IEC 60811-509:2017 pdf download

IEC 60811-509:2017 pdf download.Electric and optical fibre cables – Test methods for non-metallic materials – Part 509: Mechanical tests
1 Scope
This Part 509 of IEC 6081 1 gives the procedure for the test for resistance of insulations and sheaths to cracking at an elevated temperature.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 6081 1 -1 00:201 2, Electric and optical fibre cables – Test methods for non-metallic materials – Part 100: General
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 6081 1 -1 00 apply.
4 Test method
4.1 General This part of IEC 6081 1 shall be used in conjunction with IEC 6081 1 -1 00. All the tests shall be carried out not less than 1 6 h after the extrusion of the insulating or sheathing compounds Unless otherwise specified, tests shall be carried out at room temperature. The heat shock test was specifically developed for PVC compounds. The use of this test for other types of compounds needs careful consideration. NOTE In the absence of any requirement in the relevant cable standard, Annex A in this standard gives a recommendation for the test conditions and test requirements. 4.2 Apparatus The apparatus consists of the following parts: a) an air oven capable of maintaining the temperature and tolerance specified; b) mandrels of sufficient length made of metal or other suitable material.4.3 Sample and test piece preparation for insulations 4.3.1 General Each core to be tested shall be represented by two samples of suitable length taken from two places separated by at least 1 m. External coverings, if any, shall be removed from the insulation. The test pieces shall be prepared in one of the three following ways: a) For cores with an overall diameter not exceeding 1 2,5 mm, each test piece shall consist of a piece of core. b) For cores with an overall diameter exceeding 1 2,5 mm and having an insulation thickness not exceeding 5 mm, and for all sector-shaped cores, each test piece shall consist of a strip taken from the insulation whose width shall be at least 1 ,5 times its thickness, but not less than 4 mm. The strip shall be cut in the direction of the axis of the conductor. In the case of sector-shaped cores, it shall be cut out of the “back” of the core. c) For cores with an overall diameter exceeding 1 2,5 mm and a wall thickness exceeding 5,0 mm, each test piece shall consist of a strip cut in accordance with item b) and then ground or cut (avoiding heating) on the outer surface, to a thickness between 4,0 mm and 5,0 mm. This thickness shall be measured on the thicker part of the strip, whose width shall be at least 1 ,5 times the thickness. 4.3.2 Procedure Each test piece shall be tautly wound and fixed, at ambient temperature, on a mandrel to form a close helix, as given below: a) For test pieces prepared in accordance with 4.3.1 a), and for flat cables with major axis not exceeding 1 2,5 mm, the diameter of the mandrel and the number of turns shall be as given below in Table 1 . The mandrel diameter shall be based on the minor dimension of the core which is wound on with its minor axis perpendicular to the mandrel.
For the application of Tables 1 and 2, the diameter or thickness of each test piece shall be measured by means of callipers or any other suitable measuring instrument. Each test piece, on its mandrel, shall be placed in the oven, pre-heated to the temperature specified in the relevant cable standard or, if no other is specified in the cable standard, to that given in Annex A of this standard. The test pieces shall be removed from the oven and allowed to attain approximately ambient temperature. They shall then be examined while still on the mandrel.