CSA M421:23

1 Scope 1.1 Purpose This Standard establishes minimum requirements for electrical work and electrical equipment operating, or intended to operate, at a mine. Note: Users should be aware that federal, provincial, and territorial legislation can impose additional requirements. 1.2 Application This Standard is supplementary to, or amendatory of, the requirements of the Canadian Electrical Code, Part I, as adopted by the regulatory authority having jurisdiction. Note: Adherence to the Canadian Electrical Code, Part I, normally addresses the minimum electrical safety requirements for mining-related fixed buildings, structures, and premises located on the surface, as these are no different from other industrial facilities. Such facilities could include processing plants, camps, offices, and drys. However, specific applications can exist within or on such buildings, structures, or premises that warrant the application of this Standard, such as supplies to mobile and movable equipment operated at voltages exceeding 150 V to ground. Examples of mine equipment operating at voltages exceeding 150 V to ground are a) mobile equipment fed by portable power cables; b) movable equipment fed by portable power cables or mine power feeders where the ground-fault voltage ground potential rise (GPR) relative to the surrounding earth or structures, and the transfer of these voltages, is required to be limited to tolerable touch voltage values; and c) quick-connect couplers. 1.3 Application to non-mining structures This Standard does not apply to tunnels, aqueducts, conduits, or excavations for civil construction purposes. However, where mines incorporate such structures, this Standard applies. 1.4 Structure of this Standard Clauses 1to 4apply to all mines. The remaining clauses apply as follows: a) Clause 5applies to surface mines and quarries and to the surface portion of underground mines; b) Clause 6applies to underground mines; and c) Clause 7applies to underground coal mines. 1.5 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.