Trivia/Metal Blanks for QO

[jmellc]

Did a recent service call to a home built in 1960 with QO panels. Had metal panel blanks. Never saw metal ones for QO before. FPE was the only one I knew of before with metal blanks.

 

[jim dungar]

Did a recent service call to a home built in 1960 with QO panels. Had metal panel blanks. Never saw metal ones for QO before. FPE was the only one I knew of before with metal blanks.

In the 50's they started out as metal, and were painted gray. By the mid-80's the preferred blanks were plastic, with the metal ones becoming more expensive and loosing their paint. By the 90's the metal were no longer offered.

 

[mike7330]

And when they fell into the inside of the panel they made fireworks, thank god they are made of plastic now

 

[jim dungar]

And when they fell into the inside of the panel they made fireworks, thank god they are made of plastic now

The metal plates were phyiscally larger than the breaker opening. they sat outside of the cover, and there was a small catch on the inside.

I can't remember ever hearing of, a QO, one that fell through.

 

[Volta]

Did a recent service call to a home built in 1960 with QO panels. Had metal panel blanks. Never saw metal ones for QO before. FPE was the only one I knew of before with metal blanks.

I have found metal blanks for Pushmatic too.

 

[kwired]

And when they fell into the inside of the panel they made fireworks, thank god they are made of plastic now

The metal plates were phyiscally larger than the breaker opening. they sat outside of the cover, and there was a small catch on the inside.

I can't remember ever hearing of, a QO, one that fell through.

Back in the day when the metal blank fillers were being made the bus design of the QO panel was different than today also. If one of those were to enter the panel today it will have a harder time contacting two points of potential simultaneously.

 

[jim dungar]

Back in the day when the metal blank fillers were being made the bus design of the QO panel was different than today also. If one of those were to enter the panel today it will have a harder time contacting two points of potential simultaneously.

The bus design has hardly changed at all. Yes, there are different inter-bus insulators but those primarily come about after the 'obsolescence' of the metal blanks.

Back in the day, I dealt with many more bus replacements due to 'screw driver mis-use' than I did with blanks falling into the panels. I want to say the two most common issues were operator error: screw driver tips causing shorts and being used to 'adjust' the factory engineered breaker's plug-on jaws.

 

[kwired]

The bus design has hardly changed at all. Yes, there are different inter-bus insulators but those primarily come about after the 'obsolescence' of the metal blanks.

Back in the day, I dealt with many more bus replacements due to 'screw driver mis-use' than I did with blanks falling into the panels. I want to say the two most common issues were operator error: screw driver tips causing shorts and being used to 'adjust' the factory engineered breaker's plug-on jaws.

That is basically what I meant, the insulators have covered everything except a small area where each breaker plugs on to the bus. Old designs the entire bus was pretty exposed if no breakers were installed.

 

[jim dungar]

That is basically what I meant, the insulators have covered everything except a small area where each breaker plugs on to the bus. Old designs the entire bus was pretty exposed if no breakers were installed.

The new insulation was more of an industry pressure/standard and manufacturing issue than anything else. The mid to late 80's saw a lot of metal parts being replaced with non-metallic ones.

 

[kwired]

The new insulation was more of an industry pressure/standard and manufacturing issue than anything else. The mid to late 80's saw a lot of metal parts being replaced with non-metallic ones.

Yes the interior pan was starting to be made of non metallic components, but since then they have covered up the bus where it used to be entirely exposed. I can't recall any other series miniature breaker panel that has has such little exposed bus.

 

[jim dungar]

Yes the interior pan was starting to be made of non metallic components, but since then they have covered up the bus where it used to be entirely exposed. I can't recall any other series miniature breaker panel that has has such little exposed bus.

They fully covered the bus as part of its manufacturing process as well as marketing. Their QO loadcenter offering is now similar to their NQ panelboard.
About the same time they switched to the insulated interiors, they stopped selling replacement bus bars.