prEN IEC 60893-2:2022

Insulating materials - Industrial rigid laminated sheets based on thermosetting resins for electrical purposes - Part 2: Methods of test

Isoliermaterialien - Industrielle starre Schichtstoffplatten auf Basis duroplastischer Harze für elektrotechnische Zwecke - Teil 2: Prüfverfahren

Stratifiés industriels rigides en planches à base de résines thermodurcissables à usages électriques - Partie 2: Méthodes d'essai

Izolacijski materiali - Industrijske toge laminirane plošče iz smol s toplotnim utrjevanjem za električne namene - 2. del: Preskusne metode

General Information

• Status: Not Published
• Publication Date: 19-May-2024
• ICS: 29.035.01 - Insulating materials in general
• Technical Committee: CLC/SR 15 - Insulating materials
• Drafting Committee: IEC/TC 15 - IEC_TC_15
• Current Stage: 4060 - Enquiry results established and sent to TC, SR, BTTF - Enquiry
• Start Date: 20-Jan-2023
• Completion Date: 20-Jan-2023
• Ref Project: oSIST prEN IEC 60893-2:2022 - Insulating materials - Industrial rigid laminated sheets based on thermosetting resins for electrical purposes - Part 2: Methods of test

Relations

• Revises: EN 60893-2:2004 - Insulating materials - Industrial rigid laminated sheets based on thermosetting resins for electrical purposes - Part 2: Methods of test
• Effective Date: 25-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN IEC 60893-2:2022
01-december-2022
Izolacijski materiali - Industrijske toge laminirane plošče iz smol s toplotnim
utrjevanjem za električne namene - 2. del: Preskusne metode

Insulating materials - Industrial rigid laminated sheets based on thermosetting resins for

electrical purposes - Part 2: Methods of test

Stratifiés industriels rigides en planches à base de résines thermodurcissables à usages

électriques - Partie 2: Méthodes d'essai

Stratifiés industriels rigides en planches à base de résines thermodurcissables à usages

électriques - Partie 2: Méthodes d'essai
Ta slovenski standard je istoveten z: prEN IEC 60893-2:2022
ICS:
29.035.20 Plastični in gumeni izolacijski Plastics and rubber insulating
materiali materials
oSIST prEN IEC 60893-2:2022 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN IEC 60893-2:2022
---------------------- Page: 2 ----------------------
oSIST prEN IEC 60893-2:2022
15/948/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60893-2 ED3
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2022-10-28 2023-01-20
SUPERSEDES DOCUMENTS:
15/883/CD, 15/895A/CC
IEC TC 15 : SOLID ELECTRICAL INSULATING MATERIALS
SECRETARIAT: SECRETARY:
United States of America Mr John Gauthier
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY

SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING

Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

This document is still under study and subject to change. It should not be used for reference purposes.

Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of

which they are aware and to provide supporting documentation.
TITLE:

Insulating materials - Industrial rigid laminated sheets based on thermosetting resins for

electrical purposes - Part 2: Methods of test
PROPOSED STABILITY DATE: 2026
NOTE FROM TC/SC OFFICERS:

Copyright © 2022 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to download this

electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.

You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without

permission in writing from IEC.
---------------------- Page: 3 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 2 – 15/948/CDV
1 CONTENTS

2 FOREWORD ........................................................................................................................... 3

3 INTRODUCTION ..................................................................................................................... 5

5 1 Scope ............................................................................................................................... 6

6 2 Normative references ....................................................................................................... 6

7 3 Conditioning of test specimens ......................................................................................... 7

8 4 Dimensions ...................................................................................................................... 8

9 4.1 Thickness ............................................................................................................... 8

10 4.2 Flatness .................................................................................................................. 8

11 5 Mechanical tests............................................................................................................... 9

12 5.1 Flexural strength ..................................................................................................... 9

13 5.2 Modulus of elasticity in flexure ................................................................................ 9

14 5.3 Compressive strength ............................................................................................. 9

15 5.4 Impact strength ..................................................................................................... 10

16 5.5 Shear strength parallel to laminations ................................................................... 11

17 5.6 Tensile strength .................................................................................................... 12

18 6 Electrical tests ................................................................................................................ 12

19 6.1 Electric strength and breakdown voltage ............................................................... 12

20 6.2 Permittivity and dissipation factor.......................................................................... 13

21 6.3 Insulation resistance after immersion in water ....................................................... 23

22 6.4 Comparative and proof tracking indices ................................................................ 24

23 6.5 Tracking and erosion resistance ........................................................................... 24

24 7 Thermal tests ................................................................................................................. 25

25 7.1 Thermal endurance ............................................................................................... 25

26 7.2 Flammability ......................................................................................................... 25

27 8 Other tests ..................................................................................................................... 25

28 8.1 Density ................................................................................................................. 25

29 8.2 Water absorption .................................................................................................. 26

31 Annex A (informative) Modes of representation of capacitance ............................................ 32

32 Annex B (informative) Liquids of known permittivity values .................................................. 33

33 Bibliography .......................................................................................................................... 34

35 Figure 1a – Test specimen for Charpy impact strength test ................................................... 27

36 Figure 1b – Test specimen for Izod impact strength test ....................................................... 27

37 Figure 2 – Device for testing parallel shearing strength ......................................................... 28

38 Figure 3 – Example of electrode system for method A ........................................................... 29

39 Figure 4 – Example of electrode system for method B ........................................................... 30

40 Figure 5 – Example of electrode system for method C .......................................................... 31

41 Figure A.1 – Equivalent parallel and series representation of a capacitor .............................. 32

43 Table 1 – Sequence employed for routine measurements ..................................................... 21

---------------------- Page: 4 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 3 – 15/948/CDV
46 INTERNATIONAL ELECTROTECHNICAL COMMISSION
47 __________
49 INSULATING MATERIALS –
50 INDUSTRIAL RIGID LAMINATED SHEETS
51 BASED ON THERMOSETTING RESINS
52 FOR ELECTRICAL PURPOSES –
Part 2: Methods of test
57 FOREWORD

58 1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising

59 all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote

60 international co-operation on all questions concerning standardization in the electrical and electronic fields. To

61 this end and in addition to other activities, the IEC publishes International Standards. Their preparation is

62 entrusted to technical committees; any IEC National Committee interested in the subject dealt with may

63 participate in this preparatory work. International, governmental and non-governmental organizations liaising with

64 the IEC also participate in this preparation. The IEC collaborates closely with the International Organization for

65 Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

66 2) The formal decisions or agreements of the IEC on technical matters, express as nearly as possible, an

67 international consensus of opinion on the relevant subjects since each technical committee has representation

68 from all interested National Committees.

69 3) The documents produced have the form of recommendations for international use and are published in the form

70 of standards, technical specifications, technical reports or guides and they are accepted by the National

71 Committees in that sense.

72 4) In order to promote international unification, IEC National Committees undertake to apply IEC International

73 Standards transparently to the maximum extent possible in their national and regional standards. Any divergence

74 between the IEC Standard and the corresponding national or regional standard shall be clearly indicated in the

75 latter.

76 5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any

77 equipment declared to be in conformity with one of its standards.

78 6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject

79 of patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

80 International Standard IEC 60893-2 has been prepared by subcommittee 15C: Specifications,

81 of IEC technical committee 15: Insulating materials.

82 This third edition cancels and replaces the second edition, published in 2003, and constitutes

83 an editorial revision.

84 This edition includes the following changes with respect to the previous edition:

85 a) removal of reference to withdrawn specification IEC 60167:1964;

86 b) inclusion of reference to IEC 62631-3-3:2015, which supersedes IEC 60167:1964. Details

87 in Section 6.3 have been updated accordingly. The actual performance of the test has not

88 changed;
89 c) normative references have been updated;
---------------------- Page: 5 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 4 – 15/948/CDV
91 The text of this standard is based on the following documents:
FDIS Report on voting
15/xxx/FDIS 15/xxx/RVD

93 Full information on the voting for the approval of this standard can be found in the report on

94 voting indicated in the above table.

95 This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

96 The committee has decided that the contents of this publication will remain unchanged until 2005.

97 At this date, the publication will be
98 • reconfirmed;
99 • withdrawn;
100 • replaced by a revised edition, or
101 • amended.
102
---------------------- Page: 6 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 5 – 15/948/CDV
103 INTRODUCTION

104 This part of IEC 60893 is one of a series which deals with industrial rigid laminated sheets

105 based on thermosetting resins for electrical purposes.
106 This series consists of four parts:
107 − Part 1: Definitions, designations and general requirements (IEC 60893-1)
108 − Part 2: Methods of test (IEC 60893-2)
109 − Part 3: Specifications for individual materials (IEC 60893-3)
110 − Part 4: Typical values (IEC 60893-4)
111
---------------------- Page: 7 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 6 – 15/948/CDV
112 INSULATING MATERIALS –
113 INDUSTRIAL RIGID LAMINATED SHEETS
114 BASED ON THERMOSETTING RESINS
115 FOR ELECTRICAL PURPOSES –
116
117 Part 2: Methods of test
118
119
120
121 1. Scope

122 This part of IEC 60893 describes methods of test for the materials defined in IEC 60893-1

123 (referred to also as Part 1).
124 2. Normative references

125 The following referenced documents are indispensable for the application of this document. For

126 dated references, only the edition cited applies. For undated references, the latest edition of

127 the referenced document (including any amendments) applies.

128 IEC 60112, Method for the determination of the proof and the comparative tracking indices of

129 solid insulating materials

130 IEC 60212:2010, Standard conditions for use prior to and during the testing of solid electrical

131 insulating materials

132 IEC 60216-1:2013, Electrical insulating materials – Thermal endurance properties – Part 1:

133 Ageing procedures and evaluation of test results

134 IEC 60243-1:2013, Electric strength of insulating materials – Test methods – Part 1: Tests at

135 power frequencies

136 IEC 60250:1969, Recommended methods for the determination of the permittivity and dielectric

137 dissipation factor of electrical insulating materials at power, audio and radio frequencies

138 including metre wavelengths

139 IEC 60296:2012, Fluids for electrotechnical applications - Unused mineral insulating oils for

140 transformers and switchgear

141 IEC 60587:2007, Electrical insulating materials used under severe ambient conditions – Test

142 methods for evaluating resistance to tracking and erosion

143 IEC 60695-11-10:2013, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and

144 vertical flame test methods

145 IEC 60893-1, Insulating materials - Industrial rigid laminated sheets based on thermosetting

146 resins for electrical purposes – Part 1: Definitions, designations and general requirements

147
148
---------------------- Page: 8 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 7 – 15/948/CDV

149 IEC 60893-3 (all parts 3), Insulating materials - Industrial rigid laminated sheets based on

150 thermosetting resins for electrical purposes – Part 3: Specifications for individual materials

151 IEC 60893-4, Insulating materials - Industrial rigid laminated sheets based on thermosetting

152 resins for electrical purposes – Part 4: Typical values

153 IEC 62631-3-3:2015, Dielectric and resistive properties of solid insulating materials – Part 3-3:

154 Determination of resistive properties (DC methods) – Insulation resistance
155 ISO 62:2008, Plastics – Determination of water absorption
156 ISO 178:2010, Plastics - Determination of flexural properties

157 ISO 179-1:2000, Plastics – Determination of Charpy impact properties – Part 1: Non-

158 instrumented impact test

159 ISO 179-2:1997, Plastics – Determination of Charpy impact properties – Part 2: Instrumented

160 impact test
161 ISO 180:2000, Plastics – Determination of Izod impact strength

162 ISO 527-1: 2012, Plastics – Determination of tensile properties – Part 1: General principles

163 ISO 527-4:1997, Plastics – Determination of tensile properties – Part 4: Test conditions for

164 isotropic and orthotropic fibre-reinforced plastic composites
165 ISO 604:2002, Plastics – Determination of compressive properties

166 ISO 1183-1:2012, Plastics – Methods for determining the density of non-cellular plastics – Part

167 1: Immersion method, liquid pyknometer method and titration method

168 ISO 3611:2010, Micrometers for external measurements – Design and metrological

169 characteristics
170 3. Conditioning of test specimens

171 Unless otherwise specified, test specimens shall be conditioned for at least 24 h in standard

172 atmosphere B according to IEC 60212 (temperature 23 °C ± 2 K relative humidity (50 ± 5) %).

173 Unless otherwise specified, each specimen shall be tested in the conditioning atmosphere and

174 at the conditioning temperature, or the tests shall commence within 3 min of removal of each

175 test specimen from the conditioning atmosphere.

176 Where testing at an elevated temperature is required in one of the specification sheets of

177 IEC 60893-3, test specimens shall be conditioned for 1 h at that elevated temperature

178 immediately before testing.
---------------------- Page: 9 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 8 – 15/948/CDV
179 4. Dimensions
180 4.1 Thickness
181 4.1.1 General

182 Any method which enables the thickness of the laminated sheet to be measured at an

183 appropriate number of points may be used, provided that the equipment used and the method

184 of measurement are capable of a precision of 0,01 mm or better.

185 The following reference method has been shown to be suitable and shall be used in cases

186 of dispute.
187 4.1.2 Test apparatus for reference method

188 In case of dispute, an external screw type micrometer according ISO 3611 having faces with

189 diameters between 6 mm and 8 mm shall be used.
190 4.1.3 Procedure for reference method

191 Measure the thickness of the rigid laminated sheet as delivered to the nearest 0,01 mm at eight

192 points, two along each edge but not less than 20 mm from the edge.
193 4.1.4 Results

194 Report the maximum and minimum measured values and the arithmetic mean of all measured

195 values in mm.
196 4.2 Flatness
197 4.2.1 General
198 This test is applicable to all sheets having a thickness of 3 mm or greater.
199 4.2.2 Test specimens

200 The test specimen shall be the whole sheet or panel under test in the ‘as received’ condition.

201 4.2.3 Test method

202 When any sheet of nominal thickness 3,0 mm or more is placed without restraint, concave side

203 up, on a flat surface, the departure at any point of the upper surface of the sheet from a light,

204 straight edge 1 000 mm or 500 mm in length, laid in any direction upon it, shall not exceed the

205 value given in the relevant sheet of IEC 60893-3 appropriate to the material, its thickness and

206 length of straight edge. The mass of the 1 000 mm straight edge shall not exceed 800 g, and the

207 mass of the 500 mm straight edge shall not exceed 400 g.
208 4.2.4 Results
209 Report the maximum measured deviation from flatness in mm.

210 NOTE In cases where the sheet deviates from flatness in two directions, is saddle-shaped, measure both deviations

211 and report the highest.
---------------------- Page: 10 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 9 – 15/948/CDV
212 5. Mechanical tests
213 5.1 Flexural strength
214 5.1.1 General

215 The flexural strength is defined as the flexural stress at rupture. It shall be determined by the

216 method specified in ISO 178. Method A shall be used.
217 5.1.2 Test specimens

218 Cut the test specimens from the sheet to be tested with their major axes parallel to the sides of

219 the sheet. Test five test specimens in each direction, except for types with fibres aligned mainly

220 in the same direction. In such cases, cut five specimens only, with their long axis parallel to the

221 direction of the fibres.

222 If the nominal thickness of the sheet to be tested is more than 10 mm (20 mm in the case of

223 types PF WV), reduce the thickness of the test specimens to 10 mm (20 mm in the case

224 of PF WV).

225 When it is necessary to reduce the thickness of a test specimen, machine it, leaving one face

226 of the sheet intact. In such cases, test specimens shall be tested with the original surface of

227 the sheet in contact with the two supports.
228 5.1.3 Test method

229 The test shall be carried out with the load applied perpendicular to the plane of the laminations.

230 The test speed shall be 5 mm/min with a tolerance of ±20 %.
231 5.1.4 Results

232 Report the arithmetic mean of the results for each direction in MPa. Take the lower of the two

233 mean values as the minimum flexural strength of the sheet under test, except in cases where

234 the reinforcing fibres run mainly in one direction. In such cases, take the mean value obtained

235 in this direction.
236 5.2 Modulus of elasticity in flexure
237 5.2.1 General

238 The following test method shall be used in order to determine the modulus of elasticity in flexure.

239 5.2.2 Test specimens

240 The specimens shall be in the same form as described for the flexural strength test described

241 in 5.1.2 above.
242 5.2.3 Test method

243 Modulus of elasticity shall be determined by the method specified in ISO 178.

244 5.2.4 Results
245 Results shall be expressed in MPa.
246 5.3 Compressive strength
247 5.3.1 General

248 The following test method shall be used in order to determine the compressive strength.

---------------------- Page: 11 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 10 – 15/948/CDV
249 5.3.2 Test specimens
250 Specimens shall be cut from the sheet under test as described in ISO 604.
251 5.3.3 Test method

252 Compressive strength shall be determined by the method specified in ISO 604 with the load

253 applied perpendicular to the plane of the laminations.
254 5.3.4 Results
255 Results shall be expressed in MPa.
256 5.4 Impact strength
257 5.4.1 General

258 This test is only applicable to sheets of nominal thickness equal to or greater than 5 mm.

259 5.4.2 Charpy Impact strength
260 5.4.2.1 Test specimens

261 Test specimens shall be cut from the sheet under test in accordance with Figure 1a. Five

262 specimens, with a thickness between 5 mm and 10 mm, shall be tested in each direction, except

263 for types with fibres aligned mainly in the same direction. In such cases, cut five specimens

264 only, with their longitudinal axis parallel to the direction of the fibres.

265 If the nominal thickness of the sheet to be tested is greater than 10 mm, reduce the thickness

266 of the test specimen to 10 mm by machining equal amounts from both faces of the sheet.

267 5.4.2.2 Test method

268 The Charpy impact strength shall be determined in the edgewise direction as described by the

269 method given in ISO 179-1 and ISO 179-2 except that the specimens shall be as described

270 above, and the span shall be 70 mm. The material shall be tested with the major axes in each

271 direction parallel to the sides of the sheet, except in the case of materials whose fibres lie

272 mainly in the same direction. For these materials only specimens with their longitudinal axis

273 parallel to the direction of the fibres shall be tested.
274 5.4.2.3 Results

275 Report the arithmetic mean of the results for each direction in kJ/m . Take the lower of the two

276 mean values as the minimum Charpy impact strength of the sheet under test, except in cases

277 where the reinforcing fibres run mainly in one direction. In such cases, take the mean value

278 obtained in this direction.
279 5.4.3 Izod impact strength
280 5.4.3.1 Test specimens

281 The dimensions of the specimens shall be as described in Figure 1b. Five specimens, with a

282 thickness between 5 mm and 10 mm, shall be tested in each direction, except for types with

283 fibres aligned mainly in the same direction. In such cases, cut five specimens only, with their

284 longitudinal axis parallel to the direction of the fibres.

285 If the nominal thickness of the sheet to be tested is greater than 10 mm, reduce the thickness

286 of the test specimen to 10 mm by machining equal amounts from both faces of the sheet.

---------------------- Page: 12 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 11 – 15/948/CDV
287 5.4.3.2 Test method

288 The Izod impact strength shall be determined in the edgewise direction as described by the

289 method given in ISO 180. The material shall be tested with the major axes in each direction

290 parallel to the sides of the sheet, except in the case of materials whose fibres lie mainly in the

291 same direction. For these materials only, specimens with their longitudinal axis parallel to

292 the direction of the fibres shall be tested.
293 5.4.3.3 Results

294 Report the arithmetic mean of the results for each direction in kJ/m . Take the lower of the two

295 mean values as the minimum Izod impact strength of the sheet under test, except in cases

296 where the reinforcing fibres run mainly in one direction. In such cases, take the mean value

297 obtained in this direction.
298 5.5 Shear strength parallel to laminations
299 5.5.1 General

300 The shear strength parallel to laminations test provides data that gives an indication of the

301 degree of bonding or adhesion between laminations. The test is only applicable to sheets

302 of nominal thickness greater than 5 mm.
303 5.5.2 Test specimens
304 Rectangular test specimens are cut with the following dimensions:
305 Length 20 mm ± 0,1 mm
306 Width and thickness 5 mm
− 0,15

307 Cut the test specimens from the sheet to be tested with their major axes parallel to the sides of

308 the sheet. Prepare five sets of test specimens for each direction, each set of specimens

309 comprising two pieces.

310 The two specimens in each pair shall have widths (dimension along the laminations orthogonal

311 to the length) identical within 0,01 mm.
312 5.5.3 Test method

313 Two test specimens are simultaneously subjected to shearing stress in the device shown in

314 Figure 2.

315 The test specimens shall be arranged so that the shearing stress acts in a plane parallel to the

316 laminations. The relative rate of movement of the cross head of the testing machine shall be

317 2 mm/min with a tolerance of ±20 %.
318 5.5.4 Results

319 Calculate the shear strength by dividing the shear force through the total shear plane area

320 of 2 × 100 mm .

321 Report the arithmetic mean value of the results for each direction in MPa and take the lower

322 of the two mean values as the parallel shearing strength of the sheet under test.

---------------------- Page: 13 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 12 – 15/948/CDV
323 5.6 Tensile strength
324 5.6.1 General

325 Tensile strength defined as tensile stress at maximum load shall be determined by the method

326 specified in ISO 527-4, in conjunction with ISO 527-1.
327 5.6.2 Test specimens

328 Specimens shall be cut from the sheet under test with the major axis in each direction parallel

329 to the sides of the sheet. Five specimens of nominal thickness between 1,5 mm and 10,0 mm

330 shall be prepared from each direction according to type 1 of ISO 527-4, except in the case of

331 materials whose fibres lie mainly in the same direction. For these materials only specimens with

332 their longitudinal axis parallel to the direction of the fibres shall be tested.

333 If the sheet to be tested is more than 10 mm thick, reduce the thickness of the test specimens

334 to 10 mm by machining equal amounts from each face.
335 5.6.3 Test method

336 Carry out the test as described in ISO 527-4. The rate of separation of the jaws of the testing

337 machine shall be 5 mm/min with a tolerance of ±20 %.
338 5.6.4 Results

339 Report the arithmetic mean of the results for each direction in MPa. Take the lower of the two

340 mean values as the minimum tensile strength of the sheet under test, except in cases where

341 the reinforcing fibres run mainly in one direction. In such cases, take the mean value obtained

342 in this direction.
343 6. Electrical tests
344 6.1 Electric strength and breakdown voltage
345 6.1.1 General

346 Electric strength and breakdown voltage shall be determined by the methods specified in

347 IEC 60243-1, which describes both the step-by-step and 60 s proof tests. Either test method

348 may be used. Unless otherwise specified the test shall be carried out at 90 °C ± 2 K in

349 mineral oil as described in IEC 60296, which is reasonably free from decomposition products.

350 Immerse the specimens in oil maintained at that temperature for not less than 0,5 h and not

351 more than 1 h immediately before test.
352 6.1.2 Test specimens

353 For electric strength, test three specimens normal to laminations. For breakdown voltage, test

354 three specimens parallel to the laminations.

355 Test specimens shall be cut from the sheet under test. Specimen dimensions shall be as

356 described in IEC 60243-1.
357 6.1.3 Test method

358 Test the material using either the 20 s step-by-step test as described in 10.2 of IEC 60243-1,

359 or using the 60 s proof test as described in 10.6 of IEC 60243-1.
---------------------- Page: 14 ----------------------
oSIST prEN IEC 60893-2:2022
IEC CDV 60893-2/Ed3 © IEC:2022 – 13 – 15/948/CDV
360 6.1.3.1 Electric strength perpendicular to laminations

361 For thicknesses not greater than 3 mm, the material shall be tested perpendicular to the

362 laminations. The upper electrode shall be 25 mm in diameter and the lower electrode shall be

363 75 mm in diameter according to IEC 60243-1.

364 NOTE This test is usually not required for thicknesses above 3 mm, in the Part 3

...