Preface
This is the third edition of C22.2 No. 157 (now CAN/CSA-C22.2 No. 157) of a series of Standards issued by the Canadian Standards Association under Part II of the Canadian Electrical Code. It supersedes the previous editions published in 1979 and 1987.
The major changes in this new edition include added definitions for stand—alone and non—stand—alone shunt diode barrier assemblies, control drawing, and entity evaluations; the reorganization of clauses covering stand—alone and non—stand—alone shunt diode barrier assemblies; and renumbering of the clauses covering spacings. Also added are new clauses under markings, associated and intrinsically safe apparatus and the spark ignition curves as well as a table for marking symbols.
For general information on the Standards of the Canadian Electrical Code, Part II, see the preface of the latest issue of CSA Standard C22.2 No. 0, General Requirements--Canadian Electrical Code, Part II.
This Standard was prepared by a Subcommittee of the Technical Committee on Consumer and Commercial Products under the jurisdiction of the Standards Steering Committee on Canadian Electrical Code, Part II and was formally approved by these Committees. It has been approved as a National Standard of Canada by the Standards Council of Canada.
Scope
1.1
This Standard specifies tests for the testing of non-incendive electrical equipment and the details of construction and tests for intrinsically safe electrical equipment for use in the following hazardous locations in accordance with the Rules of the Canadian Electrical Code, Part I, and CSA Standard CAN3-M421:
(a) Class I, Groups A, B, C, and D;
(b) Class II, Groups E, F, and G;
(c) Class III; and
(d) gaseous mines.
1.2
This Standard specifies the design and constructional requirements and test procedures for equipment and parts of equipment intended for use in hazardous locations and also for associated equipment intended for use in safe locations.
1.3
This Standard applies to equipment for use in normal atmospheric conditions.
1.4
Equipment specified for use in other than normal atmospheric conditions may be subject to additional investigation.