Federal Pacific and Zinsco panels, and what to do about them

Published 2025-11-08 · 6 min read

What the problem is

Both brands have a documented history of breakers that fail to trip under fault conditions. That is a specific and unusual failure mode. A breaker that trips when it should not is annoying. A breaker that does not trip when it should removes the protection the whole system depends on.

The failure is not visible. A Federal Pacific Stab-Lok breaker that will not trip looks exactly like one that will. You cannot tell by inspection, which is why the response is replacement rather than testing.

How to identify yours

Open the panel door and look at the label inside it, not at the breakers. Federal Pacific panels are usually marked Federal Pacific Electric or FPE, and the breakers often say Stab-Lok. Zinsco panels may be labelled Zinsco, GTE-Sylvania or Sylvania-Zinsco, and the breakers are frequently coloured.

You do not need to remove the cover. If the label is not on the door, photograph what you can see and send it to an electrician.

What replacement involves

In most cases the branch wiring is fine and only the panel changes. The old panel comes out, a new load centre goes in, and every circuit is relanded and labelled. It is usually a single day with power off for part of it.

It becomes a larger job when the service size is also being increased, or when the meter can and mast need replacing at the same time. Many homeowners take the opportunity to do both at once, since the disruption and the utility coordination overlap.

The insurance angle

Insurers in Florida increasingly ask about panel brand at renewal or when writing a new policy. Some decline, some surcharge, some require replacement within a set window. If your renewal questionnaire suddenly asks about your panel, this is why.

Keep the permit and the inspection sign-off from the replacement. That paperwork is what satisfies an insurer or a buyer, and reconstructing it later is a nuisance.