IEC 60426-2007 pdf Electrical insulating materials – Determination of electrolytic corrosion caused by insulating materials – Test methods

5.5 Adhesive tapes For adhesive tapes the method of Clause 7 of IEC 60454-2 is recommended. 5.6 Flexible sleeving and tubing Sleeving and tubing (both varnished fabric and extruded) are slit open, so as to make flat sheets, which can then be prepared as for films (see 5.4). 5.7 Lacquers and insulating varnishes The lacquer or insulating varnish to be tested shall be applied in the manner recommended by the manufacturer to the surface of a test specimen of shape as shown in Figure 1 and described in 5.2. The base material of the test specimen shall be a corrosion free plastic such as polymethylmethacrylate. In case of solvent incompatibility or a baking temperature being too high for the base material, another suitable base material such as cast, hot cured corrosion free epoxy resin or glass shall be used. If the lacquer or insulating varnish is designed to contribute freedom from corrosion to another material, a test specimen of that material shall be used. The tested lacquer or varnish shall be sprayed, dipped or otherwise coated to the desired thickness and baked, if necessary, as specified or according to the directions of the manufacturer. If the thickness of coating is not determined by specification or direction of the manufacturer, it shall be of (30 ± 1 0) μm. 5.8 Cleanliness of contact surfaces When preparing and handling the test specimens, any soiling of the test surfaces, for example by perspiration from the hands, shall be avoided. The specimens shall be touched only with a pair of tweezers or with protecting gloves made of materials free from corrosion (e.g. polyethylene). After the test specimens have been machined or cut, their surfaces shall be cleaned with a soft brush.
5.9 Number of test specimens At least five test specimens made from the same material shall be tested at the same time. A specific sampling procedure may be desired. If necessary, such a sampling procedure should be specified and used. 6 Test strips 6.1 General The test strips shall be made of 0,1 mm thick, semi-hard copper of purity 99,9 Cu. Their dimensions are 1 0 mm wide and 200 mm long. The test strips shall be flat, without bends and burrs at the edges as well as any other mechanical defects or impurities on the test surface, which may have influence on the test results.