Unique Features of Zinsco Breakers

Zinsco has been one of the oldest manufacturers of electrical distribution panels and circuit breakers since their founding in the 1930s. Most circuit breakers are built for use with fan air heaters, air conditioners and electric baseboard heaters, if it complies with local electrical codes.

Furthermore, each Zinsco breaker is custom built with a unique thick design for use with load centers from Zinsco, specifically. Some will come with grounded copper wire, usually built for 120/240-Volt load capacity.

Nevertheless, Zinsco circuit breakers come in various forms, and many may not even be directly labeled with a specific Zinsco label. For non-professionals, this can pose some confusion without expert guidance. To keep confusion to a minimum, we’ll discuss how to identify Zinsco breakers by their unique features.

The Labels of Zinsco Circuit Breakers

A number of Zinsco breakers are what Inspectapedia refers to as “a Zinsco in Sylvania’s clothing.” The labels are typically blue and white, with the Sylvania name in white lettering against a dark blue background.

While the product’s labels might name it with the Sylvania name, Sylvania-Zinsco or even GTE Sylvania Zinsco, each breaker is still technically a Zinsco breaker. The Sylvania name dates from Zinsco’s acquisition by GTE-Sylvania, who would create the panels and breakers with the first Zinsco panel design for several years after. The Frank Adam Electric Panelboards—Zinsco was initially the West Coast branch of the Frank Adam Electric Company—may also feature Zinsco-type QSF electrical panel circuit breakers.

Because of Zinsco’s start as a West Coast business, the vast majority of their products have found purchase in states across the Western United States. Many of the circuit breakers retain a carved “Magnetrip” label on the cover of the panel, a Los Angeles circuit breaker, for instance, retains a red label naming Los Angeles, as well as quick emergency instructions reading, “To restore service move handle to ‘off’ and then ‘on’.”

An inspector can open a Zinsco electrical panel or even more complicated disassembly by locating each circuit breaker’s unique details, but the careful labeling and distinct colors for each circuit breaker are enough for the casual customer or beginner electrician to identify the Zinsco equipment.

The Color Codes of Zinsco Circuit Breakers

In addition, a Zinsco breaker will have a deep slot that goes over and attaches to the electrical panel’s flat connecting bus bars. If you look closely, you can often find traces of burning or arcing near the deep, long slots.

The colors of each circuit breaker—as well as a variety of other details on the exterior, such as a gray, molded plastic case—enable an expert to easily locate and identify the problems in the circuit breaker.

But it is not enough to simply know there is a color code. So, what are the color breakdowns within a Zinsco circuit that help identify the various breakers on the market?

Solid blue breakers are 15 amps, while red ones are 20 amps. Light blue or green breakers are 30 amps, while those with a light brown exterior are 40 amps. Furthermore, the GTE Sylvian Zinsco circuit breakers come with distinctly light green color switches.

An included white sticker offers users the standard torque settings for the wiring of the primary circuit breaker. The torque specs can help lower the risk of a bad connection between the main connection lugs and the aluminum wires inside the circuit panel. They may also help to decrease liability for the manufacturer, as many electricians do not carry a torque wrench.

The Three Things to Be Cautious of with Zinsco Circuit Breakers

There are three types of failure modes unique to Zinsco and Zinsco-Sylvania circuit breakers.

The first kind of failure mode is failure to trip. The Zinsco-type circuit breakers might not trip in case of an overcurrent situation. Secondly, Zinsco or Zinsco-Sylvania circuit devices, in cases where they malfunction, tend to cause an electrical arc explosion. This is when the side external casing of the breaker blows out.

Lastly, Zinsco-type circuit breakers might also not drop their power, even in cases when their currents are switched off. The breaker might seem to be put in off-switch, while the internal mechanisms are still transferring electrical current from circuit. In these cases, of course, a professional should be notified to assist with the repairs for the Zinsco circuit breaker.

Zinsco circuit breakers have been in circulation for so long that their looks, design and labels have changed over time. These changes reflect a history of evolving corporate ownership and shifts in electrical function. This can make it slightly more difficult for the typical person to identify and replace Zinsco breakers. However, a basic familiarity with the variety of unique functions, labels and color coding among the breakers can help people locate and work with their Zinsco circuit breakers.