=SE= range of transformers have never been tested at temperatures above 60° (ambient temperature).
We have carried out the tests concerning the heating of a transformer carrying a continuous thermal current equal to the nominal primary current according to the EN 60044-1 standards (section 4.6) as you can check in type test documents.

The results of these tests mean that our transformers are in class B of insulation. That is to say a maximum temperature rise of 85° and so maximum limit in working temperature 85° + 50° = 135° where 50° is the upper limit of ambient temperature. All the components have been chosen to withstand this maximum limit.

So the maximum ambient temperature at which the transformers can work for a continuous operation complying with all the requirements is 50°.

In order to guarantee the transformers working at higher ambient temperature the materials of the components (e.g. plastic housing) need to be changed or modify the transformer dimensions.

Note: temperature in terms of °C

For more information, search: files (schneider-electric.com)