1. Scope

1.1 This Standard covers the details of construction and tests for explosion-proof enclosures for electrical equipment to be used in Class I, Division 1, Groups A, B, C, and D hazardous locations and in gaseous mines in accordance with the Rules of the Canadian Electrical Code, Part I and the requirements of CSA Standard CAN3-M421-M85.

1.2 Other Standards for hazardous location equipment covering specific types of equipment shall take precedence over this Standard.

1.3 Unless otherwise marked, this Standard applies to enclosures intended for use in ambient temperatures of
(a) -50 to +40 degrees C for Class I, Groups A, B, C, and D;
(b) 0 to +40 degrees C for gaseous mines;
(c) an oxygen concentration of approximately 21% by volume; and (d) a pressure of not more than 106 kPa