Deals with insulation coordination for equipment within low-voltage systems. It applies to equipment for use up to 2 000 m above sea level having a rated voltage up to a.c. 1 000 V with rated frequencies up to 30 kHz, or a rated voltage up to d.c. 1 500 V. It specifies the requirements for clearances, creepage distances and solid insulation for equipment based upon their performance criteria. It includes methods of electric testing with respect to insulation coordination. The minimum clearances specified in this standard do not apply where ionized gases occur. Special requirements for such situations may be specified at the discretion of the relevant technical committee. This standard does not deal with distances - through liquid insulation, - through gases other than air, - through compressed air. Main changes have been made with respect to the previous edition: - Amendment of Japanese mains conditions with regard to the rated impulse voltages, the rationalized voltages and the nominal voltages of supply systems for different modes of overvoltage control - Amendment of dimensioning of clearances smaller than 0,01 mm - Alignment of the table and the corresponding formula regarding test voltages for verifying clearances at different altitudes - Amendment of interpolation of the creepage distance values for functional insulation - Amendment of creepage distance dimensioning taking into account ribs - Revision of the former Clause 4 ""Tests and measurements"" (now Clause 6) to achieve a more detailed description of the tests and their purpose, the test equipment and possible alternatives - Change of Annex C ""Partial discharge test methods"" from a former technical report, Type 2 (now called TS), to a normative Annex C. Has the status of a basic safety publication in accordance with IEC Guide 104. "