Open the door and look at the breaker handles
Federal Pacific Stab-Lok breakers have red-tipped handles and the brand name is usually on the inside of the door. Zinsco (sometimes sold as GTE-Sylvania) breakers are thin, color-coded in blue, red and green, and slide onto a bus bar you can often see between them.
Why they matter
Both designs have a documented history of breakers failing to trip under overload, which is the one job a breaker has. Zinsco bus bars also corrode and the breakers weld to them. Home inspectors in Santa Clara County flag both routinely, and some insurers ask for replacement.
What replacement involves
A like-for-like panel swap in the same location, usually a 200A service since you are already doing the work. PG&E has to release the meter, the city inspects, and the house is without power for most of one day. Three to five weeks start to finish, almost all of it waiting on PG&E.
What we do on the site walk
Photograph the panel and label, test a few breakers, read the meter and service drop, and run a load calculation for what you plan to add. You get a written scope the same day. Pricing follows the site walk, because no two services are the same.
