You've obviously missed this reply:
I didn't miss it but it is way offtopic, a transformer is built by another company than that builds the product that uses the transformer.
There is no way the transformer company can know what current the end product nominally uses and what current the fuse should blow except the max. the transformer is designed for.
Ergo the transformer company will never calculate the current use of the product in the design in of the thermal fuse and as stated earlier it can not since a thermal fuse is not a current fuse.
So what if wraper's question and all replies to it were off topic? I know it can sometimes be a pain to sift through information to find what is relevant, but I find I often learn a lot from off topic posts. If it were a political or religious rant, then I'd understand it being against the forum rules but it was still vaguely on topic.
Current and thermal fuses both serve similar purposes, they protect against fire, even though they go about it in totally different ways. In the case of an current fuse: its job is to fail open circuit, before the current through the wire causes it to get hot enough to cause a fire. In the case of the thermal fuse: its job is to fail open circuit, before it reaches a dangerous temperature. When the thermal fuse is embedded in a motor or transformer, the windings do not normally need separate over current protection, because the thermal fuse will safely disconnect them before it catches fire. Now, I accept what you said before that too much current could prevent some thermal fuses from operating correctly, so in large transformers (where the short circuit current could easily exceed the thermal fuse's rating for long enough to cause a problem), additional over current protection may be required, but in a small transformer, it's not necessary.
Is it isn't always practical to provide over-current protection to everything. One could argue that inside a mains adaptor, the short piece of cable, from the mains pins, to the transformer, requires over current protection, but where do you stop? There's never any over current protection between the first short piece of cable to the fuse holder in a battery circuit because it's not practical.
What is the rating of that normal fuse? You haven't told the most important part.
It doesn't matter.
It does matter a lot. OP asked what thermal fuse to use, 1A or 10A. If the main fuse is, say, 0.5A, there is no reason to use 10A thermal fuse. if the main fuse is 2A, of course he shouldn't use 1A version.
Yes, I agree. The thermal fuse should have an equal, or greater, current rating than the over current fuse.