IEC 60426:2007

FOREWORD
INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 General description of the test method
5 Test specimens
   5.1 General
   5.2 Cut surfaces of rigid materials (blocks, plates,
        sheets or semi-finished materials)
   5.3 Cast, moulding, injection and pressed materials
   5.4 Cut surfaces of flexible films, foils and thin
        sheets
   5.5 Adhesive tapes
   5.6 Flexible sleeving and tubing
   5.7 Lacquers and insulating varnishes
   5.8 Cleanliness of contact surfaces
   5.9 Number of test specimens
6 Test strips
   6.1 General
   6.2 Preparation of the test strips
   6.3 Cleanliness of test strips
7 Test device
8 Test conditions
9 Test procedure
10 Evaluation
   10.1 General evaluation
   10.2 Visual inspection of the test strips
   10.3 Tensile strength of test strips
11 Evaluation of corrosion on copper strips
12 Test report
Annex A (normative) Tables for the evaluation of corrosion
        on brass and aluminium strips
Annex B (informative) Notes on visual evaluation
Annex C (informative) Copper wire tensile strength method

IEC 60426:2007 determines the ability of insulating 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 consisting 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 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 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.