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 Zinsco panels and Zinsco breakers are electric panels and circuit breakers that were installed in millions of homes in the United States mostly in the 1960’s and 1970’s. Zinsco panels are also known/labeled as GTE-Sylvania, Challenger and Kearney electric panels. These panels have some inherent problems that can make them unsafe.

In this article, I will explain why Zinsco panels and Zinsco breakers are unsafe. I will explain how to identify these panels, and will give you some guidance about what to do if you have one of these panels in your home or in a home that you are considering purchasing.

What is the Problem with Zinsco Electrical Panels?


zinsco electrical panel- aluminum busbarZinsco Electrical panels have an aluminum busbar. A busbar is the part of the panel that the individual breakers attach to when the breakers are installed in the panel. It is the busbar that carries the electricity and transfers it to the breakers, then to the wires and then to the individual components in the home. Aluminum is subject to corrosion, and corrosion increases electrical resistance which causes more heat to be generated as electrical current flows. Once corrosion starts to form on the busbar, heat will be generated, and then corrosion and heat will continue to increase over the months and years. Eventually, the connection of the breaker to the busbar can get hot enough that the breaker essentially melts to the busbar.

The heat generated by the poor contacts can actually cause the contacts in the breaker to fuse together.

At this point, it is very likely that the breaker will no longer trip if a circuit gets overloaded causing an over current situation.

Electrical breakers are designed to shut off the flow of electricity to a circuit in the event of an overloaded circuit, meaning that too much current is flowing. If too much current flows through a wire, then the wire will heat up, and a fire can result. A tripping breaker helps keep a home safe by opening to shut off the flow of electrical current if too much current is flowing through one of the circuits in the home. Therefore, it is essential that breakers be able to trip when a circuit is overloaded. Some studies have shown that as many as 20% to 30% of Zinsco breakers failed to trip when exposed to an over-current event.

Another problem with Zinsco breakers is that occasionally, when the breaker is tripped or manually flipped to the OFF position, the breaker may not actually be off and will continue to send electricity out to the wire connected to it. This can be an electrocution hazard if someone shuts off the breaker to do some maintenance and touches a live wire thinking the circuit is dead. On the other hand, if a breaker trips due to over current, but is still letting electrical current flow out to the circuit, it can result in a fire as this high current continues to flow, causing the wire and breaker to heat up.

How to Know if You Have a Zinsco Breaker Panel in Your Home

Most Zinsco panels were installed in the 1960’s and 1970’s. The company eventually went out of business, but many of the panels that had already been manufactured were installed. I did a computer search of about 3700 of my inspection reports, and found that I reported Zinsco panels in 38 of those homes, that means that in this area, they are in about 1% of the homes that I have inspected.

I advise you to look at the electric panel in your home to see if it is a Zinsco panel. (While you’re looking, check to see if it is a Federal Pacific “Stab-Lok” Breaker Panel as these have some safety issues as well. See my blog about Federal Pacific “Stab-Lok” Breaker Panels.)

Zinsco Panels are normally easy to recognize. They are typically labeled with the words Zinsco, Sylvania, GTE, Kearney, or a combination of these words. You should also see the common colorful breakers (they are often red and green).

Below are some photos to aid in determining if you have a Zinsco panel in your home.    

zinsco panel
zinsco panel
zinsco breaker panel
zinsco breaker panel

What Should You Do if You Have a Zinsco Breaker Panel?

A Zinsco panel in your home will increase the fire risk in your home, and your home will certainly be safer without one, but it is not mandatory that they be replaced. One factor to consider in determining whether or not to replace the panel is the level of risk that you are comfortable accepting. (Keep in mind that we all accept a degree of risk in almost everything we do every day.)  

The best person to decide whether a Zinsco panel needs to be replaced in your home or in the home that you are considering purchasing is you  – after getting all of the information that you can get. Probably your best source of information is consulting with a licensed electrician and having them evaluate the panel. With this information in hand, you can make an informed decision that will be the best decision for you and your family.

I would NOT purchase a home or live in a home that has a Zinsco panel without at least having the panel evaluated by a licensed electrician

Here is one recommendation that I will make. If you are purchasing a home with a Zinsco panel, I would definitely recommend that you ask the seller to replace the panel because, if they replace it, you would be out no money and the home would definitely be safer. If the seller will not replace the panel, or if you already own a home with one of these panels, then the question comes back to your level of risk aversion and your electrician’s evaluation of the panel.

I hope that this information is helpful to you and helps you in your decision making about the Zinsco panel in your home. If you have any questions about Zinsco, Federal Pacific panels or home inspections in general, please feel free to contact us.

© 2020 Mike Morgan

This article was written by Mike Morgan, the owner of Morgan Inspection Services. Morgan Inspection Services has been providing home, septic and well inspection services throughout the central Texas area since 2002. He can be reached at 325-998-4663 or at No article, or portion thereof, may be reproduced or copied without prior written consent of Mike Morgan.

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