This is the sixth edition of CSA C50, Insulating oil, electrical, for transformers and switches. It supersedes the previous editions, published in 1997, 1976, 1965, 1958, and 1938 under the title Insulating Oil, Electrical for Transformers and Switches.
1.1 This Standard specifies requirements for mineral oil of petroleum origin for use in transformers, oil circuit breakers, or other electrical equipment (excluding high-voltage cables) requiring a liquid insulating and cooling medium.
1.2 In CSA Standards, 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; may is used to express an option or that which is permissible within the limits of the standard; and can is used to express possibility or capability. 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.