I'm kind of embaressed now... It turned out that the problem was in power transformer which I had recently upgraded (this is rated 600VA). It blew my flat's fuse even with no load connected at all. I didn't know that I have to design a soft start for a transformer bigger than 300VA...
Made a soft start circuit in primary winding and it's fine again.
Thanks everybody for help and comments.
Made a soft start circuit in primary winding and it's fine again.
Thanks everybody for help and comments.