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Electrical Panel Advice

ADVICE FOR OWNERS – 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.

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 eletrical 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.

Limited test results reported by J. Aronstein indicate that the central Zinsco electrical panel and circuit breaker failure problem appears to be burnups at the clip-to-bus connectionsuch as shown in our photo. The few circuit breakers tested by Dr. Aronstein were reported to trip within normal overcurrent limits. Howver a circuit breaker whose bus connection burns can lead to overheating damage to the circuit breaker itself, rendering it non-functional.

Photo (left) 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.

Where Zinsco and Zinsco-Sylvania electrical panels are discovered in buildings they should be replaced to reduce some very real fire and shock hazards. 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.

Where 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.

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 HOW TO REPORT ELECTRICAL FAILURES, 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%.

Readers wanting to read specific advice on what to do if their building contains a Zinsco electrical panel should first read ADVICE FOR ZINSCO OWNERS, then also see HOW TO REPORT ELECTRICAL FAILURES to homeowners when a Zinsco Sylvania™ electrical panel is observed by a contractor, home inspector, or electrician.

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. See ZINSCO FAILURE PHOTOGRAPHS and ZINSCO FAILURE REPORTS.

Repair advice (replace the equipment) is provided at REPLACEMENT ELECTRICAL PANELS and at REPAIR ELECTRICIANSwe 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.

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.


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