An electrical installation work is complete only when the prescribed pre-commission tests are conducted on different components and the test results are found satisfactory. By carrying out the pre-commission tests, it is ensured that different components of the system have their declared specifications/characteristics and also the system is fit for safe and reliable operation. The precommission tests for different components of an electrical system are prescribed by the Bureau of Indian Standards and International Electrotechnical Commission. The manufacturers also recommend certain site tests before commissioning their equipments. The Electrical Inspector who is the authority to certify the safety of an electrical installation may insist on the owner of the installation to carry out such additional tests as may be necessary before commencing the supply. At present there is no codified book or publication covering the various standards and guidelines for the testing of various industrial equipments. In this book, it is attempted to cover the methods and procedures of all important pre-commission tests of industrial electrical equipments.In the ensuing chapters, the requirements and procedures for testing of different components of an electrical system are given under the headlines of Transformers, Motors, Generators, Switch Board Assemblies, Cables, Relays and Protective earthing. The last Chapter deals with the preparation of completion reports. The pre-commission tests are broadly classified into pre-commission checks meant for initial inspection covering visual inspection for damages, quality of workmanship, mechanical operation etc. and the pre-commission tests meant for measurement or testing of various safety parameters like insulation resistance, earth resistance, breakdown voltage of insulation, relay characteristics etc. In addition to describing the procedure for checks and tests, attempt is also made to give essential information about the specifications and characteristics of different parts and components. For measurement of insulation resistance and earth resistance, detailed description of the measuring instruments, test procedures and interpretation of the test results are given under the chapter on Transformers. While carrying out the measurement of insulation resistance and earth
resistance of other parts and components, readers are advised to refer to the chapter on Transformers also for better understanding of the instruments, test procedures and interpretation of the test results.Check lists for pre-commission checks of each component/equipment is given at the end of the respective chapter. These check lists are not exhaustive and the users have the option either to add items or delete those found not relevant. The users may modify the given checklist as warranted by the requirements of the situation.
The list of Indian Standards relevant to each chapter is given at the end of the corresponding chapter.For further details of the equipments, testing instruments, specifications, test procedures, etc, readers are advised to refer to the relevant Indian Standards also.Before carrying out the pre-commission tests it is always advisable to refer to the manufacturers’ instructions. Products of different manufactures may have special features and characteristics and it is necessary to have a good knowledge of these special features before carrying out the tests.

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