ohm

Service connection = 4 OhmMedium Voltage Network =2 OhmL.T.Lightening Arrestor= 4 OhmL.T.Pole= 5 OhmH.T.Pole =10 OhmTower =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.

FILED UNDER UNCATEGORIZED

About Jignesh.Parmar


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Jignesh Parmar has completed his B.E(Electrical) from Gujarat University. He has more than11 years experience in Power Transmission-Power Distribution-Electrical energy theftdetection-Electrical Maintenance-Electrical Projects(Planning-Designing-coordination-Execution). He is Presently associate with one of the leading business group as a AssistantManager at Ahmedabad,India. He is Freelancer Programmer of Advance Excel and designuseful 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 andFamiliar with English, Hindi, Gujarati, French languages. He wants to Share his experience& knowledge and help technical enthusiasts to find suitable solutions and updatingthemselves on various Engineering Topics.

59 Responses to What is Earthing

Saravanakumar T says:November 28, 2011 at 6:07 amInformative. Thanks.

ReplyAnil says:November 28, 2011 at 8:09 amwhat is the minimum frequency of earthpit maintenence as per indian standards in a LVinstallation like for example in petrol pumps etc.

Our office has incomer feeder of 11 kv with sanctioned load of 600 kw in delhi. Whatshould be the value of grid resistance /Individual pit resistance and frequency of eartpit maintenance that should be observed in such instllations, asper the relevent indianIE rules.

Thanks,anil

Replyumashankar says:December 10, 2011 at 3:40 amHi 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 theminimum clearances required between two phase contacts and phase to earth clearanceand phase to phase clearance inside the oil medium (transformer oil) and also outdoorwith reference to study.

2. sizing of copper conductor, how to choose the copper conductor size for 600 A and2000 amps, how to derive and references copper contact will be single piece. wat would


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be the max amps that can allow per sqmm conductor, temperature withstand.

thank you

ReplyLaxmi Narayan Sharma says:

February 2, 2012 at 11:29 amgood information

Replytaruntripathy says:February 4, 2012 at 9:45 amWhere does electricity go after it goes through our appliances?

Replym.janardhana reddy says:

January 15, 2013 at 11:29 amIt is utilised by them as by converting into another form of energy (or) when earthedit will be nuetralised by earth potential (as earth is always at zero potential)

ReplyYallappa says:March 22, 2012 at 4:16 pmplease mail

ReplyYallappa says:

March 22, 2012 at 4:18 pmplease post technical publications to my e-mail id

ReplyJignesh.Parmar says:March 22, 2012 at 5:49 pmAll Technical Notes are Free of Cost so Just Copy & past of each Notes from Blog ElsePurchase it in PDF version at very Nominal price from Blog.

Reply

muthuvel says:May 29, 2012 at 11:56 amcan you answer?

Why the Copper(plate) earth pit needed for neutral Earthing and G.I(pipe) earthpit needed for Body earthing?

Jignesh.Parmar says:May 29, 2012 at 3:53 pmIs there any IS code which mention that Neutral earthing should be Copper !!!

Vishwa Murthy says:


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April 14, 2012 at 4:00 amSir, I have a small doubt regarding earthing of power transformer neutral..sir whetherthe earth pit connected to neutral of PTR is kept separately from the grid earth mat orthis has to be connected with the grid earth mat and whats the reason behind this.??

Reply

Upendra Badal says:June 12, 2012 at 3:06 amsir,nice to read ur article its very useful.however i have a question regarding the difference between Body earthing and NeutralEarthing for Distribution Transformer and/or Diesel generating set is there anydifferences? and can we bond both earth station together or there should be differentearthing?

Reply

Asman says:August 11, 2012 at 8:57 amThanku very much Jignesh for of the share your experiance with us and we pray for youregarding u will share your expiriance with us and u go always boss

ReplySridharan S says:August 29, 2012 at 11:35 amTo:Jignesh.Parmar

Thank you very much for your article on Impact of Floating Neutral. I live in chennaiin an apt where there are 11 flats and a transformer (3 phase, 1 neutral grounded) insidethe premises supplied by the electricity board. We had 3 major booms from thetransformer 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 isthe floating neutral (not grounded properly) on the distribution transformer side. Thelocal EB staff came and have strengthened the earthing on the transformer side. Theyhave 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 westrengthen our earthing by installing 2 new earth pits and connecting them to thecommon 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

ReplyJignesh.Parmar says:August 30, 2012 at 4:24 pmIf Transformer is dedicated to your Apartment and This transformer neutral isearthed 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 Ihave not yet done such type of Practice.


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Here please note that Neutral always drain to earth which have low impedance pathso some of current may drain to your panels Neutral earth or some at Your T/Cneutral earth.Both Neutral earth may be not at equal impedance so may be somepotential difference hence at some time you may get Neural Back at either at T/c orPanel.System is always work in healthy condition when amount of feeding current from

its feeding station (here T/C or Generator) is need to be back in same amount to itssource and drain to earth.In your case If Distance between T/C neutral earth and Your Panel is huge, If SomeOther load which are not feed from your panel but still connected on T/C may beget worse effect on system.Please concern Local authority for such type of connection.

ReplySridharan S says:August 31, 2012 at 1:43 am

Thank you for your reply

Sridharan S says:September 3, 2012 at 5:35 amDear Sir,

Thank you for nice reply.

We have a dedicated 3-phase, 4-wire 100 KVA transformer. As I told you in myearlier 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 consumerdistribution panel and got the following values:

Distribution panel currents:

R-Phase 10.4 AmpsY-Phase 7.4 AmpsB-Phase 8.4 Amps

Neutral 5.6 Amps

The earth resistance was also checked at the transformer side and we got thefollowing 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 & RegardsSridharan

Jignesh.Parmar says:


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ReplyVenkatesh says:

January 17, 2013 at 5:00 pmshall we use Earthing Backfill Compound for conventional earth pits???Sir please give a reply to my mail.

ReplyK.Sudhesh says:February 11, 2013 at 2:04 amFor my house wiring what are all the standards to be adhered for earth pitmeasurements, pipe standard and related things for safe earthing. if i get a sketch reg.earthing it will be useful..

Replynmr says:March 9, 2013 at 9:40 am

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 MTSWHAT IS THE EFFECT ON THE ELECTRICAL SYSTEM.

C. WHAT IS BASIC CALCULATION FOR ARRIVING NUMBER OF ELECTRODESARE REQUIRED FOR A 3 PHASE 415 V WORK SHOP HAVING A CONNECTEDLOAD OF 500 KW

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

Replynmr says:March 9, 2013 at 9:41 amSIRS,

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 MTSWHAT IS THE EFFECT ON THE ELECTRICAL SYSTEM.

C. WHAT IS BASIC CALCULATION FOR ARRIVING NUMBER OF ELECTRODESARE REQUIRED FOR A 3 PHASE 415 V WORK SHOP HAVING A CONNECTEDLOAD OF 500 KW

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

Reply


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Rahul says:March 11, 2013 at 7:16 amDear 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 thehelp of any chartsi mean like a thumb rule.

i didnt see any provision to ask questions in the website that is why i put my queryhere.I hope you will give me the answer.

Thanks

Rahul

ReplyAshish says:April 13, 2013 at 5:20 amwhat are the chemicals like salt charcoal etc are used in chemical earth and purpose ofeach. How to make a good chemical earth pit. When measureing the earth resistance byfall of potential method using 3 pole eath testor (C1 & P1 shorted, P2 and C2) then at thetime 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. Pleasereply.

Replymvrahul says:April 15, 2013 at 6:32 amdear sir;i have a doubt, we are using a plc block (cpu 224 ac/dc/rly) inside a panel. recently, theplc 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?

ReplyAamir shahzad says:

June 9, 2013 at 9:11 amits good information. thanksSir pls tell me the size of earth cablr for 1200kva transformer

ReplySamuel says:

June 24, 2013 at 10:40 amthanks for creating this forum where you can ask question and get response i was just


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thrilled reading through the various questions and answers provided. well thank andthank you.Sam.

ReplyAman says:

June 30, 2013 at 8:27 amDear Sir,

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

Replyupendra says:

July 2, 2013 at 12:28 amfor Conventional plate earthing IS says: Plate burred at the depth of 8 feet in the vertical

positionReply

DIRGHAYU GANDHI, VADODARA says:July 4, 2013 at 5:46 amhow can i calculate copper wire gauge? for plate earthing

ReplyAman says:

July 13, 2013 at 5:43 amthx upendra, so 8-10 feet earthing pit would be good for home earthing.

ReplyArslan says:

July 18, 2013 at 5:10 ami want to ask you one thing that, should we go for separate pits for field instrumentsand control room. or we can use single pit for both.

Replypit2014 says:

July 19, 2013 at 4:10 pm

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

Replyferoz says:

July 30, 2013 at 5:09 amJigneshsir i have confusion the pipe earthing and plate earthing plz detail

ReplyMohammad yaqoob says:

August 2, 2013 at 7:09 amDoes the eathing condutor use for neutral of distribution transformer grounding


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depends on the size of distribution transformer, if it does than could you please help meto calculate the required size of earth conductor for transformers of different capacitiessuch as 250kva,500kva,1000kva,1500kva,2000kva.on what basis we can determine thesize of copper earth conductor.I will apriciate your earl reply.Thanks,

Engieer M.YaqoobElectron UAE

Replyniklesh says:October 8, 2013 at 6:07 amwhy earthing is necessary?

Reply

Jignesh.Parmar says:October 8, 2013 at 3:00 pmThe answer of your Question is inside the answer of the question Why Human orEquipment safety is necessary?

ReplyGuru says:November 23, 2013 at 7:26 am

but one question is un-answered why copper conductor is required for Nuetralearthing? -Guru

ReplyJignesh.Parmar says:November 23, 2013 at 4:52 pmNormally We use copper for T/C Neutral earthing but As per My knowledge thereis no any relevant IS or Other Code state that Copper is required for neutral earthing.

ReplyGuru says:November 25, 2013 at 6:12 amThanks 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 checkedearthing value which is 0.2 Ohm in grid. Considering Static electricity problemchecked HVAC humidity. No Problem found in the same. What to do?

Aviral Saigal says:December 6, 2013 at 10:40 amDear sir,Normally we follow the pipe earthing (treated or non treated type) depending upon thenature of job to be executed with a depth of 3.5 m. But sir is there any possibility ofhaving 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


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this problem due to hard rock area and for pipe type earthing to follow we need to maea bore, but due to some or the other delay.Sir please help.

Replymmpatel says:

January 17, 2014 at 9:23 amSIR,I wanted to know more about Chemical Earthing that is be installed in Hilly area (wherehard rocks are underneath).

Replydileep says:

January 19, 2014 at 1:50 pmwith reference to above calculation for plate earthing area in 0.004536m but ur showingthat 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.

ReplyJignesh.Parmar says:

January 22, 2014 at 7:04 pmNot getting PointPlease clarify with Quote

Replydileep phani says:

January 23, 2014 at 5:37 pmDear Sir,

Pl explain the calculation of plate and pipe earthing .

1) How did u calculate the plate size?

2) *(R) = (100**r**/2!L) X loge (4L/d).* in formula you have given Cm. where ascome 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 PointPlease clarify with >Quote

Jignesh.Parmar says:January 23, 2014 at 6:06 pm(1) Equation for Plate size is indicating in task bar of excel sheet Just pressappropriate cell.(2) As per IS 3043, Equation for Resistance of Pipe or Rod R=(100#/2$L)*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 equationI think this is clear for your query..


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dileep says:January 23, 2014 at 5:37 pmDear Sir,

Pl explain the calculation of plate and pipe earthing .

1) How did u calculate the plate size?

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

dileep says:January 22, 2014 at 6:16 pmi didnt get reply till date sir

Reply

dileep says:January 23, 2014 at 6:19 pmsir, u took the 100 ohm-meter. pl check in ur calculations. Plate size 1.2mX1.2 m = 1.44sq-m. where as 2.88 how was it come.

ReplyJignesh.Parmar says:

January 23, 2014 at 6:32 pmDear Dileep,It show both surface of Plate earthing because both surface of plate are with touch of

soil so plate surface area would be doubleI think this is enough clearness i may explain..

ReplyJohn says:February 19, 2014 at 3:19 pmwhat is the formular to be used in calculating the size of a copper conductor required forearthing a 18MW substation.

Reply

Saurabh Mohta says:April 12, 2014 at 6:05 amsir, this is indeed a fantastic and a very organised article. Can I have some detail asregards to the comparison of The Copper and GI with the cast iron plate or pipeelectrodes and their conductivity values, my architect has been telling me about castiron pipes a lot.

ReplyPradip says:May 17, 2014 at 3:37 pm

SIR,please tell me distribution transformer neutral earthing strip ho select size copper& G.I. ?


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ReplyJignesh.Parmar says:May 18, 2014 at 11:25 amAlready given in the blog with example..review post of this blog.

Reply

sivakumar says:June 20, 2014 at 2:32 pmRespected sir,how we determine the size of conductor for respective voltage.

Reply

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