Earthing presentation pipe and plate.ppt

earthing

1. EARTHING

2. Definition of Earthing :
•Earthingistheprocessofconnectinganearth
conductortotheearthelectrode.Ithelpsto
preventelectricshocksbyprovidingalow
impedance,lowresistance,returnpathforany
faultcurrenttogetbacktothedistributionpanel.
Thishighreturnfaultcurrentwillcausethe
circuit'sbreakertotripanddisconnectthefault.
•Earthingmeansanyconnectiongiventothe
earthmassbymeansofaconductorconnected
totheearthelectrodeburiedinsoil.

3. QUALITIES OF GOOD EARTHING
The qualities of a good earthing system are :
•Must be of low electrical resistance (ideally zero but practically
between 1 to 1.5 ohm)
•Must be of good corrosion resistance
•Must be able to dissipate high fault current repeatedly
NEED OF GOOD EARTHING
•Tosavehumanlifefromdangerofelectricalshockordeathby
blowingafusei.e.Toprovideanalternativepathforthefaultcurrent
toflowsothatitwillnotendangertheuser
•Toprotectbuildings,machinery&appliancesunderfault
conditionsie.Toensurethatallexposedconductivepartsdonot
reachadangerouspotential.
•Toprovidesafepathtodissipatelightningandshortcircuitcurrents.
•Toprovidestableplatformforoperationofsensitiveelectronic
equipmentsi.e.Tomaintainthevoltageatanypartofanelectrical
systemataknownvaluesoastopreventovercurrentorexcessive
voltageontheappliancesorequipment.
•Toprovideprotectionagainststaticelectricityfromfriction

4. There are various ways of doing Earthing.
•Conventional EARTHING
–Pipe Earthing,
–GI Plat Earthing,
–Cast Iron plat Earthing,
–Copper plat Earthing
•Maintenance Free EARTHING
TYPES OF EARTHING:

5. CONVENTIONAL EARTHING
•TheConventionalsystemofEarthingcalls
fordiggingofalargepitintowhichaGI
pipeoracopperplateispositionedamidst
layersofcharcoalandsalt.
•TheConventionalsystemofGIpipe
EarthingorcopperplateEarthingrequires
maintenanceandpouringofwaterat
regularinterval.

6. MAINTENANCE FREE EARTHING
•Itisanewtypeofearthingsystemwhichis
readymade,standardized,scientificallydeveloped.Its
Benefitsare
•MaintenanceFree:Noneedtopourwateratregular
interval-exceptinsandysoil.
•Consistency:Maintainstableandconsistentearth
resistancearoundtheyear.
•MoreSurfaceArea:Theconductivecompoundcreates
aconductivezone,whichprovidestheincreased
surfaceareaforpeakcurrentdissipation.Andalsoget
stablereferencepoint.
•Lowearthresistance.Highlyconductive.Carrieshigh
peakcurrentrepeatedly.
•Nocorrosion.EcoFriendly.
•LongLife.
•EasyInstallation.

7. TECHNICALDETAILS OF MAINTENANCE FREE EARTHING
•Two‘B’classmildsteelpipes,oneinsidethe
other,aresubjectedtoHotdipGalvanization.
BackFillCompound (B.F.C)"Ashlok"earthing
systemcomeswithacompoundnamedBackFill
Compound(B.F.C)whenhasallthequalitiesofthe
idealbackfillmaterialforanearthingsystem.
Itiseasilycompactedandwhenwaterisaddedto
it,itwillabsorbuptothirteentimesitsdry
volume.
Thisconsistentlyholdsitsownshapeandadheres
toanysurfaceittouches.
Thesecapabilitiesresolvetheissuesof
compatibilityandsoil/rodcontactthatarecrucial
toanearthingsystem.
BFCabsorbswhatevermoistureispresentand
maintainswithinitself,incontrarytosurface
appearances.

8. Benefits of Back Fill Compound (B.F.C)
•Maintainsmoisturewithinthesphereof
influenceofelectrode.TheB.F.C.willcausethe
lowsoilresistivityaroundtheelectrode.,which
resultsinasignificantlylowerearthresistance,
thatcouldnototherwisebeobtainedusinga
conventionalearthelectrodeinstallation.
•Providescathodicprotectionfortheelectrode
•Enhancesthesurroundingsoilconductivity
therebymakingitmoreeffectiveforhighfault,
noise,ripples,harmonics,neutraltoearth
unbalanceandlightningcurrentdissipation.
•heenhancementbackfillmaterialhasspecial
applicationwithnon-toxicenhancerstofurther
improveitsdurabilityandperformance.

9. Measurement of Earth Resistance:
•EarthresistanceismeasuredusingEarthTester.This
meterconsistsof4terminalsE,P1,P2,andP3.
•E&P1willbeshorted&connectedtogridorelectrode
&P2,P3arethereferenceelectrodethatwillbekepton
theEarthsurfaceattwodifferentlocationsfortakingref
resistanceoftheearth.
•ThemetershowsthevalueofEarthresistancethanis
lessthan1ohm.
Factors affecting earth resistance are
1.Shape&materialoftheearthelectrode.
2.Depthoftheelectrodeatwhichtheyareburiedinsoil.
3.Specificresistanceofthesoilsurroundingtheelectrode

10. Methods of Earth Ground Testing
There are four types of earth ground testing
•Soil Resistivity (using stakes)
•Fall of potential (using stakes)
•Selective (using 1 clamp and stakes)
•Stakeless (using 2 clamps only)

11. Soil Resistivity measurement
Why determine the soil resistivity ?
•Soilresistivityismostnecessarywhendeterminingthedesignofthe
groundingsystemfornewinstallation(greenfieldapplication)to
meetgroundresistancerequirement.
•Thesoilcomposition,moisturecontent,andtemperatureallimpact
thesoilresistivity.
•Soilisrarelyhomogenousandtheresistivityofthesoilwillvary
geographicallyandatdifferentsoildepths.
•Sincesoilandwateraregenerallymorestableatdeeperstrata,itis
recommendedthatthegroundrodstobeplacedasdeepaspossible
intotheearth.
•Groundrodsshouldbeinstalledwherethereisstabletemperature.
•Forgroundingsystemtobeeffective,itshouldbedesignedto
withstandtheworstpossibleconditions.

12. How to calculate soil resistivity?
•Formula is as follows
ρ = 2ΠAR
ρ = average soil resistivity to the depth A in ohm-cm.
Π = 3.1416
A = distance between the electrodes in cm
R = measured resistance value in ohms from the test instrument.
Note: Divide ohm-centimeters by 100 to convert to ohm-meters.

13. •How do we measure soil resistance
•Fall of potential measurement
•Selective measurement
•Stakeless measurement

14. Thank you