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1、BRITISH STANDARD BS EN 60426:2007 Electrical insulating materials Determination of electrolytic corrosion caused by insulating materials Test methods The European Standard EN 60426:2007 has the status of a British Standard ICS 17.220.99; 29.035.01 ? Licensed Copy: London South Bank University, Londo
2、n South Bank University, Sun Apr 01 14:46:46 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS EN 60426:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 March 2007 BSI 2007 ISBN 978 0 580 50417 4 National foreword This British Standard was
3、 published by BSI. It is the UK implementation of EN 60426:2007. It is identical with IEC 60426:2007. It supersedes BS 5735:1979, which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee GEL/112, Evaluation and qualification of electrical insulating materials
4、and systems. A list of organizations represented on GEL/112 can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immuni
5、ty from legal obligations. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Sun Apr 01 14:46:46 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD EN 60426 NORME EUROPENNE EUROPISCHE NORM February 2007 CENE
6、LEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2007 CENELEC - All rights of exploitation in any form and by any means reserved worl
7、dwide for CENELEC members. Ref. No. EN 60426:2007 E ICS 17.220.99; 29.035.01 English version Electrical insulating materials - Determination of electrolytic corrosion caused by insulating materials - Test methods (IEC 60426:2007) Matriaux isolants lectriques - Dtermination de la corrosion lectrolyti
8、que en prsence de matriaux isolants - Mthodes dessais (CEI 60426:2007) Elektroisolierstoffe - Prfungen zur Bestimmung der elektrolytischen Korrosionswirkung von Isoliermaterialien (IEC 60426:2007) This European Standard was approved by CENELEC on 2007-02-01. CENELEC members are bound to comply with
9、the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat
10、 or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the off
11、icial versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portuga
12、l, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Licensed Copy: London South Bank University, London South Bank University, Sun Apr 01 14:46:46 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 60426:2007 2 Foreword The text of document 112/45/FDIS, future edition 2 of
13、IEC 60426, prepared by IEC TC 112, Evaluation and qualification of electrical insulating materials and systems, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60426 on 2007-02-01. The following dates were fixed: latest date by which the EN has to be implemented at n
14、ational level by publication of an identical national standard or by endorsement (dop) 2007-11-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2010-02-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard
15、IEC 60426:2007 was approved by CENELEC as a European Standard without any modification. _ Licensed Copy: London South Bank University, London South Bank University, Sun Apr 01 14:46:46 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 3 EN 60426:2007 CONTENTS INTRODUCTION.5 1 Scope 6 2 Normative references
16、 .6 3 Terms and definitions .6 4 General description of the test method7 5 Test specimens 7 5.1 General.7 5.2 Cut surfaces of rigid materials (blocks, plates, sheets or semi-finished materials)8 5.3 Cast, moulding, injection and pressed materials .8 5.4 Cut surfaces of flexible films, foils and thin
17、 sheets8 5.5 Adhesive tapes9 5.6 Flexible sleeving and tubing.9 5.7 Lacquers and insulating varnishes .9 5.8 Cleanliness of contact surfaces9 5.9 Number of test specimens10 6 Test strips 10 6.1 General.10 6.2 Preparation of the test strips10 6.3 Cleanliness of test strips11 7 Test device.11 8 Test c
18、onditions.13 9 Test procedure .13 10 Evaluation 13 10.1 General evaluation 13 10.2 Visual inspection of the test strips14 10.3 Tensile strength of test strips.14 11 Evaluation of corrosion on copper strips15 12 Test report .16 Annex A (normative) Tables for the evaluation of corrosion on brass and a
19、luminium strips17 Annex B (informative) Notes on visual evaluation .19 Annex C (informative) Copper wire tensile strength method 20 Annex ZA (normative) Normative references to international publications with their Figure 1 Test specimen of rigid material, for example textile laminate .7 Figure 2 Te
20、st specimen of flexible material, for example flexible films, foils etc. 9 Figure 3 Test strip11 Figure 4 Test device for determining electrolytic corrosion 12 Figure C.1 Apparatus for determining electrolytic corrosion of rigid insulating material 22 Figure C.2 Apparatus for determining electrolyti
21、c corrosion of flexible insulating material 22 corresponding European publications26 Licensed Copy: London South Bank University, London South Bank University, Sun Apr 01 14:46:46 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 60426:2007 4 Table 1 Degrees of corrosion of copper strips.15 Table A.1 De
22、grees of corrosion of brass strips17 Table A.2 Degrees of corrosion of aluminium strips 18 Licensed Copy: London South Bank University, London South Bank University, Sun Apr 01 14:46:46 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 5 EN 60426:2007 INTRODUCTION Electrical insulating materials at high at
23、mospheric humidity and under influence of electric stress may cause corrosion of metal parts being in contact with them. Such electrolytic corrosion is dependent upon the composition of the insulating material and the character of the metal; it is influenced by temperature, relative humidity, nature
24、 of the voltage and the time of exposure. Direct voltage produces much more rapid and extensive corrosion than alterna- ting voltage. Corrosion is more pronounced at the positive electrode. Not only copper but also most other metals, except the noble metals such as platinum or gold, are subject to e
25、lectrolytic corrosion. Electrolytic corrosion, however, is usually determined with insulating materials in contact with copper, brass or aluminium. Copper, however, is a basic metal and most frequently used in electrotechnical, teletechnical and electronic equipment, especially for current conductin
26、g parts and therefore it was chosen as a basic test metal. Other metals may be used when needed for special purposes, but the results may differ from those described in this method. Electrolytic corrosion may cause open-circuit failure in electrical conductors and devices. It may promote low resista
27、nce leakage path across or through electrical insulation and the products of corrosion may otherwise interfere with the operation of electrical devices, i.e. may prevent operation of contacts, etc. Electronic equipment operating under conditions of high humidity and elevated temperature may be parti
28、cularly subjected to failure from electrolytic corrosion. Therefore, the selection of insulating materials, which do not produce electrolytic corrosion, is important for such applications. The test method described in this second edition replaces two separate methods of the first edition visual and
29、tensile strength method. The former tensile strength method of the first edition, using copper wires, has been maintained in an informative annex. It must be emphasized that the advantage of this new method is that the same strip used for visual inspection is next used for the tensile strength test
30、in opposite to the method described in the first edition. Therefore the correlation between tensile strength and visual examination is more obvious. Licensed Copy: London South Bank University, London South Bank University, Sun Apr 01 14:46:46 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 60426:2007
31、 6 ELECTRICAL INSULATING MATERIALS DETERMINATION OF ELECTROLYTIC CORROSION CAUSED BY INSULATING MATERIALS TEST METHODS 1 Scope This standard determines the ability of insulating materials to produce electrolytic corrosion on metals being in contact with them under the influence of electric stress, h
32、igh humidity and elevated temperature. The effect of electrolytic corrosion is assessed in one test by using consecutively two methods: visual semi-quantitative method consisting in comparing visually the corrosion appearing on the anode and cathode metal strips, with those given in the reference fi
33、gures. This method consists of the direct visual assessment of the degree of corrosion of two copper strips, acting as anode and cathode respectively, placed in contact with the tested insulating material under a d.c. potential difference at specified environmental conditions. The degree of corrosio
34、n is assessed by visually comparing the corrosion marks on the anode and cathode metal strips with those shown in the reference figures; quantitative method, which involves the tensile strength measurement, carried out on the same anode and cathode metal strips after visual inspection. An additional
35、 quantitative test method for determining electrolytic corrosion, which involves tensile strength measurement of copper wire, is described in the informative Annex C. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated reference
36、s, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60068-3-4:2001, Environmental testing Part 3-4: Supporting documentation and guidance Damp heat tests IEC 60454-2:, Pressure-sensitive adhesive tapes for e
37、lectrical purposes Part 2: Methods of test1 3 Terms and definitions For the purposes of this document the following terms and definitions apply: 3.1 electrolytic corrosion kind of galvanic corrosion caused by joint action of external source of d.c. potential and some substances included in some orga
38、nic materials in presence of high humidity and elevated temperature 1 To be published Licensed Copy: London South Bank University, London South Bank University, Sun Apr 01 14:46:46 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 7 EN 60426:2007 3.2 test strip a) positive a metal strip connected with posi
39、tive pole of direct current source which forms the anode in the contact system: metal insulating material b) negative a metal strip connected with negative pole of direct current source which forms the cathode in the contact system: metal insulating material 3.3 surface of contact a) of tested mater
40、ial part of insulating material specimen which is in direct contact with metal strips b) of metal strip part of metal strip (positive or negative) which is in direct contact with insulating material specimen 4 General description of the test method The test consists of applying specified environment
41、al conditions and a d.c. potential difference to two parallel copper strips 3 mm apart, acting as the anode and the cathode respectively. The insulating material under test (test specimen) is placed across these two strips. In order to obtain a good and uniform contact between the metal strips and t
42、he material under test, the test specimen is pressed to the strips by a cylindrical loading tube. 5 Test specimens 5.1 General The preparation of the specimens depends on the type of material and the form in which it is supplied. The shape and dimensions of the test specimen are shown in Figure 1. P
43、rocedures for the preparation of the test specimen are reported beneath (5.2 to 5.7). Dimensions in millimetres 4,0 0,1 40 1 10,0 0,5 Surface of contact IEC 122/07 Figure 1 Test specimen of rigid material, for example textile laminate Licensed Copy: London South Bank University, London South Bank Un
44、iversity, Sun Apr 01 14:46:46 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 60426:2007 8 5.2 Cut surfaces of rigid materials (blocks, plates, sheets or semi-finished materials) The test specimens shall be cut out or machined from the tested material to a thickness of 4 mm, by means of a dry method w
45、ithout the use of cutting oils or lubricants and without overheating or damaging them. It is recommended to take several test specimens from various layers of the product. It is permissible to use the test specimens of thickness smaller than 4 mm, but not smaller than 2 mm. The contact surface of th
46、e test specimen shall be smoothed using abrasive paper. Care should be taken to keep parallelism of the opposite surfaces of the test specimen, in order to assure a good contact of the test specimen to the metal strips. The surface of contact should not show any flaws, cracks, inclusions or bubbles.
47、 The abrasive paper shall not contain any contaminations causing a bad corrosion index, for example halogen components. 5.3 Cast, moulding, injection and pressed materials From insulating materials delivered in the form of liquid resin, moulding powder or granules, the test specimens shall be made i
48、n shapes and dimensions as shown in Figure 1. The specimens shall be made by casting or pressing in a special mould, following exactly the technological instruction recommended by the manufacturer of the tested material. The test specimen and surface of contact shall be prepared as given in 5.2. 5.4
49、 Cut surfaces of flexible films, foils and thin sheets Test specimens of these products shall be made up in layers to form small packs placed between suitable holding plates of insulating material not causing electrolytic corrosion itself, for example polymethylmethacrylate (Plexiglas 2). The preferred thickness of holding plates is 1 mm 0,2 mm. The thickness of a pack