Having seen a number of "electrical" fires, i.e. the source of ignition was electricity, the causes I've seen mostly go from miss-use to DIY repairs.
Portable heaters on extension cords or too close to cumbustables.
Light bulbs against combustables.
NM cable tapped onto knob & tube, with some tape wrapped around the joint.
Panels with different brands of breakers jammed in, they almost fit.
Biggest cause of failures: Users and hack repairs.
I still remember the guy that swore he did not put a penny behind a fuse, that over loaded and caused a fire. He said, My momma told me to never use a penny behind a fuse. That's why I used a nickle.
It is easy to put 20 and 30 amp breakers in where those 15's were. Those will be the fires of the future.
