# Padmount Transformer Arrestors



## Big John

Anyone have experience with pad-mount transformer arrestors?










Recently had a bad bushing, and and the only thing on hand was an arrestor insert like the one pictured. Could not screw it in for the life of me because there just wasn't room to spin it without hitting everything. 

Felt like a bloody idiot, but couldn't offer any explanation for how the other ones had been installed in a compartment that size:
- Either they came installed from the factory.
- There's some dumb trick I'm missing
- Or they just disassembled the entire transformer compartment every time they want to replace one.


Also, just for kicks, I saw this photo while doing a search for that bushing. :laughing:


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## MTW

:blink:


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## BBQ

Big John said:


> Anyone have experience with pad-mount transformer arrestors?


Arresting transformers?

Homeland security is going to far.


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## Big John

Illegal transformer scum! Taking all our good padmount jobs.


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## Celtic

Did you have the right type?









*M.O.V.E. DirectConnect Elbow Arrester*













*POSI-BREAK Metal Oxide Varistor Elbow (M.O.V.E.) Surge Arrester*





These are two I just found quickly to illustrate that there is more than one type on the market.


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## Celtic

...some pdfs

35 kV Class M.O.V.E. DirectConnect Elbow Arrester Installation Instructions 

POSI-BREAK™ Solution to Separable Connector Switching Problems


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## Big John

It wasn't an elbow arrestor. This was a well-insert arrestor just like the picture I posted, it screwed right onto the draw lead stud, and then the elbow plugs into it. If you've got room, they do just spin right on.

But in this case I had no clue how to do it without literally disassembling the compartment frame, and not sure that would've even worked because of a bunch of welded stuff.


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## 8V71

Could you have maybe removed something from the back to access a screw head?


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## Celtic

that first pdf showed a threaded adaptor....any help?

Elastimold also use an interface that is threaded...see note 4 on pg 29 in this PDF:

*200 amp deadbreak - thomas & betts*


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## Celtic

8V71 said:


> Could you have maybe removed something from the back to access a screw head?


Back of the arrestor is molded...solid.
Back of the pad mounted transformer is full of oil


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## 8V71

Celtic said:


> Back of the arrestor is molded...solid.
> Back of the pad mounted transformer is full of oil


I meant the arrestor but I hear ya :laughing:


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## Big John

8V71 said:


> Could you have maybe removed something from the back to access a screw head?


 I don't think it's possible, but that's why I asked.

I made some calls and nobody could give me an answer beyond "Just screw it in!" and I didn't want to tell the customer it was impossible because every time I do that, I'm wrong. :whistling2:

EDIT: Holy smokes, Celtic. I read the wrong note, I see now it looks like that style has an internal Allen key! That might just be the trick. Good man.


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## erics37

****in sand dude. Once it gets in it never gets out.


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## 8V71

N4. BSA installed by turning internal hex bolt (accessed thru the 200 Amp​
Bushing Interface) with 5/16" hex wrench supplied with each unit. :whistling2:


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## bmart

It is called MOVE metal oxide varistor elbow. A surge arrestor that is used on Top floor of Riser cables, padmounted elbow terminations., etc. Go to Cooper Industries.com electrical apparatus #235-65 and see pictures.


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## IslandWire

That part is for when you do have room to spin it around. Otherwise we would use a Y-Well bushing adapter. It will screw into the well bushing and have (2) 200A load break bushings, one for the LA and one for the LBE.


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## bmart

We use "Feed thru bushings "on elbow racks


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## Big John

IslandWire said:


> That part is for when you do have room to spin it around....


 Yeah, but there were three of them already installed in a location where there definitely wasn't room to spin them in.


bmart said:


> We use "Feed thru bushings" on elbow racks


 I don't follow. You park the feed-throughs and jump from those to your bushings?


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## IslandWire

Maybe if you have a picture of the transformer and arrestors, I could see what you are talking about. Otherwise, I guess the manufacturer could have screwed the LA into the well bushings before they bolted them into the can and filled it with oil. Are these 200A wells or 600A wells? Is the LA 200A or 600A?


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## Big John

IslandWire said:


> Maybe if you have a picture of the transformer and arrestors...


 The picture I posted at the top is the bushing arrestor. You need a good 12" of clearance on all sides to spin that, and there isn't even that much clearance between the bushings themselves, so even if you got one on, you couldn't put in the other two.


> ...Otherwise, I guess the manufacturer could have screwed the LA into the well bushings before they bolted them into the can...


 That's really my only theory, either that or the internal hex on those spins separately of the bushing itself, and I haven't been able to confirm that yet.


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