Dry-Type Transformers-Location on different floor than panels

Status
Not open for further replies.
We have a job where they engineer specified installing a 75kVA above a drop ceiling. No-no. We told Project Manager this is not allowed, and that we need to find an alternative. Our idea was to simply install on the floor in between the 480 and 208 panels. Problem solved.
NOW, they want to our transformer to go in the basement below the space, since it "takes up too much space". My working clearance was tight, but it could have worked.
Is is acceptable to install our transformer in the basement directly below where our 2 panels are? This basement is only accessible by the landlord and his general maintenance man. The whole basement is primarily empty, divided into several hallways, corridors and rooms, none of which are being used. The main switchgear for the plaza is also in the basement, in a room at the end. It is a long (600' +) strip mall, stick built wood frame, 2 story building.
What would be requirements IF we put the transformer in the basement? The primary and secondary wires to the respective panels would be approximately 15' each.
I'm thinking we'll need disconnecting means on the secondary side....
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
I don't see any problem with the installation as you've described it. The secondary conductors should be installed per 240.21(C)(6). I don't see any need for a secondary disconnecting means.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
It is likely that you will not need any OCPD at the transfromers. Take a look at 240.21(C). If you are under the 2011 code, you will need a sign on the transformer stating the location of the primary disconnect. See 450.14.
 
Thanks to you both for the insight.
Did some math, and I do comply with 240.21....The secondary conductors will be 4/0 copper, with 225A MCB. Transformer is fed with a 125, so I'm good there.
I'm going with it!
Thanks again.
 
Status
Not open for further replies.
Top