This Standard applies to thermal cut-offs (TCO) for voltages up to and including 600 V, intended for the protection of equipment such as electric motors, transformers, fluorescent lighting ballasts, and electric heating appliances to be used indoors in accordance with the Rules of the Canadian Electrical Code, Part I.
(1) Thermal cut-offs function once only and are used for the thermal protection of equipment in which, under fault conditions, one or more parts may reach hazardous temperatures. The equipment need not be designed to generate heat.
(2) The acceptability of a TCO in any particular device depends upon its suitability for continued use under the conditions that prevail in actual service.
(3) A TCO in application is intended to function to prevent unsafe operation of equipment as a result of overheating, which may include conditions at the end of the life of the equipment.
(4) A TCO is a component and, as such, is also subject to the requirements of the applicable CSA Standards of the CE Code, Part II, for the equipment in which it is used.
This Standard also applies to TCO's for use under other than indoor conditions, provided that the climatic and other circumstances in the immediate surroundings of such TCO's are comparable with those in this Standard.
This Standard shall be applied to TCO's in their simplest possible forms (eg, melting strips or wires), provided that molten material expelled during function cannot adversely interfere with the safe use of the equipment, especially in the case of hand-held or portable equipment irrespective of their attitude.
TCO's used under extreme conditions such as corrosive or explosive atmospheres are not covered by this Standard.