This International Standard applies to outdoor and indoor bushings of any voltage used on d.c. systems, of capacitance graded or gas insulated types for use as components of oil-filled converter transformers and smoothing reactors, as well as air-to-air d.c. bushings. This standard does not apply to the following: - Cable terminations (potheads) - Bushings for instrument transformers - Bushings for test transformers - Bushings applied with gaseous insulation (other than air at atmospheric pressure) external to the bushing - Bushings for industrial application - Bushings for traction application. This standard makes reference to IEC 60137 for general terms and conditions and defines the special terms used, operating conditions, ratings, test procedures as well as general mechanical and electrical requirements for bushings for d.c. application. Where applicable, reference can also be made to IEC 61462 for composite insulators - hollow insulators for use in outdoor and indoor electrical equipment and to IEC 62155 for hollow pressurized and unpressurized ceramic and glass insulators for use in electrical equipment with rated voltages greater than 1000 V.