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™.