Preface 

This is the tenth edition of CSA C22.2 No. 24, Temperature-indicating and -regulating equipment. It is part of a series of Standards issued by CSA Group under Part II of the Canadian Electrical Code. It supersedes the previous editions, published in 2015, 1993, 1987, 1981, 1972, 1965, 1963, 1955, and 1935. The following revisions have been made in this edition (clause numbers refer to this edition of the Standard unless otherwise noted): 

 definitions added to Clause 3; 

 Clause 5.1.9 revised to include specified parameters; 

 Clauses 5.2.1.6 clarification of acceptance criteria; 

 Clause 5.6.2.4 added; 

 new Clause 5.30.3 included to improve safety measures; 

 Clause 5.32 added to include battery powered controls; 

 Clause 5.33 added for safety of electronic disconnection controls; 

 new Clause 6.14 added for clarity; 

 new Clause 6.15 included new battery requirements; 

 Clause 7.8 clarified; 

 Clause 7.9.2.3 revised testing requirements; 

 Clause 7.10.11 added testing requirement for electronic disconnection; 

 Clause 7.27.2 removed definition of cheesecloth to avoid repetition; 

 Clause 7.27.3.2 clarified; 

 new clauses added to testing in Clause 7: Clause 7.30 Battery short-circuit test; Clause 7.31 Electronic disconnection test; and Clause 7.32 Running overload test; 

 Clause A.4.3 references updated; 

 Table 6 revised (Items 2, 7, and note **); 

 Table 10 updated (Items 3, 6, and note ); 

 Annex C (normative) added; and 

 Annex D (informative) added. The use of extracts from ISO 23552-1:2007, Safety and control devices for gas and/or oil burners and gas and/or oil appliances - Particular requirements - Part 1: Fuel/air ratio controls, electronic type, was copied by CSA Group with the permission of the Standards Council of Canada (SCC) on behalf of ISO. The standard can be purchased from the national ISO member in your country or the ISO Store. Copyright remains with ISO. This Standard is considered suitable for use for conformity assessment within the stated scope of the Standard. 

Scope 

1.1 This Standard applies to temperature-indicating and -regulating equipment* for voltages up to and including 600 V between conductors and intended for general household and industrial use in nonhazardous locations, in accordance with the Rules of CSA C22.1, Canadian Electrical Code, Part I (CEC, Part I). * For convenience, the shorter term equipment is sometimes used in this Standard. 

1.2 This Standard applies to electrical control equipment for air conditioning, heating, lighting, cooling, refrigeration, cooking appliances, safety controls, and other similar appliance controls. 

1.3 This Standard does not apply to dimmers and extra-low-voltage equipment other than safety controls and room thermostats with heat anticipators. 

1.4 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.