Why some panels get flagged
A breaker's job is to shut off power when a circuit is overloaded or shorts. Some panel models from the 1950s through the 1980s have long track records of breakers that don't reliably do that, or of connections that loosen and overheat.
Federal Pacific Stab-Lok
Federal Pacific Electric panels with Stab-Lok breakers were installed in millions of American homes. Independent testing and years of field reports suggest the breakers can fail to trip under overload. Many home inspectors call them out, and some insurers ask about them.
Zinsco
Zinsco panels, including some sold under the Sylvania name, have a history of breakers that can fuse to the panel, which means they may not shut off when they should. They're also frequently flagged on inspections.
Other signs a panel is due
Even a well-regarded panel can age out. Rust, scorch marks, a warm cover, a buzzing sound, or breakers that trip often are all reasons to have it checked.
What we recommend
If you have a flagged panel, replacing it is usually the right move. Most replacements are done in a single day, including the permit and inspection.