Information to assist in evaluating the effect of solar radiation on outdoor metal enclosed switchgear including metal-enclosed bus and control switchboards is provided in this guide. Specific data in the form of a continuous current capability factor for specific maximum monthly normal temperatures at the installation location to adjust the continuous current capability of outdoor metal-enclosed switchgear to the solar radiation condition required are given in this guide. Examples of maximum monthly normal temperatures along with sources for data for the US and for Canada are also presented in this guide.

The guide provides data in current-temperature and tabulation form for use in evaluating the effect of solar radiation on outdoor switchgear. The guide applies to switchgear as defined by IEEE Std C37.20.1, IEEE Std C37.20.2, IEEE Std C37.20.3 and IEEE Std C37.20.9; control switchboards as defined by IEEE Std C37.21; metal-enclosed bus as defined by IEEE Std C37.23; medium-voltage ac controllers as defined by UL 347; motor control centers as defined by UL 845; switchboards as defined by UL 891; and medium-voltage air-insulated circuit breakers for outdoor application defined by IEEE Std C37.04.

The purpose of this guide is to provide a reference for engineers to use to enable switchgear to perform satisfactorily and have a reasonable life expectancy when operated within the temperature limits established; for example, in the following standards: — IEEE Std C37.20.1™ — IEEE Std C37.20.2™ — IEEE Std C37.20.3™ — IEEE Std C37.20.9™ — IEEE Std C37.21™ — IEEE Std C37.23™ — UL 347 — UL 845 — UL 891 — IEEE Std C37.04™ These standards specify the temperature rise limits above a standard (maximum) ambient temperature of 40 °C. This is satisfactory for indoor applications where the temperature rise is due entirely to heat release (internal losses). In outdoor...