Help... I was sleeping in the middle of the night and all of a sudden my
UPS (uninterrupted powered supply) started to beep, I thought it was normal
power interruption but after I while it didn't go away. So I went to
basement and checked, my Bedroom fuse has tripped.

Now, here is something interesting. My bedroom is equipped with a special
fuse called "AFCI" (by Siemens) 15A. Something like this:
http://www.sea.siemens.com/reselec/product/rzafci.html I reset by pushing
the handle and everything worked again!!!!! Then, I pressed the "test"
button, it tripped and I assumed that's normal, right?

My questions a

1. What causes the fuse to tripped all of a sudden???? doesn't make sense
when I was sleeping.

2. Why is this special fuse in my bedroom? When I bought the house, I
thought the builder guy told me it is for bathroom plugs GFCI protection.
Apparently it is not, because when the fuse was tripped my night light was
still on in my bathroom.

3. Does that mean my bathroom is not GFCI protected! That's not good..
should I do something?

Please help...................