This regular looking electrical panel looks like all the other panel boxes you see - except that it has a history of failures - I mean houses burning down failure! This panel is a Federal Pacific Stab-Lok. This brand is well documented to have a high rate of failure and is a fire hazard. When I saw this in one of my recent inspections I had to recommend further evaluation by a qualified electrician. There are those that say the panel should just be replaced with a brand that does not have a history of failure. For further information on these panels please type Federal Pacific Electric into an internet search engine.
Here is a URL to one engineer's paper:
This is another place to start you thinking about this safety hazard: