# Transformers and unit substations.



## DeepOne

Hmm.. mouse may penetrate a box through upper slot? .


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## MDShunk

DeepOne said:


> Hmm.. mouse may penetrate a box through upper slot? .


That's very true, but that mouse won't last very long. Neither will a snake.


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## Joe Momma

I don't see a problem with the bottom install.

I don't see a GEC, but that may be the angle.

We don't use flex for transformers(or much at all), usually hard pipe or gutters. But they did use ground bushings so it all looks okay to me.

What kVA are those big suckers?


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## Joe Momma

Oh, your talking about how they used the rigid coupling aren't you?


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## JohnJ0906

Looks like a GEC (at least it looks green) Exiting conduit at the bottom of the panel. I cant see where it goes after the bonding bushing at the transformer, though.


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## Joe Momma

JohnJ0906 said:


> Looks like a GEC (at least it looks green) Exiting conduit at the bottom of the panel. I cant see where it goes after the bonding bushing at the transformer, though.


 
That would be commonly known as an EGC, because it's the conductor grounding the equipment.


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## JohnJ0906

Got my abreviations confused on that one!:whistling2:


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## John

It looks like it might get a little hot in the there!
NEC 450.9


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## MDShunk

Joe Momma said:


> Oh, your talking about how they used the rigid coupling aren't you?


No, I was talking about the apparent lack of working space (width) in front of the panel.


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## JohnJ0906

MDShunk said:


> No, I was talking about the apparent lack of working space (width) in front of the panel.


Kind of hard to tell from the angle the picture was taken. It might be 30", but it does look less.


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## HCECalaska

what about only one wire on X0 should be a ground bond there.


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## buck

John said:


> It looks like it might get a little hot in the there!
> NEC 450.9


Would a room this small need an exhaust fan above the transformer?:blink:


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## brian john

Joe;

While it is not code, here if one were to use conduit or a gutter, everyone and his brother would have a fit and the inspector would most likely turn it down. Till you prove to him it was legal per the NEC.

Different areas, different practices.


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## Joe Momma

brian john said:


> Joe;
> 
> While it is not code, here if one were to use conduit or a gutter, everyone and his brother would have a fit and the inspector would most likely turn it down. Till you prove to him it was legal per the NEC.
> 
> Different areas, different practices.


 
You'll have to explain what you're talking about Brian because I haven't the slightest clue from your post.


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## brian john

Joe: Sorry for the confusion:



> You'll have to explain what you're talking about Brian because I haven't the slightest clue from your post.


 
In Washington DC, every transformer installation utilizes flex, even though this is not a requirement of the NEC. The few jobs where contractors installed EMT straight to the transformer have been ridiculed by other contractors and inspectors I have asked inspectors about this issue and they say (or believe) this is an NEC violation. Why we do this here and everyone has such strong feeling about this issue I DO NOT KNOW. In other parts of the country this practice is not followed.


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## Joe Momma

I've seen transformers flexed around here, but have never flexed one.

I can't remember anything in 450 saying Pipe is no permitted.

We always frown on flex around here, it does have its uses(equipment that moves, but mainly for saving time) but looks bad and says the installer is not very good with pipe.


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## brian john

Joe:

The issue here is not the installers ability to install pipe, even on jobs where the installers are the best pipe men around Flex is still utilized. My point was I am not sure why it is so instilled in the installation practices in this area. Inspectors and installers.


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## faber307

Everywhere I've worked here in MI, We flex our transformers.
Never questioned it. I guess I thought it was required. :blink:


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## MDShunk

I've only ever had to change-out but a few transformers, but I appreciated the fact that the final connection was done with flex. Made the swap a lot easier.


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## Joe Momma

Actually i did flex a step up transformer a couple months ago, it was a small project with a 1.5 inch primary and at least 3 bends in 10 feet.

Normally we pipe for the look and rigidity, but we usually hit an LB and chase nipple to the transformer


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## HCECalaska

i always fancied myself as a good pipe man, but i always flexed my transformers. the reason was for vibration dampening. i haqve heard the vibrating hum carry through building steel on transformers that are hard pipe. a short piece of flex removes this and is still a clean install. long pieces of flex 2< are just evedence of someone that isnt good at pipe.


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## brian john

MDShunk said:


> I've only ever had to change-out but a few transformers, but I appreciated the fact that the final connection was done with flex. Made the swap a lot easier.


 
Marc:

Never thought about this, but that is because 99% of the transformers are flexed connected.


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## Joe Momma

Did you remember to "loosen the bolts"

I have yet to find a transformer that hummed loudly, other than one we sent back to GE

And the chase nipples allow for easy swap out(if need be). But if we can we like to run our tranformer primary's and secondary's underground


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