Zinsco Electrical Panel Hazards
Zinsco Circuit Breaker Information Website

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This Zinsco electrical panel article discusses the electrical, fire, and shock hazards associated with Zinsco electrical components, circuit breakers, electrical panels, including certain Sylvania electrical panels and breakers which are in fact of the same product design and origin.

We include advice on how to identify Zinsco, Sylvania Zinsco, and Kearney electrical panels and circuit breakers, and repair or replacement advice for those products.

In this article series we discuss: the hazards of Zinsco or Zinsco-Sylvania electric panels; Zinsco & Zinsco/Sylvania electrical panel identification guides & Kearney electrical panel identification guide. Independent testing of Zinsco breakers confirms failures.

Zinsco failure reports, though few in number, indicate severe failures of Zinsco electrical panels / circuit breakers including failure of the circuit breaker to trip on overcurrent, arcing and burn-ups at the breaker to panel bus bar connection, and circuit breaker burn-ups.

Zinsco & Zinsco-Sylvania Panel Replacement Recommended, Zinsco Sylvania Panel Breaker-to-Bus Connection Arcing. How should Zinsco panels be repaired: electrical panel replacement alternatives, What are the typical costs to replace a Zinsco or Zinsco-Sylvania Electrical Panel?

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Zinsco Electrical Panel Advice for Homeowners and Home Buyers

Zinsco breaker burnup (C) J P Simmons & D J FriedmanZinsco and Zinsco-Sylvania circuit breakers of the design described here do not offer the level of overcurrent and fire protection provided by most other electrical panels and circuit breakers.

Watch out: OPINION: we do not recommend installing "replacement" Zinsco circuit breakers as there some indications that the performance and safety of those devices may be poor.

Article Contents

Zinsco Electrical Panel & Breaker Test Results

Limited test results reported by Dr. Jess Aronstein (who is cited further at REFERENCES) indicate that the central Zinsco electrical panel and circuit breaker failure problem appears to be burn ups at the clip-to-bus connections such as shown in our photo of a burned Zinsco electrical panel bus and breaker. A circuit breaker whose bus connection burns can lead to overheating damage to the circuit breaker itself, rendering it non-functional.

For a summary of Zinsco and UBI-Zinsco-Replacement circuit breaker test results to date, see ZINSCO CIRCUIT BREAKER TEST REPORT - separate article.

Also see ZINSCO FAILURE REPORTS where we indicate that nearly 32% of the Zinsco circuit breakers tested to date failed to trip as required by the UL testing standard. A very small sample of UBI-brand replacement circuit breakers for Zinsco panels also failed to trip.

Photo at page top of a burned and failed Zinsco main circuit breaker, courtesy of J. P. Simmons - Mr. Electric. Simmons adds: "In this case the failure damaged the main wire to a mobile home also (you can see the melted wire to the left of the main). This is a good example of why I do not like to see anyone remove these breakers. You can not tell how bad they are damaged by looking at them.

Zinsco Panel Field Failure Reports

With the exception of the more seriously failing FPE Stab-Lok electrical panels, we have not received any significant number of field failure reports concerning other electrical panel brands that also use aluminum parts and that are or were priced in the same range as Zinsco.

This means homes with this equipment may be at greater risk of fire or other electrical hazard.

Zinsco & Zinsco-Sylvania Panel Replacement Recommended?

Zinsco no-trip (C) InspectApediaWhere Zinsco electrical panels and Zinsco circuit breakers are in use, arcing, contact-point burn, and even circuit breaker case blow-out have been observed in the field.

We do not have statistically solid data that supports an unequivocal argument to replace Zinsco electrical panels.

However, based on field reports to-date and preliminary tests, where Zinsco and Zinsco-Sylvania electrical panels are discovered in buildings a homeowner should consider replacing the panel to reduce fire and shock hazards and owners should be careful to avoid overloading their electrical circuits where this equipment is installed.

Building owners or electricians encountering problems with this equipment are asked to contact us to add that information to our electrical failure data base in an effort to develop accurate safety information which is then shared with appropriate federal and state agencies.

Thanks to Mr. James Simmons, a licensed electrician with extensive field experience and the contributor of most of the photos and case reports at this web page.

Our photo (above left) illustrates a burned-up electrical receptacle whose circuit was protected by a Zinsco circuit breaker that failed to trip and in fact had burned itself in the panel.

Zinsco Sylvania Panel Breaker-to-Bus Connection Arcing

A principal Zinsco™ circuit breaker (or Sylvania™ or GTE-Sylvania™ or Kearney™ electrical panel using this circuit breaker) point of failure appears to be at the point of contact where the circuit breaker contacts clip onto the electrical panel bus, combined with the use of an aluminum electrical panel bus.

As described at ZINSCO FAILURE REPORT PROCEDURE, expert testing on this equipment has shown that circuit breakers do not trip about 25% of the time when exposed to overcurrent - risking overheating, fire and other hazards. The failure rate of competitive-brand circuit breakers is much less than 1%.

In addition to advice on identifying Zinsco™ panels, inspecting Zinsco electrical panels, and repair/replacement advice, we provide field photographs of circuit breaker failures: overheating, burnups, failures to trip, overcurrent protection failure. This document includes field reports of failures and additional anecdotal evidence.


Zinsco Panel Repairs

Repair advice (replace the equipment) is provided at ZINSCO REPLACEMENT PANELS and

at REPAIR ELECTRICIANS we list electricians who have informed us that they have specific experience with this equipment. Lots of other licensed electricians are also qualified to replace electrical panels; it's best if your electrician is one who is familiar with this issue.

Replacement Zinsco circuit breakers and replacement copper-plated bus bars for Zinsco / Zinsco-Sylvania electrical panels are advertised. Without evidence of a design change in the product or support from independent expert testing, the effectiveness of these replacements is not clear.

As a not-for-profit activity, we have been collecting information and field failure reports for Zinsco/Sylvania electrical components since 1996 in an effort to develop credible failure-rate information which is then shared with the U.S. CPSC and with other electrical failure researchers and educators.

Zinsco History, Age, Dates & Patents for Zinsco Electrical Panels & GTE-Sylvania Zinsco Electrical Panels

Sturdivan Zinsco electrical panel patent schematic 1966[Citations needed, use the page bottom CONTACT link if you can provide additional data - Ed.]

This article series discusses the electrical, fire, and shock hazards associated with Zinsco electrical components, circuit breakers, electrical panels, including certain Sylvania electrical panels and breakers which are in fact of the same product design and origin. Zinsco-type QSF electrical panel circuit breakers may also appear in Frank Adam Electric Panelboards.

Counterfeit circuit breakers, Elod Tamas "Nick" Toldy enforced by U.S. ICE at

Watch out: OPINION: we do not recommend installing "replacement" Zinsco circuit breakers as there some indications that the performance and safety of those devices may be poor.

Mike Holt has provided excerpts of a history of Zinsco Electric quoting the company founder's great-grandaughter Heather Hill (un-dated). -


Continue reading at GTE-SYLVANIA-ZINSCO FAILURE MECHANISM or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see ZINSCO SYLVANIA ELECTRICAL PANEL FAQs - questions and ansers about Zinsco Sylvania electrical panels posted originally at this page.



Or see this

Zinsco Electrical Panel Article Series

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ZINSCO SYLVANIA ELECTRICAL PANELS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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