Transformer stack top each other

[hhsting]

I have 75kva transformer bottom and on top i have 45kva transformer. I dont see anything that prohibits NEC 2017 transformer stacking but could be wrong. Is their anything I need to look out for or is in NEC 2017 regarding transformer stack on top of each other?

 

[kwired]

Main thing is any clearances required per individual unit to allow proper cooling.

 

[Charged]

Without any NEC requirements. I’m curious of any real world recommendations for spacing and clearance for servicing if needed. I was always curious why it’s not specifically addressed.

 

[kwired]

Without any NEC requirements. I’m curious of any real world recommendations for spacing and clearance for servicing if needed. I was always curious why it’s not specifically addressed.

What is there to service on a dry type transformer?

 

[don_resqcapt19]

I reworked one installation like that because the upper transformer failed as a result of excessive heat. The air being drawn in at the bottom of the transformer was the hot air coming out of the lower transformer and was higher than the design temperature for the transformers, but as far as I know there is nothing in the NEC that prohibits this. The transformers that I worked on were much larger than the ones you are asking about and were in a small electrical room.
There may not be enough heat rise in your installation to be of concern.

 

[Tulsa Electrician]

Pretty generic question! Not much to go off of. Out side on a pole, inside a vault etc.
Heat rise would be my only concern a long with proper clearance.
450.9
450.45 A-F
450.13, as mentioned

 

[Tulsa Electrician]

What a loaded question, no pun intended.

 

[hhsting]

Pretty generic question! Not much to go off of. Out side on a pole, inside a vault etc.
Heat rise would be my only concern a long with proper clearance.
450.9
450.45 A-F
450.13, as mentioned

See attached its in electrical room

 

[infinity]

It's done all of the time without any issues.

 

[infinity]

 

[Tulsa Electrician]

Take a look at the mech plans and see if the room have temp controlled ventilation. I bet it does.
If so I would say ok as long as 450.13 is applied.

A field view would be in relation to the location. If room allowed staggering the transformers when stacked. Not a code thing just a installation observation for the area.

 

[Tulsa Electrician]

I like the vibration dampeners.

 

[drcampbell]

"Dampers".

 

[Tulsa Electrician]

Splitting hair however I get it. Thank you. We we work for Wall Mart it is a requirement for any transformer hanging.
I like the way they used them for a wall mount installation. Adding that one to my tool box.

 

[Tulsa Electrician]

Back to topic.
This just for some FYI.
Took from an Eaton PDF.
As far as stacking goes it does not recommend however does not prevent. Just take precautions that's all and read the installation instructions.

 

[roger]

Here are some from a hospital project a while back. Not suspended but stacked.

 

[winnie]

I note that all of the examples of 'stacked' transformers shown actually have separate support for the transformers, and space between them.

Not simply one transformer simply sitting on top of the other.

IMHO 'stacking' as shown in the examples provided is probably fine. But the drawing that hhsting provides doesn't show any of the mounting details.

I doubt the sheet metal enclosure of the 75kVA unit is rated for any sort of weight bearing. They are pretty sturdy, but not designed nor evaluated as load bearing platforms.

Jon

 

[Tulsa Electrician]

Looks nice, racked and stacked

 

[GeorgeB]

"Dampers".

maybe not if they are wet?

 

[hillbilly1]

Quite common in manufactured power walls. A pain changing them out though. I had one that the manufacturer no longer made, and had to remove the new one from an self contained enclosure to fit in the gear enclosure. Of course none of the mount matched, and had to relocate the factory bracing.