Hello, Following your question, please find some inputs to help you in your specification: ambient temperature 40°C to low voltage switchboard installation. Based on the standard to the type of Assembly, IEC61439-1/2 the reference to the external ambient temperature is 35°C, so your personal constrain is not so high and so far, I don’t know if your Assembly switchboard is compliance with IEC61439, but I hope so, if it is the case the Original Manufacturer shall be able to produce the rated current at different temperatures, and to different type of IP level which influence the convection and so the rating of the component installed into the enclosure. The aim of IEC61439 is to propose an Assembly with a high level of Electrical Safety and Power availabily. That mean, when you get an IEC61439 Assembly you get verified performances coming from an Original Manufacturer responsible of the Design verifications and from an Assembly Manufacturer responsible of the routine verification. The sums of those verification drive to an Assembly equipment with performances verified and certified to the full life of usage of an Assembly. For example, the IEC61439 ensure the thermal stability and reliability, the rated current and the short-circuit withstand stress, all the clearances and creepage distances to the insulation coordination. This high level of performances is the guarantee to avoid safety risk to people protection and loss of service continuity. I use the opportunity to encourage you to have a look on the different blog articles referring to the same kind of topics most precisely: https://blog.schneider-electric.com/power-management-metering-monitoring-power-quality/2018/07/10/with-iec-61439-assure-thermal-stability-and-reliability-in-low-voltage-electric-switchboards/ And a small video https://www.bing.com/videos/search?q=61439+schneider+electric+india&&view=detail&mid=5FDBFF3CA4F013E51F625FDBFF3CA4F013E51F62&&FORM=VRDGAR Best regards, LV system inst. expert - Standardization officer pascal.lepretre@se.com
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