Zinsco/Sylvania Electrical Panels

Zinsco Panel

A brief history of Zinsco/Sylvania Electrical Panels

zinsco panel
Zinsco Panel
sylvania panel
Sylvania Panel

The Zinsco brand was established in 1943 when the son of the Zinsmeyer Company took over his father’s electrical business. Zinsco panels went on to be a very popular brand of electrical panels for several decades, often labeled with the name “Magnatrip” on the cover. In 1973, the Zinsco brand was sold to GTE-Sylvania and subsequent panels were altered in their configurations and some materials. However, most internal products remained the same (e.g. – breakers and bus). Full production of the panels stopped in 1981, but existing manufactured panels were still installed for several more years following.

Zinsco panels were especially desired because the United States faced several copper shortages, during WWII, the Korean War, and again in the 1960s. Their aluminum bus bars provided an alternative to the use of copper. However, in the long run, this would also contribute to its Achilles heel.

Aluminum Bus Bar (Zinsco bus bar) and Breaker problems

Over the years, electricians began to discover that the aluminum Zinsco bus bars created unforeseen problems. These problems included the aluminum corroding to the breakers, which prevents the breakers from tripping if overloaded. If an overloaded breaker does not trip, it can overheat, and the wires (which should be protected by the breakers) could result in a subsequent fire. 

Other common issues associated with the panels are the Zinsco breakers tripping internally, but the switch itself not moving. This gave the illusion of the power being on, when in fact it was not. 

Other issues are the bus bar(s) becoming loose, causing arcing in the panel.

melted zinsco breaker
Melted Zinsco Breaker
melted zinsco breaker damage
Melted Zinsco Breaker/ Damage

Do Zinsco/Sylvania panels have to be replaced?

One issue facing replacement is that no consumer recall has ever be placed on the product. The Federal Consumer Product Safety Commission (CPSC) has no opinion on these panels. No mandates or official documentation that says the panels are dangerous exists. The debate on what to do with the panels are still out. Some Electricians say they should be replaced, however, to the contrary, other electricians state they are no more dangerous than any other manufactured panel. Some insurance companies have also gone so far as to deny insurance on homes with a Zinsco or Sylvania panel present.

So what is the life expectancy of a Zinsco panel? The life expectancy of any electric panel is estimated to be approximately 60 years. Many Zinsco panels are approaching or have passed the 60-year mark. Also, many existing 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. Grounding was not required by the NEC until 1963.

So while there is no mandate or evidence that a Zinsco panel should be upgraded, the price of changing a panel is small compared to the price of a home. 

At minimum, every Zinsco or Sylvania panel is recommended to be fully evaluated by a licensed and qualified electrician for signs of corrosion and failure. 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 Zinsco or Sylvania panel has a problem, or not, is to fully take apart the panel. This is out of the scope of a normal inspection and should only be performed by a qualified licensed electrician.

Trust the Certified Master Inspectors at Absolute Inspection Services for your home inspection needs. Call us at (888) HME-INSP to book your inspection today!

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