FPE Stab-Lok Box And Breaker Information – Part 2

by Jon Bolton

Editor’s Note: Part 1 was in the October 2017 issue of the Metro.

“Rule of Six”

Electrical standards require that there be no more than six motions to terminate all power to a house. Some Federal Pacific Electric (FPE) panels have a "Rule of Six" configuration where there is no main breaker. This configuration is less expensive but may also provide even less protection. In a panel that does have a main disconnect, the main serves as a secondary back-up breaker, should one of the other breakers fail. If there is no main breaker, then this feature is eliminated.

Because we already have breakers that are prone to failure, this type of configuration has and "unacceptably high probability" of having one or more circuits completely unprotected. The current flow would now be only limited by the transformer on the utility pole which could be 1,000 amps or more!

My personal home had this very configuration. On the day I wrote this article, I purchased a new panel and breakers. Expensive, yeah, but to protect the three most important people in my life, it's a drop in the bucket. I purchased (with the guidance of my electrician) the box, breakers, SEC cable and a GFCI breaker from Home Depot for $200! It's the labor that'll run you about $800!

Engineer J. Aronstein citied an example of a close call with FPE. It was from a family who had replaced their FPE panel because of information like this that they had read on the Internet. After removing the panel and breakers, they found that the dryer circuit had jammed internally in the closed position (current flowing). If there had been a short circuit or overloading situation on that circuit, the results could have been deadly. Upon further testing, two other breakers in this same panel failed during live tests. All this from a panel that looked fine from the front!

Another design issue with some FPE boxes is how breakers fit onto the bus bars. Most plug-in type breakers fit with their jaws parallel over the bus bar. FPEs are just the opposite in that the prongs fit in such a manner that minimizes metal contact. If breakers are loose fitting like many FPE ones are, lack of contact pressure and small contact area will combine to produce arcing and overheating. FPE bus bars have slots in the bus bars that accept different types of breakers. These slots are "E" and "F" slots. Sometimes people can force an E type into an F type hole and also have a loose connection.

Some people are familiar with the CPSC press release that said that the Commission had insufficient data to accept or refute FPE’s position and that they did not have  enough money to continue testing or to continue paying for the attorneys in its legal battle with FPE. They figured it would cost several million dollars to continue testing and gather all data when their yearly budget was all of $34 million. However, testing was terminated by CPSC in 1983, and I quote, "Commission testing confirmed that these breakers fail certain UL calibration test requirements." The Commission actually suggested that everybody keep an eye on your service panel /breakers.

The site, says:

"The Commission's admonition to avoid overloading circuits is and to turn off and have devices examined which seems to be creating a problem is a poor substitute for reliable, automatic over current protection." At some point after 1982, UL "delisted" most, of the FPE protective devices stemming from the parent company's own admission that the UL listing had been secured by "deceptive means."

If your home inspector indicates that your FPE panel should be fully evaluated by an electrician, there is the possibility that the electrician can look and see nothing wrong. However, breakers burn out from the back to the front, not front to back. So, without removing each breaker for examination, you often cannot see if there has been a problem.

Most electricians or electrical inspectors can only observe the breakers and operate the toggle (“they click on and off, OK?”). But without doing live-current functional testing on all the breakers, it is impossible to determine which of the breakers in the panel is defective. Will they all trip properly on electrical overload or short circuit? Electrical contractors and inspectors are generally not equipped to do that type of testing and homeowners or potential purchasers are not likely to have the required budget for extensive specialized testing. In fact, thorough testing would most likely cost far more than changing the panel!

Dan Friedman says, “If I inspected your own home and found that it had a fuse box with 1/3 of the circuits over-fused or had pennies behind the fuses, how long would it be before you had it corrected? Would you sleep tight without it being corrected? Would the fact that your house had not had any problems (burned down yet) because of the over-fusing or pennies trick influence your decision as to whether or not to take corrective action?’

The presence of an FPE panel in the home should be classified as a “Safety Defect.” FPE breakers are primary safety devices of questionable operating reliability. It is not quite correct to call the non-tripping breaker a “fire hazard.” That term should be reserved for the electrical failure that causes ignition. The breaker’s function is to stop certain electrical sequences that could, if allowed to proceed, lead to fire in the building. If an electrical fire develops somewhere in the building, the breaker is supposed to trip and minimize the possibility of fire ignition. If the breaker is defective, fire is more likely to result.

Large main breakers have not been tested enough to prove or disapprove their reliability. Without testing each individual breaker, one pole at a time under overload and short circuit scenarios, it is impossible to determine how your home's system will perform. Such testing would also cost much more than just replacing the box in the first place.


I don’t deny that it is entirely possible that some breakers will perform as intended. However, consider this from, " absence of an explicit statement from the manufacturer and/or the US CPSC indicating that newer stock equipment is defect-free... these panels should be replaced with newer equipment.... If a  fire or other hazard occurs with this device, neither the manufacturer nor the Commission will accept responsibility for losses that you may ensue." This means that you get to pay for it.

Now you know the rest of the story.


Reprinted by Permission. Jon Bolton is a home and building inspector, water intrusion specialist and public speaker. Call 407.678.HOME or visit and Questions or suggestions? Contact Jon Bolton via email at