इंटरनेट मानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru “The Right to Information, The Right to Live” “Step Out From the Old to the New” IS 12776 (2002): Galvanized Strand for Earthing [MED 10: Wire Ropes and Wire Products] “!ान $ एक न’ भारत का +नम-ण” Satyanarayan Gangaram Pitroda ““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee”” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै” Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” IS 12776 : 2002 Edition2.1 (2004-06) Indian Standard GALVANIZED STRAND FOR EARTHING — SPECIFICATION ( First Revision ) (Incorporating Amendment No.1) ICS 29.240.20;77.140.65 © BIS 2004 B U R E A U O F I N D I A N S T A N D A R D S MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 Price Group3 Wire Ropes and Wire Products Sectional Committee, ME10 FOREWORD This Indian Standard (First Revision) was adopted by the Bureau of Indian Standards, after the draft finalized by the Wire Ropes and Wire Products Sectional Committee had been approved by the Mechanical Engineering Division Council The galvanized steel earth wire covered in this standard is used for shielding of electric transmission conductors by various electric utilities in the country. The standard prepared based on specification No.CC-203-932E Vol.-II ‘Technical specification for GS earth wire’ issued by the National Thermal Power Corporation was first published in 1989. Based on the experience gained in the industry, in this first revision the following modifications have been made: a) Alternative method of checking the compactness of the strand at the time of conducting breaking force test is added. b) Method of wrapping test is more elaborately described. c) Sampling criteria has been modified for sampling before and after stranding. d) Alternative method of marking at the end of one length when two lengths of strands are supplied in one drum is added. e) Requirement of tensile strength, torsion, elongation and zinc coating have been modified to include before and after stranding values for the properties. f) Breaking force and d.c. resistance values of strands have been modified by applying the specified stranding factor. The composition of the Committee responsible for the formulation of this standard is given in AnnexB. This edition 2.1 incorporates Amendment No. 1 (June 2004). Side bar indicates modification of the text as the result of incorporation of the amendment. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS2:1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. IS 12776 : 2002 Indian Standard GALVANIZED STRAND FOR EARTHING — SPECIFICATION ( First Revision ) 1SCOPE 5CONSTRUCTION This standard covers requirements for 5.1The construction of the galvanized steel galvanized steel earth strand used for overhead earth strand shall be as given in AnnexA. transmission purposes with the three tensile 5.2All steel galvanized steel earth strand shall grades of wires, namely, 981, 1100 and 1310. be smooth, uniform and free from all 2REFERENCES imperfections, such as spills and splits, die marks, scratches, abrasion and kinks after The following Indian Standards contain drawing and also after stranding. provisions, which through reference in this text constitute provisions of this standard. At the 5.3The joints shall be allowed in individual time of publication, the editions indicated were wires and the distance between the two joints valid. All standards are subject to revision, and shall not be less than 15m. parties to agreements based on this standard 6DIMENSIONS AND TOLERANCES are encouraged to investigate the possibility of applying the most recent editions of the 6.1The dimensions and manufacturing standards indicated below: tolerances shall be permitted in the diameter of individual wires and the lay length of the IS No. Title galvanized steel earth strand as given in 2363:1981 Glossary of terms relating to wire AnnexA. ropes (first revision) 7STANDARD LENGTH 4826:1979 Hot-dipped galvanized coatings on round steel wires (first revision) 7.1The standard length of the galvanized steel earth strand shall be between 1500 to 2000m. 3TERMINOLOGY A tolerance of ±5 percent on the standard For the purpose of this standard, the length shall be permitted. definitions given in IS2363 shall apply. 7.2Unless otherwise agreed to between the manufacturer and the purchaser, random 4MATERIAL length shall also be accepted provided one length 4.1The steel wire shall be drawn from carbon is not less than half of the standard length of the steel wire rods produced by either the acid or galvanized steel earth strand offered by the the basic open hearth process, the electric manufacturer and the total quantity of random furnace process or the basic oxygen process and length is not more than 10percent of the total shall have the following chemical composition: quantity in each shipment. Element Percentage Composition 8TESTS Carbon 0.55, Max The following tests shall be conducted on the Manganese 0.40 to 1.10 completed strand. Phosphorous 0.05, Max 8.1Breaking Force Sulphur 0.05, Max 8.1.1Breaking force of the galvanized steel Silicon 0.15 to 0.35 earth strand when tested according to procedure given in 8.1.2 shall have minimum 4.2Density breaking force as given in Annex A. The density of galvanized steel wire at a temperature of 20°C may be taken as 7.8g/cm3. 8.1.2A circle perpendicular to the axis of the strand shall be marked at two places on a sample 4.3Coefficient of Linear Expansion of galvanized steel earth strand of minimum 5m The value of coefficient of linear expansion for length suitably compressed on the dead end galvanized steel wire used may be taken as clamps at either end. The force shall be 11.5×10–6/°C. increased at a steady rate up to 50percent of 1 IS 12776 : 2002 minimum breaking force. The circle drawn shall total material offered at a time, shall be taken. not be distorted due to relative movement of the 10REJECTION AND RE-TEST component wires. The applied force then be increased until the breaking force is reached and 10.1If any of the test pieces first selected fail to the value is recorded. pass the tests given in 8, two further samples from the same batch excluding the length from 8.1.3Alternatively a galvanized steel earth which the original sample was taken shall be strand sample when cut perpendicular to its axis selected at random for testing. by an abrasive cutter shall not have wires projected out nor shrunk inside from the cut end 10.2All the samples shall satisfy the by more than 3mm. requirement of the tests. In case of any failure, the batch represented by the samples shall be 8.2Elongation deemed not to comply with the standard. The elongation of individual wires when 11PACKING measured on a gauge length of 200mm after breakage shall meet the requirements as given 11.1The material shall be suitably packed in AnnexA. before dispatch in strong non-returnable 8.3d.c. Resistance Test wooden drums. 11.2Two standard lengths of galvanized steel 8.3.1The galvanized steel earth strand shall be earth strand may be wound in a drum. tested according to 8.3.2. The values of d.c. resistance shall be as given in Annex A. 11.2.1In that case each standard length of galvanized steel earth strand shall be 8.3.2On a galvanized steel earth strand of individually welded to the other to prevent minimum 5m length, two contact clamps shall parting of the two lengths at a tension less than be fixed. The resistance shall be measured by a 15kN. The two ends where the first length Kelvin bridge or by any suitable instrument by finishes and the second length starts shall be placing the clamps initially from one end and clearly marked with adhesive tape. The length subsequently one metre apart. The test shall be between the two marks shall be treated as repeated at each metre length and the value scrapped and shall not be taken into account recorded. The value obtained shall be corrected for measurement purposes. to 200°C. The average of five such results shall be reported as the resistance of the strand sample. 11.2.2Alternatively the galvanized steel earth strand may be supplied in a continuous length 8.4Wrapping Test in a drum with markings by adhesive tape This test shall be conducted by wrapping the wire between two standard lengths. around a mandrel of diameter equal to four times the wire diameter to form a close helix of eight 12MARKING turns. Six turns then be unwrapped and finally 12.1Each drum shall have the following closely wrapped again in the same direction as information: before. The wire shall not break during the test a) Manufacturer’s name or trade-mark, (applicable for wires before stranding). b) Drum number, 8.5Galvanizing Test c) Size of galvanized steel earth strand, The zinc coating on the individual wires shall d) Length of galvanized steel earth strand, meet the requirements as given in Annex A. e) Gross weight of drum with galvanized 8.6Torsion Test steel earth strand, and Torsion value of the individual wires shall meet f) Arrow marking for unwinding. the requirements as given in Annex A g) Grade of galvanized steel earth strand given in 1 as applicable. 9SAMPLING CRITERIA 12.2BIS Certification Marking 9.1Before Stranding The product may also be marked with the Manufacturer shall prepare his own sampling Standard Mark. plan for conducting various tests covered by this specification and shall present the test 12.2.1The use of the Standard Mark is records for the verification of the purchaser if governed by the provisions of the Bureau of agreed in the contract. Indian Standards Act, 1986 and the Rules and Regulations made thereunder. The details of 9.2After Stranding conditions under which a licence for the use of One sample from every 10 drums or part the Standard Mark may be granted to the thereof for conducting all tests except d.c. manufacturers or the producers may be resistance, for which only one sample out of obtained from the Bureau of Indian Standards. 2 ANNEX A (Clauses 5.1, 6.1, 8.1.1, 8.2, 8.3.1, 8.5 and 8.6) CONSTRUCTION AND OTHER PROPERTIES OF GALVANIZED STEEL EARTH STRAND 1.Construction 7×3.00mm 7×3.15mm 7×3.25mm 7×3.33mm 7×3.66mm 7×4.00mm 2.Wire Size (D) a)Nominal 3.00 3.15 3.25 3.33 3.66 4.00 (mm) b)Max 3.08 3.25 3.33 3.41 3.74 4.08 c)Min 2.92 3.07 3.17 3.25 3.58 3.92 3.Minimum tensile strength Tensile Grade of Tensile Grade of Tensile Grade of Tensile Grade of Tensile Grade of Tensile Grade of of wire, N/mm2 Wire Wire Wire Wire Wire Wire A B C A B C A B C A B C A B C A B C (Before stranding) 981 1100 1310 981 1100 1310 981 1100 1310 981 1100 1310 981 1100 1310 981 1100 1310 (After stranding) 931 1050 1260 931 1050 1260 931 1050 1260 931 1050 1260 931 1050 1260 931 1050 1260 4.Torsion of wire on 100×D (before stranding) Min: 20 Min: 20 Min: 20 Min: 20 Min: 20 Min: 20 3 (after stranding) Min: 18 Min: 18 Min: 18 Min: 18 Min: 18 Min: 18 5.Wrap test on wire as described No wire breakage No wire breakage No wire breakage No wire breakage No wire breakage No wire breakage in 8.4 during the test during the test during the test during the test during the test during the test 6.Elongation of wire (on 200mm gauge length) in percent (before stranding) Min: 4 Min: 4 Min: 4 Min: 4 Min: 4 Min: 4 (after stranding) Min: 3.5 Min: 3.5 Min: 3.5 Min: 3.5 Min: 3.5 Min: 3.5 7.Zn-coating on wires a)Amount of coating (g/m2) (before stranding) Min: 240 Min: 240 Min: 250 Min: 250 Min: 250 Min: 250 (after stranding) Min: 228 Min: 228 Min: 238 Min: 238 Min: 238 Min: 238 b)Uniformity of coating (before stranding) Min:3 dips of Min:3 dips of Min:3 dips of Min:3 dips of Min:3 dips of Min:3 dips of 1minute 1minute 1minute 1minute 1minute 1minute (after stranding) Min:2 dips of Min:2 dips of Min:2 dips of Min:2 dips of Min:2 dips of Min:2 dips of 1minute and 1 dip 1minute and 1 dip 1minute and 1dip 1minute and 1 dip 1minute and 1 dip 1minute and 1 dip of ½ minute of ½ minute of ½ minute of ½ minute of ½ minute of ½ minute ANNEX A ( Concluded ) I S 1 8.Lay and lay length of galvanized Min: 117 Min: 123 Min: 127 Min:130 Min: 143 Min: 156 2 RH RH RH RH RH RH 7 steel earth strand (mm) Max: 252 Max: 265 Max: 273 Max:280 Max: 307 Max: 336 7 6 9.Minimum breaking force of Tensile Grade of Tensile Grade of Tensile Grade of Tensile Grade of Tensile Grade of Tensile Grade of : 2 galvanized earth strand, kN Wire Wire Wire Wire Wire Wire 0 0 2 981 11001310 981 11001310 981 11001310 981 11001310 981 11001310 981 11001310 43.7 49.0 58.3 48.2 54.0 64.3 51.3 57.5 68.5 53.8 60.4 60.4 65.0 72.9 86.8 77.7 87.1 104.0 10.Approximate mass per km of 386 426 454 476 575 687 galvanized steel earth strand (kg) 11.Equivalent modulus of elasticity 19×103 19×103 19×103 19×103 19×103 19×103 galvanized steel earth strand (kg/mm2) 12.Maximum d. c. resistance in 3.77 3.41 3.20 3.05 2.51 2.09 ohm, per km of the galvanized 4 steel earth strand at 20°C IS 12776 : 2002 ANNEX B (Foreword) COMMITTEE COMPOSITION Wire Ropes and Wire Products Sectional Committee, ME10 Organization Representative(s) Directorate General of Mines Safety, Dhanbad SHRI D. SAHA (Chairman) SHRI S. P. BANSAL (Alternate) Aerial Ropeway and Mechanical Handling Co Pvt Ltd, SHRI A. K. KINRA Kolkata SHRI RANJAN MUKHERJEE (Alternate) Amar Promoters Pvt Ltd, Solan SHRI VIRENDER AGARWAL SHRI JATINDER AGARWAL (Alternate) Bharat Coking Coal Ltd, Dhanbad SHRI R. K. PRASAD Bharat Wire Ropes Ltd, Mumbai SHRI D. M. SHAH Central Mining Research Institute, Dhanbad SHRI S. P. CHAUDHARY SHRI R. P. CHAKRABORTY (Alternate) Directorate General of Aeronautical Quality Assurance, SHRI S. B. PRASAD New Delhi SHRI SANJAY CHAWLA (Alternate) Directorate General of Civil Aviation, New Delhi SHRI R. C. SHARMA SHRI N. M. WALECHA (Alternate) Directorate General of Supplies and Disposals, New Delhi SHRI M. GANGARAJU SHRI S. M. MUNJAL (Alternate) Eastern Coalfields Ltd, Kolkata SHRI H. K. CHAKRABORTY Fort William Industries Ltd, Hooghly SHRI I. N. BANERJEE SHRI J. L. RATHI (Alternate) JCT Ltd (Steel Division), Hoshiarpur SHRI MANMOHAN SINGH SHRI S. K. SETH (Alternate) Ministry of Defence (Naval), New Delhi CDR BRAHMASWAROOP SHRI B. L. KHDWAL (Alternate) Ministry of Surface Transport, New Delhi SHRI G. P. ROY SHRI T. K. DUTTA (Alternate) National Test House, Ghaziabad SHRI D. S. MAJUMDAR SHRI B. N. SARKAR (Alternate) North Eastern Coalfields Ltd, Kolkata SHRI A. TIRKEY Oil and Natural Gas Commission, Dehra Dun SHRI R. K. GARG SHRI P. K. SOOD (Alternate) Research Designs and Standards Organization, Lucknow DEPUTY DIRECTOR (STANDARDS) South Eastern Coalfields Ltd, Bilaspur SHRI S. K. MISHRA SHRI G. RAMASWAMI (Alternate) Usha Breco Ltd, Kolkata SHRI AMIT KUMAR BASU SHRI C. K. KARMAKAR (Alternate) Usha Martin Industries Ltd, Ranchi SHRI RANA PRATAP SHRI K. K. SENGUPTA (Alternate) Vidarbha Hardware Industries, Akola SHRI O. P. DALMIA SHRI SANJAY K. DALMIA (Alternate) BIS Directorate General SHRI M. L. CHOPRA, Director and Head (MED) [Representing Director General (Ex-officio)] Member-Secretary SHRI P. VENKATESWARA RAO Joint Director (MED), BIS 5