C22.2 No.23-1980

1. Scope 1.1 This Standard applies to stationary, electrically heated, warm air, central furnaces of the forced-air type that discharge air into ducts extending not less than 30 inches downstream from the heater elements, for use on nominal system voltages of 600 V and less, designed to be used in non-hazardous locations in household, commercial, and industrial applications, in accordance with the Canadian Electrical Code, Part I. Note: The Canadian Electrical Code, Part I, provides a limitation of 150 volts-to-ground for space heating and air conditioning equipment, with certain exceptions given to equipment for installation in apartments and similar multi-family dwellings. 1.2 This Standard does not apply to duct heaters, unit heaters, or any accessories such as air-cooling equipment, electronic filters, or humidifiers that may be provided as optional parts of a complete central furnace. 1.3 This Standard does not cover the construction of ducts of a heating system with which a central furnace is employed. 1.4 The term central warm air furnace includes the following types of generally recognized central furnaces: horizontal, up-flow, down-flow, and in-line.