Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR
ACCURACY vs PRECISION of MEASUREMENTS
AFCIs ARC FAULT CIRCUIT INTERRUPTERS
ALUMINUM SECs & WIRING
ALUMINUM WIRING HAZARDS & REPAIRS
AMPS & VOLTS DETERMINATION
AMPACITY - the LIMITING FACTOR
APPLIANCE EFFICIENCY RATINGS
BACKUP ELECTRICAL GENERATORS
BACK-WIRED ELECTRICAL DEVICES
BOOKSTORE - ELECTRICAL
BUILDING SAFETY HAZARDS GUIDE
Cadet & Encore Heater Recall
CIRCUIT BREAKER FAILURE
CIRCUIT BREAKER SIZE for A/C or HEAT PUMP
Classified CIRCUIT BREAKER WARNING
CORROSION in ELECTRICAL PANELS
CORROSION & MOISTURE SOURCES in PANELS
CUTLER HAMMER PANEL FIRE
DEFINITIONS of ELECTRICAL TERMS
DIRECTORY OF ELECTRICIANS
DMM Digital Multimeter HOW TO USE
ELECTRIC METERS & METER BASES
ELECTRIC MOTOR DIAGNOSTIC GUIDE
ELECTRIC MOTOR OVERLOAD RESET SWITCH
ELECTRIC PANEL AMPACITY
ELECTRIC PANEL INSPECTION
ELECTRIC PANEL MOISTURE
Electric Power Frequency Table
EMF RF FIELD & FREQUENCY DEFINITIONS
ELECTRICAL GROUND SYSTEM INSPECTION
ELECTRICAL GROUND SYSTEM INSPECTION
ENERGY SAVINGS in buildings
FEDERAL PACIFIC FPE HAZARDS
FIRE SAFETY Checklist, CPSC
GFCI PROTECTION,Testing GFCIs AFCIs
HEATING COST FUEL & BTU Cost Table
HEAT TAPE USAGE GUIDE
Hertz - Definitions of KHz MHz GHz THz
KNOB & TUBE WIRING
LIGHTING, EXTERIOR GUIDE
LIGHTING, INTERIOR GUIDE
LIGHTNING PROTECTION SYSTEMS
LOW VOLTAGE BUILDING WIRING
LOW VOLTAGE TRANSFORMER TEST
MAIN DISCONNECT AMPACITY
MOISTURE SOURCES in PANELS
MURRAY SIEMENS Recall
PHOTOVOLTAIC POWER SYSTEMS
PUSHMATIC - BULLDOG PANELS
REMOTE ELECTRIC POWER, PHOTOVOLTAIC
RUST in ELECTRICAL PANELS
SAFETY for ELECTRICAL INSPECTORS
SE CABLE SIZES vs AMPS
SIEMENS MURRAY Recall
UNDERGROUND SERVICE LATERALS
VOLTS / AMPS MEASUREMENT EQUIP
VOLTAGE MEASUREMENT METHODS
WIND ENERGY SYSTEMS
WIND TURBINES & LIGHTNING
ZINSCO SYLVANIA ELECTRICAL PANELS
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.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved.
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.
Limited test results reported by J. Aronsteinindicate that the central Zinsco electrical panel and circuit breaker failure problem appears to be burnups at the clip-to-bus connections such as shown in our photo of a burned Zinsco electrical panel bus and breaker. The few circuit breakers tested by Dr. Aronstein were reported to trip within normal overcurrent limits. However 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.
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.
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.
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%.
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 ZINSCO FAILURE REPORT PROCEDURE 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 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.
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs) about Zinsco & Zinsco-Sylvania electrical panels and circuit breakers
Question: I am selling my house and it has a Zinsco electrical panel - are they all a fire hazard risk?
I am selling my house and just had an inspection done. I have a zinsco circuit breaker panel and would like to know is every model the same and are all of the circuit breaker panels a fire hazard risk? - Suzanne
Thanks for the important Zinsco breaker model question. We don't know if there are Zinsco-brand circuit breakers whose design is different from the ones discussed here (I don't think so), and we don't yet know if there are age or model differences among Zinsco circuit breakers and their performance, because not enough Zinsco breaker testing has yet been completed.
Question: How do I identify a Zinsco electrical Panel or a Sylvania Zinsco Panel & How do I know if My Panel is Bad?
How do I know if my Sylvania electrical breaker is a Zinsco? - Marie
How do I know if my Sylvania electrical panel is bad? - Wallace
Wallace: unfortunately it is not possible nor even safe to try to assure the safety of certain electrical problems by visual inspecting (you can't see hidden problems behind or even inside the circuit breaker) nor by testing in place the circuit breakers (you risk starting a building fire, and even a "tests-ok" breaker may fail the next time it is subjected to an overcurrent). Worse, testing in some cases (FPE in particular) can significantly INCREASE the chances that in the future the breaker will fail to trip.
Marie: see IDENTIFY ZINSCO ELECTRICAL PANELS for help in identifying Zinsco brand electrical panels and circuit breakers.
Question: My Zinsco Main Breaker is in the "Off" Position but power is still on in my panel. Help?
Have a zinsco 100 amp service, turn the main off but still get power have very little cash. So I can't replace it at this time, if I replace the main, is it safe to still use this panel? Is it safe to add new breakers? - Tim
If you still have power when the main electric panel disconnect is in the "OFF" position then this is a VERY dangerous condition as you cannot, using normal homeowner controls, turn off electrical power in an emergency, and more, it is likely that the main disconnect is not going to trip on a large overcurrent and so is not protecting the equipment and building from an electrical fire.
Question: Single Breaker Zinsco-Sylvania 100A Main Service Switch feeds a new GE Panel. Isn't this OK?
I have a Sylvania panel on an exterior wall that simply has 100 amp service to the main breaker and then a single 100 amp breaker on the branch that leads to a new GE panel inside the house with its own 100 amp main breaker.
All power comes off of the GE panel. That being said, this seems safe as to take out the Sylvania I would just have a wire from the meter to the GE panel, which would provide no overcurrent protection anyway. With the Zinsco/Sylvania I have two additional breakers to try to trip if for some reason the 100 amp main in the GE failed, plus I can kill power to the GE panel from the outside if ever I needed to in case of a fire.
Does this sounds fine or is the Sylvania still a problem? - Bob Welderman
Reply: The service entry cable between meter and new panel may be under-protected
First off. Thank you for the response. To be more specific. The wire from the meter to the Sylvania is about 4 feet and then the one from the Sylvania to the GE is about 4-6 feet as it is just on the other side of the wall. The breaker from the Sylvania to the GE is a brand new refurbished one that was tested by the electrical supplier about a year ago. - Bob.
Comment: testing by the electrical supplier? Unusual. But the basic electrical failure risk remains.
Bob, in the arrangement you've described, it is the SEC between the Zinsco-Sylvania breaker and the new GE panel that is left unprotected should a short occur in that wire or should the main breaker in the GE panel fail to trip. I agree that the risk that remains in those components is likely to be lower in frequency than risks of the need to trip a circuit breaker protecting an individual branch circuit in the building. However, because of the chances of a higher current draw at a major failure in a panel or in an SEC, the protection of that wiring is very important. Indeed we attended a house fire that occurred in just those circumstances - an SEC or main panel short.
Just to be clear, the main switch protectes equipment that is downstream from itself.
At this point, if I understand your schema, the service entry cable passes from meter to Zinsco-Sylvania breaker and from there to a main panel of another brand. So the risk of a no-trip or burnup in the service panel is less than before when Zinsco breakers were in use in that location.
Nevertheless, it's the main switch that does the heavy lifting when safety and shorts are concerned.
Question: where can I buy replacement electrical panel covers for a Zinsco ?
looking for two electric panel covers for zinsco 14" w x 20 L - Hank Vance
Hank, take a look at the article ZINSCO REPLACEMENT PANELS - This article describes replacement electrical panels and covers.
Question: was there a Sylvania Panel recall?
Sylvania Panel GRTE, 390-205-08, 380-025-15, e-52977, albiz (20-20)-c. Home Inspection comments this could be a recall item. Please advise 650-576-0777 Thank you, B Oliveira - 12/19/11
Brenda, I'm not sure what advice you are asking; please be sure to read the above articles on the hazards of Zinsco and Zinsco-Sylvania electrical panels and circuit breakers. Simply deciding on the presence or absence of a safety hazard based on whether or not there was a product recall is unreliable.
Question: What is Sylvania-Zinsco's responsibility for a faulty product?
What is Sylvania-Zinsco's responsibility for a faulty product? Were there any recall notices? Is there any compensation for their faulty product? - G Butler 5/7/12
The assignment of responsibility for product defects is a legal and technical question that we InspectAPedia do not directly address. We report on building and environmental inspection, diagnosis, and repair topics with as much impartiality as possible. I agree that it's a fair question nevertheless, and as with other controversial product defects such as the FPE Stab-Lok hazard, we will report if there are product recalls or legal actions in the matter.
Question: where do I find a licensed electrician to do Zinsco Panel Replacements?
Where to find licensed electrician for zinsco panel in my area - David Rue 5/16/12
David, ANY licensed electrician can replace a Zinsco electrical panel. The reason we like to use electricians who know about the Zinsco hazard is to avoid wasting time with someone who makes the mistake of telling you there is no possible hazard.
At DIRECTORY OF ELECTRICIANS we list some, not all, electricians who assert that they have experience with Aluminum wiring, FPE, and Zinsco electrical equipment repairs or replacements. There are no listing fees and InspectApedia has no business nor other financial relations with any topic or service provider discussed here.
Question: Zinsco Field Failure Report 7/15/12
I am a Master Electrician in Florida. I recently received a call from a customer who was having a new central A/C installed. The Installer told him that the Main 100A Zinsco breaker was turned off, but the house still had power. I assessed the situation, and told the homeowner he needed a service change. I would not even attempt to touch the service disconnect. I had the Power Company disconnect the power at the transformer, before I started. When it was safe, I attempted to remove the old Zinsco breaker, and it crumbled in my hands. If someone had attempted to work the breaker they would have been subject to a terrific arc flash - burn - explosion. I,m glad I took the safety first approach. Hank Kline DeBary FL. - Hank Kline 7/15/2012
Thanks so much for your important Zinsco field failure report Hank. It illustrates how one real-world experience is worth a dozen arm-waving speculations from a few writers who think we've made the whole thing up. Glad you knew to be safe.
Question: is there a recall on Zinsco Electrical Panels / Circuit Breakers - or recourse?
Is there a recall or some recourse from the company that manufactured the faulty Zinsco Electric Panel / Circuit Breaker? Do you have a contact for the company? Thanks! - Cynthia 7/23/12
Sorry, Cynthia, no.
Question: is it safe to replace a Zinsco-design electrical panel if I have the electric company drop power at the meter?
I have a Zinsco Panel it is listed as a Sylvania but looks exactlly like the photo above. I have a friend that is a electrician and told me he would replace the panel with a new square D 200 amp service. If I have the power company turn my meter off then no power will be running through the panel how is this job still dangerious? - Ryan 8/23/2012
Question: Reader comment: burned-up Zinsco Circuit Breaker Photos
We suggested they immediately get a licensed electrician to come out and replace the panel, but they just wanted to replace the breaker, worryingly enough.
The truly scary part, though, is that apparently this breaker was not the one that originally failed, it was set on fire by the failure of the adjacent breaker. One can only imagine what that one must have looked like, if there was anything left of it.
Feel free to include the photos in the Zinsco section of the website, if you'd like. I think I may end up making a display case in the store for this and a similarly failed FPE breaker. Maybe it'll give people a hint as to why we recommend that they replace these panels.
On a somewhat related note, I regularly recommend your site to customers with electrical safety questions, as does my father (a licensed electrician with over 40 years in the industry). Thanks for all the work you've put into it, and for trying to bring electrical safety issues to people's attention. - A.K.
Thank you for the Zinsco burn-up photos and the case report of another Zinsco circuit breaker failure. Your report is a reminder of Aronstein's frequent caveat that unless the remains of a fire are examined by a very expert forensic expert, we can not always be sure exactly what went wrong.
Nevertheless in the case you describe, and considering that based on an impartial review of the history of Zinsco product failures and field reports, our OPINION is that the product is defective, suffering from both design and performance issues.
What that fancy talk means in plain English is that simply installing a "replacement breaker" into a Zinsco panel is not a safe repair since it does nothing to address the design and product failure issues in the product. As with a few other replacement circuit breaker lines like FPE, there is unfortunately not a shred of independent test data nor field data that would support just replacing the breaker. Replacing the panel is what one should recommend.
The stunbling block for electricians and their customers is that too often all the customer has noticed is that power has been lost on one or two circuits in the building (where a breaker melted or failed to trip until the circuit wiring burned up). The customer figures that "all I need is a new $7.00 circuit breaker" and treats with suspicion the electricians's suggestion that the panel should be replaced.
To offer impartial assistance in problems like this you are welcome to provide your customers with printed copies of InspectApedia articles that you find helpful, and for a few cases listed just below we also provide special web pages that can be freely copied to other websites so long as they are not modified without our permission. Your email prompted us to make a new hazard summary page for Zinsco, Kearney, Zinsco-Sylvania electrical panels & circuit breakers. I've also added your Zinsco burn-up photos here and your report and photos appear also at ZINSCO FAILURE REPORTS as well as at ZINSCO Hazard Summary Page for Reproduction.
CONTACT US if you have suggestions for that material or if you have questions or content suggestions about other material at InspectApedia. Working together we're smarter than working alone. Thanks again, Daniel
Questions & answers or comments about Zinsco Electrical Panel Safety, buying, repairing, replacing Zinsco electrical panels & parts.
Ask a Question or Enter Search Terms in the InspectApedia search box just below.
Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.