Two electrical panel brands make inspectors, electricians, and insurers stop cold: Federal Pacific Stab-Lok and Zinsco. Both have a documented history of breakers that fail to trip, and a breaker that won't trip is a fire waiting for an overload. They were installed in millions of homes and plenty are still live. This field guide covers how to identify each one, why the breakers fail, what it means for insurance and buyers, replacement cost, and wording that refers the panel to an electrician without overstating. Document panel findings in HomeInspecto.
Electrical panel field guide
Federal Pacific and Zinsco panels: an inspector's field guide
Two brands, one defect at the core — breakers that may not trip when they should. Here is how to spot each, what fails inside, and how to write it up.
- Federal Pacific "FPE" or "Stab-Lok" labels, red or orange breaker tips
- Zinsco "Zinsco" or "GTE-Sylvania", multi-colored handles, flat aluminum bus
Why these two panels matter
A circuit breaker has one job: trip and cut power when a circuit overloads or shorts. Both of these brands have documented failure modes where the breaker doesn't do that. The wires keep heating, the insulation can melt, and a fire starts inside the wall. It is a latent hazard — a panel can sit for years with no sign of trouble and still carry the risk, which is why many electricians treat them as replace-on-sight rather than monitor.
Federal Pacific Stab-Lok
Made from the 1950s into the 1980s and installed in millions of homes. The defect is in the Stab-Lok breakers.
The failure mode
Stab-Lok breakers fail to trip under overload or short-circuit conditions at a rate far higher than comparable equipment — the exact safety function they exist to perform.
How to identify it
Look for "Federal Pacific Electric," "FPE," "Stab-Lok," or "Federal Pioneer" on the cover or directory, and the distinctive red or orange tips on the breaker handles.
Why swapping breakers won't fix it
The company is gone and replacement Stab-Lok breakers are not a reliable fix. The guidance is to replace the panel and its bus, not individual breakers.
A licensed electrician can usually confirm an FPE panel in minutes. See panel documentation in a demo.
Zinsco and Sylvania-Zinsco
Made from the 1950s into the 1970s under Zinsco and GTE-Sylvania names. The failure is in the bus, not just the breaker.
The failure mode
The aluminum bus bar oxidizes over time and the breaker-to-bus connection overheats. A breaker can even look tripped while still conducting power to the circuit.
How to identify it
Look for "Zinsco," "GTE-Sylvania," or "Magnatrip" on the panel, solid green, blue, and red breaker handles, and a flat aluminum bus behind the breakers.
Why it's treated like FPE
Documented house fires trace back to Zinsco bus failures, so electricians and insurers put it in the same replace category as Federal Pacific.
Don't rely on a breaker's position alone — a Zinsco breaker can mislead. Capture the bus and labels in HomeInspecto.
Others worth flagging
Two brands dominate the conversation, but a few more belong on the watch list for the same reason — documented trip-reliability concerns.
- Challenger. Grouped with FPE and Zinsco by many carriers and inspectors for breaker reliability concerns.
- Relabeled units. Stab-Lok-type breakers have been sold under later names, so a newer label doesn't always clear the concern.
When the brand is uncertain, that itself is worth noting for an electrician to resolve. See how uncertainty is logged in a demo.
Get the panel on the record, properly
Photograph the label, the breaker handles, and the bus, tag the brand, and refer it out — a report a buyer can hand straight to an electrician or carrier.
Insurance, buyers, and cost
These panels move deals and policies, so buyers need the practical picture alongside the safety one.
- InsuranceCarriers commonly decline, non-renew, or require replacement before they'll write a policy.
- BuyersA documented panel is a routine negotiation point, often handled with a replacement credit at closing.
- Replacement costA straight panel swap commonly runs about $2,000 to $4,500, with $1,000 to $2,000 more if a service upgrade from 100 to 200 amps is included.
Point buyers to a licensed electrician for the firm number rather than quoting one. Attach the referral to the record in HomeInspecto.
How to word it in a report
The panel is never recalled, and you aren't an electrician, so the wording threads a careful line: name the brand, state the documented concern, and refer it out.
A phrasing that holds up
"The main panel is a Federal Pacific Stab-Lok, a brand with a documented history of breakers failing to trip. Recommend evaluation by a licensed electrician."
- Name the brand and note how you identified it — label and breaker style.
- State the documented concern factually, without predicting a fire.
- Recommend a licensed electrician for evaluation and any replacement.
- Don't call it recalled — these panels were never formally recalled — and don't quote a repair price.
Factual, photographed, and referred out is the record that protects everyone. See the panel templates in a demo.
How HomeInspecto handles panels
Panel brand pick-list
Tap FPE, Zinsco, Challenger, or other, so the brand is captured consistently every time.
Label and bus photos
Prompts for the cover label, breaker handles, and the bus — the shots that confirm the call.
Built-in referral wording
Neutral, electrician-referral language that states the concern without overstating it.
Uncertainty flag
Mark a panel whose brand can't be confirmed, so an electrician knows to verify.
Carrier-ready export
A clean report a buyer can forward to insurers or an electrician the same day.
Record per property
Every panel finding stays on file for the re-inspection after replacement.
Consistent, photographed, defensible. Book a demo on your own workflow.
Frequently asked questions
Why is a Federal Pacific panel dangerous?
Its Stab-Lok breakers have a documented history of failing to trip during an overload or short — the one thing a breaker must do. When they don't, the circuit keeps heating and can start a fire. See how it's documented in a quick demo.
How do I identify a Federal Pacific or Zinsco panel?
Federal Pacific panels read "FPE," "Stab-Lok," or "Federal Pioneer" with red or orange breaker tips. Zinsco panels read "Zinsco" or "GTE-Sylvania," with multi-colored handles and a flat aluminum bus. A licensed electrician can confirm quickly.
Can I just replace the breakers?
No. For Federal Pacific, replacement Stab-Lok breakers aren't a reliable fix and the guidance is to replace the panel and bus. Zinsco's problem is in the bus itself. Document the whole panel for the electrician — start a free trial.
How much does it cost to replace one?
A straight panel swap commonly runs about $2,000 to $4,500, with another $1,000 to $2,000 if the service is upgraded from 100 to 200 amps. Refer buyers to a licensed electrician for a firm quote.
Were these panels recalled?
No. Neither brand was formally recalled, which is exactly why wording matters — state the documented concern and refer to an electrician rather than calling it recalled. See the report wording in a demo.
Name it, shoot it, refer it
Turn every problem panel into a clean, referable record
Brand pick-lists, label and bus photo prompts, and neutral referral wording — so a flagged panel is documented the way buyers, electricians, and carriers trust.
