What ambient temperatures are power distribution transformers designed to operate?

The power distribution transformers normal ambient temperature limits are -25ºC to +40ºC as defined within IEC 60076 Part 2.

With regard to cooling of air-cooled transformers the temperature conditions at the intended installation site should neither exceed :
+30ºC monthly average, of the hottest month
+20ºC yearly average.

The above figures are based on the transformer installation site being  less then 1000m above sea level.

If the transformer is required to operate at higher ambient temperatures and/or higher altitudes, then the transformer would need to be designed specially for the intended application.

Released for:Schneider Electric UK