(thermal ambient) is the recommended maximum environmental thermal limit for the safe continued operation of an electrical device. The ta rating can be found on the rating label and installation sheet, which is located on the relevant product web page. Typically, you will find ta ratings of 25 degree C for Interior products, where ta ratings of up to 50 degree C can be found for exterior products. Operating products beyond their designed ta limit is not recommended as it will stress the product components beyond their rated limits, resulting in reduced product performance or premature failure.