© BIS 2004

B U R E A U O F I N D I A N S T A N D A R D SMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

IS : 3347 (Part I/Sec 1) - 1979(Reaffirmed 1999)

Edition 2.1(1989-02)

Price Group 3

Indian StandardDIMENSIONS FOR PORCELAIN

TRANSFORMER BUSHINGS FOR USE IN LIGHTLY POLLUTED ATMOSPHERES

PART I UP TO AND INCLUDING 1 kV

Section 1 Porcelain Part

( First Revision )(Incorporating Amendment No. 1)

UDC 621.315.626-2:621.315.612.2:006.78.621.314.21

IS : 3347 (Part I/Sec 1) - 1979

© BIS 2004

BUREAU OF INDIAN STANDARDS

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

Indian StandardDIMENSIONS FOR PORCELAIN

TRANSFORMER BUSHINGS FOR USE IN LIGHTLY POLLUTED ATMOSPHERES

PART 1 UP TO AND INCLUDING 1 kV

Section 1 Porcelain Part

( First Revision )Electrical Insulators and Accessories Sectional Committee, ETDC 3

Chairman Representing

SHRI L. C. JAIN Ministry of Energy, New Delhi

Members

SHRI V. R. ANANTHANARAYANAN Bengal Potteries Ltd, CalcuttaSHRI CHANDER PARKASH ( Alternate )

SHRI B. C. BANERJEE All India Pottery Manufacturers’ Association,Calcutta

SHRI B. C. DAW ( Alternate )SHRI D. S. CHABHAL Directorate General of Technical Development,

New DelhiSHRI R. T. CHARI Tag Corporation, Madras

SHRI A. GURUPATHAM ( Alternate )SHRI K. S. CHELLAPPAN Tamil Nadu Electricity Board, Madras

SHRI N. R. SANKARAN ( Alternate )SHRI A. K. CHOPRA Punjab State Electricity Board, Patiala

SHRI NIRVAIR SINGH ( Alternate )SHRI A. N. DEB Damodar Valley Corporation, Calcutta

SHRI A. C. BOSE ( Alternate )DIRECTOR OF RESEARCH (T & D) Maharashtra State Electricity Board, BombayDIRECTOR (TRACTION AND

INSTALLATION)Research, Designs & Standards Organization

(Ministry of Railways), LucknowJOINT DIRECTOR STANDARDS

(T1) ( Alternate )

( Continued on page 2 )

IS : 3347 (Part I/Sec 1) - 1979

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( Continued from page 1 )

Members Representing

DIRECTOR (TRANSMISSION) Central Electricity Authority, New DelhiDEPUTY DIRECTOR (SUBSTA-

TION) ( Alternate )GENERAL MANAGER (T)

DIRECTOR OF TELEGRAPHS (L)( Alternate )

DIVISIONAL ENGINEER TELE-GRAPHS (C) ( Alternate )

Director General of Posts & Telegraphs, Jabalpur

SHRI B. N. GHOSH Bharat Heavy Electricals Ltd, BhopalSHRI H. M. S. LINGAIAH Karnataka Electricity Board, BangaloreSHRI G. S. MAHAGAONKAR Mysore Porcelains Ltd, BangaloreSHRI S. K. MUKHERJEE

SHRI U. S. VERMA ( Alternate )National Test House, Calcutta

DR G. M. PHADKESHRI C. R. VARRIER ( Alternate )

Indian Electrical Manufacturers’ Association,Bombay

SHRI P. S. RAMANSHRI E. P. WILFRED ( Alternate )

NGEF Limited, Bangalore

SHRI M. SANKARALINGAMDEPUTY DIRECTOR OF

INSPECTION ( Alternate )

Directorate General of Supplies & Disposals, NewDelhi

SHRI P. K. SAXENASHRI G. L. DUA ( Alternate )

Rural Electrification Corporation Limited, NewDelhi

SHRI N. S. SEETHURAMONSHRI V. SRINIVASAN ( Alternate )

W. S. Insulators of India Ltd, Madras

DR U. S. SINGHSHRI A. D. DUA ( Alternate )

High Tension Insulator Factory, Ranchi

SHRI SURENDRA SINGH U. P. Government Pottery Development Centre,Khurja

SHRI T. B. L. SRIVASTAVA ( Alternate )SHRI L. VENKATESUBBU

SHRI R. V. ACHUTHAN ( Alternate )Seshasayee Industries Ltd, Vadalur South Arcot

DistrictSHRI S. P. SACHDEV,

Director (Elec tech)Director General, ISI ( Ex-officio Member )

SecretarySHRI R. S. SARMA

Assistant Director (Elec tech), ISI

Panel for Dimensions of Bushings, ETDC 3/P3

Convener

SHRI V. SRINIVASAN W. S. Insulators of India Ltd, Madras

Members

SHRI K. N. JAYARAM Mysore Porcelains Ltd, BangaloreSHRI S. V. MANERIKAR Crompton Greaves Ltd, Bombay

( Continued on page 10 )

IS : 3347 (Part I/Sec 1) - 1979

3

Indian StandardDIMENSIONS FOR PORCELAIN

TRANSFORMER BUSHINGS FOR USE IN LIGHTLY POLLUTED ATMOSPHERES

PART 1 UP TO AND INCLUDING 1 kV

Section 1 Porcelain Part

( First Revision )0. F O R E W O R D

0.1 This Indian Standard (Part I/Sec 1) (First Revision) was adoptedby the Indian Standards Institution on 27 July 1979, after the draftfinalized by the Electrical Insulators and Accessories SectionalCommittee had been approved by the Electrotechnical DivisionCouncil.

0.2 This standard was first issued in 1965. In this revision, in place ofthe four slots arranged cross-wise provided formerly in the case oflower insulator for 250 A, and 630 A, provision has been made for twodiametrically opposite slots in the upper portion and two displaced 90°in the lower portion. In the case of porcelains for 1 000, 2 000 and3 150 A, these slots are dispensed with in lower insulators onmechanical grounds. Ventilation of these bushings takes place throughthe slotted sealing rings ( see Section 2 ).

0.3 This standard (Part I) covers the dimensions of porcelaintransformer bushings for use in lightly polluted atmospheres of up toand including 1 kV with the object of ensuring theirinterchangeability. To avoid multiplicity of sizes, the dimensions givenare only for those ratings (voltage and current) which are being usedappreciably. This part is being prepared in two sections. This section(Section 1) covers the porcelain parts of the bushings. Section 2 coversthe dimensions of the metal parts of the bushings to go with theporcelain parts of Section 1.

0.4 The dimensions given in this standard (Part I/Sec 1) have beenarrived at after a full consideration of the available sizes and anexamination of the relevant merits of different types of bushings.

IS : 3347 (Part I/Sec 1) - 1979

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Detailed dimensions have been given with a view to achievingmaximum economy in the manufacture of bushings. The porcelainparts covered by this standard shall also conform to IS : 5621-1979*unless otherwise stated in this standard.

0.5 The bushings are rated in terms of the highest system voltage ( seeIS : 2099-1973† ). The dimensions of bushings for other voltages arecovered by the following parts of this standard:

Part II 3.6 kV bushingsSection 1 Porcelain partsSection 2 Metal parts

Part III 12 and 17.5 kV bushingsSection 1 Porcelain partsSection 2 Metal parts

Part IV 24 kV bushingsSection 1 Porcelain partsSection 2 Metal parts

Part V 36 kV bushingsSection 1 Porcelain partsSection 2 Metal parts

Part VI 72.5 kV bushingsSection 1 Porcelain partsSection 2 Metal parts ( under preparation )

Part VII 123 kV bushingsSection 1 Porcelain partsSection 2 Metal parts ( under preparation )

0.6 The dimensions for porcelain transformer bushings for use inheavily polluted atmospheres are covered by the series of IS : 8603.

0.7 For bushings of up to and including 1 kV, 2-piece porcelaininsulators have been recommended.

0.8 The dimensions covered in this standard essentially apply tobushings used outdoors with inner ends immersed in oil and suitablefor normal and lightly polluted atmospheres.

*Specification for hollow insulators for use in electrical equipment ( first revision ).†Specification for bushings for alternating voltages above 1 000 volts ( first revision ).

IS : 3347 (Part I/Sec 1) - 1979

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0.9 The performance requirements of the bushings covered in this partof the standard are given in IS : 7421-1974*.

0.10 In the preparation of this standard, assistance has been derivedfrom DIN 42530 (1968) ‘Indoor and outdoor transformer bushings,voltage class 1 kV, 250 to 3 150 A’, issued by DeutscherNormenausschuss.

0.11 This edition 2.1 incorporates Amendment No. 1 (February 1989).Side bar indicates modification of the text as the result ofincorporation of the amendment.

0.12 For the purpose of deciding whether a particular requirement ofthis standard is complied with, the final value, observed or calculated,expressing the result of a test, shall be rounded off in accordance withIS : 2-1960†. The number of significant places retained in the roundedoff value should be the same as that of the specified value in thisstandard.

1. SCOPE

1.1 This standard (Part I/Sec 1) lays down the dimensions of porcelainparts of bushings for use in lightly polluted atmospheres of up to andincluding 1 kV used with transformers.

2. PORCELAIN PARTS

2.1 The dimensions of the porcelain parts for the different ratings ofbushings are given in Fig. 1.

2.2 Unless otherwise mentioned, the tolerance on the porcelain partsshall be ± (0.03 d + 0.3) mm, d being the dimension in millimetres.

*Specification for porcelain bushing for alternating voltages up to and including1000 V.

†Rules for rounding off numerical values ( revised ).

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( Continued )

Rating, kV/A d5 d7 d8 d9 d10 h1 h2 h3 r1 r2

Up to and including 1/250 50 32 34 13 2.5 1

,, ,, ,, 1/630 70 47 49 16 3 1

,, ,, ,, 1/1 000 90 65 67 16 3 1.5

,, ,, ,, 1/2 000 104 80 82 16 3 1.5

,, ,, ,, 1/3 150 125 100 100 16 3 1.5

*Unglazed.

∆Surfaces ground parallel to each other and perpendicular to axis.

All dimensions in millimetres.

IA Upper Insulator

FIG. 1 PORCELAIN INSULATOR FOR 1/250, 630, 1 000, 2 000 AND 3 150 BUSHINGS

27+0–2 14+1

–0 70+0–5 45+3

–0

43+0–3 22

+2–0 80+0

–5 55+4–0

53+0–4 32

+3–0 85+0

–655

+4–0

66+0–5 44

+3–0 85+0

–6 55+4–0

86+0–6

50+4–0 85+0

–6 55+4–0

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Rating, kV/A d4 d6 ande2

d11 d12 e1 h4 h5 h6 r3

Up to and including 1/250 60 50 8 2

,, ,, ,, 1/630 85 70 8 3

,, ,, ,, 1/1 000 110 90 10 4

,, ,, ,, 1/2 000 125 104 10 4

,, ,, ,, 1/3 150 150 125 12 4

*Unglazed.

∆Surfaces ground parallel to each other and perpendicular to axis.

All dimensions in millimetres.

IB Lower Insulator

FIG. 1 PORCELAIN INSULATOR FOR 1/250, 630, 1 000, 2 000 AND 3 150 BUSHINGS

30+2–0

26+2–0

20+2–0

30+2–0

20+2–0

46+3–0 41

+3–0 28+2

–030+2

–020+2

–0

57+4–0 46

+3–0 37

+3–0 35

+3–0 25+2

–0

70+5–0 64

+4–0 51

+4–0 35

+3–0 25+2

–0

90+6–0 80

+5–0 61

+4–0 35

+3–0 25+2

–0

IS : 3347 (Part I/Sec 1) - 1979

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( Continued from page 2 )

Members Representing

SHRI M. L. MITTAL Bharat Heavy Electricals Ltd, BhopalSHRI S. P. SINGH ( Alternate )

SHRI R. G. PRADHANANI Bharat Bijlee Ltd, BombaySHRI P. RAMACHANDRAN Transformers & Electricals Kerala Ltd,

Angamally South P. O.SHRI KURIAKOSE ANTONY ( Alternate )

SHRI P. S. RAMAN NGEF Limited, BangaloreDR U. S. SINGH High Tension Insulator Factory, Ranchi

SHRI A. D. DUA ( Alternate )

Bureau of Indian StandardsBIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification ofgoods and attending to connected matters in the country.

CopyrightBIS has the copyright of all its publications. No part of these publications may be reproduced in anyform without the prior permission in writing of BIS. This does not preclude the free use, in the courseof implementing the standard, of necessary details, such as symbols and sizes, type or gradedesignations. Enquiries relating to copyright be addressed to the Director (Publications), BIS.

Review of Indian StandardsAmendments are issued to standards as the need arises on the basis of comments. Standards are alsoreviewed periodically; a standard along with amendments is reaffirmed when such review indicatesthat no changes are needed; if the review indicates that changes are needed, it is taken up forrevision. Users of Indian Standards should ascertain that they are in possession of the latestamendments or edition by referring to the latest issue of ‘BIS Catalogue’ and ‘Standards : MonthlyAdditions’.This Indian Standard has been developed by Technical Committee : ETDC 3

Amendments Issued Since Publication

Amend No. Date of IssueAmd. No. 1 February 1989

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