XFMR mounting

Status
Not open for further replies.
T

TCL

Member
Location
Huntsville,AL
I am wanting to know any rules or guide lines asto mounting power transformers on top of control cabinets, I have done this in the past but in a situation where there wanting to mount to large of tformer on to small of cabinet THANKS
 
When you say on top, do you mean directly on top of the control cabinet with cabinet supporting the weight? Doesn't seem to be a good idea. How about mounting the transformer over the top of the cabinet with independent support. You could drop a support from above if the structure could handle the weight and is not too high above the cabinet or you could build some sort of floor mounted support around the cabinet.
 
TCL said:
I am wanting to know any rules or guide lines asto mounting power transformers on top of control cabinets, I have done this in the past but in a situation where there wanting to mount to large of tformer on to small of cabinet THANKS
Click to expand...

You have provided very little to no information regarding the transformer. How can you expect to get an answer?
If I were to take a "wild guess" there may be wall mounting brackets available if the transformer isn't too heavy. Of course you stated that the panel was mounted against a wall.
 
TCL said:
I am wanting to know any rules or guide lines asto mounting power transformers on top of control cabinets, I have done this in the past but in a situation where there wanting to mount to large of tformer on to small of cabinet THANKS
Click to expand...

There are no actual rules on this kind of thing that I am aware of.

You might run a foul of the working space and or dedicated equipment space requirements though if you are not careful.
 
Thanks for info

Thanks for info

just to give a little more detail the tformer is a 112kva 480v to 208v my issue is the cabnet is only 18 inches deep and 16 gauge steel 2 door cabnet with no center support we have mounted small 45kva tformers like this in the past with some additional support but these have no additional support but have been unable to find codes or guide lines other than 5/13 in electric handbook that says mech. strong enough which doesn't give me enough info to stop the install on code or rule violation but have contacted Hoffman tech support and they don't test there cabnets for top load capacity so that has at least stalled this for now
 
TCL said:
just to give a little more detail the tformer is a 112kva 480v to 208v my issue is the cabnet is only 18 inches deep and 16 gauge steel 2 door cabnet with no center support we have mounted small 45kva tformers like this in the past with some additional support but these have no additional support but have been unable to find codes or guide lines other than 5/13 in electric handbook that says mech. strong enough which doesn't give me enough info to stop the install on code or rule violation but have contacted Hoffman tech support and they don't test there cabnets for top load capacity so that has at least stalled this for now
Click to expand...

how much does the xfmr weigh?

if you can set the xfmr on strut that extends the weight out to the edges of the cabinet, the corners there might well be able to handle the weight.

I would be a little concerned about the mechanism used to fasten the cabinet to the wall as much as anything.

why not just build a shelf above the cabinet and set the transformer on that?
 
XFMR

XFMR

wieght is approx. 720lbs and the cabnet is in the middle of a new line free standing and space is the reason for going in the air and building frame work is what I'm suggesting but due to there is multiple tformers that have already been installed justifying rework and the old line of we have done it this way before even though not this size tformer and until they put these in I had never looked for rules on doing this because we always added some support and the wieghts wasn't that great so we kinda set a standard that shouldn't been started probably
 
TCL said:
wieght is approx. 720lbs and the cabnet is in the middle of a new line free standing and space is the reason for going in the air and building frame work is what I'm suggesting but due to there is multiple tformers that have already been installed justifying rework and the old line of we have done it this way before even though not this size tformer and until they put these in I had never looked for rules on doing this because we always added some support and the wieghts wasn't that great so we kinda set a standard that shouldn't been started probably
Click to expand...

I would not be setting 700 pounds on top of a sheet metal box.

Why not just hang it from the ceiling on all thread? A couple pieces of strut top and bottom and some all thread, and it is done.

the other possibility is to build a frame out of strut that sits around the control box but is supported off the floor to set the xfmr on.
 
XFMR

XFMR

hanging them is not an option due to overhead issue building a frame is what I'm trying to get done but the people managing the project doesn't want to change them I'm trying to find something to force the issue so that they must change the way there installing them I have submitted info I have gathered to safety Eng. and have them on our side just looking for rules or industry standard that would help Thanks
 
TCL said:
hanging them is not an option due to overhead issue building a frame is what I'm trying to get done but the people managing the project doesn't want to change them I'm trying to find something to force the issue so that they must change the way there installing them I have submitted info I have gathered to safety Eng. and have them on our side just looking for rules or industry standard that would help Thanks
Click to expand...

"Change them" sounds like they have already installed some of these monsters this way. Have there been any issues with setting a 700+ pound xfmr on a control box? If not, maybe there is no problem.
 
TCL -
I've not got much help for you - mostly some random thoughts.

I don't know if the cabinet is 2' tall x 3' wide or 6' tall x 4' wide. The picture I have is a 3' cube of Al and Fe sitting on top of a breadbox. Not pretty - but maybe workable:

16 gage is about 1/16", so 1/16" X 18" is a bit over 1 in^2 per side. That should easily hold up 40klb, that right - 40,000 lbs

unless --- it fails by buckling

Likely everyone has seen an example: Stand on a beer soda can. It will hold you up fine - until you reach down and gently, ever so slightly, quickly tap the sides. Then it collapses instantly.

So, my questions would be:
  • What say your structural engineer about supporting 720 lbs a few feet in the air on a thin steel cabinet?


  • What seismic zone are you in? Montgomery and south is Z0, AL north is Z1. Likely not a problem. However, I suspect that is why Hoffman won't rate their cabinets for top load. One can buy a cabinet rated for Z4 - but even that is not rated for any top load.


  • Even if Zone 0, is the cabinet near structural failure by buckling if it gets a hard bump during normal work?

And the answer I would expect is, "We ain't hiring no damned engineer. Get it in."

And being the woos I am - I'd be putting it in. And since the cabinet is free standing - I'd mostly be worried about getting it securely fastened to the floor. I'd have enough bolts in it that it would tear up a chunk of the floor if it fell over.

ice
 
XFMR

XFMR

yea 5 have been installed this way on a new line and when I seen them it looked bad and they don't want to re work them unless I can show a rule or standard that is being broken,like I said we have done this in the past with some support and brackets with no issue but not of this wieght or in this manner but I hopeing safety can get it done because it doesn't look like there are breaking a direct rule only common sense THANKS
 
Status
Not open for further replies.
Top