Faulty Thinking

Anyone who thinks that something is unlikely to happen because it has not yet happened is engaging in  ‘faulty thinking’.  Anyone thinking “I won’t get run over by a car while crossing this intersection on foot because I’ve crossed this intersection at least 500 times and have never been run over” had better carefully look both ways.  Or someone thinking “my car will certainly start right now when I’m in a hurry because it has always started before” doesn’t understand the life cycle of a battery.  

Why this introduction?  Because I run into faulty thinking every now and then at inspections.  The situation that occurred this week that prompted me to write this blog post had to do with an electrical panel.  

Electrical panel

Zinsco Electrical Panel

Several times a year an inspector will discover electrical panels that are known to cause problems. 

Zinsco panels (or Sylvania/Zinsco or Sylvania) are one and the other is Federal Pacific Panels with Stab-loc breakers.  Some inspectors might claim that these panels have been recalled; to my knowledge no formal recall has ever been issued by the Consumer Protection Safety Commission for either of these panels. 

However, they are widely recognized as being potentially problematic and will almost always be called out for replacement by an inspector.



This is our report language, developed over several years, for each of these panels:

This property has a Zinsco (or Sylvania or Zinsco/Sylvania) brand main service panel. These panels and their circuit breakers have a variety of problems, including buss bars made from aluminum that tend to oxidize and corrode, breakers that don’t trip under normal overload conditions, and breakers that appear to be tripped when they’re not.  These problems are a safety hazard; we recommend having a licensed electrician replace any and all Zinsco brand panels.

This property has a Federal Pacific Electric brand main service panel that uses “Stab-Lok” circuit breakers.  Both double and single pole versions of these circuit breakers are known to fail by not tripping when they are supposed to. This is a potential but serious fire hazard.  We recommend having a licensed electrician replace any and all Federal Pacific panels.

Zinsco Electrical Panel

Zinsco Electrical Panel

This week one of our inspections was on a home built in 1901.  It likely started life with a fuse panel and had a Zinsco breaker panel added sometime later, likely in the third quarter of the 20th century.  The tenant is looking to purchase the home from the owner and told me the owner was aware of the Zinsco panel and its issues.  The tenant had done some research and found that some information said it should be replaced, while other information suggested a more relaxed approach, saying that if it has worked for decades, don’t fret.  He was concerned and open, which was a nice change from the more typical home seller who can’t understand why the panel that has been there for so long now should be replaced by them before they can sell the home.  

One issue I try and help people understand is that a home is use dependent… it responds to the way in which it is used.  If a quiet older couple lives in a home, the screen door probably works fine because it is never challenged.  If a family of 5 with 3 teenagers lives in the home, the screen door may be just barely hanging on.  Electrical panels are no different.  If that same older couple lived in a home with a Zinsco panel, it is unlikely that they have risked overloading a circuit whose breaker may not trip.  Put that same family of five in the home with three hair dryers, five computers, two space heaters and a welder and air compressor in the garage, and the likelihood a circuit could get overloaded has just gone up a lot.

Electrical Panel Wiring

Electrical panel wiring

When I opened the Zinsco panel on the 1901 house this week the story was clear.  One circuit had a wire that had been scorched and had melted insulation… a sure sign of the wire having been dangerously overloaded.  The circuit breaker should have tripped and protected that wire but it clearly had not.  When had this happened?  There really is no way to know for sure.  Could have been 25 years ago when the home may have housed a family of 5… 


Faulty thinking when it comes to whether or not your car will start on its old battery is playing with inconvenience.  Faulty thinking regarding an electrical panel is an entirely different story.

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