This is the first edition of CSA C2.1, Single-phase and three-phase liquid-filled distribution transformers.

It supersedes previous editions of CAN/CSA-C2, Single-Phase and Three-phase Liquid-filled Distribution Transformers, Types ONAN and LNAN, published in 1991, 1982, 1976, 1969, 1959, 1944, 1928, and 1920.

It is written in SI (metric) units.

1 Scope

1.1
This Standard specifies the requirements for distribution transformers with the exception of those distribution transformers that are covered by CSA C2.2, C227.3, and C227.4. Note: The operation of transformers complying with this Standard by other than an electric utility may be subject to additional requirements by the electrical inspection authority having jurisdiction.

1.2
This Standard applies to single- and three-phase, 60 Hz, liquid-filled distribution transformers, insulation class 34.5 kV or less, rated at 1000 kV.A or below for single phase and at 3000 kV.A or below for three phase.

1.3
This Standard includes voltage ratings, kV.A ratings, certain mechanical characteristics, and test procedures. Also included are the following performance characteristics: energy efficiency (in accordance with CAN/CSA-C802.1), temperature rise, loading capabilities, sound level, and radio influence voltage (RIV).
1.4
This Standard also applies to self-protected transformers, with the exception of the protective equipment.

1.5
Except as specified by other CSA Standards, this Standard does not apply to auto-, testing, dry-type, welding, furnace, rectifier, network, subway-type, or special-purpose transformers, or to step-voltage regulators.

1.6
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.