# Retrofit of old switchgear



## Black Dog (Oct 16, 2011)

Make sure they shut it down.


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## Flex277 (Jun 2, 2014)

Also have capacitors hooked into 3 pole. I myself am always learning with almost little help from foreman just talks bout personal life and no useful knowledge. But as long as that breaker is open during a shutdown of the whole system should read no voltage on bus bars? Or would there


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## Black Dog (Oct 16, 2011)

Flex277 said:


> Also have capacitors hooked into 3 pole. I myself am always learning with almost little help from foreman just talks bout personal life and no useful knowledge. But as long as that breaker is open during a shutdown of the whole system should read no voltage on bus bars? Or would there



There should be a main breaker for the gear, remember the wires that hit that breaker are always live unless it's shut off by the POCO, always check your self don't take anyone's word for it.


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## Lone Crapshooter (Nov 8, 2008)

On the surface not a good idea . It looks to me that you would loose all the listing on the gear if your company is not a switchgear rebuilder. On the other hand if your company would but the whole unit and not just the breakers I would not have a problem with that.
For a contractor to put breakers in equipment that is designed for fuses without proper engineering and not having UL look at it NO WAY.

LC


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## Flex277 (Jun 2, 2014)

Lone Crapshooter said:


> On the surface not a good idea . It looks to me that you would loose all the listing on the gear if your company is not a switchgear rebuilder. On the other hand if your company would but the whole unit and not just the breakers I would not have a problem with that. For a contractor to put breakers in equipment that is designed for fuses without proper engineering and not having UL look at it NO WAY. LC


Agreed, all this switchgear is in the basement so I doubt the engineer wanted to change the switchgear cuz you'd have to cut hole and lift en out with a crane. This job has an electrical engineer so you'd think that he'd have good idea how to change these buckets out? Lol funny thing is that this is on a Campus of an engineering college


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## Flex277 (Jun 2, 2014)

Black Dog said:


> There should be a main breaker for the gear, remember the wires that hit that breaker are always live unless it's shut off by the POCO, always check your self don't take anyone's word for it.


That I understand I was planning on a shutdown with campus since this is a state job they run there own high volt. I was mainly concerned with the capacitors whether or not there would be any capacitance in the system when I shut it down were working on and if I should discharge it. And what the capacitors are even for. Cleaner power?


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## Big John (May 23, 2010)

If there are capacitors in the system they're likely for power factor correction. There's gotta be a means of isolation in there, be it a disconnect or even just some fuses. I'd pull those to isolate the bank from the system as they absolutely can hold a charge.


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## Flex277 (Jun 2, 2014)

Big John said:


> If there are capacitors in the system they're likely for power factor correction. There's gotta be a means of isolation in there, be it a disconnect or even just some fuses. I'd pull those to isolate the bank from the system as they absolutely can hold a charge.


Makes sense, itson a 3 pole bucket fuse. A 3 pole bucket were gonna end up changing it to a molded case breaker. What's the proper way to to eliminate that residual charge? Get a hot stick and some grounds? Lol


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## NacBooster29 (Oct 25, 2010)

What's wrong with the fuses? Just curious.


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## Big John (May 23, 2010)

If this was a designed system and not something somebody just cobbled together then it likely has discharge resistors (I've got some vague memory that capacitors in switchgear are required to have a bleed-down time of less than 5 minutes, but don't hold me to that). If that's the case, test between each set of plates and each plate to ground. 

If there's no voltage you bond everything together and ground it. If there is voltage you need a discharge stick, or a carefully selected resistor and some PPE. A solid ground can produce a hell of a flash, in addition it can actually damage some styles of capacitors by causing the plates to deform. So it wouldn't be your first bet if you wanted to re-use these.


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## JRaef (Mar 23, 2009)

Most PFC caps require fuses, not CBs, for protection. What is the thinking behind changing to a CB? Because if it is that the fuses are constantly blowing, that is NOT the way to "fix" it!


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## Meadow (Jan 14, 2011)

JRaef said:


> Most PFC caps require fuses, not CBs, for protection. What is the thinking behind changing to a CB? Because if it is that the fuses are constantly blowing, that is NOT the way to "fix" it!


Why so? Ive noticed that but never understood why.


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## JRaef (Mar 23, 2009)

meadow said:


> Why so? Ive noticed that but never understood why.


The purpose of a fuse in a capacitor is to prevent a catastrophic failure that can be not only messy when the electrolyte oozes out all over everything, but potentially even explosive if the pressure relief on the case fails. By the time a breaker senses and reacts to the rapid rise in current in a failing cap, it's too late.

The issue is, there is no real "load" on a capacitor feed, other than a small amount of "parasitic resistance". So the only time a protective device is necessary is if it ALREADY fails, therefore its purpose is just to limit the collateral damage. That's why replacing the fuses with a CB because the fuses are blowing all the time is such a fallacy. All that is going to do is lead to a more destructive failure.


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## Flex277 (Jun 2, 2014)

JRaef said:


> Most PFC caps require fuses, not CBs, for protection. What is the thinking behind changing to a CB? Because if it is that the fuses are constantly blowing, that is NOT the way to "fix" it!


From what I was told that every circuit in this switchgear was getting swapped. I could be wrong in that it gets swapped but I don't even have approved shop drawings on all this yet. Just says on the print and specs that all circuits get re fed from new molded case CBs. Might be a good question for an engineer when the boss goes on vacation next week lol


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## Flex277 (Jun 2, 2014)

Not a good pic but here's the capacitors


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## Big John (May 23, 2010)

Ayuh, those little guys. If you open up the tops of the boxes, they'll look like this:









Just a bunch of daisy-chained electrolytic capacitors. Whether that's even doing an ounce of good is really questionable, because there's no means to switch on or off, they're not variable, and often we see them with no protection or monitoring. 

It's not uncommon to open those enclosures and find several bulged out capacitors where they've gone bad or are going bad and nobody has any idea.


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## Bad Electrician (May 20, 2014)

We retrofit distribution equipment all the time, generally we get the manufactures involved or we hire UL for listing


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## Flex277 (Jun 2, 2014)

Well tonight was our first shutdown for this switchgear and had problems with the main breaker opening. Hit the manual trip and only opens up about halfway and still pushing voltage through. Got it to fully open once and it went to close on its own. Kind of strange right so we decided to not proceed with this and told owner rep and it's in there hands I guess. To me this didn't seem normal. Everything I've ever worked on has a tendency to do what I tell it to. This freaked me out beings it 480 and it's old as hell


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## EB Electric (Feb 8, 2013)

Flex277 said:


> Well tonight was our first shutdown for this switchgear and had problems with the main breaker opening. Hit the manual trip and only opens up about halfway and still pushing voltage through....This freaked me out beings it 480 and it's old as hell


Fun stuff lol. 480...We had 230 kV electrically operated air switch open and some gears in motor operator decided to get out of alignment half way open, that makes for some excitement!


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## Bad Electrician (May 20, 2014)

Flex277 said:


> Well tonight was our first shutdown for this switchgear and had problems with the main breaker opening. Hit the manual trip and only opens up about halfway and still pushing voltage through. Got it to fully open once and it went to close on its own. Kind of strange right so we decided to not proceed with this and told owner rep and it's in there hands I guess. To me this didn't seem normal. Everything I've ever worked on has a tendency to do what I tell it to. This freaked me out beings it 480 and it's old as hell


Bolted Pressure Switch? We service and repair. Seems someone in you firm lacked the experience to take a job like this on. With old equipment we ALWAYS plan for the switch not opening and go from there.

We service and keep them operating properly. IF you had a utility outage some 2-26 and the proper service after opening, lubrication and 95% of the time the issue is resolved.

I'll gladly come repair the switch.


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## Flex277 (Jun 2, 2014)

Bad Electrician said:


> Bolted Pressure Switch? We service and repair. Seems someone in you firm lacked the experience to take a job like this on. With old equipment we ALWAYS plan for the switch not opening and go from there. We service and keep them operating properly. IF you had a utility outage some 2-26 and the proper service after opening, lubrication and 95% of the time the issue is resolved. I'll gladly come repair the switch.


lol South Dakota is long ways from west va. You might make it in time for the sturgis rally but none of us are usually working that week


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## Bad Electrician (May 20, 2014)

Flex277 said:


> lol South Dakota is long ways from west va. You might make it in time for the sturgis rally but none of us are usually working that week


I have traveled further for less work (NOT LESS MONEY).


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## Big John (May 23, 2010)

Bad Electrician said:


> I have traveled further for less work (NOT LESS MONEY).


 Did a 10 hour round trip to turn a breaking racking handle a couple times.

_"Are you 100% sure it's completely racked in? There are cell interlock switches that have to be satisfied in order for your DCS to allow the breaker to be closed."
"Yes, yes, we tried everything! Just get down here! __It's racked in!"_

No, it wasn't.


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## Bad Electrician (May 20, 2014)

Big John said:


> Did a 10 hour round trip to turn a breaking racking handle a couple times.
> 
> _"Are you 100% sure it's completely racked in? There are cell interlock switches that have to be satisfied in order for your DCS to allow the breaker to be closed."
> "Yes, yes, we tried everything! Just get down here! __It's racked in!"_
> ...


Been there, did one the CB would not rack in, explained how to lift the lever under the CB to get it past the first few inches into the cubicle. Got there I was there all of 15 minutes.

The worst was 3 hours one way, on the way back home I asked the other electrician did you put the cover back on, he said yeah I think so, we were not back home an hour when we got the call WE left the cover off.


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## Sparky J (May 17, 2011)

So did you have to go 3 hrs. back for the cover?


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## Bad Electrician (May 20, 2014)

Sparky J said:


> So did you have to go 3 hrs. back for the cover?


Yep! 3 down, 5 minutes on site and 3 back, the price for not doing my job 110%.


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## Big John (May 23, 2010)

Oh, man. We had one like that. Accidentally left a disconnect in the "off" position. Operator called us when we were already an hour away.

_"You guys left a switch turned off."
"Well, your feeder is still de-energized, just turn the disconnect on."
"We can't operate disconnects."
"There's no power there, there's no hazard."
"Nope. We can't operate disconnects."
"It's gonna take us an hour just to get back there."
"Don't care. You left it off."_

So we drove an hour back just to throw a switch and walk out the door. I know the customers have policy and it was our mistake, but really guys? Maybe if you're unqualified to turn on a de-energized disconnect you shouldn't be responsible for operating a power plant.


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