1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58electrolytic corrosion caused by insulating materials Test methodsThe European Standard EN 60426:20
2、07 has the status of a British StandardICS 17.220.99; 29.035.01Electrical insulating materials Determination of BRITISH STANDARDBS EN 60426:2007BS EN 60426:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 March 2007 BSI 2007ISBN 978 0 5
3、80 50417 4Amendments issued since publicationAmd. No. Date Commentsits 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 immunity from legal obligations
4、.National forewordThis British Standard was 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 It supersedes BS 5735:1979, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee GEL/112, Evaluation and qualifi
5、cation of electrical insulating materials and systems.A list of organizations represented on GEL/112 can be obtained on request to EUROPEAN STANDARD EN 60426 NORME EUROPENNE EUROPISCHE NORM February 2007 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation E
6、lectrotechnique 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 worldwide for CENELEC members. Ref. No. EN 60426:2007 E ICS 17.220.99; 29.035.01 English version
7、 Electrical insulating materials - Determination of electrolytic corrosion caused by insulating materials - Test methods (IEC 60426:2007) Matriaux isolants lectriques - Dtermination de la corrosion lectrolytique en prsence de matriaux isolants - Mthodes dessais (CEI 60426:2007) Elektroisolierstoffe
8、- 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 the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
9、 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 or to any CENELEC member. This European Standard exists in three official versions (English
10、, 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 official versions. CENELEC members are the national electrotechnical committees of Austria, Bel
11、gium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 60426:
12、2007 2 Foreword The text of document 112/45/FDIS, future edition 2 of 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 da
13、tes were fixed: latest date by which the EN has to be implemented at national 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
14、 CENELEC. _ Endorsement notice The text of the International Standard IEC 60426:2007 was approved by CENELEC as a European Standard without any modification. _ 3 EN 60426:2007 CONTENTS INTRODUCTION.5 1 Scope 6 2 Normative references .6 3 Terms and definitions .6 4 General description of the test met
15、hod7 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 sheets8 5.5 Adhesive tapes9 5.6 Flexible sleeving and tubing.9 5.
16、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 strips 10 6.3 Cleanliness of test strips11 7 Test device.11 8 Test conditions .13 9 Test procedure .13 10 Evaluation 13 10.1 General
17、 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 aluminium strips17 Annex B (informative) Notes on visual evalua
18、tion .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 Test specimen of flexible material, for example flexible films,
19、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 electrolytic corrosion of flexible insulating material 22 corresponding E
20、uropean publications26 EN 60426:2007 4 Table 1 Degrees of corrosion of copper strips.15 Table A.1 Degrees of corrosion of brass strips17 Table A.2 Degrees of corrosion of aluminium strips 18 5 EN 60426:2007 INTRODUCTION Electrical insulating materials at high atmospheric humidity and under influence
21、 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 of the voltage and the time of exposu
22、re. 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 electrolytic corrosion. Electrolytic cor
23、rosion, 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 conducting parts and therefore it was chosen as
24、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 resistance leakage path across or through elec
25、trical 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 particularly subjected to failure from elect
26、rolytic 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 tensile strength method. The former ten
27、sile 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 in opposite to the method described in
28、the first edition. Therefore the correlation between tensile strength and visual examination is more obvious. EN 60426:2007 6 ELECTRICAL INSULATING MATERIALS DETERMINATION OF ELECTROLYTIC CORROSION CAUSED BY INSULATING MATERIALS TEST METHODS 1 Scope This standard determines the ability of insulating
29、 materials to produce electrolytic corrosion on metals being in contact with them under the influence of electric stress, high humidity and elevated temperature. The effect of electrolytic corrosion is assessed in one test by using consecutively two methods: visual semi-quantitative method consistin
30、g in comparing visually the corrosion appearing on the anode and cathode metal strips, with those given in the reference figures. 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
31、 tested insulating material under a d.c. potential difference at specified environmental conditions. The degree of corrosion 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
32、tensile strength measurement, carried out on the same anode and cathode metal strips after visual inspection. An additional quantitative test method for determining electrolytic corrosion, which involves tensile strength measurement of copper wire, is described in the informative Annex C. 2 Normativ
33、e references The following referenced documents are indispensable for the application of this document. For dated references, 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 te
34、sting Part 3-4: Supporting documentation and guidance Damp heat tests IEC 60454-2:, Pressure-sensitive adhesive tapes for electrical purposes Part 2: Methods of test13 Terms and definitions For the purposes of this document the following terms and definitions apply: 3.1 electrolytic corrosion kind o
35、f galvanic corrosion caused by joint action of external source of d.c. potential and some substances included in some organic materials in presence of high humidity and elevated temperature 1To be published 7 EN 60426:2007 3.2 test strip a) positive a metal strip connected with positive pole of dire
36、ct 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 material part of insul
37、ating 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 environmental conditions and
38、 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 the material under
39、 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. Procedures for the
40、 preparation of the test specimen are reported beneath (5.2 to 5.7). Dimensions in millimetres 4,0 0,1 40 110,0 0,5 Surface of contactIEC 122/07 Figure 1 Test specimen of rigid material, for example textile laminate EN 60426:2007 8 5.2 Cut surfaces of rigid materials (blocks, plates, sheets or semi-
41、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 without the use of cutting oils or lubricants and without overheating or damaging them. It is recommended to take several test specimens from various layers o
42、f 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 the 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 a
43、ssure a good contact of the test specimen to the metal strips. The surface of contact should not show any flaws, cracks, inclusions or bubbles. The abrasive paper shall not contain any contaminations causing a bad corrosion index, for example halogen components. 5.3 Cast, moulding, injection and pre
44、ssed materials From insulating materials delivered in the form of liquid resin, moulding powder or granules, the test specimens shall be made in 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 inst
45、ruction 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 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 suitabl
46、e 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 should be approximately of 4 mm or 2 mm, depending on the thickness of the tested foi
47、ls. The value of 4 mm is recommended in the case of the single foil thickness being less than 2 mm and more than 0,5 mm, whereas that one of 2 mm is recommended if the single foil thickness is less than 0,5 mm. These test blocks shall be compressed with screws made of the same material as holding pl
48、ates and then machined to the appropriate shape as shown in Figure 2. The material to be tested should protrude 0,2 mm to 0,5 mm beyond the holding plates. 2Plexiglas is an example of a suitable product available commercially. This information is given for the convenience of users of this document a
49、nd does not constitute an endorsement by IEC of this product. 9 EN 60426:2007 Dimensions in millimetres 0,2 to0,5 1,0 0,2 2 or 4 40 110,0 0,5 Surface of contact Holding platesIEC 123/07 Figure 2 Test specimen of flexible material, for example flexible films, foils etc. Apart from this, the particulars given in 5.2 apply. 5.5 Adhesive tapes For adhesive tapes the method of Clause 7 of IEC 60454-2 is rec
