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What is a Stab-Lok Circuit Breaker?

Does your home still have a Stab-Lok circuit breaker? These electric panels from the 50s helped new house buyers due to their affordable price range and easy-to-install panels of that time.

Although these are not common in modern homes made after the 90s, if you own a house from the 50s or have inherited an older property, you may come across the Stab-Lok circuit breaker panel.

In this article, we have tried to help you understand the Stab-Lok circuit breaker and how to deal with its different problems.

What is a Stab-Lok Circuit Breaker?

Federal Pacific Electric Inc. of the US produced Stab Lok circuit breakers. These were initially designed to be the primary circuit breakers in residential properties to prevent damage to your electrical network due to overload, short circuits, and any other electricity fault.

This type of electric box was named Stab-Lok due to its design. The breakers of these boxes were “Stabbed” into the botches of the bus bar to make the connections and lock those breaks in their designated places. This was easy to operate and was also a cheaper design. The company mass-produced this type of circuit breaker box during the 50s. Although they were initially designed for residential properties, many commercial properties from that time also had Stab-Lok circuit breakers.

What is the Purpose of the Stab-Lok Breaker?

Stab-Lok was used as a primary circuit breaker. It worked as the main breaker and could shut off the power supply to the whole property if the total electric demand exceeded the permitted limit or there were any other issues in the house’s electric network.

How To Identify Stab-Lok Breakers?

Here are methods to check if your home still has a Stab-Lok breaker box-

1. The Brand Logo

The FPE Company made these boots. Check the circuit breaker box. If it has the logo with the phrases “FPE,” or “Federal Pacific Electric” or “Federal Pioneer ” in any part of it, it is a Stab-Lok breaker box.

Besides the logo, the Stab-Lok circuit breaker box will feature the phrase “Stab-Lok” if it has a stab-lock design.

2. First, Confirm that your Home Uses Breakers.

A circuit breaker panel comes with red colored or colored toggle switches inside the main breaker, The switches usually remain in the “ON ” position.

3. Bus Bar

The bus bar is next to check out; a  metallic strip or bar collects electric power from incoming sources and evenly distributes it to outgoing bases.

But, if you are unfamiliar with electric circuits and systems, it is better to ask for professional help.

Before you open the circuit box, turn off your home’s primary electricity source. Usually, the Stab-Lok boxes come with E or F-shaped bus bars. Simply put, the metallic bars have engravings of shapes similar to the alphabets “E “ or “F. “ It is a distinct feature of the panel box as these bus bar shapes are in the form of the snap holes of the circuit breaker.

What Issues or Concerns are Associated with Stab-Lok Panels?

The Stab-Lok circuit breaker is still controversial due to some unfortunate incidents. These circuit boxes were made of copper breakers and aluminum bus bars. Both metals have different expansion rates due to heat. This often resulted in a loose connection between the h circuit breakers and the panel.

The circuit breakers also did not trip during short circuits or overloads. The excess heat often causes electrical fire accidents, and many homeowners with Stab-Lok Circuit breakers reported house fire incidents. For any circuit breaker box to be deemed safe, the breakers inside the box should trip to its “off” position during overload to prevent accidents.

Another problem with these Stab-Lok circuit breakers is that even if the box is turned off externally, it may remain in one position internally, resulting in high-voltage electric shock, which is fatal for any human.

During the 80s, The Consumer Product Safety Commission consulted Engineer Jesse Aronstein to check the safety of the Stab-Lok circuit boxes.

More than 50% of boxes failed the safety test. Aronstein, paired with Richard Lowry, a statistics professional, published their findings in a research paper. As per the paper, more than 2800 fires happened due to Stab-Lok circuit breakers with damages of $490 million, including 13 unfortunate deaths.

Many independent researchers found that the Stab-Lok circuit breakers had a failure rate of nearly 80%. Certain research with 830 Stab-Lok circuit Breakers installed inside a New Jersey residential complex offered similar results; 70% of these breakers reported trip failure.

In a 2002 class–action lawsuit in New Jersey, judges ruled that Federal Pacific purposefully distributed these faulty circuit breakers even when these were not safe, violating the New York Consumer Fraud Act. The court also said that the company knowingly distributed these panels despite not meeting the minimum safety requirements.

How To Replace Stab-Lok Breakers?

Although it is possible to replace individual breakers inside the FPE Stab-Lok circuit breakers, replacing the whole electrical panel and the circuit breaker box is always better. If the home has wiring from the 50s, it may not come with a grounding wire. In that case, you may need to replace your home’s whole electric panel network to prevent any future hazards.

You can connect with an expert electrician and replace the older circuit breaker with a new box from a different brand with the same amperage.

Stab-Lok Circuit Breaker – FAQs

1. What are the potential dangers associated with Stab-Lok breakers?

Ans: Due to the usage of different metals inside the circuit breaker boxes, Stab-Lok breakers may not trip during overloading or heating, leading to electrical fires and other accidents and even fatal electric shocks.

2. How do we address Stab-Lok breaker issues?

Ans: If your home has a Stab-Lok circuit breaker panel, it is always best to consult an electrical expert as soon as possible to examine this Circuit breaker box and replace the panel.

3. Are Stab-Lok breakers still being manufactured?

Ans: Federal Pacific Electric no longer manufactures these faulty Stab-Lok breakers.

4. How frequently should Stab-Lok breakers be inspected?

Ans: If your home has Stab-Lok circuit breakers, it is always better to get a yearly examination by a certified electrician. But the best solution is to replace the whole panel and box.

5. Can Stab-Lok breakers be repaired?

Ans: Although individual breakers of a Stab-Lok circuit breaker box can be replaced, it is not a safe option. So, replacing the whole box with a new and safer circuit box is better.


Stab-Lok Circuit Breaker boxes for Federal Pacific Electric were popular during the 1950s due to their cheaper price. However, these boxes have a significant safety concern as they did not pass the safety test, and many accidents were reported in homes with these boxes. If you own an older home designed during the 50s to 90s, it is better to check if it has a Stab-Lok circuit breaker box. If it’s present in your home, the best possible solution is to replace the whole panel and install a new, safer, modern circuit breaker box.

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