Anwar Pasha
Member
If it is planned to install a transformer in a basement of a historical building (under consideration), what are the specific codes requirements as per NEC needs to be fulfilled?
Transformer in basement of a Museum building
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Anwar Pasha
Member
Thank you very much for your response, the transformer will be 1000KVA, 3 Phase, 60 Hz, 13.8/400 V Dry type.
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With a dry type I see no issues exceptions with the 13.8 kV as well as the ventilation of heat.
Are you qualified to work with 13.8kv?
Do you know how many btu that you have to ventilate?
I would ask how big the museum is but 1000kva transformer is no small potato. But, how is the structure constructed?
I would not like for you to think that you can run off saying that the guys said that I can do it when you have omitted a lot of relevant information from the proposed installation.
petersonra
Senior Member
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- Northern illinois
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- engineer
who uses 400V/60 Hz? it is not a NEC std voltage.
I took it as a typo (480v) like I often do.But, it was incorrect for me to assume which I should have varified.
But, that's minor when then 13.8kv is considered as well as adaquate ventilation is concerned.
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Ragin Cajun
Senior Member
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- Upstate S.C.
An additional consideration is NOISE! Dry types are notoriously noisy and a museum is typically a quiet place.
And, I will echo the flood issus. Think of NYC, or anywhere else, and flooded basements. Even a serious water leak can mess things up!
I have worked several projects where chillers, generators, etc. have either been moved out of the basement or raised up higher.
Dependidng on the local grade, distance above sea level/storm surge,x year flood plane, etc. simply putting major equipment in the basement may no longer an option.
RC
And, I will echo the flood issus. Think of NYC, or anywhere else, and flooded basements. Even a serious water leak can mess things up!
I have worked several projects where chillers, generators, etc. have either been moved out of the basement or raised up higher.
Dependidng on the local grade, distance above sea level/storm surge,x year flood plane, etc. simply putting major equipment in the basement may no longer an option.
RC
kingpb
Senior Member
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- SE USA as far as you can go
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- Engineer, Registered
You better think about how your going to get it into the space.
But regardless, there is nothing in the NEC that precludes the installation in a basement. The rest is logistics.
But regardless, there is nothing in the NEC that precludes the installation in a basement. The rest is logistics.
To address "noise" noise must be defined in comparison to what? In a quiet environment an it that makes any noise at all is often considered to be noisy. The is similar to heat. When you expect an item to be cool to the touch is often said to be hot if it feel warm.
As such it is important to define what an acceptable noise level is in "db." If you don't then it's a matter of opinion.
Since I the size of the transfor in question is unknown transformer are from 9-500kva are between 40-60db.
In addition I have had my engineers design transformers that have lower than NEMA std db. However there is a limit to the noise reduction which up to 5db lower if I can remember. Also, I could specify that a sound test be run and a certification be provided.
Then it's up to the installer. The transformer should be located where it would be least likely to create a noise issue. Hard surfaced walls where the transformer is located has the ability to add to the noise level. By adding sound inulation to the ceiling and at least one of the walls opposite the other will go a long way to dampen any ambient noise.
Then, set the transformer on korfund pads. Make sure that you use liquidtight or another nonmetallic flexible conduit to make connection to the transformer enclosure. The thought here is to use any means that you can to prevent any mechanical transmission of sound from the transformer encloser to the building surfaces where the sound can eminate fron., through walls and floors.
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