Zinsco Electrical Panels

Zinsco Los Angeles

One of the complications of a home inspection is not everything is black and white. There are gray areas, and one of the major gray areas is the Zinsco Electric Panel.

Zinsco History

Zinsco logo variation
One of the many Zinsco logo variations

Zinsco was established as a brand in 1943 when the son of the Zinsmeyer Company took over his father’s electrical business. Zinsco went on to be a very popular brand of electrical panels for several decades, often labeled with the name “Magnatrip” on the cover. There were briefly rebranded GTE-Sylvania in the late 1970s and early 1980s. Production stopped in 1981 but existing manufactured panels were still installed for several more years.

The US faced several copper shortages, during WWII, the Korean War, and again in the 1960s. Due to the on and off again copper shortages, Zinsco switched to using aluminum on their bus bars.

Zinsco Potential Problems

A common Zinsco panel
A common Zinsco panel

Over time, electricians have discovered some of the aluminum bus bars created unforeseen problems. Some problems include theĀ aluminum corroding to the breakers, which prevents the breakers from tripping if overloaded. If an overloaded breaker does not trip, it can overheat, and potentially cause a fire. Other issues are breakers may trip internally, but the switch itself will not trip, giving the visual illusion the power is on when it is not. Other issues are the bus bar becoming loose, causing arcing in the panel, which is a safety hazard.

The problem facing home inspectors is there is no way to visually see the condition of the bus bar behind the breakers. The only way to tell if a Zinso panel is indeed a problem, or not, is to fully take apart the panel. and then put it back together. This can only be done by a licensed and qualified electrician. The other problem is even if a panel is fine on the day of inspection, it may not be fine the next day.

Do I Have to Replace a Zinsco Panel?

Bus Bar corrosion is often not visible
Bus Bar corrosion is often not visible

The question is do the panels have to be replaced? One issue facing replacement is there is no recall of these panels. The Federal Consumer Product Safety Commission (CPSC) has no opinion on these panels. There are no mandates or official documentation that says the panels are indeed dangerous. On a recent home inspection, IM Home Inspections found a Zinsco panel on a remodeled house. The seller was able to produce documents showing all permits for the work were valid, because neither the city, state or federal government considers the presence of a Zinsco panel a violation. Many electricians IM Home Inspections have spoken with will say they should absolutely be replaced, however, other electricians state they are no more dangerous than any other panel.

Regardless, some insurance companies may deny insurance on homes with a Zinsco panel. However not every insurance company does this. Home buyers should check with their insurance carrier.

The last factor is age. The International Association of Certified Home Inspectors (InterNACHI) lists the life expectancy of an electric panel to be approximately 60 years. Many Zinsco panels are approaching or past the 60-year mark. Also, many older panels simply were not designed for modern electrical issues. Homes with Zinsco panels were built long before people had home computers, big screen TVs, and today’s electrical devices. Many Zinsco panels are not grounded, and would likely not pass a modern UL test.

So while there is no mandate, or solid black and white evidence a Zinsco panel should be upgraded, the price of changing a panel is small compared to the price of a home. The peace of mind of having an upgraded panel is likely worth it.

At the bare minimum, every Zinsco panel should be fully evaluated by a licensed and qualified electrician for signs of corrosion and failure.

Zinsco panel variation
Another Zinsco variation


Does the home you are buying have a Zinsco panel? Book your home inspection today by calling 818-298-3405