The Basics: Why these panels pose a risk
If your home still uses a Zinsco electrical panel or a Federal Pacific Electric (FPE) Stab-Lok electrical panel, it may not be a question of if there’s a problem—but when. These outdated panels have been linked to serious electrical hazards, including electrical fires, due to a fundamental flaw: they often fail to trip when overloaded. At InterlockKit.com, we see customers with these panels frequently. Customers looking to install a generator interlock kit are often surprised to learn that their panel is not just incompatible—it may be outright dangerous.
Zinsco Panels
Zinsco panels, which were widely installed throughout the mid-1900s, have a known track record of failure. One of the most serious issues is that Zinsco breakers can weld themselves to the bus bar, meaning that even when a breaker appears to be “off,” electricity can continue to flow. This can result in overheating, arcing, and in worst cases, electrical fires. Other common problems include corrosion on the bus bars, poor connection between breakers and the panel, and visible melting or burn marks behind the cover.
Federal Pacific Electric Panels
Federal Pacific Electric (FPE) panels, especially those that use Stab-Lok circuit breakers, have an even worse reputation. Studies have shown that up to 60% of Stab-Lok breakers fail to trip when they should. Even more concerning, there is evidence that FPE falsified testing results to obtain UL approval. Homeowners with these panels may experience circuit breakers jamming, inconsistent power delivery, and an increased risk of arc faults—an extremely dangerous condition that can easily lead to fire.
Interlock Kit Compatibility
Using an interlock kit with either of these panels is not just unsafe—it’s potentially catastrophic. Interlock kits are designed to safely allow generator power to backfeed into your home’s electrical panel. However, that safety depends entirely on your breakers functioning properly. If your panel has breakers that don’t trip, then an interlock kit cannot prevent power from flowing into a faulty or overloaded circuit. That’s why we do not recommend installing any interlock kit on Zinsco or FPE panels.
What you should do
We strongly advise replacing these panels before installing a generator interlock kit. A modern, code-compliant panel not only eliminates the risk posed by outdated equipment but also ensures compatibility with our interlock solutions. Upgrading your panel allows for safe, efficient operation and gives you peace of mind knowing your home is protected.
How can I tell if my panel needs to be replaced?
If you’re unsure what kind of panel you have, take a look at the label or name stamped on the inside of the panel door. If you see “Zinsco,” “Federal Pacific,” or “Stab-Lok,” stop and give us a call. Our team can help you identify your panel type and advise you on the safest next steps.
About Interlockkit
At InterlockKit.com, our priority is safety. We’re not just in the business of selling interlock kits—we’re here to help families stay safe during power outages and emergencies. That all starts with a safe, reliable electrical system, and understanding your home’s electrical system. We hope this was informative for you.
