Re: DERATING OF SMDB- temp test as per IEC61439

Home Electrical Engineering Forum General Discussion DERATING OF SMDB- temp test as per IEC61439 Re: DERATING OF SMDB- temp test as per IEC61439

Spir Georges GHALI

Abhilash said:

Dear All,

Kindly support me in the below matter for Type Test  IEC61439

I want to type test (ASTA) 250A SMDB with 4 outoings as per IEC 61439. Our enclosure is IP54 . I came to know that the Incomer MCCB 250A will not withstand the fulload current while temperature rise test since the enclosure is IP54 . 

If any of you have knowledge in this topic  kindly help me friends.



Dear ;


Certainly, you know before that this SMDB should be ” Totally Type Tested ” and ” IP 54 “, so, did you use any Software to design it ( like : Sis-Power  or  Rapsoide  from Schneider Electric, XLPro2 from Legrand ) ? if yes, how this panel is not ” Totally Type Tested  &  IP 54 ” ? Because this Software helps to design the Distribution Panels to be ” Totally Type Tested ” accordignly to your specifications and installed equipments where also ” IP .. ” should be defined. Noting that this Software will choose the suitable metallic enclosure after calculation to Total Losses Powers for all installed equipments and compare it with the Heating dissipation of the enclosure. But if not ?????


By the way, normally we don't ” Dearate ” the Electric Panel, but in your case we optimize the circulated currents ( deacrese ) till the temperature rise to be constant value. Noting that in practice if the variation of temperature after ” 8 hours ” doesn't exceed” 1 K/h ” we can accept the ” Temperature Rise Test “.