Gives requirements for testing newly manufactured indoor time switches with operation reserve that are used to control electrical loads, multi-tariff registers and maximum demand devices at certain periods throughout the year. May employ various techniques for electronic circuits. Does not apply to time switches operated by remote control or synchronized by radio-frequency. Covers normative references, definitions, requirements, tests and test conditions, relationship between ambient air temperature and relative humidity, reference and limiting values of the influence quantities, electromagnet for testing the influence quantities, electromagnet for testing the influence of externally produced magnetic field and acceptance tests.