Preface This is the second edition of CSA C22.2 No. 180, Series isolating transformers for airport lighting. It supersedes the previous edition published in 1983. It is one of a series of Standards issued by CSA Group under Part II of the Canadian Electrical Code. It is written in SI (metric) units. For general information on the Standards of the Canadian Electrical Code, Part II, see the preface of CAN/CSA-C22.2 No. 0. This new edition mainly serves to incorporate the amendments to the 1983 edition and to update the reference publications. This standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group. Scope 1.1 This Standard applies to encapsulated isolating transformers for use as a circuit continuity device, intended to be installed in airport field lighting series circuits for use in nonhazardous locations in accordance with the Canadian Electrical Code, Part I. 1.2 This Standard applies to transformers that consist of primary and secondary coils that are wound upon a core, the assembly being enclosed in a waterproof case. The primary coil is connected into the series circuit and the secondary coil to the light fixture lead by means of plug/receptacle connectors. The receptacle portion of the connector is provided with the transformer to mate with the plug portion on the series circuit and light fixture cables. The transformer receptacle portion may be either built into the transformer body or moulded into the ends of transformer leads. 1.3 Transformers constructed to meet the requirements of this Standard are suitable for continuous outdoor service in ambient temperatures from a minimum of #55 °C to a maximum of +65 °C and for direct earth burial. 1.4 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.