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
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 PANEL AMPACITY
ELECTRIC PANEL INSPECTION
ELECTRIC PANEL MOISTURE
Electric Power Frequency Table
EMF RF FIELD & FREQUENCY DEFINITIONS
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
KNOB & TUBE WIRING
LOW VOLTAGE BUILDING WIRING
LOW VOLTAGE TRANSFORMER TEST
MAIN ELECTRICAL DISCONNECT
MAIN DISCONNECT AMPACITY
PUSHMATIC - BULLDOG PANELS
RUST in ELECTRICAL PANELS
SAFETY for ELECTRICAL INSPECTORS
SE CABLE SIZES vs AMPS
UNDERGROUND SERVICE LATERALS
VOLTS / AMPS MEASUREMENT EQUIP
VOLTAGE MEASUREMENT METHODS
WIND ENERGY SYSTEMS
WIND TURBINES & LIGHTNING
ZINSCO SYLVANIA ELECTRICAL PANELS
Zinsco panel and breaker safety opinions: Here we report email correspondence from a reader whose view is that the Zinsco material has been too one-sided in its criticism of that product. We include comments by industry experts who respond with explanation of the actual hazards and real failure occurrences of this product.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
This website 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.
Our experience and advice indicate that Zinsco 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.
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.
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 0.01%. That is, these product failures appear to occur at more than 2500 times more often than those of similar competitive equipment.
With the exception of the more seriously failing FPE Stab-Lok electrical panels, we have not received a large 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 are at greater risk of fire or other electrical hazard. [Other than FPE (first offender) and Zinsco, we have received a small number of Challenger and Bulldog Pushmatic complaints, along with other more rare reports under other brands.]
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.
Watch out: while opinions about aluminum components in electrical panels flash below, more significant are the actual Zinsco failure mechanism discussed at GTE-SYLVANIA-ZINSCO FAILURE MECHANISM and the actual reports & descriptions of field failures seen at ZINSCO FAILURE REPORTS. The principal failure in Zinsco & GTE-Sylvania Zinsco electrical panels appears to be overheating and corrosion developing at the circuit-breaker-to-bus connection, resulting in overheating, failure to trip, and even circuit breaker explosions.
Older background Zinsco correspondence from an electrical panel retailer / reader who has a different point of view
Newest correspondence is at the top of this text, with minor edits to text for public presentation or clarity. Reader Doug H's remarks are in italics.
Email Discussion Re: Zinsco and Zinsco-Sylvania circuit breakers
D Friedman to Doug H:
Regarding your statement, below,
Watch out: the above remark is dangerously confusing and inaccurate:
Aluminum electrical wiring is a case in point for generic problems with aluminum at electrical connections. See ALUMINUM WIRING HAZARDS.
Aluminum electrical components in panels, buses, connectors, often perform usually acceptably - but in the case of Zinsco, where failiures have been independently tested and found ocurring roughly 2500 times more frequent than with competitive products, we just can't say it's all the same or that the Zinsco problem is due to mis-use of the equipment.
The problem is not one of mis-use or "performs so well so long as ..." as you indicate - that argument is defeated by the observation that aluminum material in electrical panels performs so inconsistently comparing Zinsco, for example, with GE panels using similar aluminum components. To say that the Zinsco failures are occurring because people use those panels improperly is to infer that people who buy a Zinsco product use differently than people who buy a GE, Siemens, ITE, or other products of similar rating and use.
Doug H. to D Friedman
From D Friedman to Doug H:
I wanted to add, FYI, two other thoughts for us to discuss
DF: 1. Lots of electrical panels have aluminum components - but only Zinsco shows the failures that you see in the articles that I've posted
Daniel replies to Doug's comment: because equipment failures occur under normal loads and because the failure mechanism of aluminum wiring is traced to microfretting that occurs under normal loads, that's not an accurate conclusion. Further, as I point out in a later message above in this thread, if failures occur on product brand A and not on similar product brand B, to claim that A's problems are due to load or usage is to claim that for some reason consumes use brand A differently than they use brand B - a claim that has no supporting evidence.
DF: 2. It is not at all the case that the only choice between a Zinsco panel and others is to go to a costly copper bus 200A panel - at Home Depot I have bought a 100A GE panel, complete with circuit breakers already in the box, for less than $100.
Daniel replies to Doug: nothing in our content specifies a requirement to change panel material, cost, price point - *any* electrical product must perform as rated and certified. If a product does not, it is not giving the level of protection afforded by industry standards, nor by its competitors.
Daniel F. to Doug H:
I appreciate the professional level of discussion,
DF continues: I'm unclear about whether the problem of bus burnups and breaker burnups is due to the level of amps draw - with these arguments in mind:
1. the problem may instead be due to scoring the bus when the breaker is inserted, or due to an innate connection design problem between the breaker and bus, or due to a no-trip problem inside the breaker; Aronstein's work on microarcing that underlies the aluminum wiring overheat problem might be going on with this product as well. [Yes i agree. Many causes possible, but most usually, if not most always, burnouts are caused by heat resulting from a poor connection. Even a light load on a bad connection seems to eventually fail]
2. regardless of the price point, no circuit breaker should burn up the bus or burn up itself in usage - at overcurrent, the breaker has to trip, period, so if a circuit is overloaded the breaker has to open the circuit; regardless of its cost. [Yes, i knew all along this is the basis of your article, and it is a valid and just point, however the argument to this is often times the device is being used for something it's not intended to do, which may cause the breaker to be damaged, thus it can't trip as it should, thus forcing a burnout. A good example is the 20% rule. One shouldn't continuously load a circuit with more than 80% of it's capacity, less premature failure is eminant, and if one does load a circuit with a constant 95% it won't be enough to trip the breaker, but will be enough to eventually damage the breaker, thus it may not be able to trip when it needs to. It is kinda the un-written rule that one can't push electrical at it's maximum limit continuously or you may damage the protection device itself]
So we'd be on thin ice to say it's "ok" to use this product so long as we don't use it at the amperage ratings that either are approved for the product (drawing 20A on a 20A breaker, for example), or so long as there is never an overcurrent (drawing more than 20A) at which you are going to depend on the breaker to do its job - trip.
Daniel Comments: so we agree, that it would be ridiculous to assert that the Zinsco problems are occuring only because the equipment is being mis-used.
DF original note continues: those concerns stated, my review first will address whether we're inaccurately stating what advice home inspectors should give to consumers. I certainly agree that this particular failure has not been as deeply studied as the FPE problem. [In my personal opinion i think there just needs to be a little wiggle room, for the way things are now the Inspectors pretty much have to condemn the panel, even if it is operating in a light-duty enviroment as it was intended. Lets face it. Aluminum tends to be a light duty product, that seems to preform well under light duty applications, so the panels work fine in many applications, but that point wasn't ever made. That was all i was getting at]
Daniel comments: in sum, it is a faulty argument to blame equipment failures on mis-use when the failure occurs dramatically more often in one brand or product than among its similar competitors.
Doug H. to D Friedman:
Local person says: "Your GTE-Sylvania-Zinsco electrical panel has an aluminum bussbar, thus was a nice affordable panel in it's day, for light duty usage, such as dwellings that are plumbed with natural gas. It has preformed well and will continue to preform well in your natural gas home, so long as future tenants don't convert the high-demand appliances over to electric."
This is in no way to be mis-construed as to saying the product is safe or not safe, for most everything can be abused, but the years of un-interupted service at your home and other's homes do seem to say the product preforms as it should when used properly, however if continually over-loaded with high-demand usage, then failure is naturally going to occur, which has been documented on the following website www.InspectAPedia.com/electric/Zinsco.htm"
Here's the problem.
Home Inspectors are 'not' writing these electrical panels up as preforming less than competitors, but instead writing them up as being a fire hazards and making them be replaced to pass inspection, then quoting your websight as their basis.
Now I understand what you are doing. Trying to educate and protect the public. Which is a good and worthy thing. Plus a thankless job for the most part. So may I thank you up front for all you do to make the world a better place.
Ok now. I'm all for nice modern 200 amp panels with copper bussbars, and personally think all breakers should be of the bolt in style to prevent loose connections that normally cause the burn outs, but the probem is these Zinsco panels were an affordable, light duty box, for low-cost housing, thus many are out there, and have preformed well when used for there intended purpose, but your article doesn't give that side of the story.
Basically the Zinsco panel isn't a grade 'A' panel, but neither do I believe it is an 'F' panel as the inspectors seem to say, and no where on your site is there anyway to show the inspectors the other side the story, thus many poor people in affordable housing are being forced to upgrade to brand new expensive 200 amp copper bussbar electrical panels that they can't afford, even though they already have a 200 amp aluminum bussbar panel that has preformed well in their dwelling just as it was intended to do under light duty usage that their all gas home provides.
Somehow, unless the product has a high failure rate under the designed usage, then both sides of the story need to be given on the product, which your sight doesn't seem to do.
Maybe you need to say it preforms well under light duty usage, but with the aluminum buss bar has a high failure rate under modern high-demand loads such as electric heat, electric oven, electric hot tub, thus panel should be upgraded before converting to these high-demand type appliances.
And i've seen the photos on your websight, but that breaker was obviously rode hard for a long time to make the wires burn back and all that damage. This wasn't a quick burn or a light load. Something is usually pulling allot of power for a long time to cause that kinda look.
Anyways sorry this is so long, and i like your websight, but it just isn't 'un-biased' as education is supposed to be, thus inspectors are using it as a way to force new expensive electrical panels onto people.
I'm not sure i worded this right, but i hope you grasp the point of giving both sides the story, so as people can make a good decision based on the level of their living, rather than a 200 amp, copper bussbar, electrical panel just be forced on everybody, do to one sided websites.
With Sincerity, Doug
Thank you for your note, it is an important one and a fair question to ask.
To be clear, we are not comparing Zinsco residential equipment with commercial or other special-grade items, but rather to all of the other residential grade equipment in the marketplace, regardless of bus design or materials. With the exception of FPE Stab-Lok, which performs worse and has been more thoroughly studied, there are only infinitesimally few field reports of the kind of bus and breaker burn-ups among other residential products like those reports we receive from electricians, home inspectors, home owners, and builders for Zinsco.
By no means do we suggest that a replacement 200A panel is a requirement where service ampacity requirements are adequatge at lower levels, nor have we specified a requirement for a copper bus panel - not for low income people nor anyone else - the electrical panel size and ampacity are chosen based on the actual building load and usage according to well documented procedures.
The panel ampacity or panel size has nothing to do with the Zinsco question - a product by the way that appears in a range of ampacities itself. It would be a misrepresentation of our information to suggest that we make any such perscription, and if there is text anywhere in our content that is confusing on that point, we would be pleased to correct it.
We will review our text to make sure that this point of view is clear to our readers.
But with the present data on Zinsco - you can readily read the field reports and see the failure photos for yourself and see reports of Zinsco faiures at 2500 times greater than typically experienced in the industry - an informed professional cannot claim that a Zinsco panel offers the same level of overcurrent protection that is afforded by its competitors priced in the same range and of the same panel ampacity.
RE: Zinsco 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. This means homes with this equipment are at greater risk of fire or other electrical hazard.
Yes, this is true, but those boxes are 'not' designed for heavy duty use. They are a cost affordable box for 'residentual' usage where electrical demand is normal, meaning they work well in moderate homes, that are 'not' all-electric, thus don't have electric heat, electric ovens, electric water heaters, electric hot tubs, and other hi-demand devices.
You need to add to your article this 'fact' and state they are perfectly safe when properly used.
This may be America, but we can't all afford a nice 200 amp, copper buss panel now can we, but your article forces low-income people to put such expensive things into their moderate homes before they can sell them now don't you?
Your article is 'not' un-biased.
With sincerity, Doug
More Zinsco Advice
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.
To the best of our knowledge, replacement of this electrical equipment is not required by law, or building code, but it is recommended by experts who are familiar with the occurence of field failures with this product. As described at ZINSCO FAILURE REPORT PROCEDURE, based on that experience and on actual field failure reports we strongly recommend that the electrical panel be replaced.
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.
Continue reading at ZINSCO FAILURE REPORTS or select a topic from the More Reading links shown below.
Suggested citation for this web page
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs)
No FAQs have been posted for this page. Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References