What is the problem with Federal Pacific electrical panels?

The problem with Federal Pacific electrical panels, particularly Federal Pacific Electric Stab-Lok panels installed in millions of homes from the 1950s to 1980s, is that they have a well-documented high failure rate and safety hazard where circuit breakers fail to trip during overloads or short circuits, creating fire risk. Independent testing by experts and the Consumer Product Safety Commission found that Federal Pacific Stab-Lok breakers failed to trip in up to 60 percent of overload tests, meaning they would not shut off power when they should, allowing wires to overheat, melt, and cause fires. The panels also have design flaws including poor bus bar connections, breakers that appear off but are still energized, and breakers that can fall out of the panel. Federal Pacific Electric Company went out of business in the 1980s after lawsuits, and these panels are no longer UL listed and are considered unsafe by most electricians and home inspectors. Many insurance companies refuse to insure homes with Federal Pacific panels, and electricians recommend immediate replacement with modern panels from Square D QO, Eaton, or Siemens. If you have a Federal Pacific panel, you should have it inspected by a licensed electrician and plan to replace it, as it is considered one of the most dangerous panel brands ever installed.