CSA Group CAN/CSA-C50-14 National Standard of Canada (reaffirmed 2023) Mineral insulating oil, electrical, for transformers and switches

Preface

This is the seventh edition of CSA C50, Mineral insulating oil, electrical, for transformers and switches. It supersedes the 2008 edition of the same title and the 1997, 1976, 1965, 1958, and 1938 editions, which were titled Insulating oil electrical for transformers and switches.

The changes introduced in this edition are the following:

a) Requirements for the detection of potentially corrosive sulphur have been added;

b) Requirements for the detection of dibenzyldisulphide (DBDS) have been added;

c) Requirements for the detection of metal passivators in oxidation inhibitors have been added; and

d) Requirements concerning additives in oil have been added.

It needs to be recognized that the tests specified in this Standard do not indicate the relative service lives of different oils. Purchasers should use these tests to determine the characteristics of oils that have been found by experience to be satisfactory and to detect any significant variations in the characteristics of further shipments of such oils.

This Standard was prepared by the Technical Committee on Transformer and Switch Oils, under the jurisdiction of the Strategic Steering Committee on Electrical Engineering, and has been formally approved by the Technical Committee.

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.

Notes:

1) Use of the singular does not exclude the plural (and vice versa) when the sense allows.

2) Although the intended primary application of this Standard is stated in its Scope, it is important to note that it remains the responsibility of the users of the Standard to judge its suitability for their particular purpose.

3) This Standard was developed by consensus, which is defined by CSA Policy governing standardization — Code of good practice for standardization as “substantial agreement. Consensus implies much more than a simple majority, but not necessarily unanimity”. It is consistent with this definition that a member may be included in the Technical Committee list and yet not be in full agreement with all clauses of this Standard.

4) To submit a request for interpretation of this Standard, please send the following information to [email protected] and include “Request for interpretation” in the subject line:

a) define the problem, making reference to the specific clause, and, where appropriate, include an illustrative sketch;

b) provide an explanation of circumstances surrounding the actual field condition; and

c) where possible, phrase the request in such a way that a specific “yes” or “no” answer will address the issue.

Committee interpretations are processed in accordance with the CSA Directives and guidelines governing standardization and are available on the Current Standards Activities page at standardsactivities.csagroup.org.

5) This Standard is subject to review within five years from the date of publication, and suggestions for its improvement will be referred to the appropriate committee. To submit a proposal for change, please send the following information to [email protected] and include “Proposal for change” in the subject line:

a) Standard designation (number);

b) relevant clause, table, and/or figure number;

c) wording of the proposed change; and

d) rationale for the change.

1 Scope

1.1

This Standard specifies the requirements for mineral oil of petroleum origin for use in transformers, oil circuit breakers, or other electrical equipment (excluding high-voltage cables) requiring a liquid insulating and cooling medium.

1.2

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 by 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.