CSA C22.3 No. 7:25

1 Scope 1.1 General This Standard applies to the lines and equipment associated with underground electric supply and communication systems located a) entirely outside of buildings; b) outside of indoor supply stations and fenced outdoor supply stations; or c) inside buildings or sections of buildings where they are employed by a utility of i) an electric system; ii) a communication system; or iii) a community antenna distribution system in the exercise of its function as a utility. This Standard, which forms part of the Canadian Electrical Code, Part III, covers the requirements for the construction of underground systems and includes electric supply and communication circuits that are installed alone, in joint use, or in proximity to each other or other facilities. 1.2 Prior editions Existing installations meeting the requirements of prior editions of this Standard need not be modified to comply with this edition of the Standard, except as might be required for safety reasons by the authority having jurisdiction. 1.3 Applications The requirements of this Standard do not constitute complete construction specifications but stipulate the minimum design requirements with regard to a) safety to persons; b) continuity of service; and c) protection of property. 1.4 Exclusion The selection, design, and installation of supply transmission cables (=69 kV) are not addressed in this Standard. 1.5 Common standards Conditions not covered by this Standard are governed by equivalent Standards in common use or by the authority having jurisdiction. 1.6 Types of construction In some cases, requirements are written for specific types of construction. This does not preclude the use of other types of construction arising out of continuing advancements in the field, provided that engineering representatives can demonstrate the safety and suitability of these alternatives. 1.7 Terminology 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.