IEC 61854:2020 pdf download – Overhead lines – Requirements and tests for spacers.
4.2 Materials General 4.2.1 Spacers shall be made of any materials suitable for their purpose. Unless additional requirements are stated, the material shall conform to the requirements of IEC 61284. 4.2.2 Non-metallic materials In addition to the requirements of IEC 61284, the conductivity of the various non-metallic components shall be such that when properly installed – potential differences between metallic components do not cause damage due to discharge; – line current including short circuit current and any current flow through the spacer do not degrade spacer components 4.3 Mass, dimensions and tolerances Spacer mass and significant dimensions, including appropriate tolerances, shall be shown on contract drawings. Tolerances applied to the mass and to the dimensions should ensure that the spacers meet their specified mechanical and electrical requirements. 4.4 Protection against corrosion In addition to the applicable requirements of IEC 61284, stranded steel wires, if used, shall be protected against corrosion in accordance with IEC 60888. 4.5 Manufacturing appearance and finish The spacers shall be free of defects and irregularities; all outside surfaces shall be smooth and all edges and corners well-rounded. 4.6 Marking The fitting marking requirements of IEC 61284 shall be applied to all clamp assemblies including those using breakaway bolts. Correct position of the top of the spacer (for example arrows pointing upward), if necessary, shall also be provided.
5 Quality assurance A quality assurance programme taking into account the requirements of this document can be used by agreement between the purchaser and the supplier to verify the quality of the spacers during the manufacturing process. Detailed information on the use of quality assurance is given in a system as per ISO 9001 or similar. It is recommended that test and measuring equipment used to verify compliance to this document is routinely maintained and calibrated in accordance with a relevant quality standard. 6 Classification of tests Type tests 6.1 6.1.1 General Type tests are intended to establish design characteristics. They are normally made once and repeated only when the design or the material of the spacer is changed. The results of type tests are recorded as evidence of compliance with design requirements. 6.1.2 Application Spacers shall be subjected to type tests as per Table 1. Each type test shall be performed on three samples which are identical, in all essential respects, with the spacers to be supplied under contract to the purchaser. All units shall pass the tests. The spacers used for tests during which no damage occurs to the units or their components may be used in subsequent tests. NOTE The unit subjected to type tests can be either a complete spacer or a component of the spacer as appropriate to the test. 6.2 Sample tests General 6.2.1 Sample tests are required to verify that the spacers meet the performance specifications of the type test samples. In addition, they are intended to verify the quality of materials and workmanship. 6.2.2 Application Spacers shall be subjected to sample tests as per Table 1. The samples to be tested shall be selected at random from the lot offered for acceptance. The purchaser has the right to make the selection. The spacers used for tests during which no damage occurs to the units or their components may be used in subsequent tests. The unit subjected to sample tests can be either a complete spacer or a component of the spacer as appropriate to the test.
6.2.3 Sampling and acceptance criteria The sampling plan procedures according to ISO 2859-1 and ISO 2859-2 (inspection by attributes) and ISO 3951 (inspection by variables) and the detailed procedures (inspection level, AQL, single, double or multiple sampling, etc.) shall be agreed between purchaser and supplier for each different attribute or variable. Sampling inspection by variables is an acceptance sampling procedure to be used in place of inspection by attributes when it is more appropriate to measure on some continuous scale the characteristic(s) under consideration. In the case of failure load tests and similar expensive tests, better discrimination between acceptable quality and objective quality is available with acceptance sampling by variables than by attributes for the same sample size. The purpose of the sampling process may also be important in the choice between a variables or attributes plan. For example, a customer may choose to use an attributes acceptance sampling plan to assure that parts in a shipment lot are within a required dimensional tolerance; the manufacturer may make measurements under a variables sampling plan of the same dimensions because of concern with gradual trends or changes which may affect the ability to provide shipment lots which meet the AQL.