IEC 60112 pdf download

IEC 60112 pdf download Method for the determination of the proof and the comparative tracking indices of solid insulating materials
1 Scope
This International standard specifies the method of test for the determination of the proof andcomparative tracking indices of solid insulating materials on pieces taken from parts ofequipment and on plaques of material using alternating voltages.
The standard provides for the determination of erosion when required.
NOTE 1 The prooft tracking index is used as an acceptance criterion as well as a means for the quality control ofmaterials and fabricated parts. The comparative tracking index is mainly used for the basic characterization andcomparison of the properties of materials.
Test results cannot be used directly for the evaluation of safe creepage distances whendesigning electrical apparatus.
NOTE 2 This test discriminates between materials with relatively poor resistance to tracking，and those withmoderate or good resistance,for use in equipment which can be used under moist conditions.More severe tests,of longer duration are required for the assessment of performance of materials for outdoor use,utilizing highervoltages and larger test specimens (see the inclined plane test of lEC 60587).Other test methods such as theinclined method may rank materials in a different order from the drop test given in this standard.
2Normative 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 editionof the referenced document (including any amendments) applies.
IEC 60589:1977，Methods of test for the determination of ionic impurities in electricalinsulating materials by extraction with liquids
IEC Guide 104:1997，The preparation of safety publications and the use of basic safetypublications and group safety publications
ISo 293:1986,Plastics – Compression moulding test specimens of thermoplastic materials
ISO 294-1:1996,Plastics – Injection moulding of test specimens of thermoplastic materials -Part 1 : General principles, and moulding of multi-purpose and bar test specimens
ISo 294-3:2002，Plastics – Injection moulding of test specimens of thermoplastic materials -Part 3: Small plates
IsO 295:1991，Plastics – Compression moulding of test specimens of thermosetting materials
3 Terms and definitions
For the purposes of this International Standard, the following definitions apply:
3.1
tracking
progressive formation of conducting paths，which are produced on the surface and/or withina solid insulating material,due to the combined effects of electric stress and electrolyticcontamination
3.2
tracking failure
failure of insulation due to tracking between conducting parts
NOTE ln the present test,tracking is indicated by operation of an over-current device due to the passage ofa current of at least 0,5 A for at least 2 s across the test surface and/or within the specimen.
3.3
electrical erosion
wearing away of insulating material by the action of electrical discharges
3.4
air arc
arc between the electrodes above the surface of the specimen
3.5
comparative tracking indexcTI
numerical value of the maximum voltage at which five test specimens withstand the testperiod for 50 drops without tracking failure and without a persistent flame occurring andincluding also a statement relating to the behaviour of the material when tested using100 drops (see 11.4)
NOTE1 The criteria for CTl may also require a statement concerning the degree of erosion.
NOTE 2 Although a non-persistent flame is allowed in the test without constituting failure，materials whichgenerate no flame at all are preferred unless other factors are considered to be more important. See also Annex A.
3.6
persistent flame
in case of dispute – one which burns for more than 2 s
3.7
proof tracking indexPTI
numerical value of the proof voltage in volts at which five test specimens withstand the testperiod for 50 drops without tracking failure and without a persistent flame occurring