Preface This is the fifth edition of CSA C9, Dry-type transformers. It supersedes the previous editions published in 2002, 1981, 1977, and 1966. Changes in this edition include the following: a) updates to insulation voltage classes and dielectric tests; b) updates to Annex D (Comparison of enclosures for indoor and outdoor non-hazardous locations); and c) alignment of average audible sound level with current industry practices. Scope 1.1 This Standard applies to single phase and polyphase dry-type transformers, including those with cast or resin encapsulated coils, that are within the limits of the electrical ratings specified in Clauses 7.2 and 7.3, and that are intended for use in accordance with the service conditions for dry-type transformers specified in Annexes A and B. Notes: 1) For information on the loading of dry-type transformers, see IEEE C57.96. 2) For additional requirements for dry-type transformers in accordance with the Canadian Electrical Code, Part II, see CSA C22.2 No. 47. 1.2 This Standard deals with the standardization of voltage ratings, kVA capacities, other electrical features, certain mechanical features, and test procedures. 1.3 This Standard does not apply to transformers designed solely for test purposes, rectifier transformers, welding transformers, furnace transformers, instrument transformers, motor-starting autotransformers, or any other special purpose transformers. 1.4 In this Standard, the word \"transformer\" refers to a dry-type transformer, unless otherwise specifically stated. 1.5 In this Standard, \"shall\" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; \"should\" is used to express a recommendation or that which is advised but not required; and \"may\" is used to express an option or that which is permissible within the limits of the Standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.