Conduit Entrance for Dry Type Transformers

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Good evening,

I have am installing a transformer in a location that it would be advantageous to have the secondary circuit come out of the rear cover on the back of the transformer, directly into the panel. I have only seen this once in an existing installation. Does anyone have a reason why this couldn't be done?

Thank you :dunce:
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Manufactures instructions. I doubt you will find any that tell you it is okay to come in or out anywhere besides the sides.

Why would it matter any? I have seen them out the sides, the tops, and the bottoms (usually an open bottom at that). Why not the back?

With small ones I have seen them just come in under the front cover and pop up inside without going through a wall at all.
 

big john

Senior Member
Location
Portland, ME
Why would it matter any? I have seen them out the sides, the tops, and the bottoms (usually an open bottom at that)....
A lot of transformers have restrictions for entry due to internal wiring space. I've never seen a small dry type where top entry was permitted, usually it's floor or lower sides, only.
 

templdl

Senior Member
Location
Wisconsin
Why would it matter any? I have seen them out the sides, the tops, and the bottoms (usually an open bottom at that). Why not the back?

With small ones I have seen them just come in under the front cover and pop up inside without going through a wall at all.

There will be a drawing of the transformer which is available from the transformer manufacturer which will illustrate the areas of access. Unless there is a concern that the drawing will give you an answer that you don't want to hear and are looking for something to support what you intend to do request a drawing from the manufacture. If you need the drawing clarified contact the manufacturer directly. I worked for 2 drytype distribution transformer manufactures as a sales and applications engineer over a period of 21 years and such information is available.
Talked to the manufacturer to find out if 5hey have any margin available. Avoiding to do so would be exposing yourself to unknown liability. Get their approval and document it. .
 
Thank you for the responses. I have the manufactures cut sheets have the windows laid out on it. I try not assume something is legal because it passed inspection and not dismiss it because I've never seen it done before. It seemed like a sketchy way of doing it, but the situation called for at least raising the question.

Just to add to the stories; I installed a 750kva transformer in January that had the obligatory sticker that said "No Wiring Above This Point" (about 18" from the bottom), but all of the lugs were at the top of the core (48" from the bottom).

Thanks again.
 

templdl

Senior Member
Location
Wisconsin
Thank you for the responses. I have the manufactures cut sheets have the windows laid out on it. I try not assume something is legal because it passed inspection and not dismiss it because I've never seen it done before. It seemed like a sketchy way of doing it, but the situation called for at least raising the question.

Just to add to the stories; I installed a 750kva transformer in January that had the obligatory sticker that said "No Wiring Above This Point" (about 18" from the bottom), but all of the lugs were at the top of the core (48" from the bottom).

Thanks again.

Did you contact the manufacturer for a clarification regarding the "no wiring abve this point" tag?
 

templdl

Senior Member
Location
Wisconsin
Thank you for the responses. I have the manufactures cut sheets have the windows laid out on it. I try not assume something is legal because it passed inspection and not dismiss it because I've never seen it done before. It seemed like a sketchy way of doing it, but the situation called for at least raising the question.

Just to add to the stories; I installed a 750kva transformer in January that had the obligatory sticker that said "No Wiring Above This Point" (about 18" from the bottom), but all of the lugs were at the top of the core (48" from the bottom).

Thanks again.

Did you contact the manufacturer for a clarification regarding the "no wiring abve this point" tag?
 
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