Federal Pacific Electric Stab Lok Panels in a gangFPE Sub Panels: Risk Assessment of Federal Pacific Electric FPE Stab Lok Sub Panels vs Main Panels

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This article discusses and compares the hazards of Federal Pacific Stab-Lok® Electric Main Electrical Panels compared with Sub-Panels in buildings, and addresses the question of amount of risk reduced if only the main disconnect or main FPE panel is replaced.

This information assists building inspectors, home buyers, home owners, electricians exploring hazards associated with Federal Pacific Electric Stab-Lok® circuit breakers and service panels.

Our page-top photo shows a main FPE Stab-Lok® electrical panel and service disconnect (at left) and three FPE Sub-panels.

Replacement FPE Stab-Lok® circuit breakers are unlikely to reduce the failure risk of this equipment. We recommend that residential FPE Stab-Lok® electrical panels be replaced entirely or the entire panel bus assembly be replaced, regardless of FPE model number or FPE year of manufacture. We do not sell circuit breakers nor any other products.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Comparing the Hazard of Federal Pacific Stab-Lok® (FPE) Electric Sub-Panels vs. Main Panels & Main Disconnects

Photograph of a typical Federal Pacific Electric Stab-Lok® electric panel cover and door label. More
FPE identification photographs are listed below.


Our photo (left) shows an FPE Stab-Lok® main electrical panel. Multiple main disconnects are in the top section of the panel.

[Click to enlarge any image]

Question: Do FPE Stab-Lok® Sub-Panels Present as Much Risk as the Main FPE Panel?

A commercial insurance broker in the Western U.S. placed insurance on a hotel built in 1964.

In 2000 the Main Electrical Panel, an FPE Stab-Lok® unit, was replaced with a unit made by Murray.

The hotel includes nine remaining “sub-panels” made by FPE

The insurance company that we placed the hotel with has a policy that they do not accept properties with FPE panels.

Our question is: Do the FPE sub-panels present as much risk as the main FPE panel?

It seems in a perfect world the hotel would change out all sub-panels, but at least they have upgraded the “main” panel. Do you think this is an acceptable compromise? - (Anon.)

Reply: Replacing the Main FPE Panel reduced risk but significant risks remain with the FPE Subs. Here are some of the risk factors:

A competent onsite inspection by an expert usually finds additional clues that help accurately assess the actual electrical hazards that would not be included whatsoever in a theoretical discussion. For example there could have been a history of failures to trip, overheating, or unusual circuit usage on specific circuits serving particular areas of the hotel, or there may be other significant electrical hazards (or other hazards) outside of the FPE topic that also merit urgent attention.

That said, here are some things to consider in assessing the degree of risk that has been achieved by replacing only the main FPE electrical panel:

  1. Replacing the main disconnect & panel did reduce risks: We agree that having installed another brand main panel has reduced the overall hazard for the building (if an FPE was in that role before), but
  2. The absolute risk for a given or individual FPE sub-panel or breaker or a circuit wired from such a breaker actually depends in part on the circuit's usage. An FPE breaker does not initiate a hazard or failure - it simply fails to protect the circuit from overheating (and fire) if an overcurrent or similar hazard occurs. This behavior is detailed in FPE Technical Report - Independent Research 2007
  3. Problem history: It is a dangerous error to presume that if no problem has occurred to date, the wiring and breakers are safe. A problem could have occurred previously that resulted in a much greater chance that at a subsequent overcurrent the breaker won't trip (that phenomenon was demonstrated in independent testing);
  4. Changes in circuit use are not predictable: even if a problem never occurred on a circuit, simply a change in use (someone plugs in an electric heater) can and probably will change the risk level.
  5. Risk for similar circuits in similar use: Our opinion is that for two circuits of similar level of usage, the hazard is similar, regardless of whether or not the circuit is wired out of a main or a sub panel. Here too, hidden circuit differences, such as a poor connection, would change that picture.
  6. Two Pole breakers: It would be fair to argue that because the FPE no-trip problem is more severe on 2-pole breakers, and as a main panel would have at least one 2-pole breaker (the mains) while a sub panel that contains less than 6 switches may not have a main switch and so may not have a 2 pole switch, then the absolute risk might be lower, but that is in my opinion a "constructed" and is too theoretical an argument to be safe - if for no other reason than it does not consider circuit usage.
  7. Risk of incomplete electrical repairs: As a general opinion on electrical safety, we are very nervous about "partial" repairs of electrical hazards because of the risk that building occupants or management, thinking that an unsafe condition has been addressed, may ignore warning signs of an impending disaster. In sum, the experience of insurers with FPE failures and perhaps their review of the research has indeed led some companies to ask that FPE panels be replaced.
  8. Can't afford or need to stage-in FPE panel replacements? As a sub panel replacement is likely to be under $1000. that cost compared with a fire is surely small and reasonable. Some suggestions for people who cannot afford to immediately replace an FPE Stab-Lok® electrical panel are found at CAN'T AFFORD A NEW ELECTRIC PANEL?


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