The maximum temperature rating for RTD’s is based on two different factors. First is the element material. Platinum RTD’s can be used as high as 650ºC (1202F).
Other materials are much lower in temperature rating and vary from material to material. The other determining factor for temperature rating is probe construction.
There are construction considerations used in each of these different styles making them ideal for use in each of those ranges. No-one style is good for all ranges.