Field Failure Reports on Zinsco Electrical Panels & GTE-Sylvania-Zinsco Circuit Breakers InspectAPedia® -
Field failure reports indicate severe failures of Zinsco electrical panels / circuit breakers
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Here we provide field failure reports and additional photographs of burned or failed Zinsco and GTE-Sylvania-Zinsco electrical panels and circuit breakers. 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.
Page top photo of a Zinsco burned main circuit breaker provided by Washington state electrician J. P. Simmons
FAILURE REPORTS - Field Failure Reports for Zinsco Circuit Breaker/Panel & Sylvania Electrical Panels
We [J Simmons] see damage in about 25% of the Zinsco/Sylvania panels that are checked.
The problem occurs mostly on circuit breakers feeding circuits that have a steady heavy load on them
(like heaters, hot water tank, dryer), and on circuits that are often overloaded such as circuits that supply
the kitchen or bathroom.
In houses with Zinsco/Sylvania electrical panels and circuit breakers, I [Simmons] have tested these circuits with up to
30 amps on a 20 amp circuit breaker. The Zinsco circuit breaker will carry the overload for a long time without tripping.
This causes the connection to heat up and start arcing to the buss bar.
The problem is primarily in the panels with aluminum buss bars, but also has been seen in the ones with copper buss.
Moisture seems to accelerate the process. Readers should also see HOW TO REPORT ELECTRICAL FAILURES to homeowners when a Zinsco Sylvania electrical panel is observed by a contractor, home inspector, or electrician.
The following anecdotal reports describe observations of failures in Zinsco and Zinsco-Sylvania electrical panels, buses, circuit breakers.
Since most home owners and electricians are more focused on immediate electrical repair and safety needs than in taking photographs
and writing failure reports, our opinion is that number and frequency of these electrical failure field reports are the "tip of the iceberg" of
actual occurrence. (At left, the photo of a burned Zinsco main circuit breaker and burned greased Zinsco electrical panel bus was provided by Washington state electrician J. P. Simmons)
We estimate that only 2% to 5% of electrical failures are recognized and reported to the U.S. CPSC or to researchers such
as Daniel Friedman or Jess Aronstein. This opinion is supported by a US CPSC study of failed electrical receptacles.(1).
02/19/2008 - J.P. Simmons: Just got these pictures [more photos were provided and are on file] of a badly damaged Zinsco main that failed. 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.
2/20/2007 - Jim Shuma Zinsco no-trip, wiring burn-up report: I had some wiring burn through in my home. The circuit was overloaded, but the Zinsco panel didn't trip. Note the burned insulation, the burned outlet cover, and the wire that burned through. (See photo at left).
03/06/2007 Zinsco Main No-Trip, wire burn-up report, Jon Bolton (see photo at left).
Notice the burned wires connected to the bottom double-pole Zinsco circuit breaker?
01-08-2006 06:59 PM -- Since I started this, now I'll put in my 2 cents. I am a master electrician (obtained license while still working in the field), a certified electrical inspector and a CBO. I'm with Ryan! And I have a FPE panel in my bedroom closet (oops, Ryan just disclaimed me). PG and Tanky, do you really think you can condemn my house for having a old panel??
My parents house has a Zinsco from the 50s, split bus. You're gonna go after mine in a closet but say their's is OK because its in the garage (with paper files stacked around it). I think a change out should be allowed to stay in the closet, but with so many people having concerns, maybe I should find a way to CYA or at least strongly encourage the HO to move his panel.
One thing to think about is how many homes have panels in garages and have cardboard boxes stacked around it and in front of it. That's a violation but we don't require the garage floor to be marked "no combustibles in this area". (Oops again, I probably gave someone an idea.)
Thanks to everyone for participating, but if you're gonna zing somebody, do it backhanded with sarcasm, its funnier than the in your face stuff.
From: garland, TX (near Dallas) | Registered: Jan 2005 http://www.iccsafe.org/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=11;t=000888
01-09-2006 02:36 AM --
jboren, Yes I could and would condemn your home if I knew it was a fire or safety hazard. I believe if your parents service was a fire hazard you would have already fixed it. There are way too many government dollars available out there for someone to use the excuse it cost too much.
[DF NOTE: This is from the ICC bulletin board - ICC is the International Code Council]
May 04, 2005 - Susan R. Olympia, WA: Customer called to have a burnt up outlet in their bathroom repaired. When I
arrived on site I found the outlet completely burnt up, and the wiring badly damaged. The circuit was 12 gauge on a 20
amp Zinsco breaker.
After some tracing I found the circuit also had kitchen outlets on it. The refrigerator and
microwave they were using added up to 20 amps exactly, but they also had 2 bathroom outlets and lights on the same
circuit. The owner had two portable heaters they used for the bathroom and bedroom area, and also used the typical hair
dryer and curling iron, all on the same circuit! I asked the owner if the circuit ever tripped and she said that it had
when she used the hair dryer while the heater was on, and the microwave was being used at the same time.
This would be at least 36 amps on a 20 amp circuit! They did not have a problem using the smaller heater (1000 watts) and the
microwave and hair dryer at the same time (about 30 amps), or when using the larger heater and the microwave at the same
time. - Jim P. Simmons
January 28, 2005 - Zinsco panel, meter clip short circuits to panel?? Dear Mr. Friedman, Have you ever run into a
situation with an 70's era Zinsco panel wherein upon removal of the panel face cover, the meter can be moved in such a
manner that the lower meter clip contacts short to the panel housing. I have recently seen a panel with this condition
and was wondering if this is a known problem with some Zinsco panels. Thanks, - Phil
3-21-2004 Kory
I am a
12 year veteran electrician with a new business in hand. I am seeking hard data on the Zinsco and FPE panels, I have a
few personal experiences that make me personally aware of the dangers these brands but sound to a customer as self serving
when I make my warning "I would consider replacing that panel as soon as possible".
Most consumers look at the
panel as something that has existed for many years without harm and I feel consider my words as money making. Truth is
even if they choose another contractor I still want them to be better informed!
Any direction you could pass to
me would be appreciated. I have spent many hours searching the web and seem to find forum type input more then hard fact
9-2-2003 Split Bus Zinsco: Thought you might like to see some more Zinsco panel damage pictures. I have this panel
in my possession. This panel was badly damaged in the whole top section (above the sub main) where it is not possible to
shut the power of because it is a split-buss panel with no main breaker. The really scary part is the customer did not
know they had a problem.
I was at the site to do an estimate and noticed the Zinsco panel. I asked the customer if it
was alright to check it for him, and he agreed. He said the only trouble he knew about was the water heater didn't
always give them real hot water. I pulled the panel cover off and everything looked OK. I checked the breakers with a
volt meter and had proper voltage at all the circuits.
Then I started (carefully) removing breakers and found the top
(water heater circuit) breaker had welded itself to the buss and came apart when I tried to remove it (this could be very
dangerous for a homeowner or home inspector). I removed several other breakers and found them to be badly damaged, and
the bussing was burnt in several locations. After seeing the situation it was not hard to convince the owner that it was
time to replace the Zinsco panel. -- J Simmons
8-29-2003 Zinsco: Thought you might like to see some more Zinsco panel damage pictures. I have this panel in my
possession. This panel was badly damaged in the whole top section (above the sub main) where it is not possible to shut
the power of because it is a split-buss panel with no main breaker. The really scary part is the customer did not know
they had a problem.
May 15, 2003 - Zinsco/Sylvania breakers and panels - Dan P. Olympia, WA
I was asked to look at this customer's
home to give them an estimate to replace a Zinsco/Sylvania panel. The panel is the split buss type 200-amp with no main
breaker. The panel looked OK but when I removed some of the breakers to check the bussing I found that the 100-amp
2-pole that fed to his shop had signs of degradation on the buss. The 2-pole 30-amp breaker next to it also had started
deteriorating. They had not failed yet or caused the customer any noticeable problems.
I then tried to remove the
60-amp 2-pole sub feed breaker (it feeds the bottom section of a split buss type panel) and it would not come out. I
went to my truck and got my large screwdriver to use (carefully because there is no way to shut off the power to it) as a
prey bar. I tried to remove it again and the breaker was welded onto the buss so bad that the buss started to come out
with the breaker.
I pushed the breaker and buss back into place and let the customer know that he had a serious problem
that needed to be addressed as soon as possible. I will get him a price to replace the panel ASAP.
Pictures 1,3
,5,6 are of this panel. - Jim Simmons
April 25, 2003 - Ken W., Olympia, WA - Lacey, WA
We had recently removed a Zinsco panel that was causing some
problems for Ken Woehl. The bussing was damaged in a couple places (the problem was identified on a home inspection that
I did for him) where the breakers plugged onto it. We got a call from our customer today about a problem he was having
with the new Cutler Hammer panel we just installed for him (to replace the Zinsco).
His complaint was when he ran his
furnace and his microwave at the same time the circuit tripped. He said the breaker never tripped before (when the
Zinsco panel was in place). Code requires the furnace to be on a separate circuit, but evidently the wiring had been
altered so the kitchen microwave was on the same circuit. The circuit load with the furnace and microwave both on was
over 26 amps.
Now that we installed a good quality circuit breaker panel the breakers are doing what they should -
shutting off when there is an overload and protecting the house. The Zinsco panel has bussing damage in it caused by a
circuit that was overloaded for a long period without the circuit tripping. I have this panel in my possession for
confirmation and the pictures here are from this site. - Jim Simmons Photo 8: A Zinsco main panel , and Photo 9: A Zinsco burned circuit breaker .
- updated by J Simmons 3/8/2006
4/15/03 - Black Lake Park - - Re: Zinsco Breakers: I was called out to bid a job for the Black Lake Community
Park. I checked the panel for circuit capacity and noticed it was a Zinsco brand. I asked the customer if it was OK if
I checked it, and proceeded to pull the cover off. The breakers and panel looked to be in great shape. No obvious heat
damage or signs of conductor damage.
I proceeded to pull off the breakers and found the top 3 - 30 amp breakers all
had serious damage to the breaker and the bussing. One was so bad that the part of the breaker that pushes onto the
bussing had become welded to the buss. The breaker actually broke apart (with the connection staying on the buss and the
rest of the breaker coming out) when I tried to remove it. The panel did not have a main breaker (split buss type) so
there was no way to shut off power to the top (main) section.
This could be extremely dangerous if a homeowner,
or a home inspector had tried to remove the breaker to replace it, or check it. (I have this panel in my possession
because they had us change it). -- Jim Simmons
3/22/03 - May G. Olympia, WA
Re: Zinsco Split Buss Panel, about 40 years old: On 3/22/03 I
went out on an emergency call - The customers friend was removing baseboard electric heaters for her that were no longer
needed (she had a gas furnace installed). He turned off the circuit breaker that was marked "Main" and proceeded to cut
the wires loose on the heaters.
He thought he had the power off, the only problem was this panel was a older type that
did not have a main. It is called a split buss type panel (it does not have a main breaker) and you have to turn off all
the breakers to kill all of the power. He proceeded to cut the wires from the back of the baseboard heaters, and shorted
out one circuit when he cut it.
He had bright flash and loud bang which scared him so bad he dropped his wire cutters.
He went to the panel expecting to find a circuit breaker tripped, but and none were tripped. He was concerned so he
called us for some expert advice. I confirmed that none of the breakers had tripped even though he had shorted across a
240 volt circuit!. We recommended that they change the panel to a new one to get rid of the Zinsco panel.
Unfortunately this is not a isolated incident. The circuit breakers are very poor quality and do not provide a safe
level of over current or short circuit protection. - Jim Simmons
March 2003 - John A., Seattle WA
This message is in response to your request for descriptions of problems with
Zinsco electrical panels. Our panel (in a 1922 Seattle house) was installed in December 1960, based on the city
inspection tag we found stuffed into the wiring.
In early March 2003, on a day when we were about to leave the
country on vacation, we noticed that some of the incandescent lights in our living room were flickering slightly. At the
same time, we heard the squeal of the UPS that protects the computers in our home office (a noise it makes when it
detects bad power). It was a very windy day, and we attributed the problem to a tree branch hitting a wire. We shut off
the UPS and left on our vacation.
Upon returning, we discovered that the circuit for those areas of the house
was completely dead. The circuit breaker had not tripped, but it had failed and no power was being delivered to that
circuit. Resetting the breaker had no effect (although it did cause a sizzling noise and, after the panel cover was
removed, a visible sparking).
We called an electrician to fix the problem, and he filled us in on the Zinsco
problems. we have one other circuit with a flickering incandescent light (all other lights on the circuit are
fluorescent, and don't show the flickering), and we suspect that the problem is another bad breaker. We are currently in
the process of having the entire panel replaced.
The citations below are representative of comments observed at Mike Holt's Page on Zinsco Breakers - http://www.mikeholt.com/forum/Forum1/HTML/005092.html
as of 3/8/2006. Holt's page contains additional information. Emails were deleted from the text here for privacy.
December 28, 2002 - Don Walker, Location: Georgia, Electrician:
In Trade Since: 1982,
Registered: Dec 2002,
here's the situation.... customer complained that breaker would not trip...5 year old stuck a fork in receptacle ....sparked for several minutes...had to take broom handle and knock fork out of receptacle. heard a lot of negative about Zinsco breakers ...should I... tell customer to manually turn each breaker on and off several times (once a year) replace all breakers with new Zinsco ...replace Zinsco panel(200 amp) with a more name brand (square d...Siemens...etc)
house has all aluminum wiring.
December 28, 2002 -
Name: Tim Hausmann
Location: Illinois
Title: Electrician
In Trade Since: 1982
Registered: Apr 2002
-- Once saw a Zinsco breaker not trip when my amp probe showed 34 amps being pulled. Scared the hell out of me. By the way, it was a 15 amp breaker.
December 29, 2002 -
Name: Allen Wayne
Location: Florida
Title: Electrician
In Trade Since: 1975
-- I haven't seen many Zinsco breakers recently
but just like a stab lock fpe you can almost arc weld with them,Home depot sells a replacement for them about $25 a single pole breaker.It would be more cost efficient to just replace them with an available and affordable breaker/panel
December 30, 2002 -
Name: Todd Yetter
Location: Delaware
Title: Electrician
In Trade Since: 1988 --
Has anyone ever seen the Zinsco breakers that don't have a set screw on the terminal lug? just a pressure terminal like on the back of stereo equipment
RESPONSE:
Paul W.
Location: Washington
Title: Electrician
In Trade Since: 1991 --
Has anyone ever seen the Zinsco breakers that don't have a set screw on the terminal lug? just a pressure terminal like on the back of stereo equipment?
Yes, I have.
They have a tab underneath where the wire stabs in, to release the wire from the breaker.
Note that there is a reason that UL pulled their listing from Zinsco breakers....THEY DON'T TRIP!!! FPE also has the same problem. Bulldog Push-o-matic's, I believe, also have the same problem. But hey, on the plus side you don't have to deal with any nuisance tripping, either
Submissions of Zinsco or other electrical component field failure reports and failure photographs wanted.Contact the web author by email
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Personal communication, J. Aronstein to D. Friedman, 3/6/2006
James P. Simmons: Personal communication and photographs used in this article series, J. Simmons to Daniel Friedman, 3/4/2006, 2/19/2008. Photographs contributed to this website by Jim P. Simmons, Mr. Electric, Licensed Master Electrician,
1320 Dayton Street SE, Olympia, WA 98501, 360-705-4225, Fax 360-705-0130 or by email to mrelectricoly@msn.com
Thanks to various electricians, home owners, and home inspectors for contributing the Zinsco Sylvania-Zinsco electric panel and circuit breaker field failure reports cited above.
Thanks to David Osborn, an alert home inspector, for helpful critique regarding the need for Zinsco/Sylvania electrical panel replacement, 4/27/06
Thanks to Joe Funderburk,
Alpha & Omega Home Inspections,
Hickory Grove, SC for his photos of a Kearney electrical panel. Mr. Funderburk is a NACHI member and home inspector who can be reached at jfunderburk@aohomeinspection.com or at www.aohomeinspection.com
Thanks to Texas electrician Jeff Weissman for contribution of photographs of burned Zinsco circuit breakers. 03/06/2007. Mr Weissman can be reached at jeffweissman@gmail.com or by telephone at 713-666-6605
Thanks to reader Jim Shuma for Zinsco electric panel circuit breaker no trip report and wiring burnup photos, December 2007.
Thanks to Jon Bolton for field photographs of Zinsco electrical panels and circuit breakers, including the no-trip burnup Zinsco photo used in this article.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
Recommended books on electrical inspection, electrical wiring, electrical problem diagnosis, and electrical repair can be found in the Electrical Books section of the InspectAPedia Bookstore. (courtesy of Amazon.com)
Aluminum Wiring Information WebsiteAluminum Electrical Wiring Hazards and Repairs: in-depth authoritative info, photos, documents including selection of proper vs. ineffective repair methods. E.g.: Ideal 65 "Twister" purple connector fails in field and lab testing with aluminum wire.
Circuit Breaker, a bad one fails to trip failure at aluminum bus-to-circuit breaker connection - field report and photographs
Electrical Panels, How to Inspect in Buildings, safety for electrical inspectors, electrical panel, fusing, wiring defects, defective products. Inspection Class Presentation
Federal Pacific Electric (FPE) Stab-Lok Circuit Breaker Panel Hazards Website - Latent fire hazards, in-depth authoritative research, documents, advice on Stab-Lok electric panel and circuit breaker failures and what to do when this equipment is found in buildings.
"Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
"Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
"How to plan and install electric wiring for homes, farms, garages, shops," Montgomery Ward Co., 83-850.
"Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
"Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
"How to plan and install electric wiring for homes, farms, garages, shops," Montgomery Ward Co., 83-850.
"Home Wiring Inspection," Roswell W. Ard, Rodale's New Shelter, July/August, 1985 p. 35-40.
"Evaluating Wiring in Older Minnesota Homes," Agricultural Extension Service, University of Minnesota, St. Paul, Minnesota 55108.
"Electrical Systems," A Training Manual for Home Inspectors, Alfred L. Alk, American Society of Home Inspectors (ASHI), 1987, available from ASHI. [DF NOTE: I do NOT recommend this obsolete publication, though it was cited in the original Journal article as it contains unsafe inaccuracies]
"Basic Housing Inspection," US DHEW, S352.75 U48, p.144, out of print, but is available in most state libraries.
Aluminum Wiring Information Website Aluminum Electrical Wiring Hazards and Repairs: in-depth authoritative info, photos,
documents including selection of proper vs. ineffective repair methods. E.g.: Ideal 65 "Twister" purple connector fails in field and lab testing with aluminum wire.
Electrical Panels, How to Inspect in Buildings, safety for electrical inspectors, electrical panel, fusing, wiring defects,
defective products. Inspection Class Presentation
InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.
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Photo 8: A Zinsco main panel 
Photo 9: A Zinsco burned circuit breaker 
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