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Zinsco or GTE Sylvania Panel Failure Reports:
This article describes field failure reports of Zinsco or Sylvania-Zinsco or Kearney electrical panels: overheating, failure to trip, fires, other defects.
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.
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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.
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).
I could hear arcing and my lights were blinking, so I reset all the breakers. Many of the breakers were loose, so I pulled them and tighten the clips. The problem continued, so finally I pulled the "main" breaker (125 amp) to find corrosion and arcing on the crossbars.
The question is whether this box can be retrofitted as you suggest on your website, or will I need to replace the whole panel.
My Zinsco panel is aligned vertically (~30" tall by 14" wide) [Drawing at left, provided by the owner.]
The top third contains the breakers arranged horizontally on parallel aluminum crossbars; the middle third had the service meter; and the lower third is enclosed so I guess it covers the supply wiring from the street.
Also, the panel is outside on an exterior wall, installed around 1967.
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
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
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
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
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
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.
Also see FLICKERING LIGHT DIAGNOSIS - causes of flickering or dimming lights
Continue reading at ZINSCO OVERHEAT IR PHOTOS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or see ZINSCO CIRCUIT BREAKER TEST REPORT for a summary of Zinsco and UBI-Zinsco-Replacement circuit breaker test results to date.
Or see ZINSCO FAILURE REPORT PROCEDURE to homeowners when a Zinsco Sylvania electrical panel is observed by a contractor, home inspector, or electrician.
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