Everybody likes new. The smell of a new home is awesome! But just because you like it, it doesn’t mean that’s what you’re looking for.

Maybe you want a mid-century modern and all of the funky charm that sometimes came with it. Or the simple lines of a 60’s or 70’s rancher.

Great choices. But in certain instances you may not want everything that comes with these homes. What am I talking about? The electrical panels.

Many, many homes from the 50’s, 60’s and 70’s were built with electrical panels from Zinsco and FPE (Federal Pacific Electric), specifically their Stab-Lok load center panels. And unfortunately these panels have a very bad safety history and have been determined to be the cause of many a house fire over the years.

So let’s jump right in and look at each one of these panels and talk about their history, what made/makes them dangerous, and then do a quick wrap-up!

Zinsco

Zinsco panels began appearing in the 1930’s. Initially, they used copper bus bars in their panels. However in the late 1950’s they began using using aluminum bus bars. Additionally the breaker’s interior tripping mechanism could sometimes jam. This could create a condition where visually the breaker appears to be off or have tripped, but in reality the breaker is still on and passing current.

With the aluminum bus bars the breakers would sometimes melt to the bus bar in an overcurrent condition while simultaneously failing to trip. This led to many instances of overheating and fires.

Fortunately Zinsco panels are easy to identify.

The Zinsco label should be easily visible in the top of the panel with the cover door open. Zinsco was sold to GTE-Sylvania in 1973 and they continued to produce the panels for several years under the Sylvania-Zinsco name, so you may see a slightly different label.

Zinsco panels are also easily identifiable by their circuit breakers. 40 amp and below breakers were a very thin, narrow design compared to others. The different breaker amperages were further distinguished by different colored breaker handles, as can be seen in this accompanying picture.

FPE Stab-Lok

Produced by Federal Pacific Electric, FPE Stab-Lok were made and installed in large numbers of homes from the 1950’s up until the late 1970’s.

However over time it was discovered that the Stab-Lok breakers had a flaw in that they frequently failed to trip in an overcurrent condition leading to dangerous overheating of wires and presenting a fire hazard.

Also, similar to Zinsco panels, Stab-Lok breakers sometimes failed to disconnect a live circuit even when in the “off” or tripped position, further endangering service technicians.

Testing showed that failure rates up to 25% existed for never used breakers (never tripped or manually cycled) and an even higher rate for breakers that had been manually cycled.

In 1979, FPE was acquired by Reliance Electric which discovered that FPE had falsified safety tests to obtain UL approval for it’s panels. Yes you read that correctly! UL subsequently revoked it’s listing for these panels and Reliance Electric discontinued manufacturing them shortly thereafter.

FPE Stab-Lok panels are easily identifiable.

With the door open you should be able to find the name “Stab-Lok” printed near the top third of the panel. Also, their breakers had distinctive red tips on the breaker handles.

Summing up

You might think, with all this known information about how dangerous these two panels are that the companies would recall them and the government would mandate that they all be replaced. And if you thought that, you would be wrong.

Neither panel was ever subject to an official recall and for that reason they can still be found in older homes today. The impetus for me writing this blog piece is that last week I encountered a Zinsco panel in a home from 1974 that I was inspecting.

Conclusion

My personal recommendation is if a home you are considering buying has an FPE Stab-Lok or Zinsco panel in it, it should be replaced immediately or at the earliest opportunity. I believe they are that dangerous, even if they’ve managed to make it 50 or more years up to now.

#actionableintelligence #informeddecisions