# old oil circuit breakers



## Safari (Jul 9, 2013)

just wanted to know if anywhere in this world someone is still using these oil circiut breakers(OCB). we have them.the handle there is used for switching 11kv ON.am not kidding.


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## Big John (May 23, 2010)

They're not super common for indoor low power switching here anymore. Much of the 15kV stuff within the bast 40 years is gonna be air or vacuum, and now days they're pretty exclusively vacuum.

I mostly run into oil breakers that size on equipment built before World War II, and honestly I sweat bullets any time one is operated: They have a really bad habit of exploding when not maintained, and they are _never _maintained.


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## JRaef (Mar 23, 2009)

Another reason they are uncommon now is because older ones used oil that was PCB laden, which was outlawed decades ago. Most facilities were required to not only stop adding to them, but actually remove and replace them. There were non-PCB options for the oil, but as mentioned, non-oil based solutions were more readily available and affordable, so that's what people used.

The last one I saw was at a sawmill in Idaho 20 years ago now. It was actually leaking oil. The millwrights had a coffee can below it to catch the oil, which they would pour through a coffee filter and put back into the breaker! I explained to them that it was not only illegal for them to use this, it was a fire waiting to happen, they ignored me. 6 months later it did catch on fire and burned down a significant portion of the mill.


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## HARRY304E (Sep 15, 2010)

Big John said:


> They're not super common for indoor low power switching here anymore. Much of the 15kV stuff within the bast 40 years is gonna be air or vacuum, and now days they're pretty exclusively vacuum.
> 
> I mostly run into oil breakers that size on equipment built before World War II, and honestly I sweat bullets any time one is operated: They have a really bad habit of exploding when not maintained, and they are _never _maintained.


Scary..:laughing:


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## Jlarson (Jun 28, 2009)

JRaef said:


> put back into the breaker!


At least they put the oil back in and didn't just start pumping the red grease they use for everything into it. :laughing:


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## ScooterMcGavin (Jan 24, 2011)

A lot of our transformers had an oil switch on the 13.8kv side for isolation purposes. During an outage an operator opened the switch and it exploded in his face. Fortunately it was outside so the blast was able to dissipate but it was before 70E was real big so he didn't have all he FR gear that we have now. He survived but never returned to work. Subsequently all the switches have been removed. We still have large 115/230kv OCB's but the oil is constantly tested and they're slowly being replaced with SF6 breakers.


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## Big John (May 23, 2010)

JRaef said:


> ...The millwrights had a coffee can below it to catch the oil, which they would pour through a coffee filter and put back into the breaker...!


  I always make that joke, and we laugh, because we know it's a joke and I never in a million years believed someone would be enough of a 'tard to actually do it. Damn millwrongs.


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## Safari (Jul 9, 2013)

Big John said:


> They're not super common for indoor low power switching here anymore. Much of the 15kV stuff within the bast 40 years is gonna be air or vacuum, and now days they're pretty exclusively vacuum.
> 
> I mostly run into oil breakers that size on equipment built before World War II, and honestly I sweat bullets any time one is operated: They have a really bad habit of exploding when not maintained, and they are _never _maintained.


these OCB. scare me to death.i just have to find a way of pleasing the administration to change them.facts to be precise


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## Safari (Jul 9, 2013)

JRaef said:


> Another reason they are uncommon now is because older ones used oil that was PCB laden, which was outlawed decades ago. Most facilities were required to not only stop adding to them, but actually remove and replace them. There were non-PCB options for the oil, but as mentioned, non-oil based solutions were more readily available and affordable, so that's what people used.
> 
> the oil in it has never been replaced since i joined.we use oil insulation tester.to just test it.if it is fine it goes back in. maintenance is once a year.i think once the oil was replaced with transformer oil.do you have site where i can get modern circuit breakers of high voltage?


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## Safari (Jul 9, 2013)

scameron81 said:


> A lot of our transformers had an oil switch on the 13.8kv side for isolation purposes. During an outage an operator opened the switch and it exploded in his face. Fortunately it was outside so the blast was able to dissipate but it was before 70E was real big so he didn't have all he FR gear that we have now. He survived but never returned to work. Subsequently all the switches have been removed. We still have large 115/230kv OCB's but the oil is constantly tested and they're slowly being replaced with SF6 breakers.


thats my greatest fear,i operated it once and never again. there is only one guy who operates them now everyone seems afraid or just ignorant .apparently the SF6 breakers are used in isolating 33kv from 11kv which we use.just post me the types you use will appreciate


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## Safari (Jul 9, 2013)

Big John said:


> I always make that joke, and we laugh, because we know it's a joke and I never in a million years believed someone would be enough of a 'tard to actually do it. Damn millwrongs.



come to think of it. don't be surprised this guy must have been instructed to do so by his supervisor, i hate these guys with a passion.they order you to do what they cant do themselves silly.


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## HARRY304E (Sep 15, 2010)

nickson said:


> come to think of it. don't be surprised this guy must have been instructed to do so by his supervisor, i hate these guys with a passion.they order you to do what they cant do themselves silly.


They're crazy...:laughing:


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## EB Electric (Feb 8, 2013)

Those are some tiny OCB's. A lot of the substations we work in have OCB's on the load side of transformers into OCB and then go out to feed the plant loads. Just finished maintenance on some 44kV ocb's last week. We could operate them remotely from the control room. They definitely are still out there in service.


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## Big John (May 23, 2010)

HARRY304E said:


> Scary..:laughing:


 We have one customer, an ancient hydroelectric plant, that has ten of the stupid things, side-by-side each in it's own concrete cubicle.

Well, three out of the ten cubicles are charred black from where each one of the breakers has blown up at some point in the past. It's a pretty clear illustration of the risk involved.

Incidentally, _nickson_ while I was trying to find some pictures of these old breakers, I came across an a report about an 11kV breaker that exploded. You'll notice that they had those guys switching from _outside the building_ and it's probably the only thing that saved their lives.

http://www.google.com/url?sa=t&rct=j&q=South%20AFRICa%20breaker%20explosion&source=web&cd=1&cad=rja&ved=0CCoQFjAA&url=http%3A%2F%2Fwww.ieeeghn.org%2Fwiki%2Fimages%2F6%2F6f%2FOCB_Explosion.pdf&ei=eCMIUt2NGK2i4APfzoCADQ&usg=AFQjCNHwk33kKrsUdjdMfvbLhUvAZUYFVw


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## HARRY304E (Sep 15, 2010)

Big John said:


> We have one customer, an ancient hydroelectric plant, that has ten of the stupid things, side-by-side each in it's own concrete cubicle.
> 
> Well, three out of the ten cubicles are charred black from where each one of the breakers has blown up at some point in the past. It's a pretty clear illustration of the risk involved.
> 
> ...







> The authorised electrician undertook remote switching of an 11kV Oil Circuit Breaker (OCB) at the main substation. The OCB exploded, probably due to mechanical failure, and the resultant blast wave blew off the doors of the substation, and seriously damaged the building. The electrician broke his upper right arm when the door behind which he was standing was forced violently open. An intense fire followed, destroying all equipment within the substation.


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## retiredsparktech (Mar 8, 2011)

Big John said:


> They're not super common for indoor low power switching here anymore. Much of the 15kV stuff within the bast 40 years is gonna be air or vacuum, and now days they're pretty exclusively vacuum.
> 
> I mostly run into oil breakers that size on equipment built before World War II, and honestly I sweat bullets any time one is operated: They have a really bad habit of exploding when not maintained, and they are _never _maintained.


We had several of them, where I used to work. Our OCB's were operated several times a shift. 
They were used on the large motor test floor. Voltage range from 480 to 2300 volts. The test floor personnel never had any issues using them, as we maintained them very well. Their was a PM program in place, where the oil was changed, tank cleaned and the contacts inspected and replaced.
When the oil was changed, the old oil was black as coal.
A little later, we converted to vacuum breakers, as the maintenance on the old breakers was getting too costly.


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## Safari (Jul 9, 2013)

_*Incidentally, nickson while I was trying to find some pictures of these old breakers, I came across an a report about an 11kV breaker that exploded. You'll notice that they had those guys switching from outside the building and it's probably the only thing that saved their lives.

http://www.google.com/url?sa=t&rct=j&q=South%20AFRICa%20breaker%20explosion&source=web&cd=1&cad=rja&ved=0CCoQFjAA&url=http%3A%2F%2Fwww.ieeeghn.org%2Fwiki%2Fimages%2F6%2F6f%2FOCB_Explosion.pdf&ei=eCMIUt2NGK2i4APfzoCADQ&usg=AFQjCNHwk33kKrsUdjdMfvbLhUvAZUYFVw[/quote]*_

this link you posted is awesome thank you so much BIG JOHN. atleast the guy had a flash suit ON.we dont have them. and our guy is usually like 1 meter away when switching it on.if it was here this could be a disaster.i have sent this link to my boss.hope it will make him think otherwise.i knew i could not trust this things.


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## retiredsparktech (Mar 8, 2011)

Their, They're, There, I seldom do that!


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