GB/T 4207-2012 English PDF (GBT4207-2012)

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GB/T 4207-2012: Method for the determination of the proof and the comparative tracking indices of solid insulating materials
GB/T 4207-2012
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.035.99
K 15
GB/T 4207-2012 / IEC 60112:2009
Replacing GB/T 4207-2003
Method for the determination of the proof and the
comparative tracking indices of solid insulating
materials
(IEC 60112:2009, IDT)
ISSUED ON: DECEMBER 31, 2012
IMPLEMENTED ON: JUNE 01, 2013
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 4 
1 Scope ... 7 
2 Normative references ... 7 
3 Terms and definitions ... 8 
4 Principle ... 9 
5 Test specimen ... 9 
6 Test specimen conditioning ... 11 
6.1 Environmental conditioning ... 11 
6.2 Test specimen surface state ... 11 
7 Test apparatus ... 11 
7.1 Electrodes ... 11 
7.2 Test circuit ... 12 
7.3 Test solutions ... 12 
7.4 Dropping device ... 13 
7.5 Test specimen support platform ... 14 
7.6 Electrode assembly installation ... 14 
8 Basic test procedure ... 14 
8.1 General ... 14 
8.2 Preparation ... 15 
8.3 Test procedure ... 15 
9 Determination of erosion ... 16 
10 Determination of proof tracking index (PTI) ... 16 
10.1 Procedure ... 16 
10.2 Report ... 17 
11 Determination of comparative tracking index (CTI) ... 18 
11.1 General ... 18 
11.2 Determination of the 100 drop point ... 18 
11.3 Determination of the maximum 50 drop withstand voltage ... 19 
11.4 Report ... 20 
Annex A (informative) List of factors that should be considered by product
committees... 25 
Annex B (informative) Electrode material selection ... 26 
Annex NA (informative) Comparison on clause and subclause No. between this
Standard and GB/T 4207-2003 ... 27 
Bibliography ... 29 
Foreword
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This Standard replaces GB/T 4207-2003 "Solid insulating materials under moist
conditions comparative tracking index and Determination of proof tracking index
method".
Compared with GB/T 4207-2003, the main changes in this Standard are as
follows:
a) deleted "under moist conditions" from the standard's name;
b) deleted "voltage up to 600V" from the scope;
c) added Clause 2 "Normative references" and Clause 4 "Principle";
d) in terms and definitions, added "tracking failure", "air arc" and "persistent
flame" (see 3.2, 3.4, 3.6 of this Edition);
e) this Standard specifies that the thickness shall be 3mm or more, and the
maximum thickness is 10mm; in Edition 2003, it specifies that the
thickness shall be greater than or equal to 3mm; in both editions, they all
specify that specimens smaller than 3mm shall be stacked for experiment;
f) it is recommended in this Standard that the sample plane size shall be less
than 20mm×20mm, 15mm×15mm can also be adopted; in Edition 2003,
it specifies that it's not less than 15mm×15mm (see Clause 5 of this
Edition; Clause 3 of Edition 2003);
g) this Standard specifies that the minimum purity of platinum electrodes is
99%, and the blade of the electrode slope is approximately flat, about
0.01mm~0.1mm wide (see 7.1);
h) the power of the power supply is modified from not less than 0.5kVA in
Edition 2003 to not less than 0.6kVA (see 7.2 of this Edition; 5.2 of Edition
2003);
i) this Standard specifies that "the maximum error of the measuring device
of the short-circuit current value is ±3%" (see 7.2 of this Edition);
j) modified "The overcurrent relay shall operate when the current of 0.5A or
greater lasts for 2s" in Edition 2003 to "The over-current device shall
operate when a current with an r.m.s. value of 0.50 A with a relative
tolerance of ±10%, has persisted for 2.00 s with a relative tolerance of
±10%" (see 7.2 of this Edition; 5.2 of Edition 2003);
k) this Standard specifies that the purity of analytical grade anhydrous
ammonium chloride is "not less than 99.8%", and the conductivity of
deionized water does not exceed "1ms/m";
l) about the resistivity of solution B, it is (1.70±0.05) Ω·m in Edition 2003,
(1.98±0.05) Ω·m in this Standard (see 7.3 of this Edition; 5.4 of Edition
2003);
m) this Standard has regulations on air speed (see 7.6 of this Edition);
n) during the CTI test, if the material properties are unknown, this Standard
recommends a starting voltage of 350V (it is 300V in Edition 2003) (see
11.2 of this Edition; 6.2 of Edition 2003);
o) In the CTI test, this Standard recommends to test 100 drops first and then
50 drops, which is contrary to the requirements of Edition 2003 (see 11.1
of this Edition; 6.2 of Edition 2003);
p) refer to Annex NA for the correspondence between the chapters of this
Standard and Edition 2003.
This Standard uses translation method to identically adopt IEC 60112:2009
(Edition 4.1) "Method for the determination of the proof and the comparative
tracking indices of solid insulating materials".
The Chinese document which has consistency with the international normative
reference in this Standard is as follows:
- GB/T 16499-2008 "The Preparation of safety publication and the use of
basic safety publications and group safety publications" (IEC 104
Guide:1997, NEQ).
Compared with IEC 60112:2009 (Edition 4.1), this Standard makes the
following editorial modifications:
- added informative Annex NA to list the comparison on clause and subclause
numbers between this Standard and GB/T 4207-2003.
This Standard was proposed by China Electrical Equipment Industry
Association.
This Standard shall be under the jurisdiction of National Technical Committee
on Electrical Insulation Materials and Insulation System Evaluation of
Standardization Administration of China (SAC/TC 301).
The drafting organizations of this Standard: Guilin Electrical Apparatus
Research Institute, Shenzhen Institute of Standards and Technology, Beijing
Method for the determination of the proof and the
comparative tracking indices of solid insulating
materials
1 Scope
This Standard specifies the method of test for the determination of the proof
and comparative tracking indices of solid insulating materials on pieces taken
from parts of equipment and on plaques of material using alternating voltages.
The standard provides for the determination of erosion when required.
NOTE 1: The proof tracking index is used as an acceptance criterion as well as a means
for the quality control of materials and fabricated parts. The comparative tracking index is
mainly used for the basic characterization and comparison of the properties of materials.
Test results cannot be used directly for the evaluation of safe creepage
distances when designing electrical apparatus.
NOTE 2: This test discriminates between materials with relatively poor resistance to
tracking, and those with moderate 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 higher voltages and
larger test specimens (see the inclined plane test of IEC 60587). Other test methods such
as the inclined method may rank materials in a different order from the drop test given in
this Standard.
2 Normative references
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For undated