28 Size of Earthing Strip Wire 1.1.15
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Calculate Minimum Siz Location From To 33.8 1 1% 25 1 1% 0.624 1 1% Copper Volumetric haet capacity of conductor material (Qc) 0.0345 Reciprocal of Tmp.coeff of Resistivity at 0 deg.Centrigade 234.5 Electrical resisitivity of conductorat 20 deg.Centrigade(∂2 0.0001724 Final Temprature of conductor(øt) 395 Initial Temprature of conductor(øi) 40 Value of k Constant for 1sec 205.60 Normal Short Circuit Value Typical soil resistivity (IEEE 1 440KV 40 KA for 1 to 3 Se Soil Type Avg. Resistivi 220KV 40 KA for 1 to 3 Se Well‐graded gravel 600 – 1000 132KV 35 KA for 1 to 3 Se Poorly graded gravel 1000 – 2500 Short Circuit Ciurrent (Isc) KA Duration of Fault (Sec) Corrosion in strip per
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Transcript of 28 Size of Earthing Strip Wire 1.1.15
Earthing StripCalculate Minimum Size of Earthing StripJignesh.Parmar, www.electricalnotes.wordpress.com, [email protected] Circuit Ciurrent (Isc) KADuration of Fault (Sec)% of Corrosion in strip per YearNo of Year for Replacement of StripSafety FactorSize of Earthing Strip (Sq.mm)Actual Size of Earthing Strip (Sq.mm)ResultsFromToCopperAlluminiumLeadGIMaterialNoWidth (mm)Thickness (mm)33.811%11166271977423Alluminium11020IncreaseSize or No of Strip2002712511%11123200723313Copper2253O.K1501230.62411%1135188008000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000CopperAlluminiumLeadGIVolumetric haet capacity of conductor material (Qc)0.03450.0250.001450.0038Reciprocal of Tmp.coeff of Resistivity at 0 deg.Centrigade (B)234.5228230202Electrical resisitivity of conductorat 20 deg.Centrigade(20)0.00017240.000282640.0002140.000138Final Temprature of conductor(t)395325325500Initial Temprature of conductor(i)40404040Value of k Constant for 1sec205.60126.0534.9480.69Normal Short Circuit ValueTypical soil resistivity (IEEE 142 / BS 7430)440KV40 KA for 1 to 3 SecSoil TypeAvg. Resistivity (m)220KV40 KA for 1 to 3 SecWellgraded gravel600 1000132KV35 KA for 1 to 3 SecPoorly graded gravel1000 250066KV25 KA for 1 to 3 SecClayey gravel200 40011KV(Urban)35 KA for 1 to 3 SecSilty sand100 80011KV(Rural)25 KA for 1 to 3 SecClayey sands50 200415V10 KA for 1 to 3 SecSilty or clayey sand30 80220V6 KA for 1 to 3 SecFine sandy soil80 300Gravelly clays20 60Inorganic clays10 55Surface Soils1 50Clay2 100Sandy clay100 150Moist gravel50 700Dry gravel700 1200Limestone5 10000Porous limestone30 100Quartz, limestone100 1000Sandstone20 2000Granites900 1100Concrete300 500CopperAlluminiumLeadGI
Jignesh.Parmar, www.electricalnotes.wordpress.com, [email protected]
Earthing WireCalculate Minimum Size of Earthing WireJignesh.Parmar, www.electricalnotes.wordpress.com, [email protected] Circuit Ciurrent (Isc) KADuration of Fault (Sec)% of Corrosion in strip per YearNo of Year for Replacement of StripSafety FactorK Value for 1 secSize of Earthing Wire (Sq.mm)XLPE CablePVC CableXLPE CablePVC CableFromToAluCu.AluCu.AluCu.AluCu.33.810%00941447511536023545129400000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
Jignesh.Parmar, www.electricalnotes.wordpress.com, [email protected]
