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.

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“Step Out From the Old to the New”

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“The Right to Information, The Right to Live”

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“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 3724 (1966): Cartridge type heating elements(non-embedded type) [ETD 32: Electrical Appliances]

IS : 3724 - 1966

Indian Standard SPECIFICATION FOR

CARTRIDGE TYPE HEATING ELEMENTS ( NON-EMBEDDED TYPE )

Third Reprint NOVEMBER 1992

( Incorporating Amendments No. 1 8t 2 )

UDC 621.315.551

@ Copt’right 1976

BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHAbUR SHAH WAR MARG

NEWDELHI

Or3 November 1966

IS : 3724 - 1966

Indian Standcvd SPECIFICATION FOR

CARTRIDGE TYPE HEATING ELEMENTS ( NON-EMBEDDED TYPE )

Electrical Appliances Sectional Committee, ETDC 43 Chairman Representing

SHRI R. K. TANDAN Natio;;fb?hysicaI Laboratory ( CSIR ), New

Members ADDITIONAL CHIEF ENGINEER Directorate General of Posts & Telegraphs

( Ministry of Transport&Communications) DiRECTOR OF TELEGRAPHS (L) ( Alterrrate )

SHRI J. R. D. BAKSHI General Radio & Appliances Ltd. Bombay SHRI KAMAL NAYAN ( Alternate )

SHRI T. A. S. BALAKRISHNAN Department of Industries & Commerce, Government of Madras

SHRI E. N. NARAYANASWAMY ( Alternate ) SHRI V. G. BAPAT Buildings & Communications Department,

Government of Maharashtra Bajaj Electricals Ltd, Bombay

,\ SHRI S. U. BHOJWAN~

SHRI P. N. KACKER ( Alternate SHRI S. S. CHITNIS

SHRI S. V. SATHE ( Alternate ) SHRI P. N. DEOBHAKTA

‘Elpro International Ltd, Pune

Directorate General of Technical Development ( Ministry of Supply & Technical Develop-

RaiIw:?%ard ( Ministry of Railways ) DEPUTY DIRECTOR ( ELECTRICAL ENGINEERING )

SHRI B. K. DOSHI SHRI D. T. GURSAHANI

SHRI S. K. MURTHI ( Alternate SHRI HARNAM SINGH

Messrs Jashawantlal Kantilal, Bombay Directorate General of Supplies & Disposals

(mvelinr$try of Supply & Technical Develop-

) Chief Inspectorate of Electronics, Ministry of

Defence, Bangalore SHRI SAT DEV ( Afternate )

SHRI I. D. JAIN SHRI R. S. JAIN ( Alternate )

SHRI V. S. KALBAG SHRI M. S. KATHURIA WG CDR D. J. LAWYER

Engineer-in-Chief’s Branch, Army Headquarters

Tempo Industrial Corporation, Bombay Small Scale Industries ( Ministry of Industry ) Directorate of Technical Development and

Production ( Air ) ( Ministry of Defence ) SQN LDR S. B. PURANIK ( Alternate )

SHRI A. S. MOTAFRAM Refrigeration & Appliances Co Pvt Ltd, Pune SHRI B. K. MUKHERIEE National Test House, Calcutta

SHRI B. MUKHOPADHYA ( Alternate ) (Continued on page 2 )

BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEWDELHI

IS : 3124 - 1966

( Confinuedfrompage 1 )

Members Rcpresrnting

SHRI S. NATARAJAN The Standard Electric Appliances, Tuticorin SHRI N. RAIAGOPALAN ( Alternate )

SHRI V. H. NAVKAL The Bombay Electric Supply & Transport Undertaking, Bombay

SHRI R. V. S. RAO ( AIfcrnofe ) SHRI M. NIRULA The

SHRI MANECK S. SHAW ( Alternate ) ( Bombay )

SHRI 6. N. SINGH t Alternate )

Federation of Hotel and Restaurnnt Associations of India. New Delhr

. ( Calcutta ) SHRI P. ANANDA RAU ( Alternate )

( Madras ) SHRI JOGINDER SINGH PALL Ditz

SHRI HARDIT SINGH ( Alternate ) _ Electric& ( India ) Ltd, Delhi

SUPERINTENDING SURVEYOR OF Central Public Works Department, New Delhi WORKS ( ELECTRICAL )

SHRI Y. S. VENKAIESWARAN, Director ( Elec tech )

Director General, IS1 ( Ex-officio Member )

Secretary SHRI S. M. VERMA

&sistant Director ( Elec tech ), IS1

IS : 3724 - 1966

Indiian Standard

SPECIFICATION FOR CARTRIDGE TYPE HEATING ELEMENTS

(NON-EMBEDDED TYPE)

0. FOREWORD

0.1 This Indian Standard was adopted by the Indian Standards Institu- tion on 6 September 1966, after the draft finalized by the Electrical Appliances Sectional Committee had been approved by the Electrotech- nical Division Council.

0.2 This specification covers the general performance and safety require- ments for cartridge type heating elements ( non-embedded type ) to ensure reliable operation, personal safety against electric shock and safty against the effects of excessive temperature and fire.

0.3 ‘ Indian Standard general and safety requi;ements for household and similar electrical appliances (fourth revision ) ( IS : 302-1973 ) ’ to which references have been made in this standard with regard to general and safety requirements as well as methods of tests is a necessary adjunct to this standard. Should, however, any deviation exist between the require- ments of IS : 302-1973 and those of this standard, provisions of the later shall apply.

0.4 This standard is one of a series of Indian Standards on heating elements used in domestic and light electrical appliances. The other Indian Standards being prepared in this series will cover:

a) Solid embedded type electric heating elements,

b) Mineral filled metal sheathed heating elements, and

c) Mica insulated and ceramic bedded heating elements, etc.

0.5 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, shall be rounded off in accordance with IS : 2-1960*. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

*Rules for rounding off numerical values ( revised ).

3

IS:3724-1966

1. SCOPE

1.1 This standard covers the electrical and mechanical requirements and methods of test for cartridge type heating elements ( non-embedded type ) generally used as immersion heating units in conjunction with a sheath, and designed for connection to supplies at voltages not exceeding 250 V ac single-phase 50 Hz, or dc. This standard excludes cartridge elements in which mica is used as an element former and base insulation.

2. TERMINOLOGY

2.0 For the purpose of this standard, the following definitions shall apply to in addition to those specified in 2 of IS : 302-1973*.

2.1 Cartridge Type Heating Elements - Heating elements where the heating coils are laid through holes or channels provided in one or more formers and terminated in suitable metallic terminals provided in a base.

2.2 Former - Supports made of refractory materials with holes or channels provided for accommodating the heating coils.

2.3 Base - The piece of heat resisting and electrically insulating material provided at one end of the heating element which provides the necessary terminals to which the ends of the heating coil are connected.

2.4 Top - The piece of heat resisting and electrically insulating material provided at the other end of the heating element to prevent contact between heating coil and the sheath.

3. RATINGS

3.1 Rated Voltage - The provision of 3.1 of IS : 302-1973* shall apply.

3.2 Rated Input - The rated input shall be 1 000, 1 500, 2 000, 3 000, 4 000 and 5 000 watts.

4. MATERIALS

4.1 The relevant provision of 7.11 and 7.12 of IS : 302-1973* shall apply in addition to 4.1.1.

4.1.1 The former(s), base and top shall be made of such heat-resisting and electrically-insulating material which shall be able to withstand the thermal shocks normally encountered in service. All metallic parts shall be made of such materials as do not corrode when exposed to high tem- perature met with in use.

*General and safety requirements for househohi and similar electrical appliances (fourth revision ).

4

IS:3124- 1966

5. CONSTRUCTION

53 Therelevant provisions of 8.1 of IS : 302-1373* shaI1 apply in addition to 5.1.1 to 5.1.8,

5.1.1 The formers shall be so designed as to permit proper alignin& and to prevent their turning in relation to each other.

5.1.2 The heating coils shall be so designed and supported that they maintain their intended positions without sagging in normal workmg condition.

5.1.3 The channels shall completely enclose the heating element or where open channels are formed the opening shall be smaller than the coil diameter so as to prevent the heating coil falling ou1 when a break or sag develops in the coil under normal use.

5.1.4 The formers, base and top shall be held together to form a complete Lqrtridge by one or more bolts. The bolts nxly aiso be used as terminals i.f.required.

5.1.5 The resistance wire shall conform to IS : 3725-1966t.

5.1.6 The bottom of the base shall end in a flange so that when the cartridge is slipped into a metal sheath of an internal dinmctzr 2 mm bigger than the diameter of the former, the flange alone stays outside resting on the edge of the sheath.

5.1.7 The heating element may be provided with a suitable sheath having an internal diame!er not more than 2 mm bigger than that of the diameter of the farmers, a wall thickness of 1’5 mm and height 10 mm longer than the height of the cartridge.

5.1.8 The cartridge shall have an adequate heat dissipating surface area for the wattage and the type of the liquid medium for which it is intended.

6. DIMENSIONS

6.1 The recommended diameters of the formers art 20 mm, 35 mm and 45 mm.

7. GENERAL AND SAFETY REQUIREMENTS

7.1 Protection Against Electric Shock - The provisions of 8 of IS : 302-1973* shall apply.

7.2 Temperature Limits - The relevant provisions of Table 3 of IS : 302-1973* shall apply.

*General and safety requirements for household and similar electrical appliances ( fuurrh revision ).

tspecification for resistance wires, tapes and strips. for heating elements.

5

IS : 3124 - 1966

7.3 Electrical Insolation - The provision of 11 of IS : 302-1973* shall apply. 7.4 Moisture Resistance - The provision of 13 of apply.

7.5 Mechanical Strength - The provision of 15 of apply.

7.6 Operation Under Overload Condition - The IS: 302-1973* shall apply.

7.7 Supply Connection - The provision of 20 of apply wheq applicable.

IS : 302-1973* shall

IS : 302-1973* shall

provision of 18 of

IS : 302-1973* shall

7.8 Terminals - The provision of 21 of IS : 302-1973* shall apply.

7.9 Screws and Connections - The provision of 23 of IS : 302-1973* shall apply.

7.10 Resistance to Rusting - The provision of 7.33 of IS : 302-1973* shall apply.

7.11 Abnormal.Operation - The cartridge element shall be so design- ed that risk of fire, mechanical damage or electric shock as a result of abnormal, careless operation or operation under fault conditions is obviated.

8. PERFORMANCE REQUfREMENTS

8.1 Input - The input shall not differ from the rated input by more than 7’5 percent.

9. ENDURANCE

9.1 Cartridge type heating elements shall be so designed and constructed as to prevent, during its life, any electrical or mechanical failure. In addition, the insulation shall not be damaged and contacts and connec- tions shall not work loose due to heating, vibration, etc.

10. MARKING AND INSTRUCTIONS FOR USE

10.1 Each cartridge type heating element, or its base, shall be indelibly marked with the following:

a) Trade-mark or name of the manufacturer, b) Rated voltage, c) Rated input in watts or kilowatts,

*General and safety requirements for household and similar electrical appliances ( fourth revision ).

6

IS:3724 - 1966

d) Heating medium, and

e) Country of manufacture.

10.1.1 The heating elements may also be marked with the ISI.Certifica- tion Mark.

NOTE - The use of the ISI Certification Mark is governed by the provisions of the Indian Standards Jnstitution ( Certification Marks ) Act ahd 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 JSI and operated by the producer. IS1 marked products are also continuously checked by ISI for confor- mity to that standard as a further safeguard. Details of conditions under which a licence for the use of the IS1 Certification Mark may be granted to manufacturers or prdcessors may be obtained from the Indian Standards Institution.

10.2 Instructions for Use - Each heating element shall be provided with necessary instructions includi’ng precautions to be taken for its proper use.

11. TESTS

11.1 Categories of Tests

11.1.1 Type Tests - The tests specified in Table 1 shall constitute type tests and shall be carried out on 5 samples of cartridge heating elements of the same type and ratings selected preferably at random from a regular production lot.

11.1.1.1 Criteria ofacceptance - All samples shall successfully pass all the type tests for proving conformity with the requirements of this standard. If any of the samples fails in any of the type tests, the testing authority, at its discretion, may call for fresh samples not exceeding twice the original number and subject them again to all tests or to the test(s) in which failure(s) occurred. No single failure should be permitted in the repeat test(s).

11.1.2 Acceptance Tests - The following shall constitute acceptance tests:

Test Clause Reference a) Visual examination and inspection 11.3.1 b) Protection against electric shock 40 1 c) High voltage 42.3 I d) Insulation resistance ( dry ) 44.3 e) Leakage current 42.1 & 42.2 1

of IS : 302- 1973*

f) Moisture resistance 43 BE 44 I ~3) Input 45 J

*General and safety requirements for household and similar electrical dppliances (fourt) rcvisfon ).

7

IS : 3724 - 1966

11.1.2.1 A recommended sampling procedure for acceptance tests is specified in Appendix A.

11.1.3 Routine Tests - The following shall constitute routine tests: Test Clnu.re Reference

a) Visual examination and inspection 11.3.1 b) Protection against electric shock 40 1 c) High voltage 42.3 of IS:- 302-1973* d) insulation resistance ( dry) 44.3 1

11.2 Conditions for Test

11.2.1 The test shall be carried out with a sheath conforming to 51.7.

11.2.2 The relevant condition of 26 of IS : 302-1973* shall apply unless otherwise specified in the respective clauses.

11.3 Schedule of Tests - A schedule of type test to be carried out on cartridge type heating elements for proving conformity with the require- ments of this standard, is given in Table 1 with suitable references to relevant clauses of this standard and those of IS : 302-1973”.

SL No.

TABLE 1 SCHEDULE OF TYPE TESTS ( Clauses 11.1.1 and 11.3 )

TEST CLAUSE REFERENCE

9 ii)

iii) iv) v)

vi) vii)

viii} ix) x)

xi) xii) . . .

XIII) xiv)

Visual examination and inspection Screws and connections Mechanical strength Resistance to rusting Protection against electric shock High voltage Insulation resistance ( dry ) Leakage current Moisture resistance Input Abnormal operation Creepage distances and clearance Operation under overload condition

44.3 j 42.1 & 42.2 > of IS : 302-

Endurance 11.3.2 & 11.3.3 *General and safety requirements for household and similar electrical appliances

(fourth revision ).

11.3.1 Visual Examination and Inspection - The cartridge elements shall be visually eiamined and checked for conformity with the relevant requirements specified in 4, 5, 6, 7 and 10. There shall be no cracks or breakages of the former% base and top ( minor chipplng of these parts in their new condition may be overlooked ). The visual examination shall be repeated at the end of the type tests. The coils of the heating element shall not have sagged appreciably during test.

*General and safety requirements for household and similar electrical apppliances ( fourth revision ).

8

IS : 3724 - 1966

11.3.2 Endurance Test C For Cartridge Elements Used in Water Baths )

11.3.2.1 Cartridge heating elements shall be placed in a vessel of appropriate shape containing a quantity of 2’0 to 2’5 litres per 100 W rated input, the water being initially cold.

11.3.2.2 The cartridge heating elements shall be capable of raising the quantity of water specified in 11.3.2.1 to boiling point from cold ( about 27°C ), 1 000 times without electrical or mechanical failure when operated at the rated voltage.

11.3.2.3 Every hundredth cycle of the endurance test shall be carried out as thermal shock test, the cartridge element being removed from the boiling water and kept in cold water without any appreciable delay. The other cycles of endurance test should be carried out in accordance with manufacturer’s instructions about the use of cartridge heating elements.

11.3.2.4 At the end of the endurance test, the cartridge heating elements shall be checked for compliance with the requirements of 52.7 of IS : 302-1973*.

11.3.3 Endurance Tests ( For Cartridge Elements Used in Fluid Baths Other than Wafer - ( Under consideration. )

APPENDIX A

( Clause11.1.2.1 )

SAMPLING PROCEDURE FOR ACCEPTANCE TESTS

A-l. LOT

A-l.1 In any consignment, all cartridge type heating elements of the same make, model and type, and manufactured under similar conditions of productron shall be grouped together to constitute a lot.

A-2. SELECTION OF SAMPLE

A-2.1 The number of cartridge type heating elements to be selected shall depend upon the size of the lot and shall be in accordance with co1 2 of Table 2.

*General and safety requirements for household and similar electrical appliances ( fourth revision ).

9

IS : 3724 - 1966

TABLE 2

LOT SIZE

(1) up to 50 51 ,, 100

101 1, 200 201 ,, 300 301 ,, 500 501 and above

SAMPLE-SIZE AND CRITERION FOR CONFORMITY

( Clause A-2.1 )

FIRST SECOND REJECTION SAMPLE SAMPLE

AE;;a;cE NUMBER

(2 N, G 13) (4) 2

5 10 0 2

7 14 0 2 10 20 0 3 13 26 0 3 20 40 1 4 25 50 1 5

A-2.1.1 If required ( see A-3.2 ), additional cartridge type heating elements as given in co1 3 of Table 2 shall also be selected at random.

A-3. CRITERION FOR CONFORMITY

A-3.1 The lot shall be considered as conforming to the requirements of acceptance tests if the number of failures in the first sample is less than or equal to acceptance number Cl given in co1 4 of Table 2. If the number of failures is greater than or equal to the rejection number C2 as given in co1 5 of Table 2, the lot shall be considered as not conforming to the requirements of the acceptance tests.

A-3.2 If the number of failures is between C1 and Cz, a further sample of Nz cartridge type heating elements shall be selected and subjected to the acceptance tests. If the number of failures in the two samples combined is less than CZ the lot shall be considered as conforming to the require- ments of the acceptance test, otherwise not.

10

BUREAU OF INDIA’N STANDARDS

Headquarters:

Manak Bhavan, 9 Bahadur Shah Zafar Marg, NEW DELHI 110002

Telephones: 331 01 31, 331 13 75 Telegrams: Manaksanstha ( Common to all Offices )

Regional Offices: Telephone Central : Manak Bhavan, 9 Bahadur Shah Zafar Marg.

NEW DELHI 110002 *Eastern : 1 /14 C. I. T. Scheme VII M, V. I. P. Road,

Maniktola, CALCUTTA 700054 Northern : SC0 445-446, Sector 35-C,

CHANDIGARH 160036

Southern : C. I. T. Campus, MADRAS 600113

twestern . Manakalaya, E9 MIDC, BOMBAY 400093

Marol, Andheri ( East).

331 01 31 331 1375

36 24 99

I

21843 3 1641

1

41 24 42 41 2519 41 2916

632 92 95

Branch Offices:

‘Pushpak’, Nurmohamed Shaikh Marg, Khanpur,

I

2 63 48 AHMADABAD 380001 2 63 49

:Peenya Industrial Area 1 st Stage, Bangalore Tumkur Road 38 49 55 BANGALORE 560058

I 38 49 56

Ganaotri Complex, 5th Floor. Bhadbhada Road. T. T. Naaar, 6 6.7 16 ~HOPAL 462003

Plot No. 82/83. Lewis Road, BHUBANESHWAR 751002 531’5. Ward No. 29, R.G. Barua Road, 5th Byelane,

GUWAHATI 781003

5 36 27 3 31 77

5-8-56C L. N. Gupta Marg ( Nampally Station Road ), HYDERABAD 500001

23 1083

R14 Yudhister Marg. C Scheme, JAIPUR 302005

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Patliputra Industrial Estate, PATNA 800013 T.C. No. 14/l 421. University P.O.. Palayam

TRIVANDRUM 695035

( 034 71 6 98 32

{ ;: “sx ;2” 6 23 05

16 21 04 16 21 17

Inspection Offices ( With Sale Point ):

Pushpanjali, First Floor, 205-A West High Court Road, Shankar Nagar Square, NAGPUR 440010

2 5171

Institution of Engineers ( India ) Building, 1332 Shivaji Nagar, 5 24 35 PUNE 411005

*Sales Office in Calcutta is at 6 27 68 00 Street, Calcutta 700072

Chowringheo Approach, P. 0. Princep

tseles Office in Bombay is et Novelty Chambera, Grrnt Road, 89 66 28 Bombev 400007

$Sales Office in Bangalore is at Unity Building. Narasimharaja Square, 22 36 71 Bangalore 560002

Reprography Unit, BE, New Delhi, India

AMENDMENT NO. 3 MAY 1989 TO

IS : 37%4 - 1966 SPECIFICATION FOR CARTRIDGE TYPE HEATING ELEMENTS

( NON-EMBEDDED TYPE )

(Puge9, chse 113.2)- Substitute the following for the existing mattef:

‘123.2 Enabrance Test ( For Cartridge Elements Used in Water Baths )

11.3.2.1 Cartridge heating elements shall be placed in a vessel of appropriate shape containing a quantity of 2.0 to 2’5 lures per 100 W rated input, the water being initially cold. It is connected to the supply at&t hat the input is 1’15 times the maximum rated input which is maintained throughout the test. The heating element is operated under &se conditions for a period of 96 hours. Occasional addition of water to compensate the evaporation losses is recommended.

11.3.2.2 After the above test, the heating element is to withstand the high voltage test of 11.1.1.’

(ETDCU)

hprograpny hut, BE, New Delhi, India

AMENDMENT NO. 4 AUGUST 2006TO

IS 3724:1966 SPECIFICATION FORCARTRIDGE TYPE HEATING ELEMENTS

(NON-EMBEDDED TYPE)

. ( General) — ‘Substitute ‘IS 302-1 (1979)’ for ‘IS 302:1973’ whereverappears in tie standard,

( Pages 4 to 9, footnotes) — Substitute ‘$jlh revision’for ‘fourth revision’. ~‘”

( Page 8, clause 11.1.3) — Substitute the following for the existing:

Test Clause Reference

@ Visual inspection

1

11.3.1b) Protection against eleetric shock 8

c) High voltage 13.3.2d) Material 4 of IS 302-1 (1 979)*

e) Construction 5

f) Dimensions 6

g) Marking 10

( Page 8, Table 1 ) — Substitute the following for the existing matter

S1No.

Oii)iii)iv)

v)vi)vii)viii)ix)

@xi)xii)xiii)

Test

Visual inspectionScrew and connectionsMechanical strengthResistance to rustingProtection against eleetric shockHigh voltageLeakage currentMoisture resistanceInputAbnormal operationCreepage distances and clearancesOperation under overloadEndurance

Clause Reference

11.3.128213181613.2

1

of IS 302-1 (1979)151019291211.3,2

( Page 8, Table 1,footnote marked*) — Substitute ‘(flflh revision )’ for‘(fourthrevision )’.

1

Amend No. 4 to IS 3724:1966

( Pages 8 ancl 9, clause 11.3.1 ) — Substitute the following for the existingsubclause:

‘11.3.1 Visual Inspection — The cartridge elements shall-be visually examined.There shall be no cracks or breakage of the formers, base and top (minorchipping of these parts in their new condition may be overlooked). The visualexamination shall be repeated at tie end of the type tests. The coils of theheating element shall not have sagged appreciably during test.’

(ET32)

ReprographyUnit BIS, New DelU lndia

2