M421-16

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, e.g., the following equipment operating at voltages exceeding 150 V to ground: a) mobile equipment fed by portable power cables; b) movable equipment fed by portable power cables where the ground-fault voltage and ground potential rise (GPR) relative to the surrounding earth or structures is required to be limited to 100 V; and c) quick-connect couplers that are not mechanically interlocked with a load-break-rated disconnect switch. 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 1 to 4 apply to all mines. The remaining clauses apply as follows: a) Clause 5 applies to surface mines and quarries; b) Clause 6 applies to underground mines; and c) Clause 7 applies 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.