Hi
We moved into our new house and it already had the cooker installed and we are having exactly the same problem.
It is a Neff U1721 double oven. When I turn the bottom (main) oven on it trips the main on the fuse box and everything in the house goes off.
When I use the top oven its fine.
I am now baffled by this, hence, I am seeking any advice.
Billy
July 2009