450.45(c)

[chris kennedy]

I have an installation where I need to mount 75 and 150 kva dry type trannys over existing 45 and 75 dry types in a very tight electric room. I need to figure how much room I need between the existing floor mounts and the new trannys mounted above them. I found this as a general rule of thumb.

Transformers should be located at least 12 in. to 18 in. away from walls and other obstructions that might prevent free circulation of air through and around each unit, unless the unit is designed for wall mounting and installed per the manufacturer.

This is a premature post as I will get the model number from the existing and search the specs. I am well aware that the ventilation in this room will need to be dramatically increased.

Is there another resource for a rule of thumb for this type of install?

Thank you.

 

[cadpoint]

This was over a 8'-10" drain clean out knuckle that popped out of the wall, I left them serve space. The lower part was about 3'-0" off AFF. Note the panel height to framing heigtht, and elevation of the second Transformer there are 6" off the block wall.

We used structural footer right on the concrete footer apron, and attached directly to the wall!

Hope that helps!

 

[chris kennedy]

How did you determine the clearance between the 2? Specs obviously?

 

[cadpoint]

If you count the holes I'm 18", no we just put the smaller one on the bottom and used the HVAC lift again!

We ran out of room, we called the AHJ ahead of time! Nothing was obviously?

 

[ohmhead]

Well Chris go here its from GE install manual pdfhttp://www.geindustrial.com/publibrary/checkout/Installation%20and%20Instruction|475A667AAP001|generic

But we do the same as cadpoint we mount them three high or two high and we never have a problem . most of our rooms are tight and they have air in rooms .

If you want to get technical read the GE manual here and you have to know the temp in room with transformers on for so many hours like 24 hours bla bla its good reading have fun .

 

[ohmhead]

Well heres tight stacked transformers

150 on bottom 45 on top no space with the 4 inch conduits behind but were 8 inches off wall sometimes you just dont have the room sometimes so we installed air in room per engineer and cutler hammer said its ok .