lS:282-1982

(“Second Reoision )

Q C@Wight 1982

I::N:D 1 AN S T’U,N D A R D S I N S T I T U T I O,N MANiK BHAVAN,. 9 BAHADUR SHAH ZAFAR MARG ‘,

NEW DELHI 110002

Gr 4 October 1982

IS : 282 - 1952

.lled~ers Representing SHRI I<. ft. GUPTA Haryana State Electricity Board, Chandigarh

SHRI H. c. I<AUSHlK ( d/etYlUle ) SHRI 1’. JAYARASIAN Tamil Nadu Electricity Board, Madras

SHRI DEVADASAN EDWARD ( Alternate ) SHRI M. K. JHUNJIIUNWALA Cable and Conductor Manufacturers’ Association

of India, New Delhi SHRI T. S. I’ADMANAI)HAN ( Alternate )

SHRI I. S. KALRA Bhakra Beas Management Board, Chandigarh SHRI H. S. CHOPRA ( Alternare )

SHRI 0. P. MATHUR Electrical Manufacturina Co Ltd. Calcutta DR P. BHATTACHARYA ( Alternute )

SHRI KAJ K. MITAL Delhi Electric Supply Undertaking, New Delhi SHRI M. K. Ai-luJ~ ( Alternafe )

SHRI S. K. MIJKCIEIIJEE National Test House. Calcutta SHIII U. S. VI-:I~MA ( A//ertra/e )

SHRI A. I(. RAMACIIANDI<:\N National Thermal Power Corporation Ltd. New Delhi

SHRI S. S. [LAO ( A/rrrrJrJre ) SHRI I-I. K. RA’I‘III Maharashtra State Electricity Board, Bombay SHRI V. N. RIKII U.P. State Electricity Board, Luclcnow

SHRI V. K. AGARWAL ( Alternate ) SHRI V. K. SHARMA National Hydro-Electric Power Corporation Ltd.

New Delhi SIIILI MAIIENDRA K~J~IAR ( Al~e~rrmrc )

SHRI i<. D. SHl3’li Electra-Metal Industries, Bombay SIIRI G. .I. DI:\~ASSYMIIT~Y ( Alrermre )

Sllll l I>. Sl\~,\SUllllAblANl,\\aI Aluminium Industries Ltd. Kundara SIII~I K. Al. JACOB ( /ll~euw!e )

PROt AI. \‘Ksuciol~AL Indian Institute of Technology, Madras I’lLOl. Y. NAILAYASA Rho ( /llferrrcJle )

SHRI s. I’. SAcr~lxv, Director General, ISI (Ex-oJ%io Member ) Director f, Elcc Tech )

Secretcrry SHRI SUKH BIR SINGH

Assistant Director (Elec Tech ), ISI

TO

IS:282-1582 SPECIFICATION FOR HARD-DRAh'N COPPER COWJCTORS FOR OVERHEAD POWER TRANSMISSION

(Second Revision)

(Rzge IO, Table 4) - Substititc the follovig for the existing table:

TABLE 4 LIMITS OF LAY RATIOS OF DIFFERENT LAYERS

FJO. OF LAY RATIO FOR LAYER ZiiTRAWS Wires in Prackcts)

if

(3 1 (6) (12)

/'MClX

(1) (2) (3) (4 1 (5) (6) (7)

3 16 11 - - - -

7 17 13 - -

19 22 13 16 12

Reprography Unit, XI, New Delhi, India

IS : 282 - 1982

Indian Standard SPECIFICATION FOR

HARD-DRAWN COPPER CONDUCTORS FOR OVERHEAD POWER TRANSMISSION

( Second Reoision )

Conductors and Accessories for Overhead Lines Sectional Committee, ETDC 60

Chairman Representing

SHRI R. D. JAIN Rural Electrification Corporation Ltd, New Delhi

Members

SHR~ G. L. DUA ( AIternate to Shri R. D. Jain )

ADDITIONAL GENERAL MANAGER Indian Posts & Telegraphs Department, New Delhi ( IT )

DIVISIONAL ENGINEER ( TELE )-E ( Alternate )

SHRI V. K. AGARWAL Tata Hydro-Electric Power Supply Co Ltd, Bombay SHRI P. P. BHISEY ( Alternate )

SHR~ R. S. ARORA Directorate General of Supplies and Disposals, New Delhi

SHRI J. S. PASSI ( Alternate ) SHRI S. BHA~TACHARYA Indian Cable Co Ltd, Calcutta

SHRI T. SINGH ( Alternate ) SHRI R. T. CHAKI Tag Corporation, Madras

SARI A. ARUNKUMAR ( Alternate ) SHRI S. D. DAND Kamani Engineering Corporation Ltd, Bombay

SHRI R. V. S. MANIAN ( Alternate ) DIRECTOR Central Power Research Institute, Bangalore

SHRI T. V. GOPALAN ( Alternate ) DIRECTOR ( TRANSMISSION ) Central Electricity Authority ( Transmission

Directorate ), New Delhi DEPUTY DIRECTOR ( TRANS-

MISSION ) ( Alternate ) D ;;;Kvo; R ( TI ). RDSO, Ministry of Railways

JOINT DIRECTOR ( TI )-I, RDSO, LUCKNOW ( Alternate )

( Continued on page 2 )

Q Copyright 1982 INDIAN STANDARDS INSTITUTION

This publicatron is protected under the Indian Copyright Acf ( XIV of 1957 ) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be an infringement of copyright under the said Act.

IS : 282 - 1982

Indian Standard

SPECIFICATION FOR HARD-DRAWN COPPER CONDUCTORS

FOR OVERHEAD POWER TRANSMISSION

( Second Reoision )

0. F.OREWORD

0.1 This Indian Standard ( Second Revision ) was adopted by the Indian Standards Institution on 20 May 1982, after the draft finalized by the Conductors and Accessories for Overhead Lines Sectional Committee had been approved by the Electrotechnical Division Council.

0.2 This standard, first published in 1951, was subsequently revised in 1963 to incorporate all quantities and dimensions in metric system. This revision has been undertaken with a view to upgrade many of the essential requirements and to bring it in line with the latest engineering practices being followed in the country.

0.3 In the standard, values for constant-mass temperature coef&ient of resistance and coefficient of linear expansion are given on the basis of IEC Publication No. 28 ( 1925 ). International Standard of Resistance for copper.

0.4 Hard-drawn copper wires covered by Telegraph Wires (Unlawful possession ) Act No. LXXIV of 1950 as amended by Act No. LIII of 1953 have been dealt separately in 18:2532-1965*.

0.5 While preparing this standard, assistance has been derived from BS 125: 1970 Hard-drawn Copper and Copper Cadmium Conductors for Overhead Power Transmission Purposes, issued by the British Standards Institution.

0.6 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, express- ing the result of a test, shall be rounded off in accordance with IS :2-196Ot. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

*Specification for hard-drawn copper wire for telegraph and telephone purposes. tRules for rounding off numerical values ( revised ).

3

1. SCOPE 1.1 This specification covers the requirements for hard-drawn solid and stranded circular copper conductors for overhead power transmission purposes.

2. TERMINOLOGY 2.0 For the purpose of this standard, the following definitions in addition to those given in 1s : lS85 ( Part XXXII )-1971* shall apply.

2.1 Stranded Conductor - Conductor consisting of three or more copper wires of the same nominal diameter twisted together in concentric layers. When the conductor consists of more than one layer, successive layers are twisted in opposite directions.

2.2 Diameter - The mean of two measurements at right angles taken at the same crow section

2.3 Direction of Lay - The direction of lay is defined as right hand or left hand. With right hand lay, the wires conform to the direction of the central part of the letter 2 when the conductor is held vertically. With left hand lay, the wires c:)nform to the direction of the central part of the letter S when the conductor is held vertically.

2.4 Lay Ratio - Ratio of the axial length of a complete turn of the helix formed by an individual wire in a stranded conductor to the external diameter of the helix.

3. CONDUCTOR 3.1 Material -- The conductor shall consist of hard-drawn round copper wire having the following properties.

3. I .l Physiml Co~~.r~nn~r ,/or Hmi- Drnwn Copper

3.1.1.1 I/o/u/;re /z.sisliviry - The resistivity of hard-drawn high-con- ductivity copper is 21 function of the tensile strength. Within a range of 30 to 50 kg/mm2 tensile strength, the following formula has been found to express suficiently closely the results obtained in practice, and has been adopted in calculating the resistance given in this specification:

‘I‘

whew P = percentage increase in resistivity of the hard-drawn copper

over its resistivity when annealed, and T == tensile strength of the hard-drawn copper in kg/mm”.

*Electrotcchnical vocabulary: Part XXX11 Cables, conductors and accessories for electricity supi>ly.

IS : 282 - 1982

The resistances given in the tables, are based on standard resistivjty of annealed high-conductivity copper at 20°C modified in accordance with the above formula.

At a temperature of 20°C the volume resistivity of standard annealed copper is 0.017 241 ohm square millimetre per metre ( ohm mm3/m ).

Copper which has resistivity at 20°C of 0.017 241 ohm mm2/m is said to have a conductivity of 100 percent.

3.1.1.2 Density - At a temperature of 20°C the density of hard-drawn high conductivity copper has been taken as 8.89 g/cm3.

3.1.1.3 Coefficient of linear expansion - At a temperature of 20°C the coefficient of linear expansion of hard-drawn high-conductivity copper has been taken as 0’000 017 per Centigrade degree, This coefficient may be used over a temperature range of 0°C to 150°C.

3.1.1.4 Constant-mass temperature coefficient of resistance - at a temperature of 20°C the coefficient of variation of the resistance with temperature of hard-drawn high-conductivity copper, measured between two potential points rigidly fixed to the wire, the metal being allowed to expand freely, has been taken as 0’003 81 per Centigrade degree, which is a representative value for copper of 97 percent conductivity.

3.1.1.5 Freedom from defects - The wire shall be smooth and free from al1 imperfections such as spills and spurns.

4. STANDARD RESISTANCE, WEIGHT AND SIZE OF SOLID CONDUCTOR

4.1 After drawing, the wire shall have the resistance, weight and diameter given in Table 1.

5. STANDARD RESISTANCE, WEIGHT AND SIZE OF STANDARD CONDUCTOR

5.1 The size, weight and resistance of stranded circular conductor shall be in accordance with the values given in Table 2.

5.2 In Table 2, the areas, weights and resistances of the stranded conductors have been calculated by multiplying the corresponding values for one of the single wires of which the stranded conductor is composed by the constants set out in Table 3.

5.3 The calculated area in each case in Table 2 is given as obtained above, and is that of a solid conductor of equal resistance assuming to same specific conductivity.

5

TABLE 1 STANDARD SOLID HARD-DRAWN COPPER CONDUCTORS tj . .

(Clauses 4.1, 6.1, 6.2, 7.1, 11.3.2 curd 15.2)

SOhllNAL DIAMETEK STANDARD KESWANCI? AT MINlhlLJhl BIII:AK- MINlhlUhl

‘Stan- Masi- dard Ill u Ill

12) (3) mm 1nm

1.36: I.37

1.605 1.62

1.70; 1.72

2.12; 2.14

2.65: 2.6s

3.00: 3.03

3’25§$ 3.28

3.35: 3.38

3’55§: 3.59

3.65: 3.69

3.75:: 3’79

4.253: 4.29

4.504 4.54

4.75: 4’80

- S’OO$

25 5.305:

- S-60:

35 6.505

40 7’10§

SO 7.50s

65 9*sog

5'05 4.95 174.6 0.9014 0.9104 8.09 7.93 412.0 - 19’63

5.35 5.25 196.1 0.8019 0.8099 9.00 8.84 408.3 - 22.06

5.66 554 219-o 0.7181 0.7253 9.99 9.78 405.6 1.88 24.63

6’56 6.44 295.0 05327 0’5380 13.12 1288 395.5 1.98 33.18

7’17 7.03 352.0 0.4463 0.4508 15’38 15’07 388.5 2.07 39.59

7.58 7.42 392.7 0.3998 0.4038 16.94 1659 383.6 213 44.18

9’60 9.40 630’1 0.2488 0.2513 25.62 25.08 361.5 248 70.88

Mini- “lull1

WEIGHT PEU km

(4, (5) mm kg 1.35 12.91

1.58 17.87

1.68 20.18

2.10 31.38

2.62 49’03

291 62.84

3.22 73’75

3’32 78.36

3.51 87.99

3.61 93.02

3’71 98.10

4’21 126.1

4.46 141.4

4.70 157.5 0.9987 1*009

20°C PER km ING LOAV TENSILE (--A- -7 l ------- *-------, STRENGTH Stan- dard

hstaxi- mum

(6, 7) ohm ohm

12.21 12.33

8.823 8.911

7.815 7.893

5.025 5.075

3-215 3.247

2.507 2532

2.136 2.157

2.010 2.030

1.790 1.808

1.693 1’710

1.604 1.620

1.248 I .265

1.113 1.124

On Stan- dard Dia-

meter*

S)

kN

.667

.922

I.03

l-59

2’45

3.12

3.63

3.85

4.28

4.50

4.74

5.97

6.64

7.35

On Mini- mum Dia-

meter’j

;‘)j

kN

.657

.892

1.01

I.56

2.40

3’05

3.56

3.77

4.18

4.40

4.64

5.87

6.52

7.19

(10) MN/Ill’

458.6

456.6

455.9

450.9

445.4

440.7

437.0

435.1

432.1

4jo.7

429.2

421.3

417.6

4145

MINIMUM ELONGA- TION ON

2s cm

(II) Percent

-

-

-

- -

- -

-

-

-

-

-

-

z t3

CALCULI\- ’ ‘TEL) AUliA 5;

ON STAN- c DAUV

DlhhlETEll

(12) Ill 111”

1’453

2’011

2.270

3.530

5.515

7.069

8.296

S.814

9.898

IO.46

11.04

14.19

IS.90

17’72

NOTE 1 - The standard weight given in coi 5 is based on standard diameter and is for information only.

NOTE 2 - Minimum breaking loads after stranding shall be not less than 92.5 percent of the corresponding values given in co1 8 and 9.

*The values specified in co1 8 are the basis from which the approximate breaking load of conductors specified in Table 2 have been calculated.

tThe values specified in co1 9 are minima with which solid conductors and wires shall comply before stranding.

ZStandard sizes recommended for stranded conductors.

SStandard sizes recommended for use as solid conductors.

IS : 282 - 1982

TADLE 2 STANDARD STRANDED HARD-DRAWN COPPER CONDUCTORS

( Clames 5.1, 5.2, 5.3, 6.1, 14.2 rind 15.2 )

STAND- NUMBER ARD AND DI,\-

NOMI- ~IEI‘I;II VI NAL SSIIANIX

AKE.4

(1)

111111’~

10

14

16

2s

35

40

50

65

70

95

120

130

150

160

115

200

(2) (3) (4) (5) mm mm m tm 2 kg

312.12 4.57 10.51 94.90 l/1,36 4.0s 10.0s 91.1 j

T/l.60 4.80 13.96 126.2

3/2%S 5.71 16.42 148.3 l/l’70 5.10 IS.76 142.4

313.25 7.00 24.70 223.0 712.12 6.36 24.50 221.5

313.75 sm 32.88 297.0

7l27.35 7.9s 38.29 346’1

713.00 9’00 49.07 443.5

19/2.12 10.6 66.24 604

713.5s IO.6 68.7 I 621.1

714’25 12,s 98.48 890. I

714.75 14.2 123’0 I 112

7/540 IS.0 136.3 1 232 19/3.00 15.0 132.7 1 209

715.30 15.9 153.2 1 384 1913’25 16.2 155.7 1419

115’60 16.S 171.0 1 545 19/3’35 16.8 165.4 1 508

19/3,SS 17,s 185.8 1 693

1913.65 lS.2 196.4 1 790

AP~ROXI- CALCULA- STAND- MATE IED AREA ARD

o\‘iil~i\l.L ON S.I.,\N- WEIGIIT

I<ESISTAN~E AT 20°C APPROXI- PER km WHEN CON- MATE

NECTFV TO STAN- BREAKING VARV WElGHT

(6) ohm

I.688 1.758

1.271

1.080 1.125

0.717 7 0.723 6

0.538 9

0.463 0

0.361 0

0.267 7

0.257 8

0.179 7

0.143 8

0.129 8 0.133 6

0.115 5 0.113 8

0.103 4 0,107 1

o-095 37

0*090 20

(7)

ohm

1 ‘JO.5 1,775

I.282

1.090 1.136

0.724 9 0.730 8

0.544 3

0.467 6

0.364 6

0.270 4

0.260 4

O*lSl 5

0.145 1

0.131 1 0’134 9

0.126 7 0.114 9

0.104 4 O*lOS 1

0’095 47

0.091 20

LOAD OF CON-

DUCTOR

(8)

kN

4.38 4.30

5.93

6.77 6.63

IO.02 IO.23

13.08

15.79

20.09

27.17

27.55

38.47

47.32

52.12 53.35

58.00 62.07

64’31 65.76

73.14

77~00

Nore - The standard \wight given in co1 5 is based on standard diameter and is for information only.

8

IS : 282 - 1982

TABLE 3 CONVERSION CONSTANTS FOR STRANDED CONDUCTORS

( Clatrse 5.2 )

No. OF WIRES CONSTANT STRANDED r----.-.e--h--- ---l

Area Weight Resistance

(1) (2) (3) (4) 3 2.977 3’024 0.336 0 I 6.942 7.058 0.144 0

19 18.77 19.24 0.053 28

5.4 The resistances have been corrected in accordance with the formula given in 3.1.1.1.

6. TOLERANCES ON THE STANDARD DIAMETER AND RESISTANCE OF CONDUCTORS

6.1 Tolerances as given below shall be permitted on the standard diameter and resistances of all conductors:

a) Tolerance on standard diameter f I percent, and b) Tolerance on resistance + 1 percent when corrected to standard

weight. When corrected to standard weight and temperature, the resistance of

the conductor shall not exceed the appropriate maximum resistance given in Tables 1 and 2. 6.2 The mean diameter of the conductor shall fall within the appropriate maximum and.minimum values given in Table 1. 6.3 The cross-section bf any conductor shall not depart from circuiarity by more than an amount corresponding to a tolerance of 2 percent on the standard diameter.

7. MECHANICAL PROPERTIES 7.1 The mechanical properties of the wire shall be such that the tensile strength and elongation when tested in accordance with 14.3 and 14.4 shall be as shown in Table 1. 7.2 Wires smaller than 5.60 mm diameter shall also comply with the requirements of the wrapping test as specified in 14.2.

NOTE -For purposes of calculation, the modulus of elasticity of hard-drawn copper shall be taken as 1.27 x loo kg/cm’J.

9

IS : 282 - 1982

8. JOINTS IN WIRES, EXCEPT DlJRING STRANDING

8.1 The wires shall be drawn in continuous lengths, without joints, except those made in the soft rod or wire before final drawing.

9. JOINTS IN STRANDED CONDUCTORS

9.1 Conductors Containing Seven Wires or Less -Joints in wires, other than those permitted under 8, shall not be permitted in any wire of a stranded conductor containing 7 wires or less.

9.2 Conductors Coutairiiug More than Seven Wires - In the case of stranded conductor containin g more than 7 wires, a joint in any wire shall be permitted provided that no two joints ( other than those in wires before stranding. permitted under 8 ) occur at points in the stranded conductor nearer than 15 m. Joints shdl be hard-soldered or welded.

9.3 The breaking strength of the joint permitted under 9.2, shall be in no case be less than 220 MN/mr?.

10.1 The wire entering, into the construction of stranded conductors shall, before stranding, satlsty all the requirements of this specification for solid wires.

10.2 The lay ratios of different layers shall be within the limits given in Table 4.

TABLE 4 LIMITS OF LAY RATIOS OF DIFFERENT LAYERS

No. OF STRANDS

(1)

3

I

19

LAY RATIO FOR LAYER ( WITH NUMBER OF WIRES IN BRACKETS )

f-------- --- , 1st 2nd

!3) (6) (12) ,----h -7 f---------*-~

Max Min M NX Mire f-----*--l

Max Min

(2) (3) (4) (5) (6) (7)

30 20 - - - -

- -- 25 20 - -

.._. - 32 20 20 15

IS : 282 - 1982

10.3 For all constructions successive layers shall have opposite directions of lay, the outer layer being right handed.

11. LENGTHS AND VARIATIONS IN LENGTHS

11.1 Unless otherwise agreed between the manufacturer and purchaser, hard-drawn copper conductors shall be supplied in the manufacturer’s usual production lengths with a permitted variation of & 5 percent in the length of any one length.

11.2 Unless otherwise agreed between manufacturer and purchaser, it shall be permissible to supply not more than 10% of the lengths on any one order in random lengths, none, of them shall be shorter than 1/3rd of the nominal lengths.

12. PACKING AND MARKING

12.1 The conductor shall be supplied in coils or on drums* and one drum or coil shall carry only one continuous length of conductor. Each coil or drum shall be marked with the following information:

a) Trade-name, if any;

b) Manufacturer’s name;

c) Size of conductor;

d) Length of conductor;

e) Weight of the conductor;

f) Drum number; and

g) Any other particulars as specified by the purchaser.

12.1.1 The conductor may also be marked with the ISI Certification Mark.

NOTE - The use of the ISI Certification Mark is governed by the provisions of the Indian Standards Institution ( Certification Marks) Act and. the Rules and Regulations made thereunder. The IS1 Mark on products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well-defined system of inspection, testing and quality control which is devised and supervised by ISI and operated by the producer. ISI marked products are also continuously checked by IS1 for conformity to that standard as a further safeeguard. Details of conditions under which a licence for the use of the IS1 Certification Mark may be granted to manufacturers or processors, may be obtained from the Indian Standards Institution.

*It is recommended that the drums for bare conductors should comply with IS: 1778-1980 Specification for reels and drums for bare wire ( /irsr revision ).

11

IS : 282 - 1982

13. TEST SAMPLES

13.1 Solid Conductors - Samples for the tests specified in 14 and 15 shall be taken from approximately 10 percent of the drums included in any one consignment.

One sample, sulbcient to provide one specimen for each test, shall be taken from each of the selected drums. 13.2 Stranded Conductors

13.2.1 Tests Before Strnnding - Samples for the tests specified in 14 and 15 shall be taken by the manufacturer before stranding from not less than 10 percent of the individual lengths of wire which will be included in any one consignment of stranded conductor. One sample, sufficient to provide one test specimen for each test, shall be taken from each of the selected lengths of wire.

1X2.2 Test A.fter Strcmling - Alternatively, when the purchaser states at the time of ordering that he desires tests to be made in the presence of his representatives, samples of wire shall be taken from lengths of stranded conductor selected from approximately 10 percent of the drums included in any one consignment. One sample, sufficient to provide one specimen for each test, shall be taken from each of the selected drums.

14. MECHANICAL TESTS

14.1 General - In the case of both solid and stranded conductors, the mechanical tests shall be carried out on single wires only.

14.2 Wrapping Test

14.2.1 This test shall be carried out only on wires of less than 5.60 mm diameter.

14.2.2 The wire shall not break when tested in the following manner,

14.2.2.1 The wire shall be wrapped round a wire of its own diameter to form a close helix of eight turns. Six turns shall then be unwrapped and again closely rcwrappcd in the same direction as the first wrapping. 14.3 Tensile Test

14.3.1 This test shall apply to solid conductors and to the component wires of stranded conductors. Wherever practicable, tests of wires shall be made before stranding.

14.3.2 II’ it is not l)ossible to test the component wires of a stranded conductor before stranding, the test may be made on wires taken from the strandctl co:jductor. Tn such cases, the tensile strength of any of the wires shall be not less tha:1 92.5 percent of the values given in Table 1 and the average tensile strcrl~rh of the wires in a stranded conductor shall be not less than 9-3 pcrccnt of the values specified in Table 1.

IS : 282 - 1982

14.3.3 A tensile testing machine shall be used the accuracy of which can be easily checked and the machine adjusted, if necessary. The test samples being placed in the machine shall be straightened, if necessary, in such a way as to cause the minimum alteration in the physical properties.

14.3.3.1 When an automatic tensile testing machine is used, the load shall be applied gradually and the rate of separation of the jaws of the testing machine shall not be greater than 10 cm per minute and shall be so adjusted that the total time of testing from the moment of application of the load till fracture is between 15 to 60 seconds.

14.3.3.2 When a hand-operated lever testing machine is used 90 percent of the breaking load shall be applied quickly and the load shall then be increased steadily until the specimen breaks. The time taken to apply the balance 10 percent of the load shall be approximately 15 seconds and the total time from the application of the load to the break shall be approxi- mately 20 seconds.

NOTE - The strength of a stranded conductor in terms of the sum of the strength of the individual component wires may be assumed to be not less than the values given in Table 5.

TABLE 5 STRENGTH OF STRANDED CONDUCTOR

No. OF WIRES PERCENTAGE STRENGTH BASED PERCENTAGE STRENGTH BASED IN STRANDED ON THE SUM OF THE STRENGTHS ON THE SUM OF THE STRENGTHS CONDUUOR OF THE WIRES WHEN TAKEN OF THE COMPONENT WIRES

FROM THE STRANDED BEFORE STKANDING CONDUCTOR AND ( THAT IS IN

TESTED THE COIL )

(1) (2) (3)

3 96 92

7 95 92

19 93 90

14.4 Elongation Test

14.4.1 This test shall be performed only on wires of 5.60 mm diameter and over.

14.4.2 The load shall be applied on straightened lengths of wire having an original gauge-length of 25 cm. The extension shall be measured on the gauge-length after the fractured ends have been fitted together, provided

13

IS : 282 - 1952

that the fracture occurs between the gauge marks and not closer than 25 mm to either mark. If the fracture occurs outside these limits and if the required elongation is not obtained, the test shall be discarded and another test made.

15. RESISTANCE TEST

15.1 The dc resistance of the conductor shall be measured at room temperature. The conductor shall be in the test room which shall be at a reasonably constant temperature for sufficient time to ensure that the conductor temperature is equal to the ambient temperature.

15.2 The electrical resistance as measured shall be converted to resistance per kilometre which when multiplied by

K = standard weight per km,

W = weight per km of test sample, and

C = multiplier constant for correction to 20°C;

shall not exceed the maximum values given in Tables 1 and 2.

15.2.1 The multiplier constant shall be in accordance with Table 6.

15.3 The measurement of resistance shall be carried out to an accuracy of one part in a thousand. The length of the sample selected for the test of electrical resistance shall be suficient to give the accuracy required and shall be suitable for the method of testing employed. Certificates as to the accuracy of the apparatus shall be provided, and either party concerned shall have the right to satisfy itself that the apparatus and the method of testing are correct.

16. REJECTION AND RETESTS

16.1 Should any one of the test pieces first selected fail to pass the test, three further samples from the same batch shall be selected, one of which shall be from the length from which the original test sample was taken, unless that length has been withdrawn by the supplier.

16.2 Should all of the three test pieces from these additional samples satisfy the rec~uirements of the tests, the batch represented by these samples shall bc deemed to comply with the standard. Should the test pieces from any of the three additional samples fail, the batch represented shall be deemed not to comply with the standard.

14

IS : 282 - 1982

TABLE 6 MULTIPLIER CONSTANTS

( Clause 14.2.1 )

Factors for converting resistances at various temperatures, of hard-drawn high conductivity copper of 97 percent conductivity, to the standard reference temperature of 20°C and reciprocals of the factors, for converting resistances at 20°C to other temperatures.

TEMPERA- MULTIPLIER TURE"C CONSTANT

RECIPRO- CALOF

CONSTANT

(3)

0.94i 9 0.944 8 0.946 7

0.948 6

TEMPERA- MULTIPLIER TURE "C CONSTANT.

(1) (2) 5 1.060 6

5’5 1.058 5 6 1.056 3 6.5 1.054 2

(1) (2) 10 1’039 6 lo;5 1.037 6 11 1.035 5 11.5 1.033 5

RECIPRO- CALOF

CONSTANT

(31

0.961 9 0.963 8 O-965 7 0.967 6

7 1.052 1 0.950 5 12 I.031 4 O-969 5

7.5 1.050 0 0,952 4 12.5 I.029 4 0.971 4

8 1.047 9 0.954 3 13 I.027 4 0.973 3

8.5 1.045 8 0.956 2 13.5 1.025 4 0.975 2

9 1.043 7 0.958 1

9.5 l-041 7 O-960 0 14 1.023 4 o-977 1 14.5 1.021 4 0.979 0

15 1.019 4 0.981 0

155 1.017 4 0.982 9 16 l-015 5 0.984 8 16.5 I.013 5 0.986 7

25.5 0’979 5 1.021 0 26 o-977 7 1’022 9 26.5 0.975 8 l-024 8

17 l-011 6 0.988 6 17.5 1.009 6 0.990 5 18 1.007 7 0.992 4 18.5 1’005 7 0.994 3

27 0.974 0 I.026 7 27.5 0.972 2 I.028 6 28 0.970 4 1.030 5 28.5 0.968 6 1.032 4

19 1.003 8 0.996 2 19.5 1’001 9 0.998 1 20 1.000 0 I*000 0 20.5 o-998 1 I-001 9

29 0.966 8 1.034 3 29.5 0’965 1 I.036 2 30 0.963 3 1.038 1 35 0’945 9 I.057 1

( Continued )

15

IS : 282 - 1982

TABLE 6 MULTIPLIER CONSTANTS - Conrd

Factors for converting resistances at various temperatures, of hard-drawn high conductivity copper of 97 percent conductivity, to the standard reference temperature of 2O”C, and reciprocals of the factors, for converting resistances at 20°C to other temperatures.

TEMPERA- MULTIPLIER TURE°C CONSTANT

RECIPRO- CALOF

CONSTANT

(1) (2) (3)

21 0.996 2 I.003 8 21.5 0.994 3 1.005 I 22 0.992 4 I.007 6 22.5 0.990 6 I.009 5

23 23.5 24 24.5

o-9%3 I 0.956 8 0.985 0 0*9s3 1

l-011 4 1.013 3 1*015 2 1.017 1

25 O.OSl 3 I.019 1

TEMPERA- MULTIPLIER TURE "c CONSTANT

(1) 40 45 50 55

60 0.867 8 I.152 4 65 0.863 6 1.171 4 70 0.840 0 1.190 5 75 0.826 8 1’209 5

so 0.813 9 1.228 6 85 0.801 5 1.247 8

(2)

o-929 2 0.913 0 0497 4 OS32 3

CALOF CONSTANT

(3)

I.076 2 I.095 2 1.114 3 I.133 3

NOTE - The temperature coefficient of resistance of copper varies slightly from sample to sample according to its exact conductivity. The figures given in Table 6 are based on a value of the temperatures coefficient of resistance of 0.003 81 per Centigrade degree at 2O”C, which is an average value for copper of 97 percent conductivity.

The primary purpose of this table is to enable a resistance measured at a tempera- ture other than 20°C to be converted to the resistance at 20°C in order to determine whether the conductor under test complies with the requirements of the standard. For this purpose, the factors have been given at half-degree intervals from 5°C to 30°C. and the error in using the table between these limits for copper within the range of conductivity. 96 percent lo 98 percent will not exceed 0.06 percent.

The factors and their reciprocals have also been found of value for other purposes, such as calculation of voltage drop on heated conductors. For these purposes only, values have been given at five-degree intervals from 30°C to 85°C. It should be realized, however, that their use may lead to errors of up to 0.2 percent at the upper end of the range.

INDIAN STANDARDS

ON

CONDUCTORS AND ACCESSORIES FOR OVERHEAD .LINES

IS:

282-1982 Hard-drawn copper conductors for overheciQ power, tra%%UiS%QU, ( second revision )

398 Aluminium conductors for overhead transmission l?urPoses: (Part I)-1976 Aluminium stranded conductors (secoridrevision) (Part II)-1976 Aluminium conductors, galvanized steel reinforced L seconu

revision ) (Part III)-1976 Aluminium conductors, aluminized steel reinforced ( second

revision ) (Part IV)-1979 Aluminium alloy stranded conductors ~,alurninium;mnag~es~~~~

silicon type) ( secondrevision ) (Part V)-1982 Aluminium conductors, galvanized steel reinforced F&&tr$&g

voltage ( 400 kV and above ) 177S-19SO Reels and drums for bare wire ( firsf revision ) 1% (Part XxX11)-1971 Electrotechnical vocabulary: Part XXX11 Cables;conductors

and accessories [or electricity supply 2121 Conductors and earth wire accessories for overhead power lines:

(Part Q-1981 Armour rods, binding wires and tapes for cF$uctors ($&&i&%) \- -’ :?3w~~~~~,*~ (Part II)-1981 Mid span joints and repair sleeves for conduc[ors (fi~~~;@r~~&$

2532.1965 Hard-drawn copper wire for telegraph and t&ph$~k.purpo$$.$ 2665-1964 Cadmium copper wire for telegraph and.telephoa~f;u~~os~~ 3402-1965 Cadmium copper conductors for overhead r&ibaj?~&& ..,, I. ^. 3476-1967 Trolley and contact wire for electric traction 9708-1980 Stock bridge vibration dampers for overheid pow& l@s

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