# Old OCB



## Zog (Apr 15, 2009)

Found this beauty, coolest part was for GF detection this system used a "flash bus", basically a piece of fish paper that would allow an arc if a phase became grounded.


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## McClary’s Electrical (Feb 21, 2009)

Cool:thumbsup: Thanks.

How old is it?


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## ColoradoMaster3768 (Jan 16, 2010)

Zog said:


> Found this beauty, coolest part was for GF detection this system used a "flash bus", basically a piece of fish paper that would allow an arc if a phase became grounded.


Thanks for the post Zog. The "fish paper" looks as though it acts somewhat like "film-disk cutouts" used in old, series, constant-current street lighting circuits.


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## Lone Crapshooter (Nov 8, 2008)

I recognize the old Westinghouse oil breaker I think it is a F100 . I do not recognize that type of ground detection system. 
Could you please explain how it works.
Thanks


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## Big John (May 23, 2010)

Lone Crapshooter said:


> I recognize the old Westinghouse oil breaker I think it is a F100 . I do not recognize that type of ground detection system.
> Could you please explain how it works.
> Thanks


 Bumping this zombie thread because this is interesting.

I've never seen that style of fault detection, but if you made me guess it's designed so that L-G voltage is present on one side of that bus, and in the event of a phase-to-ground fault the voltage across the bus rises to full L-L value and punches the paper? 

They used to do the same thing for old high-voltage series street lamps. When a filament burned open it would put the total system voltage across the open lamp and burn through a piece of kraft paper to keep the string going.


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## Zog (Apr 15, 2009)

Big John said:


> I've never seen that style of fault detection, but if you made me guess it's designed so that L-G voltage is present on one side of that bus, and in the event of a phase-to-ground fault the voltage across the bus rises to full L-L value and punches the paper? .


Exactly:thumbsup:


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## Meadow (Jan 14, 2011)

This is a first for me as well.

What voltage is this for?


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## nick526 (Oct 30, 2014)

That's cool!

Here's another old timer that's still in service and feeding a VERY congested urban area:


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